Switchgrass Biofuel Potentially Cheaper Than Oil for Heating Homes

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To be filed in the category of everything old is new again: a new study from the USDA Agricultural Research Service (ARS) suggests that millions of homes and businesses in the U.S. would save money by burning biomass in their basement furnaces instead of oil, in form of switchgrass biofuel pellets. That would bring things back — way back — full circle to the days when the prevailing form of energy was distributed energy, in the form of biomass (aka firewood) burned in a fireplace. The question is, how much sense does this make today?

USDA's ARS calculates that switchgrass is cheaper than home heating oil
Switchgrass pellets courtesy of USDA.

Comparing Switchgrass Biofuel to Heating Oil

From a financial standpoint, the ARS switchgrass study shows that it makes plenty of sense, though it’s important to note that the comparison is region-specific. Namely, ARS compares switchgrass with oil heating costs in the Northeast, where heating oil prices are typically higher and vast quantities are consumed in the winter months.

Although not directly stated in the press materials, the study does not conclude that property owners should pull out perfectly good oil heating equipment to replace it with a pellet burner. It does indicate that property owners who are replacing old, outdated heating equipment would save a significant amount of money by installing new pellet burners rather than sticking with oil-burning equipment.

Based on the total cost of installing and fueling a new pellet heating system in a residence, the ARS team came up with a cost of $21.36 per gigajoule of heat (gigajoule is a standard unit of energy measurement; for example a barrel of oil contains about six gigajoules).

To produce the same amount of heat with oil, the figure is $28.22.

The ARS team notes that the savings for installing commercial pellet burners would be lower, due to higher costs for commercial-scale equipment and higher costs for fuel handling and storage, compared to oil heat.

…And Lower Greenhouse Gas Emissions, Too

In terms of greenhouse gas emissions, the study also comes out with a win for switchgrass.

ARS looked at the entire switchgrass supply chain, including the first ever study of greenhouse gas emissions related to producing switchgrass seeds, in addition to growing and harvesting the crop.

Using a standard unit of greenhouse gas emissions comparison called carbon dioxide equivalent (CO2e), the study arrived at a CO2e of 192 pounds per ton of dry switchgrass delivered to facilities for conversion into pellets or other densified forms. The densification process added another 287 pounds of CO2e.

Compared to oil, the team concluded that residences would lower their greenhouse gas emissions per gigajoule of heat by 146 pounds of CO2e  (and by 158 pounds compared to natural gas, by the way).

Switchgrass And Priorities

Beyond confirming the expectations of switchgrass fans, the study makes an interesting point about where to prioritize the replacement of petroleum fuels with biomass.

We’ve become highly accustomed to thinking about switchgrass biofuel as a gasoline replacement, but the study suggests that this focus is misplaced.

The study found that a ton of switchgrass pellets for home heating could replace about 17.2 megajoules or about 116 gallons of home heating oil, but when used for bio-gasoline the conversion was only 6.2 megajoules or about 50 gallons of gasoline. Greenhouse gas emissions would also drop more significantly with home heating oil replacement compared to gasoline replacement.

In other words, the immediate payoff for replacing older home heating equipment in the Northeast would be substantially more than replacing gasoline with switchgrass biofuel.

That finding dovetails with President Obama’s Better Buildings Initiative, a public-private initiative that focuses on energy upgrades for the nation’s stock of old, inefficient buildings, and it could lead to new incentives for property owners to replace worn out oil heating equipment with pellet burners.

In the context of the Obama Administration’s obsession with electric vehicles through the EV Everywhere initiative, the study also supports energy planners who foresee the eventual replacement of liquid-fueled vehicles with electric vehicles.

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Tina Casey

Tina specializes in advanced energy technology, military sustainability, emerging materials, biofuels, ESG and related policy and political matters. Views expressed are her own. Follow her on LinkedIn, Threads, or Bluesky.

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