Paint the Roofs White
A low-cost, low-tech solution to fight climate change just won an endorsement from Energy Secretary Stephen Chu yesterday: paint the roofs white.
The idea is simple: Black roofs absorb most radiation as opposed to white roofs which reflect a good bit more. A two-page summary of a technical paper done by an old colleague of Chu's at the Lawrence Berkeley Laboratory and a commissioner on the California Energy Commission advances the concept:
Most existing flat roofs are dark and reflect only 10 to 20 percent of sunlight. Resurfacing the roof with a white material that has a long-term solar reflectance of 0.60 or more increases its solar reflectance by at least 0.40. Akbari et al. estimate that so retrofitting 100 m2 (1000 ft2) of roof offsets 10 tonnes of CO2 emission. (For comparison purposes, we point out that a typical US house emits about 10 tonnes of CO2 per year.)
So painting 1,000 square feet of black rooftop white can offset the emissions of a typical US household. Or in the big picture, as Chu pointed out, lightening the color of roads and roofs could have the equivalent effect of taking every car in the world off the road for 11 years.
Another booster for this idea has been Climate Progress' Joe Romm who wrote about the concept earlier this year and again today after Chu's comments.
California has been requiring this option for building owners since 2005, justified solely on energy efficiency gains. With carbon offsets for efficiency, there's also a possibility for owners to make money on the switch by monetizing the carbon reductions.
Storing the Sun
Last week, the Washington Post published an op-ed repeating an old mantra for those who try to dampen enthusiasm for renewable energy. The authors complain solar and wind energy are intermittent and that they are of limited use without the technology to store energy.
The search is on for breakthroughs on storage technology -- indeed the American Reinvestment and Recovery Act (ARRA) has money to support this work.
I expect to see more and more evidence to overcome these objections in the months and years ahead, but here's a start reported today in the Guardian: The Andasol 1 solar thermal plant near Granada, Spain, has the ability to provide nearly round-the-clock power using energy from the sun.
Andasol 1 features vats of lava-like salt that collect the suns rays during the day. It releases the energy by heating water and generating steam which drives turbines. The completed Andasol project is expected to provide power to 150,000 households, or 600,000 people, when it is complete in 2011. Even more important, it will help prove that the old arguments against renewables won't necessarily stand up over time.
Is Coal the Fuel of the Future?
Every one is looking for the silver bullet that will get the United States off of fossil fuels. My hunch is that we’ll pursue all of the alternatives like wind and solar, but we’ll spend a lot of resources making our dirtiest fuel, coal, less dirty. And while clean coal has its skeptics, others recognize it has a place in the mix.
I place myself in the latter camp. I’ve just penned my thoughts on why that’s the case in a guest commentary for Law360. Click here (subscription required) for the full article.
Renewable Portfolio Standards: An Avenue for Fostering Alternative Energy Projects
Government’s response to the focus on climate change must be holistic and visionary. One regulatory avenue for fostering alternative energy projects that assist in the battle against climate change is a Renewable Portfolio Standard (RPS). At its core, an RPS is a requirement that retail electricity suppliers purchase a certain percentage or quantity of renewably generated energy. Currently 25 states and Washington DC have mandatory targets for retail electricity purchases and 4 states have non-binding goals. In 2007 the House of Representatives passed an RPS, but the US Senate did not.
While most RPS programs share a common goal of encouraging the production of renewably generated energy, they vary in terms of purchase goals, timeframes for compliance and eligible technologies. Wind, solar, and geo-thermal are eligible under most of the RPS programs, but eligibility criteria varies widely with respect to other technologies and fuel sources such as bio-mass, landfill-gas, municipal solid waste, hydropower, and fuel cells. While the advantages in terms of climate change impacts associated with renewably generated energy may seem obvious (no emissions), less obvious may be the results stemming from the expansion of several states’ RPS programs into non-renewable areas.
