3. VEGETABLE-OIL FILTER 4. DIESEL FILTER 5. SUPPLY VALVE 6. RETURN VALVE 7. CYLINDERS These power the car. And they don’t care if they’re running on diesel or old frying oil.

car key in the run position and tapped into it as a power source. Splitting it to provide juice to each valve circuit, I crimped the wires into the solenoid leads, grounded the circuits with eye terminals screwed into the chassis and pushed four wires through a hole I’d drilled in the corner of the glove compartment. Attaching the two toggle switches at the driver’sside end of the glove box provided the most visceral satisfaction of the entire project, when the audible click of the valves switching confirmed my success.

I put 40 litres of filtered vegetable oil in the tank and waited for a good reason to drive more than a few kilometres – long enough for the grease to heat up. When the time came, I ran for several minutes with diesel directed back into the vegetable-oil tank (supply valve off, return valve on) to purge air from the vegetable side and with some trepidation, flipped the supply valve to on. It worked.

Of course there were a few more issues. I’d hastily chosen not to clean the tank before installation and, every so often, a glob of solidified goo would plug the intake line and cause the engine to sputter. I’d have to switch to diesel, find compressed air and evacuate the line back into the tank. This happened a couple of times before I realised a much easier, if slightly disgusting solution: wiping off the sticky end of the line (and reminding myself that it was basically food), I blew through it. Eventually I did get around to cleaning the tank.

Overall, my grease car’s performance has been very satisfactory. Fuel economy and power are unaffected by the conversion and I’ve found fuel collection and processing (all oil ideally should be prefiltered before being put in your car’s grease tank) to be acceptable chores, even if they’re not very clean or always convenient. My oil comes from many different types of restaurants and, as long as I begin with a relatively clean source, filtering (usually using passive solar heat and a sock-shaped filter attached to the lid of a bucket) is relatively uneventful and even easy. The only real problem is that it tends to make people hungry as I drive by.

FOR LOCAL BUSINESSES and farmers, it’s the price that makes biodiesel attractive. For the handful of greenies, some of them trekking across the Cape Peninsula to get their fill-up, it’s the bonus of the warm fuzzy feeling of doing good for the planet.

“It really is a mindset,” says Craig Waterman. His company, Green-diesel, is one of a handful of local biofuel producers.

Biofuels are regarded as an important element of South Africa’s environment policy. Last October was set as the date for countrywide implementation of a five per cent biodiesel mix at filling stations – which never happened. That inititiave appears to have bogged down, not least because five per cent of the national distribution is 40 million litres.

From its anonymous warehouse in the industrial area of Stikland in Cape Town’s northern suburbs, Green-diesel shoves used chip fryer oil in one end and pours good, clean biodiesel out the other. (Some clever stuff with processors and catalysts happens in between.)

It’s perfectly safe for conventional diesel engines, though manufacturers are wary: one limits the biodiesel proportion to 5 per cent to comply with warranty restrictions. But not only does the stuff burn cleaner (100 per cent biodiesel reduces CO2 emissions by 75 per cent, Waterman says) it has no deleterious effects.

Nine years ago, Waterman and his wife Bettina were running a transport company. They started making biodiesel purely for themselves to keep fleet operating costs down. “When the diesel price went over R10, we started getting enquiries.” He saw a gap waiting to be exploited and now produces both fuel and processor kits.

Used oil is the basis of the business. “Places you would not think of collecting from… hospitals, army bases, canteens.” Here’s the thing: research has shown that less than 1 per cent of domestic oil is recovered in South Africa, Waterman says.

There’s stiff competition. A lot of used oil goes into the production of animal feed and small amounts to producing paint products. Exports, too: Europe is a big market and exporters will get paid in Euro. Complicating matters is that the two main oils used for culinary use are palm (imported) and sunflower. Soya oil is produced locally, but rarely used in deep fryers. Also, by law, no biodiesel may be imported and new oil is out of the question, unless subsidised as in the EU and USA.

Green-diesel is a “non-commercial” producer, which means it is subject to an annual cap of 300 000 litres. That works out to 25 000 a month. Its pump price more or less tracks the retail diesel price and is typically about R1 cheaper. There is an additional incentive for local farmers who export to the EU, which audits their carboon footprint. To eke out production, an extra purification stage is being implemented that will skim additional fuel from the water extracted as part of the biodiesel process. The biggest customer is a supermarket chain that takes 2 000 litres a week of production and supplies much of the feedstock.

Biofuel at this stage, then, is still a cottage industry. Blending at refinery level is years away, says Waterman. There are plenty of hoops for big-scale producers to jump through: plants grown for biofuel production may not be irrigated, have to be grown on marginal land and are subject to restrictions on what may be grown. “Our neighbouring countries are years ahead of us in this respect,” he says. - Anthony Doman