The advisory team met to evaluate mechanical, electrical, and plumbing (MEP) systems for the Medford High School project, focusing on lifecycle cost analyses and sustainability goals. The committee reached a consensus to recommend an all-electric air-to-water heat pump system and reviewed preliminary solar energy configurations to reach net-zero energy targets.
[Matt Rice]: All right, so it is 535. I see that we have a good critical mass of folks on. So why don't we dive right in? Let me just, I'll start off with a quick introduction to welcome everybody. This is technically our 6th meeting of the MEP and Sustainability Advisory Team for the Medford High School Project. We are going to be diving into some topics this evening for which the goal is to forward a recommendation or really a series of recommendations back to the full building committee. for their review and hopefully their acceptance at their upcoming October 6th meeting. So we have some detail in terms of the process that we're going to go through as we get into it and I'll turn it over to Martine. shortly after we do the introductions here. But I just wanted to sort of set that expectation up front that this group is really an advisory one as the name of the group suggests. And we will be generating recommendations really over the course of this meeting and the next one upcoming before that October 6 meeting. The other thing I just wanted to point out before we jump into the introductions is in terms of our chat feature, we do have the chat feature active today. If people want to use that to interact or if rather than sort of putting hands up, we can certainly put things in the chat and we'll take questions as they come. We are going to try and manage sort of the interactive pieces after we get through presenting a bunch of information, because there is a lot of information to present. And in some cases, some of the information that will be forthcoming may preempt or address questions that are coming up. So we'll take a pause as we're going through and just note when it's a good time for people to ask questions and we can field those. Certainly you can use the raise hand feature. We would prefer that versus folks just jumping in, but either the raise hand feature or the chat, we'll manage questions and comments through those two devices as we go. So let's just start with the introductions. And I'm forgetting on Zoom the best way to do this other than me just running down the list here as we go. But I'm going to start it off and then we can figure out how to go from there. So my name is Matt Rice. I'm an architect with SMMA. And I'm just going to go down my list here. I think, Ken, you're at the Medford Public Schools.
[Kenneth Lord]: Yes, correct. I'm Ken Lord, I'm the Chief Operations Officer for the school district.
[Matt Rice]: All right, Martine.
[Martine Dion]: Martine Dion, Director of Sustainable Design at SMMA.
[Matt Rice]: Stella.
[O2nzoxaatsQ_SPEAKER_13]: Stella Driesen, Electrical Engineer, SMMA.
[O2nzoxaatsQ_SPEAKER_00]: Thank you, Alicia.
[Alicia Hunt]: I'm the Director of Planning, Development and Sustainability for the City of Medford.
[Matt Rice]: All right, Austin.
[Andre Leroux]: Hi, Austin Dietz. I'm a parent of a potential future enrollee, and I'm a solar project manager.
[Matt Rice]: Thank you. Brenda?
[O2nzoxaatsQ_SPEAKER_01]: Good evening. Brenda Lam, project coordinator with the sustainability team at SMMA. Apologies, I can't have my camera on tonight.
[Matt Rice]: Thank you. Emily?
[Emily Ehlers]: Hi everyone, I'm Emily Ehlers. I'm a mechanical engineer with SMMA.
[Matt Rice]: Alright, jumping around here. I'm Helen.
[Kimberly Talbot]: Hi Helen Fantini, project manager with SMMA.
[Matt Rice]: And Jenny.
[Jenny Graham]: Everyone, I'm Jenny Graham. I'm the chair of the building committee and a parent in the district.
[Matt Rice]: Alright, Jessica.
[Jessica Parks]: Hi, Jessica Parks. I am a school committee member and member of the Medford Energy and Environment Committee, and I have a background in sustainable design and project management. And a parent.
[Libby Brown]: Hi, I'm Libby Brown. I'm a Medford parent, resident, and an architect, and a member of the School Building Committee.
[Matt Rice]: Um, Linda.
[Martine Dion]: Hi. Good afternoon. Linda Laporta with left field the O. P. M. Uh, and we have Paul.
[Paul Ruseau]: Hello. All Russo member School committee member and member of the school building committee. Also, Jenny Graham is the vice chair of the school committee. She didn't last that kind of important
[Matt Rice]: The Rohan name.
[O2nzoxaatsQ_SPEAKER_00]: Hey, Rohan, plumbing engineer from A-Cal. James is not able to enter today, so I'm attending on behalf of him.
[Matt Rice]: Thank you, Rohan. That's why I did not recognize. Thank you. Appreciate that.
[O2nzoxaatsQ_SPEAKER_00]: Sarah.
[UdfiATpNBs8_SPEAKER_12]: Oh, I'm popping in and out, so I'm transitioning home from work here. So I am, well, I'm a Medford parent, but I no longer have kids in the school system as of last year. I'm a sustainable design consultant by trade, and I'm part of the visioning committee.
[Matt Rice]: Thank you. And then, I don't know, Sam, how you ended up being last, but you are last.
[O2nzoxaatsQ_SPEAKER_09]: Hi, everyone Sam Riley is the climate planner for the city of.
[Matt Rice]: All right, did I miss anyone in terms of the jumping in or out or as things were moving around and zoom. Great. Okay, so let me find my screen sharing button or I'm already sharing my screen. Look at that. Let me just maximize it then so that everyone can see where we are. And I am going to turn it over to Martine at this point.
[Martine Dion]: Thank you, Matt. So we've got quite a big agenda tonight with a heavy part of the discussion focused on the HVAC systems, the lifecycle cost analysis, the preliminary lifecycle cost analysis, of the HVAC system. We're also going to talk about very preliminary solar PV assessment, a bit about the red list free materials, embodied carbon, and if time, water efficiency and storage. So, and then sort of the next step. Next. So we wanted to give a bit, just a refresher to everyone in the case there are people here that weren't at previous meetings and also to understand what's in the project relative to some of the systems we're going to talk about. So the project is seeking lead silver minimum, and that's through a requirement through the MSBA Green School Policy, but also a goal that came through a motion, which we'll review in a minute, from the school committee. Stretch energy code is also mandated by the Green School policy. They fully support the MEP building enclosure commissioning and fund the commissioning. And then they require a specific set of materials and indoor environmental quality points. And then the project will be seeking additional reimbursement to the level of 4%, which is offered by MSBA. The Specialized Stretch Energy Code, when you show that you meet the Specialized Stretch Energy Code, you get an additional 3%. And then if you meet 5 points in lieu of 3 points for these materials and IEQ credits, you get an additional 1%. All of this is part of the project. In terms of the stretch code, just again a refresher for the fact that Medford has adopted the specialized stretch energy code, which means that you need to basically comply with the standard stretch energy code. And then there are three pathways, all electric and two fossil fuel heating. This project is pursuing the all electric. We are comparing to a baseline that is fossil fuel. The fossil fuel pathways in the stretch code require that you do everything, you get your project fully ready for electrification. So you have to own, design, the full electrification infrastructure for your project, even if you're not going all electric per the specialized code. And you also have to install the renewable energy to offset that fossil fuel. When you go all electric, you do not have to install the renewable energy. You can just do the renewable energy readiness that's required in the standard stretch code. In July, the school committee and the school building committee adopted a motion, and that's on the next slide, Matt, if you can advance. So, those were established as goals for the project. One is the minimum lead silver certification, and then strive to achieve net zero energy. That'll be addressed today when we talk about the systems and the PV. Specify red list free and healthy materials and seek to obtain the 1%, the additional 1% MSBA reimbursement that is sort of tied to healthy materials. Prioritize water efficiency and stewardship. So a minimum goal of 30% better than the benchmark, which is the lead benchmark. and look to, you know, as much as possible, eliminate potable water or reduce potable water for irrigation use, minimize total cost of ownership. So, designing systems, looking into the initial cost as well as the maintenance and replacement costs, which is what the life cycle cost analysis discussion we will have tonight will address. Next. So net zero energy and minimizing cost of ownership. So we're going to go through next slide. We're going to talk about the energy goals for the project, as well as give you a preliminary view of the lifecycle cost analysis. So in order to get to net zero, a project needs to produce as much energy through renewable energy than the energy consumes for this project. And basically in order to plan and design for that, we need to set early goals. So this project has a goal of 35 kBTU per square foot per year. And that's taking into account the fact that this is a school with CTE programs. You may design your school and then put the PV, but again, how you use the school usually makes a difference. So there's usually a little bit of contingency in the planning. for occupant behavior. And we try as much as possible when we design and at the beginning of the occupancy to look and see how the school is being used and educate the users so that we can optimize the energy use and hopefully make the net zero energy goal. Next. That's the same slide. Next. I guess that's a slide that probably needed to be out. How do we get there? How do we get to our goal to basically reduce as much as possible while bringing a functional operating school that provides the educational program that it needs to? in getting that sort of low energy use intensity? Well, we basically optimize passive strategies, as well as the thermal performance of the enclosure. So super insulated and airtight enclosure are part of the strategies here. Triple glazing, all electric HVAC. We'll talk about this a lot tonight. And then plug load management. As you can see here, there's a circle around everything that's sort of the active systems we call active systems. Those strategies basically are going to be included as part of the project's compliance with the specialized stretch code. Next. Next. Thank you. Life-cycle cost analysis. So I'm going to give you a bit of an overview. The presentation that was sent yesterday was still in the works. We sent it so that everybody could get sort of as close as possible to the presentation, could get some of the information ahead. and prepare for tonight's presentation. We've made a bit of changes. There were some last-minute costs that came in today, so we had to adjust a bit of the tables, but you'll see they're not huge changes. So what is a lifecycle cost analysis? It's really looking at the system's and looking at their initial cost and the cost of ownership, so the operation cost over 50 years. So, the lifecycle cost analysis for this project includes the initial cost, the replacement costs, so the different portions of the equipment for the HVAC system have to be replaced. some at 15 years, that's their sort of life cycle, some at 20 years. So all of this is taken into account and included into the LCCA. Maintenance costs, energy savings and energy costs from utility, from the utilities. And then this is a 50-year life cycle cost. Because we're measuring all of these costs over 50 years, we have a 3% cost escalation applied, and it's brought down to a net present value. We're also going to show you incremental costs and payback and incentives, a little bit of an early look at the potential incentives for the project. Next.
