Veggie power
Low-grade vegetable oils may fuel turbo generators for power plants

BY DAN LEMKE

Minneapolis, Minn. - Flicking on a light switch or firing up the blender may soon come courtesy of a lowly source - vegetable oils.

The Center for Diesel Research at the University of Minnesota is conducting AURI-supported research on vegetable oils’ potential as fuel for turbo generators.

Power companies rely on turbines to produce electricity, especially during peak-demand periods. While classified as a combustion engine, turbines can burn a wide range of liquid fuels - from light No. 1 diesel to heavy No. 6 diesel to natural gas.

 

Soon vegetable oils, including low-grade soybean soapstock and recycled oils, may join the list of turbine fuels. Some of these oils have little value - just the left-over dregs from soybean processing.

“Turbines are a very forgiving type of engine, which is why we’re confident vegetable oils will burn,” says Ken Bickel, principal investigator at the Center for Diesel Research. “They can offer the same advantages as biodiesel because they’re renewable, reduce dependence on foreign sources and could open new markets for ag products.”

Turbines operate by compressing fuel before it is sent to a flame holder. From there, gasses from the burning fuel drive a turbine, which powers a generator to produce electricity.

Unprocessed vegetable oils are cheaper than processed fuels. But characteristics such as the oils’ viscosity, metal content and energy potential aren’t yet certain. Bickel is testing to see which vegetable oils meet turbine manufacturers’ specifications and are candidates for further testing. Economic issues such as storage, raw material costs and transportation will be considered.

After the oils are qualified, fuel samples will be analyzed and tested in laboratory turbines for emissions and other data.  Then they will be tested in small industrial equipment before being readied for the marketplace - with huge opportunity.

Bickel estimates that feeding turbines at two large Minnesota utilities could require 55 to 60 million gallons of oil annually, even though the turbines operate only about 300 hours each year.

“It’s potentially a significant market,” Bickel says. “(Using vegetable oils) is primarily a potential cost savings for utilities where they can reduce fuel costs by using fuels that are unprocessed.”

Price is a primary consideration but environmental issues also factor in. The State of Minnesota has set a goal of producing 10 percent of the state’s electricity from renewable sources by 2015. While not a mandate, this target encourages utilities to try renewable energy.