The variety of RPS programs has allowed for many designs and policies to be demonstrated. Although not technically renewable, combined heat and power, energy efficiency and demand side energy efficiency have found their way into several of the RPS programs. By reducing demand for electricity, air emissions from current fossil fuel fired power plants is reduced to the extent that power is not needed. Arguably, the impact from reducing the demand of one megawatt of power, should have the same air emissions impact as the creation of one megawatt of renewably generated power and as such the nexus to demand management and energy efficiency in an RPS becomes self evident. Energy efficiency, demand management, and renewable energy should co-exist in an RPS and are a fundamental part of the future of our energy delivery system. As states continue to adopt and refine RPS programs, policy makers should bear in mind what this future of a sustainable energy delivery system may look like.
The US Department of Energy (DOE) has promoted (in part) a vision of the future that includes a hydrogen based energy delivery system that begins with small-scale distributed generation (DG) systems fueled by hydrogen. These DG systems provide stationary power and may also dispense hydrogen for hydrogen-fueled vehicles. DOE has funded several projects that evaluate the potential for the generation of wind-to-hydrogen, solar-to-hydrogen, geothermal-to-hydrogen and hydro-to-hydrogen, hydrogen generation systems. The common denominator is that renewably generated electricity is used to power an electrolyzer to generate hydrogen. Renewably generated hydrogen is the future. To bridge the gap to the future, however, Renewable Portfolio Standards should be developed that include hydrogen generated from fossil fuels.
One notable Wind-to-Hydrogen (also Solar-to-Hydrogen) demonstration funded by DOE is in Hawaii at the Kahua Ranch test site. There, the wind turbine has been configured to produce 48VDC, the solar array has been redesigned to produce 48VDC and each of these generation sources is connected to 24 battery cells allowing 48VDC short term electricity storage. The electricity is used to power an electrolyzer that generates hydrogen which is then stored in a low pressure hydrogen storage tank. When electricity is needed the hydrogen is used to run a 48VDC Plug Power Gencore Fuel Cell system.
Fuel cells utilize hydrogen and hydrogen-rich fuels to generate electricity and useful heat in a remarkably efficient way. A fuel cell is an electrochemical device that combines hydrogen and oxygen to create electricity heat and water. Because the conversion of hydrogen occurs without combustion, fuel cells do not produce the emissions normally associated with combustion such as carbon dioxide, oxides of nitrogen, carbon monoxide and particulates. Fuel cells are secure, reliable and high-quality power at the point of demand, with some systems able to provide high quality thermal energy as well as electric energy. Because many renewables like wind and solar produce intermittent power, a natural symbiotic relationship exists since fuel cells have the ability to generate electricity regardless of weather conditions. Fuel cells can act as a power storage technology converting off-peak generated wind and solar energy to peak power. Clean power that emits virtually no pollution during the power generation is a natural complement to intermittent renewable technologies such as wind and solar.
Introducing fuel-neutrality for fuel cells into every RPS in the short term will provide a bridge to renewably generated hydrogen. Currently, supplies of renewably generated hydrogen are scarce and the delivery systems not readily available. Simply put, today’s fuel cells that use existing fossil fuels (much more efficiently and cleaner than any combustion engines) can also use hydrogen from renewable sources as they become cost-competitive and the production and delivery of renewably generated hydrogen catches up with the demand. In this manner, the use of hydrogen from the conversion of hydrocarbons is seen as a temporary expedient to the long-term development of fuel cells. Moreover, even when they run off of fossil fuel derived hydrogen, the inherent efficiencies of the fuel cell systems, and the lack of combustion is an incremental advancement in the fight against climate change.
The vision of the future displayed in the Kahua Ranch project will only be advanced in the short term if fuel cells that utilize hydrogen reformed from fossil fuels are made a part of any federal RPS. At its core, a RPS should promote technologies that have a legitimate chance of substantially lowering pollution, reducing stress on the utility grid, spurring economic development, increasing our energy independence and fostering demand for hydrogen production and delivery systems that will eventually be renewably generated.
Initially, it may sound counter intuitive, but by allowing hydrogen generated from fossil fuels in any RPS, a critical component to generating the demand for renewably generated hydrogen will be in place and our path toward a more sustainable and energy independent future will be advanced. This model is not without precedent. New York, Pennsylvania, Connecticut, Minnesota, Colorado, Maine all include fuel cells as renewable resources regardless of the fuel supplied.