[Matt Rice]: Martina, I'll just add on the cost escalation because it came up at the eco charrette that we had earlier. That 3% cost escalation is compounded over the course of the 50-year period or whatever the time period that we're looking at is.
[Martine Dion]: Right. Thank you, Matt, for clarifying. In July, we had a few meetings in June and July, and it was agreed upon the committee and the school building committee that the three systems that we were going to compare were a 100% ground-source heat pump system, what we refer sometimes as geothermal, a hybrid of a ground-source heat pump system and an air-to-water heat pump 50-50, an air-to-water heat pump 100%, so no geothermal, air-to-water heat pump system is option three. These three systems are compared within the design, the building design, so all of the code required and the high efficiency enclosure, lighting, et cetera, that's all equal across those three projects. And the code baseline is a fossil fuel system. So it has a natural gas boiler and a water-cooled chiller system. As required by code, the code requires that for the size of your building, type of your building, we use ASHRAE system number seven. Next. Now, we've conducted the building lifecycle cost analysis. However, because the pool project is separate from the MSBA project, we are doing a separate LCCA for the pool. And we do not have, this is in progress, and we're gonna have the results in the next few weeks, but we do not have those results tonight. We just wanted everyone to understand that those two have to be separate or have been elected to be separate because it's not included in MSBA's project support. Next. I'm sorry, don't go yet. For the pool, we're going to look at an air-to-water heat pump, full electric pool, system including electrical heating of the pool water, and then we're going to compare to the code baseline of natural gas boilers for the water heating.
[Matt Rice]: And Martin, I just want to clarify 1 point about the pool and the relationship of the pool to the rest of the project. It is included in the project that we are doing the current Medford high school addition renovation project that we have ongoing. The difference with the pool is that it is not reimbursed renovation costs. for the existing pool and that is part of the rationale in terms of breaking it out. The other rationale though is really because it is such a different type of system from an energy consumption standpoint that it's from a just analysis standpoint and making sure that we're trying to look at things evenly. We're looking at the rest of the high school building, everything included versus the pool itself.
[Martine Dion]: So the pool has a pretty high EUI, energy use intensity, and that can sometimes muddy the waters with the overall school, especially when you compare to other schools, which as part of the discussion, sometimes they are. So it was best at first to look at them separately. I know people have raised their hands, but we want to hold a bit after. I'd like to go through the LCCA at minimum.
[Matt Rice]: And then we can circle back in if folks have a question that is queued up, if you want to put it in the chat, we can sort of queue up responses as we go through as well. I just, I mentioned that other piece, just because I know we have a lot of community members that are very passionate about the pool, and I don't want to give anyone the implication that it is not included in the project.
[Martine Dion]: Right, no, thank you, because I didn't make that clarification. And I know Sonny also sent a bunch of questions. I think a lot of her, I would say a good chunk of her questions will be addressed through the presentation, but I have it nearby, so when we are in the question, I want to make sure we cover what she asked, in the case others don't ask it. So one thing we wanted to make sure you understood is the impact of the geothermal system in terms of what we call the bore field, or the bore means the wells. And because we have a large school with quite a large amount of energy being used, large system, the bores require a lot of area. And so we already did some kind of assessments around what the difference between the 100%, the option 100%, ground source heat pump, and the hybrid. And part of this is also tied to the deeded area. So what's available without the deeded area is about 8.6 acre. And that is fully covered, or that fully covers in terms of area, that fully covers the 50%, you know, the hybrid. But if the project would elect to go 100% ground source heat pump, we would need to, you know, have bars located in the deeded area. Keep that in mind as we go through the numbers, the CCA numbers.
[Matt Rice]: Yeah, just I want to clarify on the terminology on the property. There is a deed restriction on a portion of the property. It's not that there's just deeded land or non deeded land. It's all it's all owned by the City of Medford. The area in the red, the Borefield area in the red is the portion that is available for development on deed restriction land, deed restricted land. and that blue or purple, whichever color that other one is, is on the non-deed restricted land. That's the designation on non-deed restricted land.
[Martine Dion]: Great. Next. Okay, so again, a bit of, you know, overview relative to, you know, the ground source heat pump options, option one and option two, in terms of the bore area, the location of the bore wells, the fact that a good chunk of the bore wells have to be in the main parking area, Um, requires because of the staging and the phasing of the project, it requires a temporary system for 3.5 years. that temporary HVAC system and the energy it would be using when the school opens for 3.5 years is all included in the life cycle cost analysis. As we go through the next three slides, these are going to be three tables, three or four tables where we're going to share the LCCA. There's a lot of notes at the bottom, which I am not going to read. but I welcome you to take a look. They are just, this is all to make sure that as people look at the presentation or even look at the presentation after this meeting, understand what's included, sort of a bit of details around what's included in our assumptions. So here, Here, in terms of the baseline, the baseline is more expensive than option 2 and option 3, whereas the 100% ground-source heat pump comes out more expensive upfront, as you can see here in the initial cost. It's about $15 million or so. However, in terms of the 50-year cost, it's less expensive. It's about $9 million less expensive over 50 years, so it's not recuperating the I just want to make sure I make the math quick here, but the $15 million, $16 million of the initial cost. Whereas the other two options, option two and option three, less expensive than the baseline system fossil fuel. So that's what this shows. And then we're going to dig in a bit. We're going to look at the initial cost and the incremental cost, the paybacks, and how that relates to the total cost. So in terms of the ground source seed pump, obviously, it's more expensive. $16 million, there it is. However, this is the system that's included in the PSR budget. So we own that system right now. However, the option two and option three being less expensive, then these would be obviously cost reduction to the existing budget. The Ground Source Seed Pump, when you do the simple payback, is 41 years. It's not very attractive right now. We looked at the payback with incentives, the mass-save incentives. These would be the mass-save incentives because those are incentives that are, I wouldn't say guaranteed, but they are there and they're very much reliable. So, 33 years with the incentives. The option 2 and option 3 don't have a payback because they're less expensive. Option 2 is a 3.2% reduction compared to the PSR estimate, overall project total cost. option three is 5.6% reduction. And as you can see on the right, the annual energy costs for option two and option three is obviously less because those systems are less efficient. They're still very efficient, but they're less efficient than the ground source seed pump. Next. So to give you an overview of the lifecycle cost analysis with all the costs, the different cost components that are included, the installation costs we just talked about, the replacement costs. So the replacement cost, as I mentioned, includes all the components of the systems that need to be replaced after 15, 20, 25 years. Obviously, the fossil fuel system, the boiler is 25 years, whereas the heat pump systems have a combination of 15 and 20 years. Air to water heat pump is more in the 15-year range. The fossil fuel system as I mentioned, has to include the electrification readiness and the offset, the PV that offsets the fossil fuel energy production. Maintenance costs. So the replacement costs, again, are a bit higher, a bit more higher with the ground source heat pump, but much higher with the baseline. Estimated maintenance costs. They're pretty close overall. Estimated energy costs, so again, the ground source seed pump is the cheaper because it's more efficient, but these savings are not enough to recuperate the initial costs, unfortunately, over option two and option three. And then all the way to the right, we have the estimated incentives. So I just make, I want to make it clear here that National Grid has a lot of really good incentives for the energy efficiency target or Design of the project, which is measured through their commercial and industrial program path to. It's so we're looking at 30% better than the baseline. It's their baseline. It's not always exactly code, and then they have this really compelling incentive program for heat pumps, and it pays the most for ground source heat pump. However, it's capped at $3 million. So, whether the project, whether it's Heat pump, it's $4,500 per ton, but capped at $3 million. So the ground source heat pump would cap it. There's no question about it. The hybrid is a little bit less at $2,550. And then the air to water heat pump is also a bit less. The far right shows the EUI. Remember that target of 35 EUI? That's our target. Right now, we're trending at between 36 and 40. This is a big building with a lot of programs, including the CTE programs. Those right now are at the schematic design level. As we hone down on the design Equipment that will go in those spaces will be able to work and track and adjust our energy models to see how we can get closer to 35.
