03 Mar 2009: Analysis

Pursuing the Elusive Goal
of a Carbon-Neutral Building

Yale University’s recently opened Kroon Hall is a state-of-the-art model of where the green building movement is headed. Yet even this showcase for renewable energy highlights the difficulties of creating a building that is 100 percent carbon neutral.

by richard conniff

Early this year, a new building opened on the Yale University campus that set out to achieve the architectural Holy Grail in the age of global warming — getting to carbon neutral. Designed by Hopkins Architects, a British firm with a long history in the green building movement, the new home of the Yale School of Forestry & Environmental Studies is, on almost all counts, a striking success. It has simple but beautiful lines, incorporates the latest sustainable ideas and technologies without loudly announcing them, and manages to transform what had been a ruined landscape into a green campus. In a feat of no small symbolic value, the school bullyragged the university into shutting down a fossil fuel power plant that had formerly occupied the site.

Yale’s new Kroon Hall promises to change the lives of the people who have begun to inhabit it, and perhaps also beyond, as a model for where the green building movement needs to go next.

But Kroon is also a reminder of what even some of the best hearts and minds in the sustainable design movement cannot yet achieve. For a “green premium” unofficially estimated at about 5.7 percent of construction cost, the Kroon design team managed to reduce projected energy use and emissions by 61 percent below the levels for a comparable building of conventional design. The biggest savings came not from sexy new technologies but from figuring out how to make the design function like an old-fashioned cathedral, with a slender profile for maximum daylighting, an east-west orientation for greater solar gain on the long southern exposure, careful use of shading, and plenty of stone and concrete to store thermal energy. A solar photovoltaic array and geothermal wells will supply much of the remaining energy load. “We got damned close to carbon neutral,” boasted a construction manager who initially scoffed at the whole idea of green design. But perhaps inevitably, the school will still have to purchase offsets to mitigate the carbon emissions it could not avoid.

Figuring out how to get the rest of the way to carbon neutral, and not just damned close, has become an urgent question as the timetable for global warming has rapidly worsened.

Last year, the United Kingdom imposed a zero energy building (ZEB) mandate on all new homes starting in 2016 — just seven years from now — and on all new commercial structures starting in 2019. Patrick Bellew, a British environmental engineer whose company, atelier ten, worked on Kroon Hall, described the mandate as “a collision of wills between politicos wanting to be seen” to live up to their climate treaty commitments, and developers, designers, and government functionaries, who get stuck with the job of figuring out how to do it.

“Everybody’s freaking about what the potential impact is on the cost of buildings,” said Bellew. Then, echoing Samuel Johnson’s remark about the prospect of hanging, he added, “It does do a terrific job of focusing people’s minds.”

In the United States, interest in zero energy buildings and neighborhoods has also grown, driven by cost and national security issues, as well as by climate change. The Departments of Energy and Defense are currently researching high-performance and “net zero plus” buildings, which would reduce demand by 70 percent and use renewable energy to supply the balance (and in some cases produce a surplus, hence the “plus”). The World Business Council for Sustainable Development has launched a corporate drive for ZEB development, and a separate proposal to make all new structures and renovations carbon neutral by 2030 is also circulating in the building community.

That 20-year time frame may sound relatively comfortable, but actual energy use per square foot in U.S. buildings has not improved much in the past 90 years, since 1920. Buildings here account for 39 percent of total energy use and 68 percent of electricity — roughly half of it from coal. And those stark facts have many green building advocates looking for new ways forward.

Like Kroon Hall, most attempts at sustainable development now focus on the U.S. Green Building Council’s voluntary certification process, Leadership in Energy and Environmental Design (LEED). Builders accumulate points on a checklist of criteria — such as site selection,
Critics say LEED is not just too narrow, but undervalues energy performance.
reduced light pollution, construction waste management, and so on — to achieve a LEED ranking, from LEED certified to LEED silver, gold, or platinum. LEED has functioned, said Bellew, as “a terrific kick up the backside for the industry, raising the level of awareness and understanding.” But it has also served more as a status symbol for an elite fraction of new buildings than as a broad response to a global crisis. So far, 2,300 commercial buildings have earned a LEED rating, with another 17,800 projects in the pipeline.

