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Energy harvesting: micro and macro
April 9, 2008
Have you heard about the thermoelectric generator for which your head can serve as its own power source for an EEG monitor? At room temperature, the internal thermopiles of the energy harvester can generate about 2 to 2.5mW, as Margery Conner reported in a post from October.
She reports today that the generator has now been augmented with solar panels to compensate for limited power-generation capability when ambient temperature approaches body temperature.
But what if you are looking to harvest solar energy on a grand scale—for example, in quantities sufficient to meet all US energy needs. The “Ask Pablo” column in Salon tackled this problem earlier this week in response to this question: “I've read in more than one place that 100 square miles of solar panels in the U.S. would meet all our energy needs. Wondering if you thought this was accurate and, if so, achievable?”
Pablo’s response, in part: “At 12,000 kWh per capita, electricity demand is roughly 3.6 trillion kWh…. To generate 3.6 trillion kWh per year, we would need to install about 12.5 billion square meters of solar panels, or around 4883 square miles.”
There must be 5000 square miles of unused desert somewhere around here, but that’s not the main problem, Pablo suggests: “A typical solar panel contains between 800 and 1570 grams of silicon…per square meter. If we assume an average of 1185 grams, we would need 14,812,500 metric tons of solar-grade silicon. The projected annual production of silicon by 2012 is 144,000 metric tons, which means that it would take over 100 years to meet our needs of silicon to make all those solar panels!”
In conjunction with Semicon West last year, I reported on the efforts of the semiconductor industry to address solar power in the post titled “Semi industry can help solar power.” But I guess the semi industry needs to pick up the pace.
Posted by Rick Nelson on April 9, 2008 | Comments (3)