[Matt Rice]: Next, just 1 point on the before we leave this in addition to the programs that are within the building, the extreme amount of usage that the building gets both in the evening hours as well as on the weekends during the school year over the summer. All of these things build up, which is a great thing as a community resource to have the building. But the reality is, is that the building then uses a bit more energy during those additional hours of use. And that is all factored into the eyes.
[Martine Dion]: Right. Next. So, just a few takeaways here before we move to, I don't know if you want to do a bit of Q&A before we move to a detailed description of the HVAC system, or do we want to go through that?
[Matt Rice]: I think it would be good. Why don't we do these takeaways, and then we can field some questions. Okay.
[Martine Dion]: So yeah, as I mentioned, fossil fuel baseline initial cost is more expensive than the hybrid and the air to water option two and three. The challenges with 100% geothermal, as you saw, higher cost upfront. We do have the sort of bore field areas that are tied to the deeded land areas. So that's a bit of a challenge there. The 100% ground-source heat pump is included in the budget, so the other alternatives would bring first-cost reductions. And that is wrong on that slide. I updated our... It's actually a 40-year payback in 33 years, so we'll have to correct that, Matt. I forgot to correct that slide this morning. And then on the 50-year cost of ownership, all three systems are less expensive than fossil fuel base system. So with that, we can start with the questions. Should we start with the ones in the chat, Matt?
[Matt Rice]: I think that makes sense. And then we can wrap in maybe any of Sunny's questions that are tied to this particular topic. So I think the first question that was there is from Paul. And it was, if the high school doesn't have any gas and the pool does, will the cost of the utility hookup be listed with the pool?
[Martine Dion]: There's already a gas a gas line on the site. But to your point, Paul, we need to be careful at how there's an exemption, Matt, right, with the utility, because the fact that we get this $3 million is tied to the fact that the school is not using fossil fuel. So we have to make sure that that's all uh, clarified and coordinated with, um, the utility. Um,
[Matt Rice]: Yeah, and we have been, we have had these discussions with the utility being upfront about the pool in terms of the actual grid about sort of the pool's presence and its relationship. The exception that Martine was noting is that for vocational purposes or educational purposes, say, in a science lab, there are exemptions if we want to bring gas to the building for those 2 specific uses, and then I believe National Grid understands the pool in a different way with the recognition that it has a much different need from a technology standpoint and energy consumption standpoint than sort of an otherwise sort of traditional high school without a pool.
[Martine Dion]: So the next question is kind of tied to this a bit. Jessica Parks asked the question, will a gas boiler pool impact our ability to achieve the max MSB incentive points? And then to achieve net zero, second question, to achieve net zero, will we need to size for an electric boiler, electrification readiness pad if the pool use gas? So the first question, my understanding is the pool is not part of the MSBA scope. And so the building, the school building will meet the specialized stretch code. And with that, will get the 3%. The net zero energy component of the pool, so the pool has to meet the specialized energy stretch code. And so if the pool opts to go natural gas, it will have to do the electrical readiness and it will have to install a PV system that offsets that gas boiler. So when we do the LCCA, all of these components will be part of the LCCA. So the cost of the electrical readiness and the cost of the PV that would need to be installed if the pool goes through with a gas boiler will be included in that option. So I hope, Jessica, that we've answered your questions.
[Matt Rice]: And Jessica, if you want to chime in and we'll go back to Paul as well. I do want to give people an opportunity just to follow up if either to confirm that we have answered the question or if it needs further clarification, let's take the time now to go through that.
[Jessica Parks]: Yes, yes. And, um, just, um. So, as long as we are, because I was just also thinking about from the. you know, if for some reason we were to lose, you know, one incentive point, you know, 1% of say, you know, just, you know, throwing this in the air. I know we don't know what we're getting, but like even, you know, 200 million or 100 million, whatever the reimbursement rate we're going to get from the MSBA is 1% of that. It would be worth looking at against, you know, the cost of an electric boiler and then the maintenance and everything like that. If it was going to be factored into that. So that's kind of where that question was coming from. Are we looking at it that way? But if it's not going to be impacting that, then.
[Martine Dion]: Yeah, Matt, I think that's a really good point. I mean, that's my understanding, but it may grant. a clear check with MSBA?
[Matt Rice]: We can certainly follow up on that with them.
[Paul Ruseau]: Okay, thank you. And you did answer my question, but I sort of had another question with what was just said. So, since the pool will have to meet the stretch code, So like in the scenario where we do a gas boiler, we will do the gas boiler, we'll put all that PV stuff in, and then that could just be used to help offset the high school, right? Or do we not actually fully get the PV up and running?
[Martine Dion]: No, so for the high school, We are looking at PV, but you do not have to install a PV protocol because you're going on electric. You could build a school without a PV. For the pool, if you go all electric, you do not have to put a PV. But if you go with a natural gas boiler, you're going to have to put a PV at minimum the size of the fossil fuel, basically energy consumed.
[Paul Ruseau]: Thank you Martine. When I think about that, It's not so much that, you know, if we're doing rooftop, for instance, like I assume the rooftop of the pool area is not big enough to provide the energy offsets of a gas boiler, but maybe I'm wrong.
[Martine Dion]: That's a great point, because while the pool is a small area, the energy consumed to heat that pool is quite high. The EUI for the whole building is 35. For a pool, it can easily be in the 200. Oh my gosh. KVTU per square foot, but it's only for that small area, right? And that's why we're making them separate because we don't want to muddy the water between the two. And so that PV system, you're right. We haven't done, because we're still going through the LCCA right now. We haven't done all the calculation, but that PV system may need more area than the pool building itself. And that will all be talked about when we have the life cycle cost analysis of the pool.
[Matt Rice]: All right, often had a question as well. It was, do these account for any potential change in utility tariffs that may be associated with going to 100% electric, demand charges or demand only rate?
[Martine Dion]: So that's a really good question. We know that the quantity, the way the utility rates work right now is the more you use, If you look at industrial or high commercial, their rates, commercial rates are sometimes smaller per kilowatt hour than residential, which is less per meter or a school, which may look a lot on your utility bills, but compared to the big commercial user. That's the utility rate structure. What's happening now with people using less energy, especially when you go net zero, is the utility now are revisiting those rate structures and they're in some case they may increase your rate because they provide for the service, but then you don't use as much. So they're going to charge you more for each kilowatt hour. However, so I don't have an exact answer for you, Austin, because I'm hearing it being talked about. But we do not have projects that have gone on board with full net zero the way this one may go. We have projects in construction, but they haven't been connected yet full time. So my short answer, if that was short, is that there is a high chance that the rate per kilowatt hour will go up and the demand charges may go up. However, If you don't have renewable energy, I don't think that's going to be the case. But if you do have a battery and a PV, then the rate structure may change a bit. However, if you do net zero, you're not going to pull a lot from the grid as much. And if you have the battery storage, you're probably going to send back more energy to them than you're going to pull. And if you do it in the right time, at the peak, you save a lot of peak demand charges. So in the end, those costs shouldn't be, it's a savings for the owner of net zero versus additional cost. I think we need to keep that question kind of in our discussions, Matt, with the utility and try to see what what's coming. So that's my hope. Austin, I hope I answered your question right, but that's the best we know now.
[Andre Leroux]: Yeah, I appreciate that. I just think looking, trying to look at this As the sum of its individual parts, you have, uh, you have these systems where you're going to an all electric, so you're, you'd still be potentially paying a demand charge and going to an all electric building is a very, that's likely a very expensive demand charge. It's on a, you know, per kilowatt basis. Um, and then you would, and then on top of that, like right now, I know we'll get to the solar in a minute, but like that solar doesn't look like it pencils out at the moment. It's a very, very, very expensive.
[Unidentified]: Right.
[Andre Leroux]: And, and the battery, like we haven't even, I think the battery right now is, is, uh, you know, maybe I don't know what level it's being considered. Right. So if, if, you know, unless until those become serious discussion points, which I hope they will be, um, you know, you're going from a building that has a, a one heating source in the form of, of primarily gas right now, I believe too. All electric and that that comes with with considerable change, whether it's upgrade costs, whether whatever it may be right.
