IB recently interviewed UW-Madison adjunct professor John Nelson about the sustainability movement, including “green-building” concepts. Part of the interview was presented in the August edition of In Business magazine, where Nelson recommended a more pragmatic view of sustainability. Nelson describes himself as a “green” pragmatist (not a skeptic), and he gave us plenty of things to think about, IB decided to present his views more fully (this week and next).
John Nelson took a few moments to ponder the quote, and whether the statement made him roll his eyes or say, “Yes, but …”
The quote, uttered by Rick Fedrizzi, president and CEO of the U.S. Green Building Council, during the 2009 Green Build conference, is as follows: “We are actually at a leverage point where green building no longer needs to be proven, but implemented. The potential of green building, when green design, green technology, and green materials come together, is undeniable.”
Nelson is solidly in the “yes, but” camp, because in his view, the environmental footprint associated with a building has five phases, and its construction is the smallest part. Of the five phases — making, using, operating, changing, and demolishing, Nelson said the majority of ecological footprint occurs in the operating and using. So while building considerations are important, they are not nearly as important as building use — which is why Nelson views himself as a sustainability pragmatist.
“You’ve heard of the glass is half-full, or the glass is half-empty?” he asks. “The optimist says the glass is half full, the pessimist is half empty. The pragmatist says the glass is twice as big as it needs to be. I’m a pragmatist. Just look at the glass and what’s in it, and tell me what you’re trying to get accomplished with it.”
Nelson was critical of IB’s coverage of the U.S. Bank Plaza’s success in the green-built category of our Commercial Design Awards. The article touted the retrofit’s reduction in peak-hour energy usage, rather than the one-third reduction in energy usage, and Nelson definitely places more value on the latter. With buildings, the key sustainability metric is eROI, or energy return on investment, and based on that, Nelson was more impressed with what was done.
“Yeah, this is good stuff,” he said. “I’m surprised. They must have done more than just cut the front off of the building.”
That they did, including the replacement of the building’s major operating systems, but don’t try to sell him on the extensive use of glass for natural “day lighting.” His research into day lighting in large, deep buildings is that it has minimal impact on lighting and energy use, and there is a “consequential penalty” for extra heat loss and gain from windows in Wisconsin’s harsh and dark winters. He views the plaza’s “glass box” as one whose skin loses energy in the winter, and absorbs heat in the summer, at multiples of the rate of more efficient skins.
“The challenge still is that that is a glass box,” Nelson said, “and this is a climate with extreme conditions.”
Even if the building is correctly oriented with the sun? “Sure,” he responded, “because, what the sun does for you when it helps is way offset by what it does against you when it hurts, or when it’s not there. Generally, people tend to scale their thinking about residences to large commercial buildings. So people tend to think of passive solar energy in a home, and then they think, ‘Well, why don’t we do that in large commercial buildings?’ It just doesn’t scale. The energy profile is different. It’s an apples-and-oranges kind of comparison. Technologies and concepts that work in homes don’t necessarily scale to large commercial buildings.”
The Challenge with Renewable Energy
In Nelson’s view, the challenge with renewable energy is that it’s very low-grade, very diffuse, and intermittent. The Holy Grail has been about making renewable energy become cost effective and therefore more commercially viable, but Nelson believes this is the wrong path to follow.
“My specific answer to that is that it’s less about renewable energy becoming cheaper and more about conventional energy becoming more expensive,” he opined. “I say that because at first physical principles, the energy we use right now is a combination, at least for fossil fuels, a combination of stored solar energy and geothermal energy, and it took hundreds of million of years to create. We use it rather quickly, and when one thinks about that energy source, for which we have a very refined system of technology to use it, ranging all the way form an oil well to an internal combustion engine, or a boiler or something like that. When you think of the limits to substituting a renewable system with those early characteristics we listed — intermittency, low-intensity, diffuse — those are the opposite of a block of coal or a gallon of gasoline. It’s not a technology limitation; it’s a fundamental first-principles limitation. You’re dealing with something different.
“Inherently, low-grade energy systems are more expensive to deploy. My answer to your question about when will it be come commercially viable, it’s not when there is some brilliant, disruptive technology breakthrough, it’s when the cost of what we’re currently using goes up a lot.”
Such as when we experienced high gasoline prices two summers ago?
“That’s the very edge of it,” Nelson stated. “So this term eROI, in order to use a gallon of gasoline, burn a gallon of gasoline in your car, there needed to be, for you to have transportation that day, it took a lot of energy expenditure to make that possible. The car had to be made. The oil had to be pumped out of the ground, it had to be refined, it had to be transported, shipped, all that stuff.
“How much energy do I need to spend in order to get a useful piece of energy? The answer is [an eROI] of somewhere between 60 and 100 to 1. So for every unit of energy I spend making a fuel source that I can use, I get between 60 and 100 units of energy use. So when I squeeze that handle for the gas tank, theoretically, if you’re in a big truck, and fill the tank between 60 and 100 gallons, it would have taken the equivalent of 1 of those gallons to make that tank of gas.
“Renewables are far lower than that,” he added. “Renewables are on an order of magnitude lower than that. So it takes a lot of energy to make a solar collector, and I make about 60% of my electricity with solar PV (photovoltaic), so it takes a lot of energy to make a solar PV panel. The factory that makes the solar PV runs on conventional energy. The factory that makes the gallon of ethanol runs on electricity and natural gas. It doesn’t run on ethanol.
“That’s the challenge with the cost-effectiveness because that first scientific principle, these renewable sources never approach, even closely, energy return on investment similar to fossil fuels.
For green building, he noted that the best metric for energy savings, the equivalent of miles per gallon, is called the Energy Utilization Index (EUI). This is the total energy used annually per square foot of area.
For water usage, which is more driven by occupancy than physical area, the applicable metrics are total gallons or gallons used per person.
Next week, a more in-depth look at whether the goals of climate change legislation are realistic.
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