Blackout Highlights Solar Energy Potential

Officials don’t yet know the exact cause of the August 14 U.S./Canadian power outage, but it was an obvious demonstration of both countries’ vulnerability to loss of power. It’s also known that the area was under an extreme heat wave and even at 4 PM, the solar energy resource was nearly ideal, according to Segue consulting, which specializes in renewable energy.

Washington, D.C. – August 18, 2003 [] “The next morning’s newscasts stated that alternatives to our current power system are much too costly … but are the alternatives that costly?” asked Christy Herig of Segue consulting. “What about solar and efficient use of energy?” Segue consulting asks us to consider some common myths about solar energy. The greatest of these myths being the amount of land required for photovoltaics (PV). A conservative estimate of the solar energy reaching the ground in the United States is 1,500 kWh per square meter per year (actually ranging from 1200 to over 2000). With 15 percent solar-to-electricity conversion via PV usable energy is 1500×0.15 = 225 kWh/sq.m/yr. A PV array conversion efficiency of 15 percent is near the upper achievable limit today, but is certainly conservative in the long term and this figure assumes horizontally mounted collectors, hence no provision needed for row spacing or shading considerations. Assuming that hydrogen would be used as the primary energy storage medium, and using 70 percent for energy-storage-energy round trip efficiency via, e.g., fuel cells, the useable energy collectable by unit of ground surface is 225×0.7 = 158 kWh/sq.m/yr, said the firm. Providing the entire US energy requirements of 28,000 billion kWh per year would thus require a total collecting area of 17.5 million hectares, said Segue. That is less than the area presently occupied by hydroelectric power plants. Because solar technologies such as PV are highly modular and can be incorporated in common building materials such as glass and roofing products, much of this resource could be deployed on already urbanized landscapes, near points of the greatest electricity use. It would only take a small percentage — 15 percent of urbanized land — consisting of buildings, highways, parking lots, exclusion zones to build the PV power structures, said Segue. “In terms of the cost of such a huge deployment of solar generation capability, it will, no doubt, be staggering,” said Herig. As society, we could certainly afford it, says Herig, who offers the following scenario. The consulting firm asks, what if, starting in 1973 (the oil embargo year), the U.S. had invested the amount it spends yearly on fossil fuel subsidies — US$40 billion — in deploying PV power plants at market price? The firms notes that back in 1973, $40 billion in current dollars was worth — $10 billion and PV installations cost was $35/Watt; assuming that massive and consistent purchases would have induced yearly cost reductions of five percent per year, down to a minimum achievable cost of $1.50/Watt; further assuming a 10 percent overhead on initial investments, reinvestment of 70 percent of systems’ revenues in new PV systems (breeder effect), systems’ output degradation of once percent a year, and systems’ maximum life span of 30 years, the total installed PV capacity in the US today (2003) would be equal to 64 GW and growing at an exponentially accelerating rate of eight GW per year. “Continuing under these assumptions, PV would be in a position to provide 100 percent of the US energy consumption by 2044,” said Herig. “However, the investment was not made, and a truly robust energy infrastructure is only achieved with both diversity of fuel resources and technologies.” “Investments should be made in all resources with a plan to decrease fossil fuel dependency to a level of equal to the U.S. production and increase investments in both renewable technologies such as wind, solar, biomass, while making sure that future investments in the electricity grid incorporate design features amenable to renewable technologies,” said Herig.
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