Wood pellets have become an increasingly popular alternative fuel source, and are even more environmentally friendly compared to coal. In fact, greenhouse gas emissions from wood pellet-based electrical plants are between 74 and 85 percent lower than those of coal-firing plants, a University of Illinois study revealed.

Wood pellets are made from trees harvested from forests throughout North Carolina, South Carolina, Virginia, Georgia and other southern states. Wood from these forests is pulverized and shaped into small, all-natural wood pellets that are then exported from the U.S. to Europe. In recent years the volume of pellets shipped overseas has increased dramatically in response to the European Union's 2020 stricter carbon emissions laws. The goals of such legislation are reducd greenhouse gases, increased energy production from renewable resources and improved energy efficiency.

With such a sky-rocketing demand for pellets, questions have been raised about the impact of wood-pellet manufacturing on the environment. The environmental costs – logging, animal dislocation, processing and oil-fueld shipping across the Atlantic Ocean to Europe -- seems to defy logic. But experts contend that using wood pellets is still more energy-efficient and carbon safe than burning coal, even when factoring in harvesting, production and transportation. 

"One of the concerns with wood pellet production has been that it's going to lead to an increase in the harvesting of trees in the southern part of the U.S., and that the emissions that go into both the production of these pellets and their transportation to Europe will result in a product that is not going to save a lot of greenhouse gas emissions when it displaces coal-based electricity in Europe," Madhu Khanna, a professor of agricultural and consumer economics at the University of Illinois, explained in a news release. "Basically, wood pellets look really good next to coal, even when you account for everything else."

Wood pellets manufactured from a combination of forest and agricultural biomass is even more environmentally friendly than all wood pellets; they can reduce carbon emissions by an additional 28 to 34 percent. 

"You can produce wood pellets not just from forest biomass, which is how it's currently done, but you can also use agricultural biomass crops like miscanthus and switchgrass, which increases the savings dramatically," Khanna said. "And that's because agricultural biomass is able to sequester a lot of carbon in the soil while it's growing. Compared with forests, they sequester much more carbon. And as a result, the greenhouse gas intensity produced by the pellets made with agricultural biomass is much less. So the benefits from pellets increase if you're able to source it from agricultural biomass rather than just from forests."

Using agriculture biomass more frequently may lead to additional land-use changes, too. This includes harvesting existing trees and planting more trees, which is known as "afforestation." While this may seem like a negative, environmental deficit, such changes will eventually lead to a buildup of forest carbon stocks within the next few decades, simply because forest managers will maintain their land and keep forests forested in preparation for an increased demand of wood pellets.

"All of that land starts sequestering carbon, which lowers the greenhouse gas intensity of wood pellets even more," Khanna added. "So that's actually a positive land-use change in the sense that it lowers greenhouse gas intensity as opposed to deforestation, which releases carbon."

The extent to which the environment can benefit from alternative energy sources, such as wood pellets, is dependent on proper planning and forest management. Since more trees will need to be cut down in the future to make pellets, more trees need to be planted now.

The study was recently published in the journal Environmental Research Letters.

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