Previously, we’ve seen that there’s no such thing as sustainable energy because all energy use produces heat, which at some point (around the year 2200, at current rates) will make the planet too hot for us. Along the same vein, The Bulletin of the Atomic Scientists has an article which makes the point that there’s no such thing as renewable energy either. So even if we could use all the energy we wanted — which we can’t because eventually, we’d boil — we are never going to have a source of energy that’s inexhaustible.
At this point, most people say “ok, the sun isn’t technically inexhaustible, but it’ll be around for a couple billion more years, so for all intents and purposes, it’s renewable.” And it’s true, sunlight in and of itself is virtually renewable, but the problem is that we can’t make direct use of sunlight: we need solar panels, and they’re made using non-renewable resources like neodymium. They also have a shelf-life, and need maintenance. Solar plants, like all power plants, are designed for a couple of decades of use, and require a lot of groundwater during maintenance, for cleaning and cooling; in the desert, where solar plants generally live, groundwater is not renewable.
Wind power requires wind mills which are built with steel, concrete, and rare earth metals. Same with hydropower, which needs dams and turbines. Geothermal power and biomass also need turbines and engines; and what’s more is that unlike solar, wind and hydro power, these two energy sources tend to be used at a rate faster than they can be renewed. So even though the source of the energy is renewable, it doesn’t renew quickly enough. After all, trees are biomass, and until oil became the primary energy source, deforestation was a very real concern.
The truth is, there’s no horn of plenty when it comes to energy, and at our current usage, even if the entire planet switched to 100% solar power tomorrow, we will eventually run out of energy. It might take longer and damage the environment less (except for heating up the planet), but it will happen. So ‘renewable,’ ‘sustainable,’ and ‘green’ are serious misnomers when talking about even the most politically correct of energy sources. At best, we can say that alternative energy sources are more efficient and clean — but win/win solutions, they are not.
Now, it could be that some magical new technology will be invented that’s made from abundant elements like carbon and hydrogen, doesn’t create heat as a byproduct, and uses sunlight as an energy source. But until we can plug in our iPhones into ficus trees, it’s better if we just assume that won’t happen.