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Solar Panels: John O'Donnell on Nathan Myhrvold, Steve Levitt, and Steve Dubner

John O'Donnell:

Error-riddled ‘Superfreakonomics’: New book pushes global cooling myths, sheer illogic, and “patent nonsense” — and the primary climatologist it relies on, Ken Caldeira, says “it is an inaccurate portrayal of me” and “misleading” in “many” places: Yes Nathan is howlingly off base.  Not because solar panels are (whatever cover with whatever relative emissivity), but because solar panels, like wind turbines and solar thermal power plants, eliminate the emission of CO2 which would otherwise occur from electricity production.

As Ken Caldeira so grippingly points out (and I tried to make graphically clear in my Stanford talk last year) , each molecule of CO2 released thermal energy when it was formed — that’s why we formed it.  In the case of electricity generation, about 1/3 of its thermal energy went out a wire as electric power, the rest was released promptly as waste heat.  But each molecule of CO2, during its subsequent lifetime in the atmosphere, traps 100,000 times more heat than was released during its formation.

A hundred thousand is a big number.  It means that running a handheld electric hairdryer on US grid electricity delivers a planet-warming punch comparable to [the heat directly emitted by] two Boeing 747s operating at full takeoff power for the same time period.  The warming is delivered over time, not promptly, but that don’t matter; the planetary heating is accrued, the accountants would say, the moment you hit the switch.

The thermal energy balance for a solar panel runs vastly in the other direction.  If our solar panel is pure black, and 14% efficient, then for each kWh of electric power that comes out, there are 7 kWh of heat that were absorbed and radiated.  But each kWh it generates it eliminates the release of 1.4 pounds of CO2, which during its lifetime in the atmosphere will absorb 210,000 kWh of heat.  So the energy balance for the solar panel (when it’s connected to the US grid) is about NEGATIVE 209,993 kWh(heat) per kWh(electric) — since some fossil power plant somewhere is being turned down based on its generation. And hey, if it’s blue instead of black, that might increase to negative 209,995 kWh.