[Martine Dion]: So, just to partially answer your question, we have so we have the cost escalation. We have a blended rate of the electrical rate that we have in those calculations for the energy cost blended rate, which includes demand charges. It's based on your current utility bills, but then we escalate those costs over the 50 years at 3% compounded for both the electric rate and demand charges. Because you are absolutely right, the demand charges are raising year on year to higher.
[Andre Leroux]: It's using current demand as the baseline. The baseline is the current demand. Not a 100% electrical interconnect demand baseline.
[Martine Dion]: The baseline is the current demand charges. And then those are applied through, it's a blended rate, it's a blended rate of the demand charges and your supply, right?
[Andre Leroux]: I guess that's maybe that's my question. for you all to consider is using the current utility bill baseline demand as a correct baseline if we're going from a building that heats predominantly with gas to a building that's going to heat predominantly with electric.
[Martine Dion]: So I see what you're saying, but that's the best rate we know right now. So if they, you know, and they're being raised, but what I want to remind you is yes, the, the, Natural gas is cheaper now, but the electric system is three times more efficient. There's a balance there. But to your point, I don't know that we will be able to get a clear response from the utility to what would be their rate. Um, I'm pretty sure that we won't. So we're, we're happy to discuss the rate we have now and, and adapt it, you know, maybe, um, maybe Sam or Alicia would want to be part of that discussion. Um, and we can adjust that. Um, but the, but the relationship of the three systems will be the same because we would apply those same rates. Um, those different rates to the three systems. So, hopefully that that helps.
[Matt Rice]: We do have a couple other questions. I know we have to get back into the main content as well. I thought, can you threw your hand up and then you pulled it down? Did we already cover your question?
[Kenneth Lord]: I was going to kind of hold it for you. Talk about PV. I was interested in if we've looked at the roof and Jim roof, if they can support the weight of PV. I know there's issues with the gym roof, but.
[Martine Dion]: Right, I think we could maybe Matt, we could talk about that when we get to the PD.
[Matt Rice]: Yeah, happy to do that. Yeah, and then we have a couple other questions. Maybe by the time we get to 630, I think we should pivot and keep moving into the systems, but we'll cover a couple more here. So, Jessica asked what assumptions are being used that make the air to water heat pump the lowest maintenance costs? I don't know if that's you Martine or if that's Emily that wants to answer.
[Martine Dion]: I can start, Emily, you can add on. We are looking at each component, and I guess these costs are coming from previous projects, discussions, and industry maintenance, sort of general maintenance costs, right, Emily?
[Emily Ehlers]: Yes, yeah, exactly. It's coming from industry standards as well as previous knowledge from other projects that we've worked on.
[Martine Dion]: Is the gas connection to the pool the existing gas connection? I think the best person to answer that will be the engineers. It could be that there's an upgrade. I'm not sure.
[Kenneth Lord]: It's going to have to move because it's on right now. The meters are on part of the maintenance shop. That's getting demolished, but okay. All right into the building. So.
[UdfiATpNBs8_SPEAKER_12]: Okay, well, it's existing or not was was triggering something for me and I couldn't remember if it was related to mass save or code. So. And it may be nothing, I may have dreamt it, but there's always hope, right?
[Martine Dion]: For the modeling, are you using the current Medford High School electric rates? Yes. We got the information from Brenda earlier in the year and we used a two-year average of your current electric rate.
[Matt Rice]: So, but the question, and Alicia, you can chime in here. It seems like there may be a different rate for the city versus for the high school. Is that what is implied here? No.
[Alicia Hunt]: We have a rate for all municipal buildings that is better than the publicly posted advertised default rate. Oh, okay. Just wanted to make sure that we will continue to procure that way.
[Martine Dion]: Yeah. No, you're right. Your rate is lower and we're using that one. But we're compounding at 3% cost escalation. Oh, yes. Oh, yes.
[Alicia Hunt]: And it's been going up over the years, but it's better than the utility rate.
[Martine Dion]: Yeah. Okay, great. Install cost for option one and two. Yeah, the temporary HVAC system cost is included, in option one and two in the initial cost. And it does have our energy, our utility energy costs do have the three and a half years of utility costs of that temporary, of that temporary HVAC system.
[Matt Rice]: All right, then the last one goes back to Alicia.
[Alicia Hunt]: I was just making a point that the battery can offset the demand. And in fact, we have people trying to sell us that for other buildings right now. And it does look like there's good payback on them. And in fact, we are using the DPW battery in a dispatch program and making revenue off of it every year.
[Martine Dion]: So that when I don't have that for this week, but you'll see when we get to PV, I'm going to talk about that, Alicia. And it's great that you're bringing that up because we've seen on other projects that there's a saving, there's peak load savings, cause you're, you've got your PV, right. And you're storing, and then there's revenues for excess production that you can send them, send back. And it's, it's significant revenues. So OK. Emily, I think it's your turn.
[Emily Ehlers]: Thanks, Martine. OK, so now we're going to dive into the three mechanical system options that we mentioned earlier. So the first being the full geothermal option, the second being the hybrid system that mixes the geothermal with the air to water heat pumps, and the third being the full air to water heat pump system. Next. So I just wanted to show the slide to give a quick overview of how heat pumps actually operate. So because we are doing the all electric pathway, heat pumps are the best technology on the market right now to meet that and the code requirements. With heat pumps, how they operate is they extract heat from a source and then reject it to another. And that source can be ambient air, it can be water, or it can be the ground. So over on the left hand side, that's the ground source heat pump system diagram or the geothermal. So in the summertime, how it operates is it extracts heat from the chilled water return system from the building, and then it rejects that heat into the ground through those bore wells that we mentioned earlier. And then the reverse happens in the winter. The system will extract the heat from the ground and then reject it into the hot water supply system that serves the building. And then over on the right hand side, this is how the air to water heat pump system operates. So in the summertime, it's a similar thing where it extracts the heat from the chilled water return from the building. Only this time, instead of rejecting the heat to the ground, it rejects it to the ambient air. And then again, the reverse happens in the winter where the system will extract the heat from the ambient air and then reject it into the hot water supply system. Heat pumps in general have excellent efficiency. Just to compare to a standard electric resistance boiler or an electric radiant panel, those will have a coefficient of performance or a COP of one. The ground source system has a COP around four, and then the air-to-water has a COP around three. They're much more efficient than your standard just electric boiler without a heat pump. And then why the ground source heat pump is more efficient than the air to water heat pump is that temperature differential of the source. So for the air side, our design conditions for this area in the summertime, the ambient air is at 91 degrees. And then in the winter, the ambient air is at seven degrees. While for the ground source side, you're always rejecting or extracting from the ground temperature. And in the Boston area, it's typically pretty constant at the depth that we dig these boreholes to. So somewhere around 50 to 55 degrees year round. So that's why the ground source tends to be more efficient because it's a more of a constant that you're pulling the heat source from. Next. Okay, so now kind of an overview of the system diagram. So for the full geothermal option, we can start over on the left-hand side, those green pipes, that's the ground loop. So they would run down through the bore wells out on the site, and then it would run into the mechanical space within the building, that's that gray box outline. And then within the mechanical space, we could tap off and provide some capacity to the domestic hot water heat pump system. So that supports the plumbing systems in the school. And then it would run to a water to water heat pump. So for this system, the heat pump component is inside of the building in the mechanical room. Then the heat pump converts the ground loop to a four-pipe hydronic system. So that means it has chilled water supply and return and hot water supply and return. Um, and that four pipe system runs out to the rest of the building and serves all the terminal units that supply, um, the spaces within the building. And then it also runs up to the rooftop units. So we would have single zone rooftop units serving areas like the pool and the auditorium and the gym. And then you'd also have rooftop units that we call DOAS units, and those supply ventilation to all of the spaces in the school. And on the hot water side, what we like to do with these heat pump systems is add a backup electric boiler. And that's really just for backup emergency use in case anything goes wrong with the heat pump. We don't want the building to be without heating capacity in the winter. Next.
[Matt Rice]: So, Emily, I apologize. I'm looking at the number of slides that we have in the amount of time that we have left and I'm, I'm a little worried that we're not going to be able to get through the content. Um, if we get into this much detail on the systems, I think I think we can use the Q and a, as we get towards the end. If people do want us to get into a little bit more detail about how each 1 of them functions. We can open that up to folks, but I think we're going to need to give either just skipping through or if you want to give just a very high view of like, this is how the parts and pieces are working, but we got to speed it up a little bit.
[Emily Ehlers]: Okay. Yeah, yeah, no problem.
[Matt Rice]: Thank you. Yep. If I can advance the slide, it seems like I've lost my functionality. Okay.
