Science and sensibility

Posted 8/21/12

I got some shocked questions recently from friends horrified by gruesome reports of birds fatally burned mid-air at a solar energy facility in the Mohave Desert. Buried in the news coverage was the …

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Science and sensibility

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I got some shocked questions recently from friends horrified by gruesome reports of birds fatally burned mid-air at a solar energy facility in the Mohave Desert. Buried in the news coverage was the fact that this was not a conventional photovoltaic (PV) array, but rather a solar thermal installation using concentrated solar power (CSP). The plant deploys 300,000 garage door-size mirrors that concentrate sunlight to boil water in three 40-story towers, producing steam for turbines that generate electricity. It’s a hybrid system that combines steam with the burning of natural gas and other fossil fuels. BrightSource Energy, which developed the $2.2 billion facility, says it can power 140,000 homes. They are planning an even larger plant with a 75-storyboiler tower near Joshua Tree National Park, but because it’s near a major migratory flight path, permitting may be delayed.

While minimizing the number of bird deaths, BrightSource promised to look for remedies, and offered to compensate with a $1.8 million donation to programs to spay and neuter domestic cats who, they pointed out factually but irrelevantly, kill up to 1.1 billion birds worldwide each year. Humans are presumably smarter (subject to debate) and more personally accountable than cats, and there are lots of statistics that help us compare feline predation with human-caused damage. Five billion birds die in the U.S. every year; up to 1 billion from flying into buildings; 67 million from pesticides; 60 million by colliding with cars; 2 million in oil and wastewater pits; up to 328,000 in wind turbines. The BrightSource website recites some of these statistics in a further attempt to distract us from the deeper question.

The question is: is CSP a sensible and environmentally responsible technology? Using solar power to create steam is a roundabout path to electricity generation, compared to PV. Google was an initial BrightSource investor, but withdrew in 2011 citing the lower costs and increasing productivity of PV. At the 2011 G-20 Summit, the chairman of Spain’s Iberdrola, one of the world’s largest electric utilities, called CSP technology “senseless,” citing CO2 emissions and the huge amounts of water used: 2,642 gallons per megawatt hour produced. In drought-stricken California, this ought to be a serious concern.

And BrightSource’s website also touts its steam production for enhanced oil recovery and mining. With BP and Chevron as major investors, could the real attraction be the environmentally disastrous use of steam in hydraulic fracturing known as cyclic steam injection, used to literally melt bitumen in oil sands production?

Ultimately, this is also a battle between utility scale, corporate controlled power generation and decentralized individual and micro-grid PV systems that are more resilient and less prone to corporate monopoly. Two-point-two billion dollars would buy about 1,000 megawatts of community-owned solar PV capacity, or solar PV installations on 220,000 homes, with no songbirds incinerated in mid-flight. As citizens and as consumers, we should demand the best possible energy alternatives. I am grateful to my bird-loving friends for steering me to a deeper understanding of what’s wrong with CSP.

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