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Three Buildings Net Zero Energy - Building Priorities Briefing

We explore three commercial buildings without power bills, and contrast the many meanings of "zero" in energy and carbon. First, a commercial building proven to be zero energy -- and then some. In the first 12 months after construction, this building produced more energy than it consumed. Then we learn about two more buildings presented in the ZEB session at Globe last month. The Energy Minute is about the meaning of zero: What should be counted when designating a building "net zero energy" or "zero carbon"? In the Program Notes we have photos and links to more information for those of you who are researching the net-zero option for your own buildings. (podcast) (photo)


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Program notes

What is the meaning of zero? We explore zero energy buildings and contrast that with carbon neutral buildings.

Case study: 31 Tannery Road, Branchburg, NJ.

Thirty-one Tannery is the corporate headquarters for Ferreira Construction. It's also the first zero energy commercial building in the U.S. Two hundred people work in this 42,000 square foot living lab of sustainability. It has 1,200+ PV modules on the roof -- 223 kilowatts -- and solar thermal provides its hot water.

The radiant HVAC system has nine miles of tubing in the slab. The condensing boiler operates at 95 percent efficiency and above. The list goes on -- sensors, controls, monitoring -- it's a hands-on showcase of energy efficiency and renewable energy systems.

Denis Du Bois interviews Joe Grabowski, Vice President for building owner-occupant Ferreira Construction, who was very involved in the design of the building.

The rooftop solar array atop Ferreira's headquarters helps the building operate on net zero outside energy. (Photo courtesy Ferreira)


I talked with Joe Grabowski, vice president for Ferreira, who was very involved in the design of the building.

I asked him why Ferreira decided to build its own zero-energy headquarters.

Joe: We really didn’t set out to build zero-energy, per se. We just put into practice, in the various areas, and did them the best we could. The zero-energy is achieved by what we like to say is energy diet, exercise and a trainer. You don’t want a building that is an energy pig, so we put a lot of concentration into energy efficiencies. We added to that renewable energy, which is sort of the exercise. The sort of detail that put it all together was the monitoring; the system that we have to monitor and adapt to the way that we use energy and use it efficiently.

Denis: How much additional investment do you think you made in the upgrades that made it a zero-energy building?

Joe: Off the top of my head, I think the renewable energy portion was about a million and a half. It went up to close to two million with energy efficiency issues that we put in. Our original payback was about 8 years, but it looks like we’re going to come out better than that because of rising energy costs and also because of getting a better efficiency that even we expected.

Denis: What do you think the payback will be then?

Joe: Right now we’re looking at somewhere around 6 years.

Denis: Your project qualified for some incentives, as I understand.

Joe: Now our particular project we did. New Jersey had a rebate system, so we received a rebate. There are tax incentives for doing this. We have the S-RECs, certainly we have the money that we’re making in terms of electrical energy production in offsetting our bill.

Denis: So those rebates and taxes; how much of your initial construction cost was offset by those?

Joe: The incentives, in our case, were rather large. I think our rebate with the utility company was something like $860,000, on the $1.5 million in terms of the solar equipment that we purchased.

"Our original payback was about 8 years, but it looks like we’re going to come out better than that because of rising energy costs and also because of getting a better efficiency that even we expected."
--Joe Grabowski, VP, Ferreira.

Denis: How did your lenders feel about all this zero-energy building talk?

Joe: That’s an interesting question because at first they were really not concerned with that. They were really looking at it as an added expense, and it wasn’t up until effort on our part to convince them of the value.

Denis: How did you convince them?

Joe: Probably just a lot of elbow grease and commitment to the project. I think our convincing effort, that what we were doing in showing them spreadsheets on how we calculated energy savings and what it would do and how it would reduce the costs and add value to the building. Eventually they said okay.

Denis: these projects are always learning experiences. What were some of your interesting lessons from this project?

Joe: One of the things that we did learn in here is in our field people tend to concentrate in their areas. If you’re a renewable energy person, you’re thinking about renewable energy. If you’re an engineer, maybe concentrating on energy efficiency as you do that. Then there’s controls and monitoring systems.

This is really a group effort in those areas. Putting a lot of effort into energy efficiency, effort into renewable energy and then being able to combine the technologies and making it work. So we had parameters that not only did we want the project to be efficient and work, this building had to work financially, it had to be comfortable, it had to meet certain standards and we were able to achieve those.

Denis: Were you surprised at the end of your first year when you came out with a surplus of energy?

Joe: I don’t think we were surprised only because all the work we had done upfront. I think what surprised us was how much. We not only achieved net zero, we went beyond that and produced a whole extra month of electricity than we use. So that part was surprising.

