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Posted: Jan 24, 2013
Carbon Cycle 2.0 initiative seeks alternative ways to reduce emissions
(Nanowerk News) History is rife with new inventions that initially seemed beneficial but later turned out to have unforeseen environmental consequences. Chlorofluorocarbons, for example, were viewed as miracle chemicals and used in huge amounts starting in the 1960s in a myriad of ways, from refrigeration to firefighting. Then they were found to be depleting the earth’s ozone layer.
What if we could assess technologies for hidden environmental dangers before they hit the marketplace? And even better, what if the technology’s positive impacts could be maximized and negative ones minimized before the technology is even deployed, as part of the development process? The Emerging Technology Assessment (ETA) Team at Lawrence Berkeley National Laboratory (Berkeley Lab) is working to do just that, using energy and environmental analysis techniques to estimate potential impacts of early-stage technologies.
“We’re trying to identify environmental, economic, social and other impacts of a technology well before it actually exists in the world,” said Jeff Greenblatt, a Berkeley Lab staff scientist who heads the ETA team. “My greatest hope is that we deploy technologies that are beneficial to humanity and also have the smallest possible environmental footprint, and we make decisions fully informed as to what those footprints are.”
The team, consisting of about a dozen Berkeley Lab researchers in the Environmental Energy Technologies Division, has conducted analyses of technologies as diverse as solar photovoltaics, drought-resistant biofuels, carbon sequestration and electrochromic windows. New projects they are pursuing in collaboration with other divisions at Berkeley Lab include artificial photosynthesis, energy storage technologies and hybrid vehicles for the developing world, among others.
Their comprehensive analytical approach was developed as part of Berkeley Lab’s Carbon Cycle 2.0 initiative, which seeks to stimulate multidisciplinary research to accelerate the development of a carbon-neutral energy system.
“ETA’s strength is in pulling together a multitude of analytical tools, including geographic information systems (GIS), lifecycle analysis and scale-up scenarios, and asking questions that no one else is asking,” said Don DePaolo, head of Carbon Cycle 2.0 and also an Associate Lab Director for Energy and Environmental Sciences. “Berkeley Lab scientists are working on such a wide variety of clean energy technologies. ETA can help ensure that those technologies have the desired effects not just in the lab but in the marketplace.”
For example, ETA team members Arman Shehabi and Nicholas DeForest led an analysis of an electrochromic window glazing, which can switch between transmitting and blocking infrared shortwave solar radiation while allowing visible light to pass, so that the change is unnoticeable to the building occupants. This capability can ease the heating and cooling needs of the building without compromising the aesthetic or daylighting benefits of the windows. Berkeley Lab scientists led by Delia Milliron at the Molecular Foundry have been working on materials to optimize both the transmitting and blocking capabilities.
Berkeley Lab scientists are working on electrochromic window glazing, which can switch between transmitting and blocking solar radiation.
For their analysis Shehabi and DeForest selected 16 U.S. cities to represent most of the climate profiles in the country and chose two building types, a commercial office and a mid-rise residential building. Taking into account heating and cooling loads for different building types in different climates, they modeled the building energy demand with electrochromic windows for a wide range of different transmitting and blocking performance targets. Their results show that in nearly all U.S. regions the energy savings potential was larger when optimizing the blocking state (which reduces cooling needs) than the transmitting state (which reduces heating needs). These results were published recently in the journal Buildings and Environment.
“This type of early-stage feedback can help the designers of these systems know where to focus their efforts and help them establish critical performance milestones,” said Shehabi. “Rather than just trying to make the best performing cell overall, this tells them that optimizing the blocking state is necessary to outperform competing technologies and provide the greatest overall energy savings.”
In another analysis, Pei Zhai, Dev Millstein and other Berkeley Lab researchers looked at the impacts to human health, land use, weather, climate and greenhouse gas emissions associated with large-scale photovoltaic (PV) installations in 10 states. They found, for example, widely varying levels of avoided carbon dioxide, nitrogen oxide and sulfur dioxide emissions from state to state, depending primarily on the state’s main energy source (coal, natural gas or other). These results were published recently in the journal Energy.
“Our study shows policymakers that they shouldn’t focus only on locations with abundant solar resources,” said Millstein. “Government subsidies based not just on installed capacity, which is currently the case, but also on the potential for avoided emissions may lead to larger reductions in regional pollutant and greenhouse gas emissions.”
For new technologies the ETA team often starts with a life-cycle energy, water, or materials analysis to understand the technology’s impacts when scaled up, and then uses other models as needed, such as an atmospheric chemistry model or energy system model. “We look at all the inputs, such as energy, water, materials, land use, and so on, through the product’s entire life, from the production of raw materials through end-of-life disposal and recycling,” said Greenblatt. “Rather than having a model we apply to everything, we use what models are available as questions demand them.”
Afterwards they may run a sensitivity analysis to see how their assumptions affect the results. Next, the team is working on expressing all the impacts in terms of cost. “While on the one hand I’m reluctant to combine all the pros and cons into a single number, we realize it’s important to be able to put things on equal footing to understand the tradeoffs,” Greenblatt said. “If you can put a dollar figure on it, it at least puts it on a relative scale. Monetization will help to make the conclusions more useful to policymakers and others.”
While they will continue to work with research teams within Berkeley Lab, the ETA team is also starting projects with groups and companies outside the Lab.