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When used to generate power or move vehicles, fossil fuels kill people. Particulates and ozone resulting from fossil fuel burning cause direct health impacts, while climate change will act indirectly. Regardless of the immediacy, premature deaths and illness prior to death are felt through lost productivity and the cost of treatments.

Typically, you see the financial impacts quantified when the EPA issues new regulations, as the health benefits of limiting pollution typically dwarf the costs of meeting new standards. But some researchers from Lawrence Berkeley National Lab have now done similar calculations—but focusing on the impact of renewable energy. Wind and solar, by displacing fossil fuel use, are acting as a form of pollution control and so should produce similar economic benefits.

Do they ever. The researchers find that, in the US, wind and solar have health and climate benefits of over $100 for every Megawatt-hour produced, for a total of a quarter-trillion dollars in just the last four years. This dwarfs the cost of the electricity they generate and the total of the subsidies they received.

Enlarge / Used Tesla Model 3s can be had for less than $20,000 now. (credit: Getty Images)

The launch of a new electric vehicle these days is invariably met with a chorus of "this car is too expensive"—and rightfully so. But for used EVs, it's quite another story, particularly used Teslas, thanks to a glut of former fleet and rental cars that are now ready for their second owner.

"Due to a variety of reasons, Tesla resale values have plummeted, making many Tesla models very affordable now. Plus, for some consumers, an additional $4,000 Federal tax credit on used EVs may apply, sweetening the deal even further. Buying a used Tesla can be a great deal for the savvy shopper, but there are significant things to look out for," says Ed Kim, president and chief analyst at AutoPacific.

Indeed, a quick search on the topic easily reveals some horror stories of ex-rental Teslas, so here are some things to consider if you're in search of a cheap Model 3 or Model Y.

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It doesn't take a lot of energy to dig up coal or pump oil from the ground. By contrast, most renewable sources of energy involve obtaining and refining resources, sophisticated manufacturing, and installation. So, at first glance, when it comes to the energy used to get more energy—the energy return on investment—fossil fuels seem like a clear winner. That has led some to argue that transitioning to renewables will create an overall drop in net energy production, which nobody is interested in seeing.

A new study by researchers at the UK's University of Leeds, however, suggests that this isn't a concern at all—in most countries, renewables already produce more net energy than the fossil fuels they're displacing. The key to understanding why is that it's much easier to do useful things with electricity than it is with a hunk of coal or a glob of crude oil.

Energy efficiency and utility

The basic idea behind the new work is that while it's energetically cheap to extract fossil fuels, the stuff that comes out of the ground isn't ready to be put to use. There are energetic costs to making it into a useful form and transporting it to where it's needed, and then there is lost energy when it's being put to use. That's especially notable for uses like internal combustion engines, where significantly less than half of the energy available in gasoline actually gets converted into motion.