In recent years, there has been more and more talk of a transition to renewable energy on the grounds of climate change, and an increasing range of public policies designed to move in this direction. Not only do advocates envisage, and suggest to custodians of the public purse, a future of 100% renewable energy, but they suggest that this can be achieved very rapidly, in perhaps a decade or two, if sufficient political will can be summoned. See for instance this 2009 Plan to Power 100 Percent of the Planet with Renewables:
Timescale and lack of funds are by no means the only possible critique of current renewable energy plans, however. It is not just a matter of taking longer, or waiting for more auspicious financial circumstances. It will never be possible to deliver what we consider business as usual, or anything remotely resembling it, on renewable energy alone. We can, of course, live in a world of renewable energy only, as we have done through out most of history, but it is not going to resemble the True Believers' techno-utopia. Living on an energy income, as opposed to an energy inheritance, will mean living within our energy means, and this is something we have not done since the industrial revolution.
Technologically harnessable renewable energy is largely a myth. While the sun will continue to shine and the wind will continue to blow, the components of the infrastructure necessary for converting these forms of energy into usable electricity, and distributing that electricity to where it is needed, are not renewable. Affordable fossil fuels are required to extract the raw materials, produce the components, and to build and maintain the infrastructure. In other words, renewables do not replace fossil fuels, nor remove the need for them. They may not even reduce that need by much, and they create additional dependencies on rare materials.
Renewable energy sounds so much more natural and believable than a perpetual-motion machine, but there's one big problem: Unless you're planning to live without electricity and motorized transportation, you need more than just wind, water, sunlight, and plants for energy. You need raw materials, real estate, and other things that will run out one day. You need stuff that has to be mined, drilled, transported, and bulldozed -- not simply harvested or farmed. You need non-renewable resources:
• Solar power. While sunlight is renewable -- for at least another four billion years -- photovoltaic panels are not. Nor is desert groundwater, used in steam turbines at some solar-thermal installations. Even after being redesigned to use air-cooled condensers that will reduce its water consumption by 90 percent, California's Blythe Solar Power Project, which will be the world's largest when it opens in 2013, will require an estimated 600 acre-feet of groundwater annually for washing mirrors, replenishing feedwater, and cooling auxiliary equipment.
• Geothermal power. These projects also depend on groundwater -- replenished by rain, yes, but not as quickly as it boils off in turbines. At the world's largest geothermal power plant, the Geysers in California, for example, production peaked in the late 1980s and then the project literally began running out of steam.
• Wind power. According to the American Wind Energy Association, the 5,700 turbines installed in the United States in 2009 required approximately 36,000 miles of steel rebar and 1.7 million cubic yards of concrete (enough to pave a four-foot-wide, 7,630-mile-long sidewalk).