[Emily Ehlers]: Yeah, so for the hybrid options, same thing, only now we're adding the rooftop air to water heat pumps to supplement the indoor water to water heat pump, and that would serve the four pipe system as well. Next. And then with the full air to water system, all of the heat pumps are up on the roof, and they're still serving that single four pipe hydronic service to the building. Next. Okay, so the first thing to consider when deciding between these different systems is you could think about the maintenance reliability and lifespan. So as Martine mentioned, this equipment, the heat pumps, they have particular lifespans before they need replacement. So for the full geothermal option, we have that indoor water-to-water heat pump. Those typically have a lifespan of around 20 years. And also with the system, the pro is that it's less equipment up on the roof, so you're not concerned as much about outdoor exposure and the elements. Next. With the hybrid system, again, we have a portion that's that indoor water-to-water heat pump with the 20-year lifespan, but now we have also those rooftop air-to-water units, and those have a shorter lifespan, around 15 years or so. Those rooftop units also are exposed to the elements, so there is that consideration. They also have a defrost cycle that they need to go through in the winter that can take some of the heating capacity away from the school at certain times when it needs to defrost the ice on the coils. With this hybrid system also, there is much more complexity when it comes to the controls because you're combining two separate systems into one. So that is something to take into account. It is more complex to operate. Next. And then with the full air to water system, again, those units up on the roof have about a 15 year lifespan, and you have to consider that defrost cycle. But it does have the simplest controls out of the three options.
[Martine Dion]: Next.
[Emily Ehlers]: And then the second thing to consider with these system options is how much space they take up within the mechanical room inside the building and then also up on the roof. So the image over to the right is a very preliminary roof plan. It in no way reflects how it will actually look, but it just shows the size of the mechanical equipment and how much space it does take up. For the full geothermal option, we don't actually have any heat pump equipment up on the roof. This is just the baseline single zone Rooftop units and the ventilation units, exhaust fans, things like that. So you can see already they do take up a significant amount of room. And why this is something to think about is because any space that we take up on the roof makes it harder to add more PV up there. and that could impact our ability to reach that net zero goal. You also have to think about the more equipment you have up on the roof, the more structure you may need, supports, dunnage, access, and then just maintenance safety. And then if you're adding more mechanical space within the building, you also have to take into consideration that that's taking away programming space, you have to find space in the building where that can go. So for the full geothermal option, it takes up the most amount of mechanical room space because the heat pumps are inside, but it takes up the least amount of roof space. Next. For the hybrid system, it's a mix, so it takes up mechanical room space inside of the building, as well as roof space you can see outlined in the red. I start to show some of the air-to-water heat pumps up on the roof. Next. And then for the full air-to-water heat pump, since the heat pumps are all up on the roof, you need limited mechanical space within the building. But now you need to make space for all those Rooftop heat pumps, so you can see them outlined in red, they do take up a significant amount of space. Next. Okay, so here's just a breakdown comparing the percentages of usable roof space. And this doesn't account for, as I said, like the walkways up on the roof, access, clearances, so that percentage will be greater. And so you need to take that into account when you think about placing the PV up there as well. It really needs to be closely coordinated. Next. Okay, and then the third topic to discuss when deciding between the system options would be the phasing. This project has some complex phasing and just a quick recap is phase one would be renovating that blue gym and pool wing. and then adding that pink new classroom space wing off the back of the building. In phase two, we would be adding the front side of the building and demoing part of the existing building. And then phase three, the new building is complete, but we would be demoing the rest of the new, the existing building, sorry. Yeah. So with the mechanical systems, how they come into play can get a little complex with this phasing. So for the full geothermal option in phase one, we would place part of the geothermal system to serve the phase one of the new school. And because we need to use a lot of site for the full geothermal option, we would need to use that de-restricted land up on the north side of the site. So for phase one, we would do part of the geothermal install, the well fields up on the site, and then inside the building, we would put the water to water heat pumps, the pumps, the rooftop units, and the space terminal units. Next. Okay, and then as Martine mentioned, For the full geothermal option, we do have to bring in temporary heating and cooling systems to serve the second portion of the new building. And that's because you can see there's still that existing building on this lower part of the site. And that's where the additional geothermal well fields need to go. So because we can't dig the well fields until that is removed in phase two, we will bring in temporary boilers and chillers to service the second portion of the new building. And then in phase three is once all that demo work is done, the existing building is completely gone, then we can finally construct the rest of our geothermal fields and add the rest of our water-to-water heat pump system, and we can remove those temporary systems. Next. Okay, so the hybrid systems, this first round is looking at it if we are using the deed-restricted land up on that north end of the site. So that makes the hybrid option a little bit simpler than if we were to use the south side for geothermal. So for this one in phase one, we would put the geothermal up on that north side of the site, and that would just serve this first phase of the new building. Then in phase two, that would be the air source heat pumps. So you don't have to worry about any site work for that. They would just go up on the roof and we could complete all of that within phase two. So for this hybrid option, all of the new work would be completed by the end of phase two instead of the end of phase three in construction. Next. Next.
[Matt Rice]: So nothing there, right?
[Emily Ehlers]: Nothing there, yeah, yeah. Okay, now the other side is if you did the hybrid option, but you needed to use the non-dew restricted land, which is on the south side of the site. So that would mean that the first phase of work would be your air sides phase. So you would construct all the air to water heat pumps up on the roof, and those would service the phase one portion of the new school. Then in phase two, again, because we can't construct those geothermal wells until the existing building is fully demoed, we would need to bring in those temporary systems to service the phase two of the new school. Next. And then in phase three, once that new building is completely demoed, we can complete our geothermal work and remove those temporary systems. Now for the full air-to-water heat pump system, this one is the simplest when it comes to phasing because we're not doing anything with the site or the deed restrictions. So for phase one, you would just install your air-to-water heat pumps to serve the phase one portion of the new school. Then in phase two, next, yep, you would install your air-to-water heat pumps serving the phase two of the school. And then that's it. You would be done at the end of phase two. Next. So here's just kind of a summary of everything I just went over. I know it's a lot at one time. But the main takeaways are that if you went with the full geothermal option or the hybrid option that uses the non-dehydrated land on the south side of the site, both those options would need temporary heating and cooling systems until the end of phase three. And then if you went with the hybrid option that uses the deed restricted land up on the north side of the site or the full air to water heat pump system, you can complete those at the end of phase two of construction and you don't have to deal with any temporary systems or pay for any temporary systems. Next. So here's just a breakdown of everything we just went over. I'm not going to read through everything for the sake of time, but as we discussed there really are a lot of pros and cons to each of these different systems when you look at all the different considerations. But Yeah, it really comes down to, you know, thinking about the cost, of course, but also the maintainability, the lifecycle of the equipment, the space use, and then also the phasing of this project is pretty complex.
[Matt Rice]: And if all that complexity is not enough, Emily, I do also want to point out the fact that we have had communications back from DCR and EA that if we are to use the deed restricted property to put geothermal wells below. The deed restricted property that does drive us into an article 97 permitting process. It does require a two thirds vote of the state legislature to pass that. And so there is some time and then there are some permitting cost as well. That is layered on top of it, which just adds to the complexity. So it is an additional consideration. over and above, if we just went back to this slide, for that upper right-hand corner scenario, the hybrid option that uses the deed-restricted land, this would drive an Article 97 process. Obviously, if we're not doing any geothermal work, like with the full air-to-water heat pump or the use of the non-deed-restricted land, these two on the bottom do not have an Article 97 permitting process attached to them.
[Emily Ehlers]: Yeah, and the cost associated with that Article 97 is not accounted for in the LCCA. That's one of those bullet points at the bottom of the chart for the LCCA, so just keep that in mind. It's not accounted for in those systems.
[Matt Rice]: Thank you. And this is this is the conclusion of the mechanical system selection study point and we can get into some PV discussion after that. I do want to pause here, though, for a little bit discussion because again, just to go back to my statement at the beginning of the meeting. One thing we are looking, we need this group to do is to forward some recommendations to the full building committee. And one of those recommendations is really going to be on the mechanical system selection that really incorporates the thought process from the LCCA, but also the detail that Emily just went through. We will rely on both Ken and Ryan Pike with the district Um, to have a little bit better understanding of sort of the mechanical needs in the operational desires of the systems. But from understanding the overall financial impact to the city, as well as the environmental impact to the city and the community, that's really where we're looking for feedback from this group and. We really should have a little bit discussion now about if people are leaning towards 1 of the systems versus the other, it would be good to talk that through. We don't need to come to a consensus agreement this evening. That's part of the reason why we have the October 1st meeting. But given that this has a lot wrapped into it, as you can tell by the 44 slides that we just went through to get through it, there's a lot of detail and aspect to it. So if people have preferences already, if they have questions to establish preferences, we want to cover that now before we jump over to the PV, because we will revisit PV and the rest of the topics when we get to the October 1st meeting as well. So, I saw Paul's hand up go 1st. I'm not sure if that was if you beat Ken or not, but go ahead. Paul.
