Anyone who has worked in the oil industry for a while understands that there’s another meaning to “light sweet,” besides the low-fat dessert the words might first bring to mind. Light, sweet is a kind of crude oil, named for its comparatively low sulphur content, the ease with which it flows out of the ground, and apparently, its sweet taste as well.

Heavy crude oil, sometimes also described as sour, tends to have a more viscous quality. This makes it harder to get out of the ground and barrel for barrel, heavy crudes typically produce less refined fuel than lighter grades.

All crude oils, in other words, are not created equal.

Now, if there was an infinite supply of light, sweet crude oil in the world, oil companies might never have bothered going to the trouble of producing the thicker stuff. Fact is, there’s significantly more heavy crude oil in the world, and a substantial amount in the U.S., particularly California. Because heavy crude is typically a lot cheaper than light crude, companies often find it economical to produce, despite its lower quality.

Factor in all the transportation costs that are saved by producing oil domestically, and that heavy stuff starts to look even more appealing.

That brief primer in crude oil economics offers a sense for why some new emissions policies being proposed are misguided. Specifically, a Low Carbon Fuel Standard being considered by Congress would effectively favor light crudes across the board, no matter where they came from and how much it would cost to produce them.

You can read more about the problem with this overly-simplistic approach to reducing emissions on the site Secure Our Fuels, which offers a scenario of how laws passed in Washington would affect the worldwide crude oil trade:

Saudi crude wins out over Canadian crude. Nigeria beats Colorado. And Libya wipes the floor with California. Just because North American crude happens to be deeper, denser and a little bit more remote than our competitors’ oil.

It might seem inconceivable that a well-intentioned policy could actually increase our dependence on foreign oil, but that is the risk you run with sweeping policies that fail to address the complexity of oil economics that we’ve hinted at above.

When it comes to achieving a balanced energy policy that is good for the environment, the economy and the country, good intentions aren’t enough. They may do more harm than good.