What makes biomass fuels

In May the UK went an entire fortnight without using any coal to generate electricity. The last time this happened, Queen Victoria was on the throne. From having had its first coal-free day in summer to recording its first coal-free week in May , the UK has done an impressive job of weaning itself off the dirtiest fossil fuel.

But as environmentalists cheer the good news and policy-makers give themselves a pat on the back, a terrible truth has come to light: biomass power plants — a key renewable-energy source and one of the main replacements for coal-fired power — are emitting more carbon dioxide from their smokestacks than the coal plants they have replaced.

In its haste to get rid of coal, the UK may have inadvertently made global warming worse. The logic behind biomass energy is simple. Trees and plants absorb carbon dioxide from the air, use photosynthesis to isolate the carbon, and then use it to build tree trunks, bark and leaves.

But when the plant dies, it rots down and much of the carbon is released back into the atmosphere as carbon dioxide. Now as we all know, burning fossil fuels releases carbon from geological reservoirs, which would have remained locked up for many millions of years if left untouched. So switching from fossil fuels to biomass energy seemed like an obvious way for European Union EU nations to meet their obligations under the Paris climate agreement signed in Several countries embraced bioenergy and started to subsidize the biomass industry.

In the UK, the Drax Group has led the way with this green and leafy energy revolution. Standing next to the train track at Drax in September , I watched as 25 wagons of wood pellets were slowly disgorged into one of the four Albert Hall-sized storage domes.

My guide told me that most of the pellets are made from the sawmill residues and waste left over from managed forestry in the US and Canada. This can include tree tops and limbs, misshapen and diseased trees not suitable for other use, and small trees removed to maximize the growth of the forest. Virtually every day shipments arrive in ports at Immingham, Hull, Newcastle or Liverpool, each carrying around 62, tonnes of wood pellets — enough to keep the boilers going for two and a half days.

Unloading the ship takes three days and requires 37 freight train journeys. The size of the operation at Drax is absolutely staggering. However, Drax says that by creating a market for timber waste it is helping to prevent deforestation.

However, those calculated savings rest on a few key assumptions: first, that the carbon released when wood pellets are burned is recaptured instantly by new growth; second, that the biomass being burned is waste that would have released carbon dioxide naturally when it rotted down.

But are those assumptions right? The residential and commercial sectors use firewood and wood pellets for heating. The commercial sector also consumes, and in some cases, sells renewable natural gas produced at municipal sewage treatment facilities and at waste landfills.

The electric power sector uses wood and biomass-derived wastes to generate electricity for sale to the other sectors. Biomass explained. What is energy? Units and calculators. Use of energy. Energy and the environment. Also in What is energy? Forms of energy Sources of energy Laws of energy. Also in Units and calculators explained Units and calculators Energy conversion calculators British thermal units Btu Degree days. Also in U. Also in Use of energy explained Use of energy Energy use in industry Energy use for transportation Energy use in homes Energy use in commercial buildings Energy efficiency and conservation.

Also in Energy and the environment explained Energy and the environment Greenhouse gases Greenhouse gases and the climate Where greenhouse gases come from Outlook for future emissions Recycling and energy. Nonrenewable sources. Oil and petroleum products. Diesel fuel. Heating oil. The main biomass feedstocks for power are paper mill residue, lumber mill scrap, and municipal waste. For biomass fuels, the most common feedstocks used today are corn grain for ethanol and soybeans for biodiesel.

In the near future—and with NREL-developed technology—agricultural residues such as corn stover the stalks, leaves, and husks of the plant and wheat straw will also be used. Long-term plans include growing and using dedicated energy crops, such as fast-growing trees and grasses, and algae. These feedstocks can grow sustainably on land that will not support intensive food crops. Energy Kids Biomass Basics U. When anything is burned, it can create emissions and ash.

Our facilities have state-of-the-art cleaning processes that keep emissions below state regulatory levels, and we reuse our ash. Biomass fuels provided about 4 percent of the energy used in the United States in Of this, about 46 percent was from wood and wood-derived biomass, 43 percent was from biofuels mainly ethanol , and about 11 percent was from municipal waste.

Researchers are trying to develop ways to burn more biomass and fewer fossil fuels. Using biomass for energy cuts back on waste and greenhouse gas emissions. Biomass offers other significant environmental and consumer benefits, including improving forest health, protecting air quality, and offering the most dependable renewable energy source. You can read about how we turn biomass and other residuals into energy here.