Wind power is only available when the wind is blowing. Similarly, cloudy skies means less solar power. The use of renewable energy resources for generating electric power is limited by the fact that renewable resources are not always available. This is why renewable energy is commonly described as an “ intermittent ” energy resource. Intermittency, or “ variability,” is renewable energy’s Achilles heel. Intermittent resources are considered potentially problematic because the output from individual units may vary widely in response to variation in available wind and solar energy, which can only be predicted to a moderate degree of accuracy. The assumption seems to be that non-renewable energy resources – namely, fossil fuels – are not intermittent. If the past three months have taught us anything, it is that not all fossil fuels are created equal in terms of availability. Unlike coal and fuel oil, natural gas cannot be stored […]