A June 1st article at CNN Money profiled large-scale solar technology projects. Public schools in central New York are adding solar panels to reduce their expenses, with the assistance of a state program. And according to The Discovery Channel, even the Vatican is adding photovoltaic cells to the Paul VI auditorium! Is there a solar revolution occurring?
According to Travis Bradford, there is. The author of Solar Revolution: The Economic Transformation of the Global Energy Industry, is the president and founder of the Prometheus Institute for Sustainable Development. The book was published by The MIT Press.
Bradford traces the history of energy generation and its ties to economic development. He points out that historically, natural resource depletion led to the collapse of civilizations, beginning with deforestation and its attendant soil depletion. Currently, our world is at "peak oil": we've reached the maximum amount of oil that we can extract from the earth and now rates of production will decline.
Conventional energy generation is at risk because of peak oil, potential supply disruptions (i.e., the current war), and the aging infrastructure of the electrical grid. He cites the environmental problems of "stored sunlight" alternatives such as coal, oil, and natural gas. He also analyzes current alternative technologies such hydroelectric dams; nuclear, wind, biomass, geothermal, and ocean power; and hydrogen fuel cells. He points out that these alternatives each need to be deployed on a large scale.
Additionally, the problem of intermittency – i.e., spikes in demand, whether expected or unexpected — is not solved with large-scale alternatives. Demand spikes can lead to problems such as rolling brownouts, and currently is dealt with by expanding the grid. The problem with expanding energy production to meet intermittent demand is that energy is underutilized during the remaining low-demand times. This, of course, is a wasteful use of limited resources.
Three key continua exist in analyzing methods of creating power from the sun: passive-active, thermal-photovoltaic, and concentrating-nonconcentrating. Passive solar energy is usually created usually through building design, such as in the design of a greenhouse. Active solar energy, on the other hand, is stored or converted to other applications. These applications are thermal or photovoltaic, the second key continuum. Thermal solar energy applications use derived heat in, for example, rooftop solar water heating systems. Photovoltaic applications, or PV, capture light energy onto a specific material which creates a direct electric current. Finally, concentrating systems focus sunlight using mirrors or lenses. Nonconcentrating systems are simpler and easier to maintain.