Biomass Energy and Its Environmental Benefits

Biomass energy is having so many benefits for the environment such as reducing air and water pollution, increasing soil fertility and reducing erosion, and improvement of the wildlife habitat.

Carbon Cycle

Carbon cycle is a way of nature for moving carbon around the Earth to support life on it. Carbon dioxide gas is the most common carbon item in which one carbon atom is bound with two oxygen atoms.

Photosynthesis in the plant’s leaves breaks the carbon dioxide in to two, which keeps the carbon for making carbohydrates, and oxygen is exhaled in the air. So when plant dies or it is harvested for burning then it gives back the carbon to air, and that carbon is absorbed again by plants.

While on other hand fossil fuels are made of plants millions of years ago through organic changes. The carbon, which was absorbed by those plants that time, is being emitted now by fossil fuels burning. As there are no extra plants to absorb that carbon that’s why the cycle becomes out of cycle.

If we look the picture below we can see clearly there are two different carbon cycles working one is the natural one between plants and air and perfectly balanced. Second one is human made cycle in which carbon is gained from Earth and emitted into the atmosphere.

Environmental Benefits

As part of the carbon cycle biomass reduces air pollution as shown in the above picture. It reduces carbon dioxide emissions up to 90 percent as compared to fossil fuels. While Sulfur dioxide and other pollutants are also reduced significantly.

It reduces water pollution also as fewer fertilizers and pesticides are used to grow energy crops, and erosion is reduced. Agricultural researchers in Iowa had discovered that planting grass and poplar trees in buffers along waterways can capture the runoff from corn fields and streams will become cleaner.

Food crops extracts the nutrients from the soil while on other hand energy crops improves soil’s quality. Prairie grasses are having deep roots and puts nitrogen and other nutrients in the soil. As Prairie grasses can be replanted every 10 years because of that soil gets minimal plowing that causes soil to erode.

In simple words biomass crops are better for wildlife habitat than the food crops. As they are the native plants so it attracts a variety of birds and mammals. It also improves the habitat for fish by increasing water quality in nearby streams and ponds. Unlike food crops, energy crops are having long time for being harvested and energy crops can be timed to avoid critical nesting or breeding seasons.

All above-mentioned benefits are described in comparison with food crops such as corn, wheat, and soybeans. But comparing with undisturbed natural habitat energy crops is not as good.

But best thing about biomass is that it is much closer to the natural world rather than the modern industrial agriculture.

Harvesting Prairie grasses is not so much different than the fires that sporadically swept across the plains. May be the plantation of poplar and maple trees wont same as varied forests, but are certainly closer than pesticide-laden monocrops.

Anyhow the environmental benefits of the biomass centers on the point that the energy crops will be managed with sustainable agricultural practices. As using chemical inputs increases food crops productivity if it will be done for energy crops then the consequences will be adverse. If biomass energy shows unforeseen environmental effects then it will be better to alter those methods for reducing the effects.

Bottom Line

Aside from the environmental benefits, biomass energy is also having economic and energy security benefits. For example if we grow our fuels at home then we can reduce the need to import oil and also can reduce our exposure to disruptions in that supply.

Because of biomass energy usage, farmers and rural areas will be having new outlets for their products.

In United States, biomass is already supporting 66,000 jobs and if the dream of the DOE became true then that figure will get three times more.

Biomass Conversion into Energy

Ancient way of converting biomass into energy is just to burn it for producing heat, as humans practiced it for thousands of years. Still this is the most common way for conversion of biomass into energy in United States and elsewhere also.

The heat generated from biomass can be used for heating, cooking, and industrial processes, or for producing electricity.

Using biomass for burning haves some problems regarding some energy waste and also some air pollution if it is not carefully controlled.

There is a process for enhancing biomass energy while burning it with coal in power plants; this is called “co-firing”. Biomass can reduce the use of coal in a boiler for up to 20 percent. Co firing of biomass with coal contains benefits like lower operating costs, reductions of harmful emissions and most of all greater energy security. Co-firing is capable of developing and surviving independently for increasing power generation today. In 2000, the co-firing of switchgrass with coal was tested at Alliant’s Ottumwa Generating Station in Iowa; this test was a jointly conducted by the Chariton Valley Biomass Project, Alliant Energy, The U.S Department of Energy, and local biomass groups.

This project got so much successful that in 2005 Alliant Energy got the permission to build a permanent biomass processing facility at the plant. That plant is capable of co-firing up to five percent of its energy with switchgrass.

For converting biomass into energy there are number of non-combustion methods. These methods haves the capability to convert raw biomass into gases, liquid fuels, or solid fuels so that it can be used directly in the power plants for generating electricity. Biomass usually contains carbohydrates, which are composition of oxygen, carbon, and hydrogen and that can be broke down into different types of chemicals from which some are very useful fuels.

This non-combustion conversion of biomass can be done in following three ways:

Thermochemical

When biomass in the plant is heated but hasn’t burned then it breaks into various gases, liquids, and solids. Then these processed products can be further refined into useful fuels such as methane and alcohol. When biomass convert into gas it captures methane released from the plants and then burn it in a gas turbine to produce electricity.

There is another method, which is to take these fuels and run them through fuel cells, converting hydrogen rich fuels into water and electricity. This process haves few or no emissions.

Biochemical

Bacteria, enzymes and yeasts are also capable of breaking down the carbohydrates of biomass. Such as process of fermentation, which is used to make wine, in this process biomass changes into alcohol, which is a useful combustible fuel.

There is another similar process like fermentation, which is used to turn corn into grain alcohol or ethanol, and then it’s mixed with gasoline to make gasohol.

When bacteria breaks down biomass it also produce methane and carbon dioxide. That methane can be captured from sewage treatment plants and landfills and can be used for heating and power.

Chemical

Biomass oils such as soybean and sunflower and canola oils are capable of being converted chemically into a liquid fuel similar like diesel fuel and also into gasoline additives. For example cooking oil used from restaurants can be used for making biodiesel for trucks. There is also a better way for making biodiesel by using algae as a source of oils.

There are many people who believe that biomass takes more energy to produce fuels from biomass than the fuels themselves contain. In simple word it can be said that it is a net energy loser.

But most of studies done in last 10 years had confirmed that the production of ethanol is a positive energy balance. U.S. Department of Agriculture made a study in 2002 regarding that matter and it shows that technological advances in ethanol conversion and efficiency increases in farm production have caused the net energy value (NEV) of corn ethanol to increase gradually over time. It also shows that every British thermal unit (BTU) of energy, which is used in the production of ethanol, leads to a 34 percent energy gain.

This is truth also that it can be done much better. Currently corn-based ethanol is gained from the corn plants, for producing ethanol only corn kernels are used but not the entire kernel.

To make ethanol from energy crops we can extract four or five times more energy than we had consumed on crops growing. And if we make electricity from that then the obtained energy ratio get high up to 10 times more than that.

For having a sustainable biomass energy system in the future its necessary to replace the fossil fuels with the biomass or other renewable fuels to plant and harvest the crops.

Another issue regarding biomass energy systems is that biomass contains less energy per pound than fossil fuels. So it means that raw biomass is not typically cost effective for shipping more than about 50 miles before it is converted into fuel or energy. This particular issue regarding biomass shows that biomass energy systems are likely to be smaller than their fossil fuel counterparts. Reason for making smaller biomass energy systems is that it’s hard to gather and process more than this quantity of fuel in one place.

But that is not the drawback of biomass energy it can be beneficial for the local, rural communities and even individual farms. So that they will be able to design energy systems that are self sufficient, sustainable, and perfectly adapted to their own needs.