Renewable energy rundown: Biomass

July 8, 2020   By Caitlin Cosper

Renewable energy rundown: Biomass

This is the fifth and final part in a SaveOnEnergy series discussing the ins and outs of different forms of renewable energy. See the SaveOnEnergy Learning Center to read the first four parts.

In this series, we’ve covered a range of renewable power sources. Some, such as geothermal power, have been commonly used for decades. Others, including solar power, have recently risen in popularity due to technological advancements. This week, we’re discussing the oldest form of renewable power – biomass.

So, what’s the deal with biomass? What is it made of and how does it work? Read on to learn the basics of this form of renewable energy.

What is biomass?

Biomass is organic material that comes from plants and animals. These sources contain energy stored from the sun, which they convert into energy for themselves.

Think back to middle school science when you learned about photosynthesis – or the process that allows plants to absorb energy from the sun. These plants store that energy for later use. When sources of biomass – such as plants – are burned, they release the chemical energy in biomass as heat.

Biomass itself can be burned or it can be converted into liquid biofuel or biogas. A prime example of biomass is wood. Naturally occurring wood can be burned for heat, but it can also generate electricity for homes and businesses. In fact, wood was the main source of energy globally until the mid-1800s.

Here are a few other sources of biomass:

  • Agricultural crops and waste materials. These can be burned for fuel or converted into liquid biofuels.
  • Food and yard waste. These can be burned to generate electricity or turn into biogas in landfills.
  • Animal manure and sewage. These can be converted into biogas and burned as fuel.

What’s the difference between the forms of biomass?

There are some key differences between biomass, liquid biofuel, and biogas and how they transform into electricity.

As we mentioned earlier, solid forms of biomass, such as wood and garbage, have a relatively simple transformation into energy. When you burn them, they produce heat, which can warm your home.

Biomass can also be turned into biogas, which forms when natural sources such as paper, food scraps, and yard waste decompose in landfills. Another method to produce biogas is through processing sewage and animal manure in a special piece of equipment called a digester.

Additionally, biomass can be converted into liquid biofuel. Common types of liquid biofuel include ethanol and biodiesel, which can be burned for energy.

According to calculations from 2017, biomass accounts for approximately five percent of total primary energy use in the U.S. From that five percent, about 47 percent comes from biofuels (primarily ethanol), 44 percent from wood and wood-derived biomass, and nine percent from biomass in municipal waste.

Biomass and the environment

Biomass and biofuels are all forms of renewable resources. Not only do the resources needed naturally derive from plants and animals, but they are cleaner alternatives to fossil fuels such as coal, petroleum, and natural gas.

That said, burning biomass does release carbon dioxide – a greenhouse gas associated with global warming. However, the carbon emissions from burning biomass are normally offset by the amount of carbon captured by plants during photosynthesis. This makes biomass a carbon-neutral source of power.

There are, of course, some other drawbacks to burning biomass. Burning large amounts of wood can release harmful pollutants such as carbon monoxide. Moreover, relying too heavily on wood as a power source can lead to deforestation, or the disappearance of forests by cutting down trees faster than they can grow.

Biofuels are also a carbon-neutral source because the plants used to make biofuel (such as corn or sugar cane) absorb an equal amount of carbon as is emitted while burning them. You may recognize the word “ethanol” from the gas station. In 2007, the U.S. government set a target to use 36 billion gallons of biofuel by 2022, which led to almost all gasoline in the country containing some ethanol.

Finally, biogas plays a similarly complicated role in environmental health. While the formation of biogas is a natural event, it is composed primarily of methane and carbon dioxide, both of which are greenhouse gases. The facilities that produce biogas normally burn the methane for heat or to generate electricity. But here’s what’s tricky: burning methane produces more carbon dioxide. However, methane is a much stronger greenhouse gas than carbon dioxide, so the overall greenhouse effect is lower.

Can biomass power my home?

Odds are biomass is already somewhat responsible for the heat or electricity in your home! Every time you light a fire in your wood-burning fireplace, you are heating your home using biomass.

If you’re looking for a way to power your home with biomass without lighting a fire in July, you may be in luck. There are several biomass power plants throughout the Lone Star State and many more across the country. Depending on where you live, you may be able to enroll in a power plan that draws a portion of your electricity from these power plants.

Investing in renewable energy sources can help to minimize your home’s environmental footprint while supporting sustainable projects. Whether it’s solar, wind, hydropower, geothermal, or biomass, powering your home with clean energy is always a solid choice.

The following are the other entries in the series:

Renewable Energy Rundown: Solar

Renewable Energy Rundown: Wind

Renewable Energy rundown: Hydropower 

Renewable Energy Rundown: Geothermal

Caitlin Cosper is a writer within the energy and power industry. Born in Georgia, she attended the University of Georgia before earning her master’s in English at the University of North Carolina at Charlotte.