Almost very article on solar power concludes with the rather obvious fact that the sun doesn’t shine at night (or even on some days). Almost very article on wind energy gives prominence to the fact that the wind doesn’t always blow. Some articles on electrical production point out that there is almost no remaining opportunity for new dams to generate electricity.
Put those three things together and you have the beginning of the end of our dependence on foreign oil.
One of the wonderful things about being a continent-spanning country is that we are not all under the same weather pattern at the same time. We have a variety of climates that create a variety of opportunities. No one region has to be energy independent in order for the country to be energy independent as a whole. We just have to think out of the silo.
According to the US Department of Energy, about 7% of US energy came from hydropower in 2006. The limiting factor on the amount of energy we can get from hydropower is the amount of water flowing into the impoundments behind the dams. During periods of peak demand, the water is drawn down quickly; when demand slackens, the water can build up again. But, in general, we use the total amount of water available over the course of a year except that a minimum downstream flow has to maintained for ecological reasons and water can only be allowed to build to a certain height behind the dams for safety reasons before it must be released.
Suppose that we had a lot of new solar capacity. We would get our maximum output from that capacity during the day which happens to be the time of peak demand. All things being equal, we would then be able to turn the dams down to minimum flow during the day since the solar energy would meet the demand. Then we’d have more water to use for generation at night when the sun isn’t shining. Note that the effect is that we already have a mechanism which is the equivalent of being able to store solar energy.
Same thing goes for wind: if it’s blowing, the water builds up behind the dams; if it’s not blowing, we release the water from the dams. Effectively we’ve bottled the wind.
In fact, we can hold the water until the time when both the sun doesn’t shine and the wind doesn’t blow.
In practice we’d run the dams during the day and avoid burning some natural gas (accounted for 20% of our electricity in 2006) and oil (2%). We’d just hold back enough water to meet nighttime demand because that’s when we’ll all be charging our electric and plug-in electric hybrid vehicles.
All we need is the will to rebuild our national electrical grid so that energy can flow from where it’s currently abundant to where it’s currently needed. We don’t need expensive ways to store solar and wind power to make those technologies practical. Our existing dams are that storage mechanism. Our size and the variability of weather over our expanse are another buffer.
But we need to rebuild the grid and then we need to add regionally appropriate power-generation capability to it. Wind and solar can be done much more quickly than new nuclear capacity (which ought to be built as well for baseline supply).
All of the presidential candidates agree that our dependence on foreign (meaning Middle Eastern) oil is both an economic and a national security danger. To a greater or lesser degree, they think that burning fossil fuels is an environmental threat. One of them should take the bold step of proclaiming that, if he or she is elected president, the nation will be a net exporter of oil in fifteen years. Details to follow – but rebuilding the grid is the immediate first step.