Critics say LEED is not just too narrow, but also undervalues energy performance. “Many of the corporate sponsors of LEED are interested in a focus on products,” said Harvey Sachs, a senior fellow with the American Council for an Energy Efficient Economy. “That’s nice. But the elephant in the room is energy consumption.”

Another voluntary program, run by the U.S. Environmental Protection Agency, ranks buildings by energy efficiency and awards the Energy Star label to the top 25 percent. But Sachs argued that some LEED silver buildings would not qualify. “A green label building is not necessarily an energy efficient building,” he said, and that leaves “the more extreme” critics of LEED “muttering under their breath or shouting to the heavens about greenwash.”

In response to such criticisms, the U.S. Green Building Council (USGBC) commissioned a study of energy use in the 552 buildings that had achieved a LEED rating as of 2007. In many cases, the owners and occupants themselves didn’t know how much energy their buildings were consuming. Only half said they would supply records on actual energy use, and only 121 ultimately delivered.

LEED gold and platinum buildings in the study had been designed to be about 37 percent more energy efficient than conventional buildings of the same type, according to the study by the New Building Institute. But they actually performed just 28 percent better. (Some of the conventional buildings in the comparison also dated back as much as a century.) A researcher on the study said smart meters to give commercial building managers real-time data on energy use would cost $2,000-$5,000, with the likelihood of a rapid payback. But few building owners make the investment.

In a recent article, Environmental Building News didn’t quite suggest that LEED “rip plaques off the walls of underperforming buildings” but said
Most builders tend to exaggerate the cost and overlook the rewards of building green.
that “to continue leading, USGBC needs to reserve the label ‘LEED certified’ for buildings that have their actual performance documented…” Tom Hicks, a vice president at USGBC, replied that LEED now requires buildings to earn at least two points, out of a possible 69, for energy and atmosphere improvements, and it weighs those points more heavily in its overall rankings. Hicks said USGBC is also working to address a separate criticism that LEED ignores how much energy it takes to get people to and from a building.

While LEED plays catch-up, some state and local governments are working to move sustainable design out into the broader construction community. Boston has implemented a green building code requiring buildings over 50,000 square feet to meet the standards for LEED certification. Portland, Oregon, has developed an ambitious high-performance building program — but can’t go beyond state building codes to make it happen. Instead, the city is now considering a “feebate” system, with new construction permit fees being assessed per square foot, and rebated to buildings that achieve LEED gold and platinum ratings. To address weaknesses in LEED, the buildings would also have to reduce energy use by 35 percent below comparable conventional buildings to qualify for rebates. Building code changes focused on energy are likely to become more widespread because of a residential green building standard approved early this year by the International Code Council, for adoption by state and local governments.

Some jurisdictions are also pursuing a market-based strategy with the idea that simply making people think about how much energy they use will change behaviors and real estate values. In California, commercial buildings now must report their annual energy use to the state, and starting next year they will also have to disclose that information, along with a building’s Energy Star rating, to potential buyers and tenants. In Washington, D.C., large commercial buildings will soon have to make their energy performance a matter of public record. In effect, buildings will sell or rent, like cars, with an estimated miles-per-gallon label.

Most builders have so far missed the economic implications of such changes, tending to exaggerate the cost and overlook the rewards. In
There’s a sweet spot where going aggressively green gets to be cheaper than a more modest approach
practice, the green premium may add 2 to 10 percent to construction costs. But the green label added 10 percent to the sale price for Energy Star buildings and 31 percent for LEED certified buildings, according to a 2008 study from the University of Reading. Studies also suggest that the combination of lower vacancy rates and higher rents adds up to a rental premium of 4 to 11 percent a year.

