Can we use vegetable oil as fuel in our cars and in electrical generators? The short answer is yes. The longer answer is, well, yes, with a good number of qualifications.
First of all, all biofuels are essentially vegetable oil before they are refined into ethanol, biodiesel, or the class of biofuels falling under the unwieldy but technically accurate label of fuels that are chemically identical to gasoline but not derived from petroleum.
The technical, environmental and social concerns about large-scale biofuel production would take entire books to fully document (and those books exist) or a whole archive of blog posts on the subject (like TreeHugger has done, nudge, nudge…).
Suffice it to say for now that switching over all of our cars, trucks, ships, and airplanes to run on liquid fuels derived from plants and not petrol is a monumental undertaking, rife with environmental problems. It’s also perfectly possible to generate electricity on a commercial scale from biofuels. A number of studies have shown it’s actually more efficient to generate electricity from biofuels and then power electric cars than burning the fuel directly in internal combustion engines. The same issues apply here though.
That said, on a more limited scale and on the individual level, it is entirely possible, and not overly complicated, to convert diesel cars to run on waste vegetable oil.
And importantly, as GreaseCar.com points out, straight vegetable oil is not biodiesel.
Note however, as How Stuff Works (another Discovery site) reminds us, running your car on straight vegetable oil (remember, not biodiesel made from waste vegetable oil, which exists) is a bit of a legal grey area, though no one has actually been fined yet for doing so:
Not deterred? Even more excited to convert your car? How Stuff Works has all the info you need to get started. Check out: Can any car be converted into a grease car?
As for electrical generation on the home level, remember that the original diesel engine, built by Rudolf Diesel in 1893 was designed to be run on a variety of oils. Consequently it’s no surprise than you can buy diesel generators today perfectly capable of making electricity from vegetable oil.
One such example: A 6.6 kW Lister generator can be bought for $4,600—quite a bit more expensive than comparable diesel generators using contemporary technology (the Lister engine was invented in 1929), but those aren’t ready out of the crate to use straight vegetable oil.