[Paul Ruseau]: Thank you. Um, so, I mean, I certainly, um, you know, I was all gung ho on geothermal all the way, but I, I think that the hybrid option is the way to go. The savings to the total cost of the project up front. Is substantial and, you know, we've been doing a lot of work in the regular meeting to. Um, Reduce costs where we can, um, and this seems like one where reducing the costs, um, to the initial project expense. Um. I don't I don't have a slide in front of me and it was like, let's maybe 20Million or something. Um, it's a big number. Um. It's a lot of slides back.
[Matt Rice]: I'm sorry. Yeah, I know.
[Paul Ruseau]: Yeah, it's. The upfront initial costs. That's the previous slide, I think, right?
[Martine Dion]: It's 16 million. I'm sorry. It's, it's, uh, some, it's, it.
[Paul Ruseau]: I think it's the previous slide. One more.
[Martine Dion]: Yeah.
[Paul Ruseau]: One. Oh, there it is. Oh, yeah. So yeah, 16 million or whatever that number is. And that's a, that's a big chunk of change. Um, and I think, you know, we have to, I would be fine with spending that money if there was really that much of a big difference in the actual long-term costs, but there isn't. So that's why I would be very much open to voting for the... Oh, wait, I'm sorry. No. Yeah, the difference between the geothermal and that is nearly 20 million. The... Yeah.
[Matt Rice]: On the initial cost side.
[Paul Ruseau]: So this, this initial cost side, this is the part that we're going to be voting on. So. Um, yeah, that's why I very much support that option. And the fact that the, the savings, um, and the utility costs. I mean, I don't like the complexity factor, but, um, I'm going to go out on a limb and bet that nothing is as complicated as maintaining our current systems. So. So that's, you know, that's where I land.
[Matt Rice]: Ken, do you want to chime in?
[Kenneth Lord]: Sure. comment on one thing Paul said, our current system is not complex at all to maintain. It's actually just because it's so fragile that the issues are. It's literally turning boilers on and off, so it's not complex at all. I am concerned about the complexity of option two. Each of the ground source and air source systems And now we're going to have both as well as trying to manage the 2 of them together. I feel adds unnecessary complications to maintaining this system long term the ground source system. themselves, although very attractive, with this complex site and complex phasing, just add another layer on top of everything else we're going to have to accomplish and conquer in this project that I don't think is worth You know, trying to drill all those wells in places where we have to wait until the building's gone and then get the wells drilled and then get the parking lot built and everything else, the short term issues that that is going to create or having to go through article 97 to me is not worth the ground source. I am interested in option 3 because of that as well as it is the lowest initial cost. And, you know, we've heard time and again that this is an expensive project and we need to do what we can to try to bring the cost down as much as we possibly can.
[Paul Ruseau]: Can I ask a quick question about what Ken just said? Of course. Option three, if I'm, am I correct that that will be the one that's hardest for us to get to net zero?
[Martine Dion]: No, it's just going to mean a bigger PV system. So it's not specifically harder, but it may be slightly short of net zero. And we can look into that, how much that is. But it's not the difference. It's probably going to be 100% to 90% versus It's not going to be a 30% lower.
[Matt Rice]: I think in terms of the degree of difficulty, it is not quite as severe. That's what your point is, Martine. But I think your answer to Paul's initial question was not quite right. I think it is more challenging or more difficult. By difficult, we mean more expensive because it's going to take more panels to meet the load because the air-to-water heat pumps are a little less efficient than the ground source heat pumps. That's what drives that equation.
[Kimberly Talbot]: Right. Yes. Um, Austin had a question in the chat.
[Andre Leroux]: I think regarding the roof, but the units on the roof, I guess it's sort of in the vein of sort of in the vein of what was just mentioned about PV, right? Like, if you're if you're trying to maximize PV. Um, yeah, strategically place. The mechanical units on the roof to maximize, you know, all the North roof line, all of, you know, a lower a lower tier or something like that.
[Emily Ehlers]: Yeah, so with that, to an extent, we try to strategically place them, but they do, there's an extent. They need to be relatively close to where they're serving. So if it's like a rooftop unit with dock work, they need to be relatively close to the zone that they're serving. And then the air to water heat pumps, they need to be relatively close to the mechanical room that they're running to. because otherwise you're going to have much longer pipe lengths, exposed pipes on the roof or in the building. It just adds more complexity to the system. We try to keep them pretty close to the zone that they're serving.
[Martine Dion]: So I'd like to add to that, Austin, that when we talk about PV, hopefully we'll have some time to talk about PV, To get to net zero, we're going to need high canopies anyway. There's not enough difference between the systems needed, between the hybrid and the air to water heat pump to justify a PV benefit because there's already a need for high canopy at the roof to get to net zero.
[Andre Leroux]: Do you mean to say that because you have, you don't have enough real estate on the roof. Regardless of the system, regardless of the mechanical system that we're talking about. So, therefore, you need to create the space with a hierarchy. Okay.
[Unidentified]: Right.
[Andre Leroux]: Okay. That makes sense.
[Paul Ruseau]: I just wanted to chime in and say, I've been convinced.
[Emily Ehlers]: I see another question in the chat from Libby, who's going through the process of Article 97 permitting, and that it's not even a guarantee, it's hard for her to recommend, which is good to know. And she said, the full air to water system is also complete in phase two, correct and less complex to maintain. Yes, that is. That is true. Yes. So the air to water system would be completely finished at the end of phase two, instead of phase three, like some of the other system options. Um, it still has complexity. All these heat pump systems have complex controls, but because it's just that single type of system serving the one hydronic loop compared to the hybrid system, it is simpler to operate.
[Matt Rice]: All right. Any other thoughts on system type or the LCCA before we pivot over to some discussion on PV?
[Jenny Graham]: Can I just ask a quick question? How do we, if we're not going to decide about this tonight, like We're going to run I think we're going to just like run out of time every which way. So, I guess I'm interested in, like, some of the folks who haven't really weighed in and particularly those of you, those of you who, like, no way more than I do this. Like, if we were, if we're coalescing around option 3. Is there any is there some reason not to decide that tonight? Is there a reason to. consider something else or is there like actual agreement here and we don't need to prolong this discussion I think is sort of what I'm interested in knowing about.
[Matt Rice]: There's no reason just answer the piece of that question. There's no reason that we can't make that decision tonight as a recommendation. I don't think it'll be forwarded to the building committee until the next meeting comes up. But it would also lessen the pressure on the October 1st meeting to not have to consider that one as well. We could focus instead on just photovoltaics and mass timber.
[Jenny Graham]: I am curious from some of the other folks on the call, Austin, Sarah?
[Andre Leroux]: I support option three. I think for the reasons that have already been laid out, I think with a well-built structure, the extreme cold that you often hear about with heat pumps is, I think, is probably not a problem. I don't know, Matt, Martine, you guys can speak to that from prior experience, but, you know, Um, so, like, having, you know, some of these other concerns that has some of the cons that have been raised, I don't, you know, they're, they're, they're weighted equally in the form of being in the box, but I don't know, you know, I don't know how, how much of a con some of those, some of those are. But, yeah, I would support less, less complex for, for Ken and his staff at the end of the day.
[Matt Rice]: Let me just touch on the extreme temperature piece and then Emily may want to chime in as well. But in a lot of the detail that I didn't let Emily get into in those diagrams, there are backup and supplementary systems to account for those sort of peak demand, either cooling or heating. and to anticipate that and address it if it needs to get to that point. If it doesn't, the systems, as you suspected Austin, should be able to handle the majority of the conditions without the backup systems in play.
[Andre Leroux]: I guess one final question. Would be our, I think, I mean, I don't I deal with it personally on a residential scale, but dehumidification is really challenging. And if a system's not designed properly, that can be really challenging. How are there. Are there considerations around dehumidification for each of these options that are worth. Mentioning as far as building. Comfort and indoor air quality, or are they all sort of about the same?
[Emily Ehlers]: So in terms of indoor air quality and dehumidification, that would all be done through the ventilation rooftop units. And those are the same across the board for all the options. OK.
[Matt Rice]: All right. Can you have your hand up as well?
[Kenneth Lord]: I was just going to say the only reason I think we might want to either tentatively decide or hold off on a decision is we kind of said we weren't going to decide tonight and it was going to be the next meeting and I don't know if. everyone's here to have their voice and not be able to speak up. I don't know if there's a significant number not here tonight. That would be my only concern about making a final decision tonight. But we could potentially make a tentative decision and revisit it quickly next time to see if there's anybody who wants to weigh in anything else. But
[Jenny Graham]: Yeah, I think that's fine can, but, like, we cannot rehash the last hour and a half exactly 1st and watch the video or something. Yeah, we, we have to be able to get to the rest of what is, like, 75 slides here.