Most builders also seem to be unaware that the cheapest way to avoid wasting energy is to think about it from the start. “You need integrated building and design,” said Harvey Sachs, “with the engineers, architects, and owner talking to each other a lot earlier, instead of just throwing the floor plan over the wall to the HVAC guy and saying, ‘Live with it.’”

There’s actually a sweet spot, said Bill Browning, a partner in the sustainable design firm Terrapin Bright Green, where going aggressively green gets to be cheaper than a more modest approach. Making a building 20 or 30 percent more energy efficient than a conventional design costs more “because you’ve added more expensive measures to the building, but you haven’t cut the basic load enough that you can downsize or eliminate systems,” Browning noted. If you can make the fabric of the building do the work instead, as passively as possible, you can cut the fundamental load of a building in half and “very safely start downsizing and eliminating components of the energy system.”

But that sweet spot fades away, Browning added, as you get beyond an 80 percent improvement in energy efficiency. Then the builder is back in the position of “throwing gazillions of dollars at it, piling on renewable energy systems till you’ve got enough to make it fly.” That means even the best-intentioned buildings, like Kroon, are likely to run up against the “damned close to carbon neutral” limit, and environmental engineers like Patrick Bellew will have ample reason to keep worrying about how to get to the “zero energy” finishing line.

The rest of the building community, meanwhile, still needs to leave the starting blocks.

POSTED ON 03 Mar 2009 IN Business & Innovation Climate Pollution & Health Science & Technology Sustainability Urbanization North America 


Yale spent more than a million dollars on Kroon halls rain harvesting and storage facilities. Only an Ivy League type could waste that kinda money. If you have never been to CT you might not know that they have tons of water and the only reason that will ever change is if there is a severe drought which turns most of the North- east into a desert. Even if that happened the rain water storage unit would be empty like every other lake pond and stream. What's next, sand conservation in the Sahara??? I wonder if Yale could not think of anything better to waste $1.5 million dollars on? Green is a religion and like most religions you need a lot of faith and not a lot of common sense. Have we really evolved all that much from the societies that sacrificed virgins to sun gods and volcanoes? I don't think so.
Posted by f1fan on 04 Mar 2009

Very good article. It's about time someone shed some light on the limits of LEED, which in some cases can actually inhibit truly green building.
Posted by Alan Freund on 04 Mar 2009

For this School of Forestry (&ES) building I wonder if a (sustainably harvested) wood stove or furnace could have provided the small remaining heat load? This would have required a winter superintendent (besides a chimney preferably up the building center), which in this economy is job creation! Perhaps a teaching assistant, researcher or grad student would have liked to make a little extra and help the planet. After all, wood heating goes back thousands of years and has not destroyed the biosphere's integrity like "fossil fuels" have.
Posted by James Newberry on 04 Mar 2009

The University of Reading study (by Fuerst & McAllister) on the "green premium" mentioned in this article is available at http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1140409

Posted by A.P. Bell on 05 Mar 2009

The comment about water misses the fact that to
get water to a building entails a large energy
footprint. Kroon is not so much about "saving"
water in a wet climate, as it is about capturing
water where it falls. It is effective precisely
because there is sufficient rainfall. The cost of
pumping water is considerable. In California, water
uses 40% of peak demand electricity. Kroon is not
a religion, it is science and technology. Religion is
believing that can look the other way and that
some external force is going to lower our carbon
Posted by PGH on 05 Mar 2009

Sorry PGH, water is cheap as cheap can be in CT. In fact sewar or water treatment of waste water is probably more expensive in many areas than actual water. Your argument might have more validity if Kroon hall were actually off the water grid, but I assure they are not, and I would be extremely suprised to hear that a fire marshal signed off on undersizing inlet pipes based on the water storage dependent on mother nature. Yes Kroon hall will take less water from the local utility but I bet the actual payback in dollars will never be realized.

I am for green when green makes sense, and I am for a university striving to push the envelope of green buildings, but common sense still needs to prevail. Your comparison of Southern California with CT may be true, but it is also devoid of common sense, as anyone who is familiar with both climates could attest.
Posted by F1fan on 05 Mar 2009

This is something else I don't get or perhaps misunderstand. This building has 4 1,500-foot "open column wells" they are using to cool and heat the building geothermally.

