You might have heard wild-eyed sounding rumors in the past about the European Union legislating net zero buildings. Those weren’t rumors.
A few years ago, the EU parliament required all new buildings to be “nearly net zero” (being defined by each state) starting in 2019. Existing ones that undergo major renovations will have to hit energy performance targets set by the member states. In the UK, new homes need to hit that target even sooner – they need to be carbon neutral by 2016.
Now California (any surprise?) has established a net zero beachhead in North America. Under an executive order issued by Governor Brown on April 25th, by 2020 half of new State buildings and major renovations will be net zero and all by 2025.
If you’re wondering how they are going to design these buildings, one could look to the net zero projects on the drawing boards in New York City: P.S. 62 on Staten Island (starting this year), Solar 2, and Cornell’s Roosevelt Island campus. And if they can do it, perhaps it’s time that we follow California and the EU’s lead?
That would be a bad idea. The first part of net zero – extraordinary load reduction – is something that all new buildings could and should achieve. We’re seeing it with these projects and we’re seeing it with Passive House. But the second part – generating solar electricity onsite – just isn’t possible for many buildings in New York. It’s no coincidence that all three New York net zero projects have large roof to square footage ratios, and are also in open areas of the city without neighboring buildings to shade their roofs. A high-rise just doesn’t have enough roof area for PVs to generate its own energy and the only way they could meet a net zero mandate would be to purchase expensive renewable energy credits. According to our research director, Richard Leigh, “for almost any commercial or residential use, even with efficient lighting and appliances, the solar resource to get above three stories and meet net loads with on-site collectors just isn’t there, even out in the open countryside.”
So let’s build super energy-efficient buildings and install whatever onsite renewables we can. But as we look towards the next generation of green buildings, let’s remember that while net zero can be done for low-rises it doesn’t work for high-rises.
First of all people should have to get a permit to install PV in the City, proving that it is impossible to do Solar Thermal, or else be given a one way trip to Siberia.
There is no reason to prefer 15% efficient conversion over 98% efficient conversion of solar energy if the transportation problem is absent (electricity is easier to transport over long distances than BTUs). The major load in most buildings is thermal not electric, certainly on the residential front.
Russel,
Thank you, perhaps we can learn from the research that places a 3-4 story height limitation on net zero buildings. Why must we have tall buildings? If we are to create a new generation of green buildings, we must rethink core ecological concepts. Reduced height buildings not only significantly reduce ecological footprints, they also provide enormously increased opportunity for productive green spaces. This would not be about following the EU or California. This would be about creating a new live/work paradigm for a new Metropolis.
The design of PS 62R, a NZEB school, is intended to challenge the SCA Design Standards. We intend to assure that our Standards don’t stagnate and to move forward, past Code level, in the design of high-performance schools. We constantly revise our standards in this regard.
The effort to continually capture improvements began in earnest when in 2007 we built PS 276M known as the Battery City Park School. This was our first “green incubator” used to challenge the green design standards of the Green Schools Guide by using non-standard experimentation. Together with Dattner Architects and Battery Park City Authority we enhanced our Standards by including features such as:
• Use of additional occupancy and daylight sensors
• Exterior solar shading and day-lit stairs
• Daylight harvesting
• Increased content of recycled and rapidly renewable building materials
• Applied envelope inspection protocol
• Alternate energy source: 50 kW/hr photovoltaic panel array
• Total energy recovery heat wheel applied
• Energy modeling used during design phase
• High performance building envelope
• Green signage program providing interactive opportunity for teaching students
• Dashboard providing interactive opportunity for teaching students
Using PS 62R with cutting-edge technologies as our “sustainability lab” it is our intension of applying these new “Lessons Learned” to SCA Standards of design. I can’t reveal all of the particulars at this time; however, I can report that together with SOM the following were included in PS 62R design were beyond our Standards:
• Expanded commissioning to include the entire high-performance envelope
• Whole team involvement from pre-design through post-construction
• Extensive daylighting, in some spaces 98% daylight autonomy
• Use of combined chilled-beam with displacement-air ventilation
• Low-energy Kitchen equipment and procedures
• Inclusion of solar thermal collectors
• Geothermal well-field for ground-source heat pumps
Finally, I can state that one of my future goals is to encourage our designs to be at the leading-edge of building performance. Essentially meaning that all of our projects could potentially be designed as “net-zero ready” or NZE3 (extremely energy efficient).
Russell, your assertion that net-zero “just isn’t possible” in New York is not quite correct.
In 2002, Kiss + Cathcart, Architects was commissioned by the National Building Museum to develop a realistically sustainable high-rise building for their exhibition ‘Big & Green’ (our design is published in their catalogue if you want to check, or you can go to our website http://www.kisscathcart.com/2020/overview.html) in collaboration with all the engineering disciplines represented at Arup New York. Although no net-zero high-rise design has been built to our knowledge, we nevertheless believe our design disproves your assertion that net zero “doesn’t work for high-rises”. I agree that energy efficiency efforts should come before the application of on-site renewables, and I also agree with some of your commenters’ points, that solar thermal in many cases has a stronger claim than PV to scarce rooftop space, and that high-rise and super-tall buildings are often dubious propositions to begin with. Nevertheless, we accounted for self-shadowing and neighborhood shadowing in a dense, transit-rich environment, and the building’s energy budget worked out to zero, even at 150 stories. Note that our commission was for a spec building to be completed in 2020, so we assumed incremental improvements in building system and PV efficiencies – assumptions that are still on track 10 years later.
Let me also say that I think we should be careful about pouring cold water on European and Californian “wild-eyed” regulatory innovations. The Europeans have always been way ahead of us on day-lighting regulations that appear unrealistic when applied to office buildings on this side of pond, but only because Americans have become habituated to “fat” buildings — buildings that provide no daylight to a majority of their users, and that are endowed with little passive resilience. Which is the more radical? To me, a European office building where everyone gets an operable window, if compared to an efficiently lighted American office building where many occupants must still ask “how’s the weather outside?” seems the more common-sense design.
Thanks for all the thoughtful comments. A few responses:
Regarding solar thermal versus solar PV, I strongly agree with your point (though I might recommend sending people to the northern reaches of my home country of Canada since it will require less fuel for travel). Richard Leigh, Director of Research, wrote a blog post last year (http://blog.urbangreencouncil.org/2011/10/to-pv-or-not-pv/) showing how solar thermal has a 2:1 advantage over PV in terms of greenhouse gas emissions. And the payback is way better too.
John, that’s a great a question on the optimal building height. The urban planning question is whether low-rise buildings can support public transit and, if not, would any gains in building efficiency compared to high-rises be offset by increased transportation impact.
Richard, it’s extraordinary to learn that the SCA is using PS62 as a testing ground and that the project will be informing your design standards. It’s a fabulous project that I look forward to seeing more of!
Collin, Dick Leigh is going to respond regarding your intriguing study. Certainly Europe is ahead of North America on green building and environmental policy, and we should look to them for ideas. But on net-zero, I worry they may have adopted a wonderful-sounding goal without working through how it will happen. Insisting on net-zero buildings may lead us to a much more expensive carbon-free future than one with central carbon-free power.