[Martine Dion]: I think also that the, you know, the questions and some of the discussions, obviously they would get through watching this and maybe with, I don't know, Matt, we were gonna issue meeting notes before next week.
[Matt Rice]: Yeah, I mean, the recording will be available too.
[Martine Dion]: The recording is here so that, you know, they have the information on their questions and next week we wouldn't have to represent some of this.
[Matt Rice]: We will not, we don't have the time. So Sarah, do you want to go ahead?
[UdfiATpNBs8_SPEAKER_12]: Yeah, you know, I think option three is fine, but I see your notes down here below about the utility incentives and for option three, that's the lowest value. That's right, I'm seeing, right? It's the 2.1?
[Martine Dion]: Yeah. So I don't know if- It's an estimate, but it is- Yeah, no, I know.
[UdfiATpNBs8_SPEAKER_12]: So, we wouldn't be maxing out the potential utility incentives if we went with option 3, whereas, you know, potentially 3Million for the ground source heat pumps again, that does help offset those costs those initial costs.
[Matt Rice]: Yeah, yeah, just not not at the scale when we look at the overall 50 year life cycle cost implications. Right.
[Martine Dion]: So it's 900,000. Let's say it's 900,000 difference could be less. We don't know. But the savings on option three is way over that, right? Briscoe savings is in the tens of millions. Okay.
[Matt Rice]: Maybe Alicia and then Jessica.
[Alicia Hunt]: So I was sort of waiting to sort of see other people weigh in and where the opinions are falling. As the city's sustainability director, we have made commitments to net zero. We really want to achieve it, but we're also looking at the reality here. And if we were comparing, if we were debating here between some fossil fuel stuff or things with significant changes in the EUI, I was expecting to see a significant difference between the ground source heat pump EUI and the air source. And when we look at that, it's not significant enough, in my opinion, to make the argument that we should pay this much more upfront money. And the lifecycle savings is also significant. So if we were going to have significant lifecycle savings for the ground source heat pump, we could make that argument. But those numbers just aren't there to really say we have to do this, even though we were kind of hoping to show and to showcase it and be doing that up here, especially with building a new building. A little bit of me wonders what would be different if we weren't looking at some of this deed restriction issues? How much of this all would be different? But I'm not sure it would be that significant. How much is that actually going to change the 50-year cost? And how much would that actually change the upfront costs? So it really feels like it's a really good environmental answer to say air to water. It's not perfect, but it's really solid and it's financially makes a lot of sense. And if this pushes us to put more solar on the site, if it means we really need to lean into the carport as well as, you know, the various things on the roof, I think that that's fine, right? Like it's okay. So, I just wanted to chime in on that and and I'm not going to argue against this in a big public meeting. So.
[Matt Rice]: Appreciate that perspective. Thanks. Why don't you go and I know that Stella, our electrical engineer had a comment and then I think we're going to pivot over to PV if that's all right.
[O2nzoxaatsQ_SPEAKER_13]: Yeah, no, I. Okay, so next. I'm just waiting for my.
[Matt Rice]: Yes, Stella, just let Jessica. Yes, sir.
[Jessica Parks]: Yes. No, I won't be. Most of my thoughts are in line with what Alicia said, actually, so I don't need much time. My only question was in terms of. Just the canopies for PV and is there any effect on performance? And I know you talked briefly about it with Austin going for the higher canopies versus the lower, but is there any. kind of effect on performance or access for replacement or maintenance or anything like that, even using the higher canopies. And that would be my main question. Otherwise, I'm kind of in line with Alicia at this point.
[Martine Dion]: Yeah, I will address that in the PV section. But yes, they bring a bit more efficiency. Um, then the lower ones, and that accounts for, you know, getting closer to net 0.
[Matt Rice]: And I think what Jessica was also interested in is just the impact on the mechanical system equipment and sort of replacement. Oh, yes. Oh, well, I don't know. Emily, if you want to chime in on that.
[Emily Ehlers]: Yeah, so as long as we're meeting so the manufacturers give us required clearances to make sure that we're getting enough air circulation around the units, since they are heat pumps. So as long as we're meeting all of those, and we have like the proper access side. access to the unit, then it's not typically an issue. But this is all the things, great points that we do coordinate during the design process with those high canopy systems.
[Matt Rice]: Okay.
[Jenny Graham]: Um, could we just ask people, um, the Medford team to like, give us a thumbs up in, uh, their reactions. If they support a tentative recommendation for option three, so that we can be clear about what this team sort of coalesced around. I just, I want to make sure we're hearing from everybody. Alicia Rohan.
[Matt Rice]: I'm seeing 1 of 1 of our engineers, so sorry about that.
[Jenny Graham]: Okay, so I'm seeing. Unanimous thumbs, so I think that's important to know when you put out the minutes that that's sort of where the group is at and like. You know, if folks have questions, Matt, maybe they can try to get them to you directly instead of waiting for a meeting. Um, so that. If we, if there's some reason for us to reconsider next week, we can, um, but, um. You know, where we all listen to the same thing and came to the same conclusion. Despite, like, maybe all starting in some different place.
[Matt Rice]: I wonder if it even makes sense for I can work with will to send out to the full group just a specific note on this topic, just let letting them know where we were in this. And if they have interest or questions, either contact us review the recording as well. So they can hear the dialogue and the rationale.
[Jenny Graham]: Yeah, I think that would be really a good productive way to make sure we get to all the other exciting topics that you have for us next time.
[Kimberly Talbot]: Yeah, I'm just going to call attention to Sonny's email. She did have a question about she's also seemingly drawing the same conclusion, at least with respect to full geothermal asking about is there an option that isn't 5050 so I think we can probably respond to that email, but I don't know if there's a, that's not what was studied. Not what was studied. So we would.
[Martine Dion]: Yeah. That would take many more weeks because we would have. Okay. We were all set. Yeah. Okay.
[Kimberly Talbot]: Great.
[Matt Rice]: All right. I know Stella's been waiting patiently. So I just, if you want to give us a quick segue question or comment.
[O2nzoxaatsQ_SPEAKER_13]: Super quick. Super quick. I just, I don't want to rain on geothermal parade, but the option one and option two is not because of geothermal or which HVC system is half of it, of the HVC system, but anything temporary not to forget is going hand in hand with temporary electrical, which means that we'll have to build entirely electrical system for a temporary HVAC equipment, feeders, panels, whatever it takes, depending on the extent of the entire system, and then remove it and then build another system, electrical, feeders, panels, who knows what else, because it would be different sizes. It's not like you can use the same feeder to just reroute and reuse it. Most likely there will be either abandoned or removed and then the second system would have to be installed. So, I don't know if it's accounted in the estimate or definitely needs to be addressed.
[Matt Rice]: I think we have the spirit of those costs captured in the LCCA. We can go back and double check to see in sort of the final iteration whether there needs to be some additional costs added there.
[O2nzoxaatsQ_SPEAKER_13]: Yeah, I'd just be surprised later if something comes out.
[Matt Rice]: And just before you dive in here, Martine, I will preface the fact that we probably have another 20 slides. We have this topic. We have another topic as well that follows after. So we're not going to be able to get through everything. And we sort of understood and estimated that in advance. And that's, again, why that October 1st meeting exists. So we'll get through what we can here, probably through the photovoltaic piece, and maybe field a couple of questions. And then I think we will pick it back up again on the 1st.
