Uses of Biomass





Biomass is the solid form of biological energy sources which includes things like wood, wheat chaff, corn, algae and any other solid biological energy sources. Here we provide an outline of the various uses of biomass.

Thermal Energy

Large bonfire. Image by Fir0002.

Large bonfire. Image by Fir0002. License: GNU FDL

Probably the most familiar and easy to understand use of biomass is burning to produce thermal energy. Burning wood is one of the most common biomass uses worldwide and has been used by humans for millennia. In addition to wood any biological material that can be dried and burned could be used to produce thermal energy. Certain ovens and heaters can use pelleted biomass fuels to produce heat for cooking or homes. Combined heat and power systems burn wood waste to produce electricity and heat.[1] Wood shops or other locations that require electricity and have many wood scraps get a lot of use from such systems. Of course fireplaces, camping, wood stoves, and many other activities make use of biomass thermal energy.

Chemical Processing

Biodiesel sample in flask. Image by Shizhao.

Biodiesel sample in flask. Image by Shizhao. License: GNU FDL

Transesterification is a process that converts fats into biodiesel. Oils (triglycerides) react with an alcohol using a catalyst like sodium hydroxide (lye) to produce biodiesel and glycerol.[2] Vegetable oils from biomass are most commonly used for the production of biodiesel. Rapeseed and soybean oil are popular biodiesel feedstocks but waste vegetable oil is commonly used as a cheaper alternative. Algae, animal fats (waste), and other plant sources are also used. Once produced biodiesel can be used in a diesel car with very limited modifications.

Biomass integrated gasification combined cycle power stations are biomass driven power plants. Biomass gasification is a process where biomass is brought to high temperatures without combusting through the addition of steam. Gases from the biomass are released as a result and are captured and stored as biogas fuel. IGCC power stations typically convert coal to syngas but substituting biomass results in a renewable energy biomass based syngas. Resulting gas from this process is similar to the final product of waste to energy systems that use landfill gas to produce biogas as mentioned below.

Below is a video explaining coal fed integrated gasification combined cycle (IGCC) power. Biomass can be used instead of coal and the process is the same as described in the video.

IGCC power technology is an advantageous way of using biomass and coal for energy because it minimizes the amount of pollutants released during operation. Currently there are only a few IGCC plants operating worldwide. Current and expected regulation on carbon emissions from coal power sources have made investors turn away from coal including IGCC.[3] Biomass might be the right “green energy” source to keep IGCC technology around.

Biochemical Processing

Ethanol plant in Turner County, SD, USA. Image by Jon Platek.

Ethanol plant in Turner County, SD, USA. Image by Jon Platek. License: US PD

Bioalcohols like ethanol, butanol, and propanol are produced by yeasts, enzymes, or other micro-organisms consuming sugars, starches, and cellulose in plants. Sugarcane is a very popular crop for producing ethanol because of this. Corn for E85 is the most used ethanol biomass in the United States due to its low cost and local source. E85 is an up to 85% ethanol blend with gasoline used in flex fuel cars that are designed to use either E85 or gasoline.[4]

Large steaming compost pile being cooled to prevent combustion. Image by Ramiro Barreiro.

Large steaming compost pile being cooled to prevent combustion. Image by Ramiro Barreiro. License: CC BY-SA 3.0

Composting can recycle biological waste on a residential and industrial scale to produce soil amendment through the action of a variety of micro-organisms. Landfill volume and off gassing can be reduced if organic waste is separated, composted, and resold for agriculture. Additionally waste does not need to be covered and potentially harmful leachate is consumed during the composting step. Mechanical biological treatment is one such system that separates waste and uses either composting or biogas generation.

Landfill gas or biogas (mainly methane) is produced from bacteria consuming organic waste in landfills. Management of landfill gas can be a problem by itself so many waste companies are employing waste to energy programs to use this methane as fuel. One gas collection system in Sioux Falls, SD is connected to an ethanol production plant and provides all of its energy. Waste Management operates 110 landfill gas to energy projects which power over 400,000 homes.[5] Below is a diagram of a residential scale biogas plant for use in developing nations or rural areas.

Diagram of a domestic biogas plant. Image by Unknown.

Diagram of a domestic biogas plant. Image by Unknown. License: US PD

Sources:

1. Combined Heat and Power Partnership
2. Transesterification of Vegetable Oils to Produce Biodiesel Fuel
3. The Administration’s Ugly Prediction for Coal Generation and Electric Rates
4. US DOE: Flex Tech
5. Waste Management: Think Green

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