Organic matter is well known as a source of carbon-neutral energy, but is biomass renewable? In this article, we’ll address that question and a take a look at how sustainable biomass energy really is.
If you are new to the world of biomass, you might want to first read our article on what biomass actually is. This will help you gain a broader understanding of the topic.
What Actually Is A Renewable Resource?
Before we address the question of whether or not biomass is a renewable resource, let’s first take a look at what the term renewable actually means.
We can define ‘renewable’ as a natural source of energy that does not become depleted as we use it. With this in mind, we should now take a look at where biomass comes from to see if it falls under this category.
Where Biomass Comes From
Biomass has numerous sources, all of which occur naturally. Some, however, do have a human influence behind them and therefore we might choose to consider them ‘unnatural’.
Trees, Crops & Plants
The biomass industry mostly consumes organic matter deriving from trees, crops, and plants. This can include everything from wood products through to food crops and garden waste.
The biomass industry uses these sources in different ways. Depending on the type of biomass, they are capable of producing either electricity, biofuel, or even biogas.
All of these examples occur naturally and can be regrown in order to replenish stocks. We can, therefore, consider them to be renewable when managed in a sustainable way.
The biomass industry also makes use of both animal and human waste to create biogas. Waste is a completely natural byproduct that is replenished on a continual basis. This means it is also renewable and will exist for as long as there is life on earth.
This is slightly more of a grey area when it comes to renewable biomass sources. We can use garbage as a biomass source in one of two distinct ways which we will now explore.
1. By burning it to create electricity
Some people consider the burning of municipal waste (Refuse Derived Fuel or RDF for short) to be a form of biomass energy. Whilst this is not entirely true, the process is almost certain to involve the combustion of some organic matter. This is biomass, but in theory, is not naturally occurring.
Most of the organic matter found in RDF consists of food waste. This is not naturally occurring and is a byproduct of our inability to manage the wastage of food appropriately. We can, therefore, consider this type of biomass to be unnatural and non-renewable.
2. By leaving it to rot in landfill
When we send waste to landfill, it is left to rot. This process produces natural gas, mostly consisting of methane. Landfill gas is a type of biogas which we can tap and store for later use.
Landfill gas has the same problem as RDF when it comes to its renewable credentials. Whilst the gas may occur naturally as garbage decomposes, any organic matter that is sent to landfill is a man-made problem and does not occur naturally. Therefore, we should consider it to be non-renewable.
So Is Biomass Renewable Or Non-Renewable?
Well, this all depends on the type of biomass we are talking about. Let’s now discuss this in greater detail.
Renewable Biomass Sources
All naturally occurring forms of biomass are indeed renewable. If we manage these sources in a sustainable way, they will not become depleted as we consume them. Renewable sources of biomass include the following:
- Wood products including whole trees, logs, wood chips, offcuts, and sawdust.
- Energy crops such as wheat, corn, sugarcane, canola/rapeseed, soybean, sunflower, and potatoes.
- Waste products such as animal and human waste. This can also include used animal pen bedding.
- Animal fats commonly used in the biofuel industry to make biodiesel, an alternative to diesel fuel.
Non-Renewable Biomass Sources
There are, however, some distinct types of biomass which we should consider as non-renewable. This is because they are not naturally occurring and are a direct by-product of our inability to control waste.
With a stronger emphasis on reducing man-made waste (especially food waste), these types of biomass may become depleted and are therefore non-renewable:
- Organic matter found in waste streams, which some power companies burn in order to generate electricity.
- Natural gas formed as a result of people sending waste to landfill sites which then begins to rot.
What About Its Environmental Credentials?
So, we now understand that most forms of biomass are indeed renewable. Let’s now take a look at the environmental credentials of Biomass. There are arguments on both sides of the debate here.
Most scientists agree that renewable forms of biomass are environmentally friendly. This is because they are carbon neutral, meaning they release the same amount of carbon dioxide when burnt as they absorb whilst they are growing.
Whilst carbon neutral sounds like a good thing, we shouldn’t associate it as one of the true ‘green energy sources’ such as solar, wind, and geothermal. These energy sources all occur naturally and we do not need to burn them in order to generate power.
When it comes to garbage, we can consider this form of biomass to be less environmentally friendly than the other types. RDF is especially less kind to the environment as the waste it burns is likely to include non-organic compounds such as plastics.
We can conclude that most forms of biomass are indeed renewable energy sources. Most of these occur naturally and, when managed sustainably, will not become depleted as we use them.
There are several types of biomass that we should not consider renewable due to the fact they are waste products produced by man. These products do not occur naturally and may become depleted as our attitude towards waste reduction improves.
It is important to understand that whilst there are environmental concerns surrounding biomass, it is still far more environmentally friendly than fossil fuel alternatives.