What's the difference between biofuels and biodiesel?

— The EditorsSanta Fe, New Mexico
Hmmm...it seems like you need some educating, here. And being the jackbooted, card-carrying henchman of the liberal media--and author of the white-knuckle-ride non-fiction biofuel thriller entitled Greasy Rider--that I am, I'm just the person to provide it. In fact, I'll go beyond simply defining "biofuels" and "biodiesel." I'm going to give you the Ultimate Glossary of Sustainable Energy for Huggers of Tall Perennial Woody Plants That Consist of a Main Trunk and Branches. I promise that it will be as unbiased as Webster's Dictionary. Almost.
Alternative energyA term cleverly hijacked by the nuclear and coal industries to lump themselves together with biofuels, solar, geothermal, and wind as "alternatives" to oil. The correct phrase to use when referring to green power is "renewable energy" (see entry below). Unfortunately, the PR flacks for coal and nuclear have been so successful in their efforts that "alternative energy" has become a part of the lexicon. Its use instantly sends Sierra Club types into seizures.
BiofuelsFuel (either liquid or solid) created from organic, renewable materials (usually plant matter). Common biofuels include ethanol (which I explain below as evil in most forms), biodiesel, cow farts, and even wood chips. The drawback to biofuels is when they're produced from food crops, like corn or soybeans because this creates a competition between energy producers and the starving masses for the same commodities. The result can be a rise in food prices, placing a heavy burden on the poor and people in Third World countries. That's why biofuels from sources like algae hold so much promise. I use biofuel in my veggie-powered car, but it's a recycled waste product--a.k.a. french-fry grease that comes from restaurant deep-fat fryers.
BiodieselDiesel fuel that's made from renewable organic sources such as algae, vegetable oils, or animal fats. It can be pumped straight into the fuel tank of a diesel vehicle. Most of the time, it's mixed with traditional dino-diesel. A sign at the gas pump for B2 fuel, for instance, indicates that the contents are two percent biodiesel and 98 percent fossil fuel. B20 is 20 percent biodiesel and 80 percent traditional diesel. B99 is as close to the pure, uncut Grade A stuff as you can get.
Clean coalThe words "clean" and "coal" go about as well together as "benign" and "Death Star." No such technology exists, no matter how much politicians pandering to voters in Pennsylvania and West Virginia like to talk about it. Around 47 percent of the electricity produced in the United States comes from coal, and coal power accounts for about 42 percent of the world's carbon emissions (otherwise known as greenhouse-gas emissions). It's the most carbon-spewing fuel we've got. Making it "clean" largely involves capturing the carbon it emits and burying it underground or beneath the sea.
EthanolEthanol is simply pure alcohol, like what you can extract from beer, wine, or vodka. It's generally made from corn, which is very bad. Here's why: Corn is a highly water- and fertilizer-intensive crop that encourages erosion of the topsoil (even though it tastes so damn good on the cob). When corn-based ethanol is in demand, it shoots up the price of corn, and farmers plant fewer other crops, like soybeans and wheat, which also become costlier. On top of that, huge natural gas-fired plants are needed to distill ethanol from corn. The real promise of ethanol comes from potentially getting it from algae or plant waste like sawdust, grass, and corn stalks.
Do you have a question of your own?
Nuclear powerThere's been a big push to promote nuclear power as a clean source of energy (discounting the tens of thousands of tons of radioactive waste from nuclear plants that we're already sitting on in the U.S.) because it doesn't produce greenhouse gases. As distasteful as the prospect may seem to environmentalists, though, this form of energy may be a necessary ingredient in dramatically reducing emissions in the near term.
Renewable energySimply put, energy created from natural sources--like solar, wind, geothermal, and biofuels. Unlike fossil fuels, you can never run out of renewable energy (at least not until eight billion years from now, when the sun expands into a red giant and swallows the earth like a guppy).