Indiana has enough pig manure, garbage and other biological waste to supply electricity to a third of the state’s households, according to a Purdue University study released this fall.
However, the cost of converting the biomass into electricity in some cases isn’t economical.
Purdue’s State Utility Forecasting Group identified hundreds of farms, plus dozens of landfills and wastewater treatment plants, in the 2013 Indiana Renewable Energy Resources Study.
Researchers identified seven primary forms of biomass: forest and logging debris, solid waste, wastewater, landfill gas, livestock manure, crop waste and algae.
Potentially, these wastes could pump 11,000 gigawatt hours of electricity onto the grid each year in Indiana. That’s enough juice to power more than 900,000 of Indiana’s 2.5 million homes, assuming they use average amounts of electricity.
Households aren’t the biggest consumers, though, noted Douglas Gotham, director of Purdue’s utility forecasting group.
Residential customers account for about 20 percent of Indiana’s energy consumption, according to the U.S. Energy Information Administration.
In other words, biomass could produce roughly 6.5 percent of the electricity in a state that already has been slow to embrace renewable energy.
Coal produced about 89 percent of Indiana’s electricity in July, the most recent month for which federal data was available. All renewable energy, excluding hydroelectric power, produced 1.6 percent. Nationally, those rates were 39 percent and 4.7 percent, respectively.
“One of the characteristics that makes biomass a very attractive source of renewable energy is its ability to be converted both to electricity and to liquid fuels for the transportation industry,” the utility researchers wrote.
Fair Oaks Farms in Jasper County, for instance, captures 500,000 gallons of cattle manure a day that an outside company compresses into natural gas.
The gas fuels a fleet of 42 trucks hauling milk to Indianapolis, Kentucky and Tennessee. The fleet previously consumed about 2 million gallons of diesel fuel per year, said Mark Stoermann, dairy project manager.
The fuel usually costs Fair Oaks $1.50 to $2 less per gallon than diesel, which currently hovers near $3.50 per gallon.
The system is “revenue neutral” for Fair Oaks, but addresses the farm’s need to get rid of the manure, Stoermann said.
Biomass has its hangups, though.
The process of converting waste to energy often is not cost-effective without subsidies, Gotham said.
A city that builds a power plant to convert garbage into electricity has to pay, on average, five to 10 times more to run the facility than it would for a coal plant. And upfront costs for solid-waste power plants are the highest among all types of power plants, according to an April report from the Energy Information Administration.
Cities are better served by building plants to get rid of the trash rather than to generate electricity, the Purdue report said. Otherwise, the facilities would “be hard to justify financially.” And the notion of burning trash or other wastes has not won over skeptics.
Residents of southern Indiana stopped Liberty Green Renewables from building wood-burning power plants in Scottsburg and Milltown.
The proposals spurred complaints from area residents, leading groups such as the Indianapolis-based Citizens Action Coalition to intervene, because of potential pollution, among other concerns such as the impact on local infrastructure.
Liberty backed out of its plans in 2011 without saying why.
Citizens Action Coalition does not “categorically object” to biomass, said Executive Director Kerwin Olson. Biogas digesters, like what Fair Oaks has, or landfill gas converters both work well, he said.
However, the group does take issue with the broad definition of “biomass,” which makes it hard to regulate, he said.•