What is in this article?:
- Switchgrass pellets have potential in replacing fuel oil
- Substitution would save money
• Studies suggest there are opportunities to use homegrown feedstocks for producing heat, and that we can save money, reduce petroleum use, and cut greenhouse gas.
Substitution would save money
Substituting switchgrass pellets for fuel oil for home heating would also save money. Totaling all costs associated with installing an appropriate residential heating system and fuel consumption,
Adler’s team concluded that each gigajoule of heat produced using switchgrass pellets would cost $21.36. Using fuel oil to produce the same amount of heat would cost $28.22. The savings would be less in a commercial facility, because capital costs for a commercial biomass boiler, storage, and fuel-handling equipment are five times greater than the costs for components that use fuel oil.
According to the team’s calculations, heating with switchgrass pellets would continue to be less expensive even if switchgrass production costs rose 200 percent and the price of fuel oil dropped 70 percent. These findings are based on the average heating-oil price from the 2010-2011 heating season, which was $0.90 per liter.
But even if fuel-oil prices dropped to their 10-year average of $0.62, it would still cost less to generate a gigajoule of heat using switchgrass pellets.
Coal is a somewhat different story. Although substituting biomass for coal in electric generation substantially reduced greenhouse gas emissions, it would come at a high cost to domestic consumers.
Using coal, it would cost $31.03 to generate each megawatt of electricity, but using switchgrass briquettes would cost $154.62, and switchgrass cubes would cost $156.52. (Briquettes and cubes were used in this series of life-cycle analyses because of their lower energy intensity relative to pellets.)
So even though greenhouse gas emissions would drop dramatically by using switchgrass to generate power, these reductions are achieved at a high cost relative to coal — an outcome called “positive abatement costs” that policymakers would like to avoid.
Using projections from the U.S. Department of Energy’s “Billion Ton Report,” the scientists concluded that by 2022 there would be enough sustainably harvested biomass available in the northeastern United States to offset the entire regional demand for heating oil. This would save consumers between $2.3 and $3.9 billion per year in fuel costs.
It would also reduce greenhouse gas emissions in the Northeast—currently around 885 million tons of CO2e every year — by 5 percent. Many renewable-fuel projects are tasked with finding cost-effective strategies for generating electricity with biomass instead of coal, but replacing fuel oil with switchgrass pellets in home heating systems could become just as beneficial.
Adler is now working with Plainview Growers president Arie Van Vugt to determine the carbon footprint of using biomass rather than fuel oil to heat the nursery’s greenhouses and how much it costs to reduce that carbon footprint using various fossil fuel alternatives. Plainview Growers has two production locations in New Jersey and sells more than 160 million nursery plants produced from seeds every year.
Van Vugt, who also started a company called “Pequest Energy” with the goal of using locally grown and sustainable sources of biofuel for energy production, already burns pellets made from locally grown warm-season grasses to heat some of his greenhouses.
The scientists have published their results in Environmental Science & Technology. Wilson, who conducted the work as part of his master’s program, was the lead author. Adler notes that this research — which is the first published life-cycle analysis of the costs and benefits of using switchgrass-derived fuel for U.S. thermal generation — demonstrates that the energy contained in switchgrass pellets compares favorably with that contained in petroleum-based fuels.
“We can use a ton of pellets made from dried switchgrass to replace 116 gallons of fuel oil that contains 17.2 megajoules of energy. Or we can use a ton of switchgrass pellets to replace 50 gallons of gasoline that contains 6.2 megajoules of energy.
“So using biomass to replace fuel oil displaces more than twice as much petroleum as using biomass to replace gasoline,” says Adler.
“If we use the switchgrass to replace fuel oil instead of the coal used to generate electricity, we also substantially reduce greenhouse gas emissions at a much lower cost to consumers — and help meet our long-term goals for domestic energy production from alternative fuels.”