I was reading this Blog post on Depleted Cranium in which the spin of an Italian energy company is being highlighted. It has built what it calls a ‘combined cycle’ solar/gas power plant. The gas part has a capacity of 752MW of electricity production, while the solar part is good for 5MW. Peak. In practice, it should average around 1MW.
A megawatt seems like a big number, and it is in the domestic electrical sense. But let’s consider a different unit for power. One megawatt is roughly 1,350 horsepower. So the solar section of this plant, with its 30,000 square metres of solar collectors, is good for the same amount of power as three V8 Supercars, four or five sports cars, or a dozen family cars.
I need to do conversions like this myself from time to time because energy and power units are something I don’t have an instinctive feel for, unlike mass and length and velocity.
And I find it instructive to remember that chemical energy (eg. that in combustible fuels) is far more densely packed than electrical energy storage devices of all kinds, and that chemical energy using devices generally have much more power available to them than electrical energy using ones.
The maximum power produced by a 100 horsepower car engine is equivalent to a 240 volt domestic power source producing 310 amps. Most domestic power points are rated (in Australia) at just 10 amps.