Consumption Growth 101 Why Solar Power Won't Cut It

Why Solar Power Won't Cut It

Energy security in a post-Fukushima world will be interesting. After three serious accidents, (Three Mile Island, Chernobyl and Fukushima), public opinion is hardening against nuclear power. Elected governments are being forced to follow. Would you eat beef from Chernobyl or vegetables from Fukushima? Me neither.

If nuclear power is unacceptable and fossil fuels are going to run out, will renewable energy save the day? A few straightforward calculations show that such a prospect is fanciful.

Nevada Solar One is a large scale solar thermal power station. It is 1.6 square kilometres in area and produces around 134,000MWh per year. Thus the overall energy production of the plant is 82.7kWh per square metre per year. Note that this includes all the sundry space required, not just the area of the collectors. Would it be possible to scale up Nevada Solar One to supply the entire world with energy?

Global energy consumption in 2010 was in the order of 131,400TWh. Divide 131,400E12 by 82.7E3 to get 1.59E12 square metres, or 1.6 million square kilometres. Therefore, with no speculations that may or may not prove correct, based on data of what is known to be possible, an area of 1.6 million square kilometres of solar power stations (one million Nevada Solar Ones) would be required to supply global energy demand.

Such a project couldn't be completed overnight. Thirty-five years might be a reasonable schedule. Let's say that a plan was embarked upon to convert the entire world to solar energy over the next 35 years using currently proven technology. Problem is, global energy demand is growing at about 2 percent per year. At that rate, by the time the project was finished the energy demand has doubled and therefore the land area required has also doubled.

Three million square kilometres is the size of Australia.

The Jevons Paradox demonstrates from centuries of data that energy consumption efficiency improvements will most likely increase demand rather than reduce it.

Generation efficiencies will certainly improve. The laws of physics won't however and hence all efficiency improvements have limits. All the while that generation efficiencies are improving, the demand continues to double every few decades.

In other words: To convert the whole world to solar power, start by setting aside land equal to the size of Australia.

What about wind, wave, hydro power and biofuels? They are actually all derivatives of solar energy. They help, but not much. What about geothermal power? Most geothermal energy is stored energy, not renewable energy, and inaccessible anyway. The amount being continuously renewed is too small even if it could all be tapped. What about tidal power? Smaller still. The largest renewable energy opportunity is solar power and on the scale of global energy demand it just won't cut it.

July 2011