The Solar Option
December 12, 2012
Over the past several years there have been over 25 studies which, in aggregate, conclude that the USA and the entire planet could meet most or all of its energy from a combination of already-commercialized ‘high value’ energy efficiency and renewable energy. Solar energy promises to be an important part of that mix.
Solar technologies (rather than passive solar building design) come in four distinct technology clusters, of which two are absolutely economic. Solar daylighting, which brings full-spectrum sunlight into a building without the heat, is being used in residential, commercial and industrial buildings including Best Buy and Walmart. Not only does this technology zero out electric lighting needs during the day, even on the cloudiest days, but customers buy 11% more the day they are installed in retail stores, students are sick less in solar daylit schools, and employees are more productive – all verified in peer-reviewed studies.
Solar water heating and solar space heating and cooling is also economical. In my own home, my solar water heating system added $6+ to my second mortgage and saved me $22+ per month on my utility bill – and for 10 months met 100% of my hot water load, and 50% in the two cold winter months. One million US buildings have solar water heating, compared to the City of Tokyo which alone has one million buildings with solar water heating. The International Energy Agency 2004 study says the world has 70 GW-thermal equivalent, a huge generation contribution. Solar thermal-driven air conditioning systems are now on the market and thousands of buildings have solar thermal radiant floor heating, radiator systems, and hybrids with geothermal heat pumps. Solar thermal systems are performance-certified by the non-profit Solar Rating and Certification Corporation (SRCC).
Concentrated solar power is in a revival, with trough systems in the lead worldwide with the recent 64 MW system in Boulder City, Nevada and Ivanpah solar power tower being built using mirrors on 3,500 acres of desert to generate 390 MW. The desert is sunny 330 to 350 days per year, making it an ideal location for concentrated solar. In concentrated solar, the move is towards molten salts which can store heat on non-sunny days and overnight to create steam to turn a steam electric generator or a heat engine such as a Stirling, Brayton, or an Organic Rankine Cycle engine, used for over 30 years in the geothermal industry. Heat engines do not require water which makes them ideal for arid applications. A 2005 report by national laboratories on behalf of the Western Area Power Administration concluded that the practical accessible solar resource in the southwest was 6,800 GW -- nearly seven times the current total US electric generation.
Solar photovoltaics, the direct conversion of sunlight to electricity, gets the most news coverage and policy attention. We have used solar photovoltaics since the 1960’s on space satellites and most are still powered by solar today, as is the International Space Station. The US military is utilizing solar blankets (for field phone charging) and panels at Forward Operating Bases in Iraq and Afghanistan. And photovoltaics is commonly used in infrastructure from roadside sign boards and overhead sign lights, to phone switches and cellular towers, to remote or redundant on-site electric generators. These systems are absolutely cost-effective when measured against diesel generators and far more reliable than the electric grid. Most of these systems are tied to battery banks and in many cases hybrids with small wind. Aside from absolute electric reliability, they have superb electric power quality, meaning no surges, sags or transients that harm digital solid state equipment.
Innovations in photovoltaics in buildings are in full swing, with companies offering solar roofing shingles, novel roof and ground-mounted hardware, peel-and-stick panels for metal-seamed roofs, and even solar laminated–on-building roofing membranes. The industry is standardizing installations, solar panels (modules) are UL certified, and installers are also certified through the North American Board of Certified Energy Practitioners (NAPCEP). Larger photovoltaics systems on building rooftops now routinely reach 5 MW; larger utility-scale 50 MW systems are also being deployed throughout the United States. Companies now offer power purchase agreements to end users so the private sector builds the project at their own expense, signs a long-term power agreement, and the customer just buys the electricity. The federal investment tax credit and accelerated depreciation, State System Benefit Funds and State Renewable Energy Portfolio Standards, and State Clean Air Act SIP funds and solar energy credits (SRECs) drive the cost down to competitive levels, with small escalators for operations and maintenance, smaller increases than those experienced by traditional utility companies.
The Solar Foundation, in partnership with BW Research and Cornell University, released the full National Solar Jobs Census 2012 report on November 14, 2012 and reported that the U.S. solar industry employs 119,016 Americans. This figure represents the addition of 13,872 new solar jobs and a 13.2 percent employment growth rate over the past twelve months. During the same period, employment in the overall economy grew at a rate of 2.3 percent (according to the Bureau of Labor Statistics), signifying that 1 in 230 jobs created nationally over the last year were created in the solar industry. According to the Energy Information Administration, solar electricity production facilities— including photovoltaic (PV) and concentrating solar power (CSP) — produced a total of roughly 1,800 GWh in 2011, a 50% increase over 2010.
The media has given Americans the impression that all solar is manufactured overseas. The majority of solar daylighting systems are manufactured in the US, as are the majority of solar water heating collectors. The US has over 50 photovoltaics manufacturing plants including recent large output assembly lines in Hattiesburg MS, Atlanta, GA and in Somerset, NJ, just to name a few. And US jobs for installing all this solar are also increasing: at of the end of September, 2012 installers employed 57,177 people in the U.S., a 17.5 percent increase over 2011.
We are just at the early adolescence stage of solar technologies. We can soon expect to see new materials and processes that enhance energy concentration and allow solar material to be applied as a paint or as a roof sealant or window laminate. And in terms of energy generation capacity, a 2005 study by Navigant funded by The Energy Foundation found that just the roof space that has good solar access with no other uses could supply nearly one-third of current US electricity. In other words, we have only seen the beginning.
The views expressed in these essays are those of their respective authors and do not necessarily reflect the views of Physicians for Social Responsibility.