Fuel Cubes: Cheap, Clean Energy Source?
Renewafuel, a start-up company from Minnesota, has invented cubes of plant materials that provide twice as much energy as other biomass and about the same amount of energy as coal. Because these "fuel cubes" are made of materials such as switch grass, corn stalks, and wood fibers, they don't contribute to global warming, the company says.
Fuel cubes, which are basically an aggregate of several types of biomass, such as grass, wood, grains, and seed hulls, are processed into dense cubes that look like coal briquettes. The combination of biomass types can be adjusted depending on the materials available in different geographic locations. Renewafuel says the cost to make the fuel cubes is competitive with the cost of coal.
Besides being more potent than raw biomass, fuel cubes can also be more easily integrated into the current coal-burning infrastructure. The cubes can be substituted for coal in existing burners with little or no modifications. This advantage might enable fuel cubes to enable companies to use biomass without building new facilities.
But some people are concerned about where the biomass will come from. Similar to concerns with ethanol, harvesting material for the cubes might generate side effects - notably in cutting down trees - that outweigh their value.
A mining company in Ohio called Cleveland-Cliffs is already using the fuel cubes to heat a pelletizing furnace at one of its Michigan mining facilities. The company has bought a 70% controlling share in Renewafuels, and it has plans to use the fuel cubes at sites in Minnesota, too.