Net zero by 2030: a conversation with architects Eric Corey Freed and Bill Maclay, part 2
by Jon Floyd, Better Buildings by Design Conference Chair
In part one of this two part series, I chatted with architects Eric Corey Freed and Bill Maclay about design trends and the difference between designing Net Zero buildings for commercial and residential purposes.
In part two, I continued the conversation with Better Buildings by Design 2014 keynote speaker Eric Corey Freed and leading Vermont architect, Bill Maclay of Maclay Architects in Waitsfield, to discuss some NetZero projects they have led and how they envision Vermont meeting the ambitious goal of Net Zero by 2030.
Here are the highlights of the conversation with Eric and Bill.
Q: Can you share a project or multiple projects that embodies your thoughts on Net Zero and specifically how the projects were successful, and how those successes could be replicated on a larger scale?
A: (Eric): We just did this Zero Net Energy Center for the International Brotherhood of Electrical Workers (IBEW), and essentially it was this educational training facility where they had 2,000 journeymen electricians that go through, and they wanted their building to be Net Zero so the electricians could see it. So here you have an electrical union training electricians about Net Zero in a Net Zero facility, so I love the synchronicity of all that. I just think that was amazing.
I did a project for a transit agency, a learning center; it was essentially like a mini-museum/exhibit. The interior was all this fun, colorful stuff like a museum would have, and it talks about what this transit agency does in terms of their zero-emission vehicles, generating their own hydrogen to power the vehicles, how to use natural gas to do it, and how they use solar as a transformer. They were doing a lot of cool things, and they wanted a building to showcase that.
So the building itself has a ten-kilowatt solar array. This solar array sits on the ground, because it’s part of the exhibit so you can climb up to it and touch it. And then behind it they have solar trackers that don’t really work that well but were old and we tried them anyway. And then behind that they’ve got this transformer thing where the solar power then takes natural gas and converts it into hydrogen, and that’s what they use to power the buses. It was a fun project in that not only is it educating people about it, but then they can actually walk outside and touch and see the actual equipment. So that was kind of fun.
In terms of scalability, with commercial buildings, it depends on the type of owner. If it’s a developer, they’re not going to care about Net Zero at all. Yes, it’s a nice marketing pitch, but it’s not enough for them to stand up and take notice. The developers tend to say things like, “okay well we’ll put in the conduit in the roof and you know whoever buys it can add solar later.” That’s kind of the reality of it, but if you’re an owner-occupied building and you’re going to be there for ten years, Net Zero will most likely, depending on where you live , most likely will pencil out for you. The nice thing about Net Zero is that it’s quantifiable. It’s a number; it’s a tangible number. It’s not this abstract idea of, “yeah we have a green building.” Well how green is it? It’s LEED silver, so it couldn’t be greener. Net Zero is a thing; you know it’s either you’re Net Zero or you’re not. And so that’s why I like the certification for it.
A: (Bill): In any Net Zero project, you want to look at sort of the standard strategies at the beginning of what people call integrated building design. That is orienting the building along the east/west axis so that you don’t have overheating, you maximize solar gain. You want to keep the massing relatively simple so that there isn’t as much heat loss from the envelope of the building. People have looked at these principles in terms of energy efficiency and passive solar design from the beginning.
The really three key elements are reducing the loads. So from our perspective, we look at creating a metric at the very beginning of the design process based on the amount of energy consumed per square foot of building area. We all know the fuel mileage of our cars, but almost none of us have any idea what the fuel mileages of our buildings are. If you don’t measure it, then it’s pretty hard to come up with good solutions. So for Net Zero, you really want to look at energy conservation and doing that to a metric. For a typical residential, classroom and office buildings, that wants to be somewhere in the neighborhood of 10 to 25 maximum KBTUs, thousands BTUs per square foot per year for all of the energy consumption in the building. When you do that, then you want to look at how you use mechanical systems and provide comfort in the building.
That’s where we typically have been using either air source or ground source heat pumps and coming up with ways that the mechanical systems, when you insulate well, you can start to cut back on the distribution too, in the building, and saves some money that offsets some of the additional cost of the insulation.
Then, once you’ve done those two things, you achieve your energy intensity level that’s appropriate for Net Zero buildings. Then you add the renewable energy which typically is most commonly photovoltaics as the way of powering the building.
Q: Is there one project in particular the last couple of years that really stands out in terms of embodying those elements that you just described in terms of a Net Zero process?
A (Bill): Well, I mean two of the projects I think that we’re the most proud of, one is the Coastal Maine Botanical Gardens, I think in terms of being an education center that relates to nature and connecting to nature and is a Net Zero building. Then I think the other one is the State Office Building in Bennington, just demonstrating that we can make large buildings that are Net Zero, which I think many people don’t think we can do.
I suppose the third throw in there is NRG systems which does actually have a minor amount of gas used for it, but there’s an office manufacturing facility that’s been there for – in two phases for, I don't know, between five and ten years depending on which phase. They get literally thousands of people a year who come to visit the building because people are looking for examples of where 60 and 70,000 square foot buildings actually can be renewably powered or Net Zero.
So it’s just another example of how powerful that is in driving peoples’ thinking towards the future. I think those are some of the projects that I think we’re the most proud of. We do, actually, quite a few residential homes. So we’ve done Net Zero homes in a number of places as well.
The process is the same for residential and for commercial buildings. That being said, commercial buildings often have a lot more loads inside the building, so they’re what people call internal load dominated buildings. There are different measures in terms of accomplishing that that you might end up doing on a residential home.
Q: In Vermont, what do you see as ways to replicate Net Zero on a larger scale so that we as a state and builders in the design community, everyone will start building with Net Zero in mind? Is there anything on the policy fronts or what are ways that you envision us being able to replicate this on a larger scale?
A: (Bill) Well, I think one thing, for instance, New York and other places have started actually documenting the energy intensity of buildings, the Federal Government and some state and city governments have mandated for their buildings to be Net Zero by a certain date.
Those are some of the places we’re getting people, instead of building this 10 percent, 20 percent, or even 30 percent better than code, to actually say, “No, we are on the path to Net Zero, and are we designing either a Net Zero building or a Net Zero ready building.”
I think the other development that has incredibly been helpful is the net metering process. If on your own site, you don’t have enough solar energy available; you actually can put solar systems on another property in the same territory of your same utility. They will credit the power from one place over to another. For example, our office, which is a Net Zero building in the Historic Village on an existing 1850s carriage house is Net Zero. It uses a solar car port that’s right next to our office. On the same property, we have an apartment. We have two apartments and it would have been a single-family home. They actually get their power from a power purchase agreement with tracking collectors that’s actually my house that’s nine miles away. The power from there also helps to power our house that’s nine miles away.
Not every site is going to have the solar onsite, particularly as we think about buildings and community, larger buildings and communities. I think when we start thinking from a community perspective, we can start to say, “Oh, let’s get the building to the Net Zero ready standard and then we can figure out is there a place to put a solar system.” That may be outside of that town or another location, or even when you do solar on your own site, like let’s say you had a big church that happened to have a south-facing roof. You might put in more PV than the church needed and that actually might help lower income people in that neighborhood.
I think it’s that sort of community way of thinking that more and more people are realizing really does make sense in terms of, how do we get ultimately, our villages, our towns and the entire State of Vermont being Net Zero.
Thanks again to Eric Corey Freed and Bill Maclay for their contribution.
What do you think Net Zero by 2030 means for Vermont? Share your thoughts with us in the comments below.