Large-Scale Green Power: An Impossible Dream?

Chasing after windmills and photovoltaics could well be the stuff of fiction.

Wind and solar cells (photovoltaics or PVs) are two renewable energy technologies that many hope will eventually provide the United States with massive amounts of clean, sustainable electric power for the indefinite future. Indeed, it is often suggested or implied that the United States can look to a future where most, if not all electric power can be provided by wind and photovoltaics [1, 2]. But careful analysis shows that will not be possible unless consumers are willing to pay five to 10 times what they pay for electricity today.

Both wind and sunlight are unpredictable and intermittent. The wind blows at different speeds at different times in different places. Sometimes the air hardly moves. Sunlight is available only in the daytime; it is weak in the morning and late afternoon and is dramatically reduced by cloudiness, which is location-dependent and unpredictable. That's nature, as we all know from our everyday experience.

On the other hand, the public requires electricity on demand, which requires dispatchable electric power generators. Lights must go on when the switch is flipped, the computer must start and operate steadily on demand, etc. Very few people would be willing to operate their homes or businesses only when the sun shines or the wind blows. So the question becomes one of how to accommodate the inherent mismatch between what we demand in electric power availability and what nature provides in light and wind, which are inherently not dispatchable [3, 4, 5].