Out of the frying pan and into the power grid

If fry grease can run a Mercedes, why can't it power the restaurant it came from?

That's the idea behind Owl Power Company's Vegawatt power system, a machine that converts a restaurant's waste oil into electricity and hot water.

A concept drawing of the Vegawatt system that converts restaurant waste grease into 5 kilowatts of electricity.

(Credit: Owl Power Company)

Co-generation, where a fuel is burned to make electricity, is regularly done at landfill incinerators or industrial biomass generators. There are also home co-generators, such as the Freewatt from Climate Energy.

Owl Power's twist on co-generation is that it lets restaurants use what's normally a waste product as a fuel for themselves.

James Peret, the president and CEO of Owl Power Systems, is a mechanical engineer who started to work with a grease car, which uses vegetable oil to power a diesel engine. He realized that a lawnmower-size diesel engine could be used as a co-generator as well.

The company now has a prototype of the Vegawatt power system which it will begin beta testing with restaurants in the fall and release next year.

For restaurant owners, the generator shouldn't be a big change. They just dump their used fry grease into the Vegawatt system rather than their existing dumpsters.

Owl Power System intends to lease the machine, which is about 6 feet high and 2 feet deep, to restaurants for $400 a month. It's appropriate for restaurants that have two or three fryers--that covers a lot of McDonalds and donut shops, said Peret.

The electricity and hot water the machine generates won't cover all a restaurant's energy usage, but it could be used during peak times when electricity is most expensive.

Between 50 and 80 gallons of oil will cover about one-third of the electricity usage in a restaurant, Peret estimates. They also avoid paying hauling charges.

A leasing model, where Owl Power does the maintenance, means that companies don't need to purchase the machine.

"The minute restaurants hear about this, they say, 'When can I get it?'" said Chad Joshi, chief operating officer of the company.

Even though it is a waste product, fry grease has become more valuable to restaurant owners, particularly as rising soy prices have made biodiesel from soy uneconomical for producers. Enthusiasts collect it for making "grease cars" and there have even been reports of grease bandits.

[carlhage]

There is only a scant reference to "Reduce domestic hot water energy costs", but there is more energy in heat than electricity due to the efficiency of an internal combustion engine. Engine cooling water could be used for building heat, and a heat exchanger in the exaust stream could recover heat there as well. Of course the building must be designed for circulating water heating. Also not mentioned is air pollution. Diesel backup generators don't need to conform to automotive emission standards, but they should! Micropower heat-electric seems a good idea, especially if waste biofuel is used, but emissions control will be important. The $400/mo price seems high since generators are under $4K.

[atish505]

I agree. $ 400/month looks pricey except for large store chains.
$ 200 should be reasonable for small restaurants/joints.

Second, the emissions from the generator need to be controlled.

[mlamonica]

Air emissions is a good questions. The company told me that systems this small are not regulated, but that they are conform with air quality rules.