Columnist Dawn Stover has an intriguing, but ultimately misleading, article in the Bulletin of the Atomic Scientists arguing that no energy source is "renewable"–because the equipment to harvest them is not also renewable, or because they are imperfect in some other way.
Permit me to disagree. Here's a hint: "renewable energy" means "renewable energy sources."
Let's examine the difference between an exemplary renewable energy source–the kinetic energy of the wind that is used to generate electricity or for other purposes–and a typical fossil energy source.
Ms. Stover might have argued that all energy sources are renewable–the only difference is time scale. Ultimately, the fossil fuels that we retrieve by mining or drilling will be "renewed"–we only have to wait a few hundred million years. But instead, she chooses a confusing path, at times talking about how the energy source isn't immediately renewed (geothermal) or competes with other needs such as food (biomass) or, in the case of wind, the materials that go into wind turbines.
Still, the difference between wind, a renewable energy source, and a fossil fuel that is not renewable, is pretty clear. To understand it, all you need to do is park at the base of a wind turbine and wait for a train full of fuel to pull up, or look around for a pipeline delivering fuel. Whoa! There isn't one. Why? Because wind power produces energy without using fuel–its fuel is the kinetic energy contained in the wind that causes the turbine's rotor to spin.
This year, U.S. wind farms will generate enough electricity to power the equivalent of roughly 11 million average homes. Next year, they will do the same, or more. And after they do, the wind resource will remain the same as it was before–because it is renewable.
In addition to mentioning materials such as steel and cement, which are not renewable but which we are unlikely to run out of in the foreseeable future, Ms. Stover focuses on the rare earths used in wind turbine generators. I've blogged about this previously. To make a long story short, the central rare-earth problem (China has the world's largest deposits and wants to restrict them for domestic use) is in the process of being solved. As their price has skyrocketed, new producers have come online, and manufacturers of products like wind turbines and hybrid cars are working to reduce the quantity of rare earths their products need.
Still, that's a side issue. Wind energy is the quintessential renewable energy source–renewed every day as the sun heats the atmosphere and drives our weather systems. As long as the sun shines, the wind will be there, ready to provide the energy we have the wisdom to tap.
Can wind generate electricity at $0.04 per kilowatt-hour?, September 19, 2011
Good news on the magnet front, March 24, 2011
Those pesky magnets, July 29, 2009
U.S. Department of Energy 20% Wind Energy by 2030 Technical Report, 2008 (see Chapter 3, "Manufacturing, Materials and Resources")