It is the easiest and most available source of energy for those without access to an electrical grid or other sources of energy. Food, waste products, firewood: all of these are sources of biomass energy.
For many people in the world this is the only option for producing energy and therefore worth learning more about the opportunities and challenges biomass presents socially, economically, and environmentally.
What is biomass energy and how is biomass energy used?
Biomass energy is any natural organic matter that can be burned directly or converted to other forms of fuel and is used often for lighting, cooking and heating. It can also be defined as energy that is produced from plants and animal-based organic materials, such as crops, woody materials, and animal manure.
It is a large source of energy in many rural parts of the world where access to an electrical grid or other energy sources are limited and biomass feedstocks are abundant.
As humanity searches for solutions to our energy challenges, it is likely that biomass energy will play an increasing role in transitioning toward a fossil fuel-free energy future.
However, as with every other energy resource, there are advantages and disadvantages to the production and use of biomass energy.
The most common types of biomass energy fuels
The most commonly used raw material inputs for biomass energy production are agricultural byproducts such as fuelwood, crop residues, or human and animal waste products.
Trees are the largest biomass feedstock, where fuelwood is often easily accessible. Dried dung from livestock is also a common source of energy used throughout the developing world.
Advantages of biomass energy
#1 Abundant and renewable source of energy
Biomass is the cheapest and most available energy resource, and is the main source of energy for the world’s lowest socioeconomic groups.
Biomass is a byproduct of living organisms, and as such, is a truly renewable resource for energy.
Biomass can be an output from waste residues, providing an opportunity for upcycling the waste material for energy production.
As opposed to the highly technical renewable energy production of wind and solar energy, a major benefit of using biomass as an energy source is that it can be easily sourced and stored (for instance wood and dried waste products).
Biomass is an endless source of renewable energy and can produce value-added products such as biofuel and biogas. Heat and electricity can also be generated through the conversion of biomass energy.
#2 Biomass can help with waste management in addition to energy production
Biomass energy production can reduce the need for landfills in communities and reduce overall methane emissions.
When municipal solid waste is used to produce energy instead of storing that waste in landfills (also known as “waste-to-energy”), it reduces the requirements for landfill space and eliminates the potential for toxic landfill leaks.
By reducing the need for additional landfills, also eliminate the methane gas (a potent greenhouse gas) that would have been emitted by those landfills.
Large amounts of organic waste and agricultural residues are created every day. Waste from livestock and unwanted surplus of crop residues can be converted into usable energy. This presents a great opportunity to assist low-income populations to have energy security.
#3 Biomass can be generated from local sources
Biomass energy can be produced domestically, reducing the need to rely upon imported foreign oil.
Local energy production reduces the amount of transport and therefore decreases the prevalence of a society dependent on fossil fuels from transport. This in addition to the lower emissions of biomass compared to conventional fossil fuels.
#4 Biomass can offset emissions from fossil fuels
Although some carbon emissions are released as the biomass energy is burned, biomass energy feedstocks* such as switchgrass and algae capture carbon dioxide during their growth cycles, making them potentially carbon neutral sources of fuel. In contrast, fossil fuels never capture carbon emissions, but instead release carbon when burned.
Biomass can be used instead of fossil fuels which helps reduce overall carbon emissions.
Biodiesel is derived from biomass, which can be used to power vehicles and helps reduce emissions from transportation.
#5 Variety of organic sources
Unlike fossil fuels, biomass can be used to produce fuel from a variety of organic sources that are widely available. Examples of biomass that can be used to produce fuel include corn, soy, switchgrass and other native prairie grasses, industrial hemp**, algae, solid waste, wood chips, animal manure, sewage, and mulch.
Disadvantages of biomass energy
#1 Health hazards
Biomass can be harmful to human health if combusted in enclosed space, such as a domicile for cooking. Such is the case in a home without proper ventilation, where airborne toxins from the burning particulate matter produce health risks.
Biomass from livestock excrement, which often contains harmful bacteria, can be detrimental to the ecosystem and human health. During a heavy rainfall event, the waste material will runoff into nearby waterways which many people use for drinking and bathing.
This exposure can lead to an assortment of illnesses like gastrointestinal diseases and developmental problems such as stunted growth in children.
#2 Decline in sustainable behavior
In the case of waste-to-energy, the development of permanent processing facilities in particular communities might discourage overall recycling participation rates or the development of other forms of clean energy, such as wind and solar energy.
#3 Energy use
Some biomass feedstocks, such as corn and soybeans, require large amounts of energy to grow and process. This results in very little to no net gain in energy resources. These biomass feedstocks also require energy to transport to where they will be processed and made into fuel.
The use of trees as a biomass energy feedstock can lead to widespread deforestation. This is particularly concerning, as the need for forests and their important role in carbon sequestration in a world of climate change cannot be understated. We need to be be planting forests, not cutting them down for fuel.
Land use change from deforestation produces large amounts of greenhouse gas emissions and can present dangers for human safety where trees provide important protection from natural events like flooding (via water retention) and landslides (holding soils in place).
Deforestation is one of the leading causes of increased greenhouse gas emissions and also produces runoff that acidifies waterways and causes harmful algal blooms that destroys aquatic ecosystems.
#5 Use of arable land
The production of some biomass energy crops requires arable land that could otherwise be used for food production. In a world with increasing natural resource scarcities of food, water, and other basic human necessities, the use of our world’s suitable arable land and other natural resources may need to be dedicated to producing sufficient food to feed a hungry human population.
#6 Source of emissions and air pollution
Although biomass is capable of producing 10 times more energy than renewables such as solar or wind (due to availability), biomass can also emit some of the highest levels of greenhouse gases.
For instance: gases like methane, nitrous oxide, and carbon-dioxide are released into the atmosphere during biomass production.
Large scale production if drawn from sources like cow dung can also produce excessive amounts of methane a greenhouse gas 4 times more concentrated than.
The removal of material with high quantities of methane, such as peat deposits, also releases vast amounts of the greenhouse gas.
Some biomass energy resources can also release air pollutants when burned, such as nitrous oxide, soot, ash and carbon monoxide.
#7 Unpredictability and seasonability
Biomass harvest can be unpredictable: The accumulation, harvesting and storage of raw biomass materials is quite lengthy and sometimes expensive compared to that of fossil fuels.
What’s more some biomass energy feedstocks are seasonal.
Safely harnessing biomass energy has the capacity to drastically improve energy resources for those far from an electrical grid.
Smart agroforestry practices can help ensure economic and energy security while protecting important natural resources.
Technologies continue to develop that will expand capture opportunities and improve the efficiency of utilizing biomass as a renewable energy resource. This will also allow for the transition out of economies that depend on fossil fuels.
The use of biomass as an energy resource is sure to become more prominent, however, the advantages and disadvantages, and therefore, the sustainability, of biomass energy are largely dependent upon which type of biomass is being utilized.
The biomass feedstocks that we choose to rely upon should not compete with food production, should work in concert with the restoration of forests and other natural ecosystems, and should not place an unsustainable demand on natural resources.
* “A feedstock is defined as any renewable, biological material that can be used directly as a fuel, or converted to another form of fuel or energy product.” – U.S. Department of Energy
** Where permissible.