Couldn't they just use those wells for drinking water? Wouldn't it make sense to pump the water up the well though a heat exchanger and than out through toilets instead of putting it back, presumably warmer in summer, into the same well and waiting longer for it to cool?

The rain water system and this system seem rather inefficient when coupled. Or perhaps they are rather redundant and redundant is not green. Am I missing something?
Posted by f1fan on 05 Mar 2009

The million dollar number in the first comment just seemed off, so I checked with Yale Facilities and got this preliminary analysis--and read through to get to the bottom line about payback:

Storm water quantity management systems are required for any building, and must meet state and local codes. For several reasons, we installed a system that exceeds the minimal requirements. We calculate that we paid a premium of $460,000 over the cost of a minimally acceptable system. This is primarily for systems that collect, store, treat, and pump the water to the toilets and irrigation system. It also includes credit for the reduced size of the potable water system.

New Haven is one of several older coastal cities in the northeast that is burdened with a combined sewer system. A combined sewer is one in which sanitary waste and storm water discharge are carried in the same piping system. In heavy rain, this can cause a Combined Sewer Overflow (CSO) event, which is when the volume of water and sewage is greater than the capacity of the treatment facility, and sewage is released into Long Island Sound. To correct this, the City has been running new storm sewers in a series of projects occurring over several decades. Until this is complete, there will be risk of a CSO event. Our system performs beyond a minimally acceptable storm management system by reducing the quantity of storm water discharged to the combined sewer system of the Regional Water Pollution Control Authority during a rain storm, helping to prevent a CSO event. There is no cost benefit to Yale for this, but is certainly an environmental benefit to all of New Haven, CT, and Long Island.

Many buildings in the northeast are equipped with foundation drains to cope with the abundance of ground water and to keep basements and underground spaces dry. Our building has these drains, which would normally discharge directly to the storm sewer. Our building uses this water to replenish the storm water holding tank, so that potable water is never used for irrigation, and rarely used for toilet flushing. This is what provides the benefit to Yale.

Assume we save 500,000 gallons potable water per year at approximately $2.50 per ccf: 500,000 g / 13.4 g/ccf x $2.50/ccf = $93,300 per year.

Simple payback would be about 5 years.
Posted by Richard Conniff on 05 Mar 2009


Thanks Richard,
I got my information from the link above which claims a payback of 10 years.

It would seem that the storage is more about regulating sewar flows than re-using rainwater. I feel a little better that perhaps Yale is not as dumb as I suspected. However I am worried about conneticut's public schools and basic math skills.

I am familiar with CSO events.

I thought a CCF was (748 gallons.) So 500,000 gallons would equal 668 ccf's. x $2.50 (your number) = $1671 a year.

Using your $93,300 number water would need to cost over 18 cents per gallon and flushing a toilet would cost more than a quarter.

Not sure about the payback but I still feel better understanding the reasoning behind the decisions. I am all for green when it makes sense.
Did I get the math wrong?
Posted by f1fan on 06 Mar 2009

In fairness, I hit my source with this water question at the end of the day yesterday, and he now replies, "Mea culpa! I was in a hurry and should have checked my math."
Posted by Richard Conniff on 06 Mar 2009

Fair enough. A lesser man might have run, or tried to get me censored. Now I may have to go and buy one of your books.

Consider doing a story on Fuel Cell Energy at www.FCE.com. They are in your neighborhood and I think their stuff is cool, but i suspect they get screwed over by environmental rules slighted towards solar and wind.
Posted by f1fan on 06 Mar 2009

Thanks for the article about Yale's new building and the discussion about achieving net-zero energy use and carbon emissions. Bill Browning's point about reducing loads as much as possible is spot on. Harvey Sachs' point about integrated design is also important, as shown by the experiences of developers here in Portland. Where teams stay together they can build their skills so each generation of projects gets more efficient for less cost. See for example this third-generation project that is 61% more efficient than code: www.ohsu.edu/ohsuedu/about/transformation/commons/upload/002907_CHH_facts.pdf

In general, adding solar electric capacity to a building is an expensive way to get to net zero carbon. One option would be to put the building on a long-term contract with a utility or provider of renewable electricity that has no carbon burden.