[Martine Dion]: Right, so we are clear here. I just we wanted to bring you a picture of. pictures of what we're going to talk about. For roof photovoltaic systems, we are looking at two different types of systems. The top picture shows a low ballasted system. Those are the close to the roof system with low angles that are usually not visible from the ground. And then below there's a high canopy system, which we talked about a bit earlier. Those are visible and they usually have to be above the HVAC. and clear the HVAC systems. For the parking, there are different, again, different types. Just to go back for the high canopy system, that's more efficient to, you know, to Jessica's question earlier. So the PVs are, when they're all together and there's more of them, connected that adds to the efficiency of the system. For the parking, a similar situation where we have, you've probably seen systems that only cover, canopies that only cover parking spaces. very popular. And then we have, that's the one on the bottom, the bottom right. And then at the top right, we have what we call the long span canopies. And those cover both the parking space and the driveway. And they usually have to be a bit higher for clearances. But those provide for the highest output per square foot. of energy. And I know that Austin, you probably will have a lot of comments and we're looking forward for your input on this. If we don't have time to cover tonight, we can continue next week. So our preliminary assessment, we're working with Solar Design Associates. They did some analysis and we came to the result that in order to get to net zero, we would need to have the roof of the school about half to two-thirds be a high-roof canopy, and then the low-ballasted roof PV canopy likely would be where the existing gym and pool portions are, the side part there. For the parking right now, we're using the current parking option, the ground parking option, and that provides for the other 50%. And we can get to that other 50% with a mix of hybrid sort of strip-only covered parking spaces and a portion of it as long span. Next. So we also wanted to give you sort of the impact of installing your structure there, but having the PV owned by a third party through a power purchase agreement. And what does that mean? There's a lot of writing here. I'm going to try to go quick. Versus owning your own system. So for a PPA, this is where you basically lease your roof and your parking to a PPA, a Power Purchase Agreement to a third party, and they basically design, procure, install, maintain, and replace. the PV system, they also do all the coordination with, well, most of the coordination related to the PV. But I have to say that Stella, that you just heard that our design and electrical engineer would be involved in some of those conversations. And that a PPA, a large PPA system contract would likely include a battery storage. Your part is to provide for the solar PV readiness at the roof and the parking, so that's the building owner under PPA, and then the electrical utility infrastructure. The financial benefits is that you have no cost up front, but in terms of everything, the incentives, the annual revenues from the savings from all of the production of the PV, the RECs, the selling of the carbon offsets, all of that is owned through the PPA. There are some contracts where you can negotiate the RECs, and I won't go into details of that, but basically what you get as an owner if you sign with a PPA is a reduction on your electrical rate, and that's a certain amount. I did an estimate here from, you know, the past projects we're aware of, that is all negotiated. When we talk about LEED, if you do a PPA and you don't own the RECs, you're not going to be able to get the renewable energy points. If you own the RECs, then we have to make sure that the commissioning gets done, and that's been very challenging in some of our projects. If you decide to own the PV, and then we'll talk about that in a minute with some of the costs, you pay for everything, you maintain everything, and then you get all the benefits still. You get the incentives up front, some of the incentives, state incentives up front. You get all the savings, utility savings, peak savings. And then some of this is still in progress. We'll have more next Thursday on that. And then you get the lead points. Next. So what we did here is a first high-level calculation of the updated production that was provided to us, the assessment that was provided to us by Solar Design Associate and how much it would cost for the roof, the parking, total cost and then battery storage. And we compared to the three options that were sort of priced through alternates in the PSR. So for the roof in the PSR, what was priced was about 50% of the area low ballasted, which is equivalent to $3 million and only provides about 20% of the overall energy of the school. What we looked at with the capacity is on your roof is 50%, and that's much more expensive. That's like more or less $20 million. For the parking in the alternate for the PSR, we had looked at 100% net zero PPA and only the parking structure. What we've looked at here is, what you have here is the parking cost of just the parking with the 50% and the parking structure. So that totals, that's about another $20 million, and that totals $40 million And then you add to that the battery storage, which is another close to 5 million. All of these are approximately, you know, estimated at this time. I want to say that the structure cost in our update is out of the cost of a recent parking structure priced on another one of our school. So both the panels and the structure, I got the cost per watt for that, and that's what we used here. Your alternative three, PV3 in the PSR, included ownership of the PV in the structure, and that was about $59 million. It included the battery storage as well. So there's a bit of difference of where we are and what you had in your alternate, because we're at about $45 million, and this was about $59 million. So there would be, Matt, correct me if I'm wrong, but I think we would need to you know, to the cost. So that's where we are now. And next week, I'm going to have a sort of a similar life cycle cost analysis, not as much with, you know, the cost analysis. you know, the maintenance and the replacement, but more about the life cycle of the PV system and the comparison between the PPA and your ownership for those three options and what does that mean, you know, over the life of the system and your annual revenue. So, that will be next week. I'm sure we have a couple of questions here, so do we want to spend 5 minutes maybe?
[Matt Rice]: Yeah, I think that would be good. I know there's some questions in the chat and I think generally, certainly if answers are available now, if not, if you just want to give Martine and the team some feedback or things to incorporate into the presentation for next week, that's fine as well. Austin, I'm going to let you go first because I know this is your space.
[Andre Leroux]: Sure, I will go through a couple of things. One, it would be helpful to see installed system size, not just kilowatt hours. I think that's a hard concept for people, I think, to conceptualize. So what is the size of the roof system? What is the size of the carport?
[Martine Dion]: Do you mean in square footage or kilowatts?
[Andre Leroux]: In terms of kilowatts.
[Martine Dion]: Okay.
[Martine Dion]: Yeah. That's what we had originally, but we agreed with the SDA that we were going to do kilowatt hours.
[Andre Leroux]: Maybe show, show both.
[Martine Dion]: Yeah, we can show both. Good point.
[Andre Leroux]: And I guess I'll just, I'll just offer like on a, on a commercial system, I think it's good that we're looking at both, both the PPA versus the ownership. If you're looking at a multi megawatt system, um, trying to maintain that On your own, like, there are standalone maintenance contracts certainly that exist, you know, but that then becomes an operational cost. Whereas all of that is generally baked into the cost of a PPA. So, I just think that for next. uh for next time um you know that's something to to be considered um and just sort of discussed uh some of the some of the and i'm happy to provide sort of a little primer on that it sounds like uh alicia's got a lot of experience with it as well sort of the the um costs and benefits of of both um so maybe we'd be happy to collaborate right matt i think that that would be good yeah Um, yeah, and I guess I'll just say, like, the 2nd, the question, like, these costs on a dollars per watt basis. Like, I tried to back into the system size for just the roof and I was getting like, 8 dollars a lot, which is like. three to four X more than I've ever seen. So wondering just like what that cost.
[Martine Dion]: So the cost for the low ballasted roof is $3 a watt per square foot. It's because you have general conditions and other things in here. It's the $3 a square foot. I mean, sorry, $3 per watt. And that's the price we just got on a recent project. The cost of the higher canopy is more in the $5 to $7 range because of the structure. And we recently had an estimate on a large, on a 5.5 megawatt, where the structure, the panels were three and the structure is about four. So it's about seven. So that's why I use seven. And I use it for the roof and for the parking canopy, because at this point, that's all I have in terms of where it's still in schematic design. Would the structure of the roof be cheaper than the structure of the parking possibly? We would need to adjust that as we do the design.
[Matt Rice]: So we have three minutes left. I do want to respect people's time. I think, Ken, I saw your hand go up first, then Paul, and maybe we can try to squeeze both comments or questions in, and then we probably have to wrap it up.
[Kenneth Lord]: Two quick questions. How much of this PV cost was carried in the current estimates we're probably talking about again? And has the pool roof in particular and the gym roof been evaluated for structurally being able to hold this much equipment as well as the HVAC equipment?
[Martine Dion]: So the 1st part, the 3 in the comments of that of that slide table, you have what was none of the PV costs were carried as part of the budget came. They were all alternative. And I think the goal is to get a decision to for a recommendation next week to the building committee to add. It would be an add the PV or keep it as an alternate, but hone down on. what exactly that alternate would be, because it would have to differ a bit from what we had in schematic design.
[Matt Rice]: So I think the life cycle cost portion of the photovoltaic analysis is going to be key there, because in the absence of that, we're talking about adding $19 million, $21 million to the project. And I know based on discussions recently from other space reductions, that's a challenging concept. So we need to provide everyone the information in terms of what the life cycle cost benefit would be if we're making that investment or suggesting that we make that investment.
[Martine Dion]: Yes, and Alicia mentioned, oops, sorry.
[Matt Rice]: I just want to let Paul chime in, because we have like a minute left.
[Paul Ruseau]: Sure. So I just wanted to, you know, the points that we could be getting here is a lot of money. So, I mean, that is, I mean, as far as I can imagine, I just can't imagine how that doesn't offset having a maintenance contract with somebody. I mean, three percentage points, that's, I mean, if they give us $400 million, that's what? $12 million. We're talking real big money here. So I know we need more time and more analysis on this, but leaving that on the table to me seems short-sighted. I know that how short is sort of a question we, you know, we're talking 50 years, but like the finances of Bedford and everything, like none of us know what 50 years, like, will we finally stop funding school systems the way we do in the next 50 years? Um, you know, there's a lot of impossible to know that kind of a timeframe, but I do feel like that that's a lot of money that, um, would be helpful to, to reduce the cost overall. So.
[Matt Rice]: Yeah, yeah, and that that's what exactly what the PV life cycle costs will attempt to illustrate. All right, we are now at 731, so I do want to let everyone go and appreciate everyone's time. Certainly on the Wednesday when there's lots of things going on in the middle of the week. So we will reconvene on the 1st. I would appreciate everyone's feedback and input this evening as well. Thank you everyone.
[Paul Ruseau]: Thank you everybody. Thank you.
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