There were a whole bunch of dynamics that went into that. The monitoring system really brought out for us some interesting dynamics in people that we didn’t expect. When we were leasing space, at the end of the day I would be the person going around turning off the lights in offices and asking people to be conscious of turning their lights out.

We have a display in our lobby that shows how we’re using energy, how we’re consuming it and how we’re giving back to the world in sense of saving energy. Without even asking anybody, it’s sort of taking over sort of a human dynamic. People, now that they can see it, (it was intangible before), they’re actually wanting to contribute.

We find that when people leave their office they turn the lights out. Or they’ll provide a suggestion for saving energy which never really happened before.

Denis: You’re obviously a unique case in that you're a construction company. You have an army of engineers at your disposal. Should a typical building owner expect the same results that you’ve seen?

Joe: No. It’s something that in our case we were building a new building, which gives you a lot more leeway in terms of the design and what you’re doing. So if you’re building a new building, you have that. But there are all different types of buildings and they have their different types of issues to deal with.

But certainly the typical building owner should take from this that they could make enormous leaps towards that goal, that there are many things that you can do to reduce your energy consumption, to save money and to do it in financial ways that make sense and make your building more comfortable and easier to operate.

Denis: I understand you invite people to tour the building. What do they get to see?

Joe: We made the building a learning tool. We have a walkway system that takes people up to the roof; and we’re joking here because we give so many tours of the building we’re thinking about opening up a gift shop.

The fire department came over and said how would we fight a fire on a building that has solar panels? When the governor of New Jersey visited us, we were able to take him up there and show him these things. It helps people when they can touch and see them, to feel that they’re attainable. This is something they can understand.

We have a kiosk in the lobby that shows all of our visitors what’s going on. Throughout the building we have ways to show the internal workings. In our conference room, behind a wood panel we can open it up and show you the zone tubing that goes down into the floor and the controllers that work.

And hopefully what they’ll take from that, if they can’t use those particular strategies, will take the overall strategy and apply them to different technologies to have the same results.


Thirty-one Tannery will have its second anniversary in July 2008. It's the first zero energy commercial building in the U.S. To be precise, it's a net zero electric energy building; it still uses natural gas. It's not completely accurate to say it has no power bill, because utility demand charges and standby charges still apply. And the building isn't carbon neutral. In its first 12 months the building's avoided emissions were 530 metric tons of carbon, roughly equivalent to the CO2 from 100 typical American cars.

Ferreira Construction web site

Energy Minute: The Meaning of Zero Energy and Carbon Neutral

Zero energy, zero carbon -- what do they mean, and what's the difference?

Third half: Two carbon-neutral ZEBs presented at the Globe 2008 session

Zero energy buildings were the topic of a popular session at the Globe Conference on Business and the Environment, March 2008 in Vancouver British Columbia.

Peter Busby presented two carbon-neutral commercial designs at the Globe 2008 conference in Vancouver. (EP photo)

The panelist with the most interesting information to share about commercial buildings was Peter Busby, Managing Director of Busby Perkins + Will and Chair of the Canada Green Building Council. Busby talked about two of his firm's projects that are net zero energy buildings. Both are in the design phase, and both will be carbon neutral.

Canada is serious about green building. It has its own Green Building Council, and the World Green Building Council is based in Toronto Ontario.

Busby Perkins + Will web site
Canada Green Building Council web site
World Green Building Council web site
"Globe Conference Draws Leaders from around the World" (EP)

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From Canada -- A whole community shuts off its power.

Earth Hour. Millions of people in cities on six continents turned off their lights. Participants in more than 400 countries made a highly visible statement in support for global action on climate change. Hartley Bay, BC, Canada went a step farther.

Earth Hour web site

Small Energy Group web site


I am working with a school that would like to build a netzero high school in Minnesota. I have built four high performance schools accomplishing up to 50% energy savings.

I would appreciate any information that would be helpful in pursuing the goal above.


I've been researching net-zero energy buildings for the last few months and from what I can tell, after a 50% energy savings (fantastic by the way!!) the balance is met with on-site generation. Wind, solar, geothermal, co-gen, have all been used. In a high school co-gen (with the swimming pool for example) could be used. Or there could be opportunities for the students to interact/build/learn with solar PV or solar hot water. The DOE web site EERE has some decent examples with some info but no exact specifics.


Noveda's 31 Tannery Project has entered it's second year of Net Zero Electric.

Have you checked out the cool real-time monitoring display at Noveda.com?

We have designed a Net Zero Elementary and Net Zero Middle School. We have reduced energy use by 75% (energy modeled). Both schools will be completed in 2010. Both are currently under construction.

i wanted to know how building materiial selectiion for envelope is done in case of ZEB. and how is it different from green building materiial selection.is enegy plus used for simulation fo envelope