For example, our home gets all its electricity from a wind farm in eastern Oregon via a 5-year fixed-rate contract with our utility, PGE. At a bit over 1 cent per kWh added cost, it's a bargain compared to putting solar PVs on the roof, even with incentives and tax credits to reduce the initial cost.

LEED buildings can be low-energy, but the system should require transparent monitoring and reporting to ensure better performance.
Posted by Mike O'Brien on 10 Mar 2009

Mike OBrien, If you actually believe that as you say "our home gets all its electricity from a wind farm in eastern Oregon" than I have a bridge to sell you.

I am sure if you do a bit of research you will learn that a large percentage of your power does not come from a windmill. Perhaps you would check and get back to us with the facts.
Posted by f1fan on 11 Mar 2009

Thank you, Richard, for this timely and insightful article. It couldn't come at a better time for us at the National Wildlife Federation. We have exceptionally visionary leadership in place and a commitment to carbon neutrality or better for our direct emissions and beyond. We are experiencing first-hand how LEED-EB can be a step on that ladder, but that we need to be mindful of its limitations, ensuring that we greatly increase energy performance, better manage our demand, shift to on-site renewable energy generation, and better monitor performance to achieve reductions on the scale and within the timetable mandated by the science!
Posted by Julian Keniry on 12 Mar 2009

It's interesting to know that we're still striving to be carbon neutral by throwing money at profiteers such as LEED. I don't believe a building needs to prove itself through an expensive plaque. Instead, allow the visitors to take notice of the entrance of light to the building and the reusing of materials. Another idea is why expend carbon to make new materials for a new building instead of using old buildings? We're still using our conventional ideas and methods that everything needs to be newly made which takes energy!
Posted by Heather Bromberg on 18 Mar 2009

As long as we're trapped in the paradigm of building new structures to save energy while ignoring existing structures waste we're lost.

Attempting to get 100 percent carbon neutral operations on this new structure while the building across the street still burns fuel oil is simply chasing the horizon. Get what improvements you can and move on.

I wonder if there wasn't an existing building in the area that could have been rehabbed rather than putting up a new structure. My suspicion is that glory seeking exceeds function in a forestry studies building in urban CT. How much energy would have been saved be teaching forestry in a forest community?
Posted by Pangolin on 13 Apr 2009

I am for green when green makes sense, and I am for a university striving to push the envelope of green buildings, but common sense still needs to prevail. Your comparison of Southern California with CT may be true, but it is also devoid of common sense, as anyone who is familiar with both climates could attest.

Posted by jon on 16 Nov 2009

Energy Star is a subset of LEED certification - so to claim Energy Star as a better measure of energy usage than LEED doesn't make sense. The article makes some good points, and LEED does need to continue to evolve, but this author should have done better research - it perpetuates inaccurate perceptions of a peer-reviewed program that is attempting to constantly raise the bar. I have no relationship to the USGBC other than being a LEED AP.

Posted by john on 16 Oct 2010

Comments have been closed on this feature.
richard conniffABOUT THE AUTHOR
Richard Conniff is a 2007 Guggenheim Fellow and a National Magazine Award-winning writer, whose articles have appeared in Time, Smithsonian, The Atlantic, The New York Times Magazine, and National Geographic. His upcoming book, Swimming With Piranhas at Feeding Time: My Life Doing Dumb Stuff With Animals, is due out from W.W. Norton in May. He is the author of six other books, including The Natural History of the Rich: A Field Guide and Spineless Wonders: Strange Tales of the Invertebrate World. Conniff has also written for Yale e360 about carbon offsets and his proposed green scorecard for Congress and the Obama administration.



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