14 Biomass Energy Disadvantages and Drawbacks Explained

Biomass energy disadvantages are emissions, deforestation, seasonality, inefficiency, waste, cost, development, low-density, and non-scalability.

These drawbacks are discussed as follows;

1). Biomass Energy produces Greenhouse Emissions

Although biomass energy has been projected as a zero-emission type of energy, it is associated with the emission of greenhouse gases.

It has been observed that the use of biomass energy can reduce carbon dioxide emissions by 20%. However, other greenhouse gases may be emitted in much larger quantities.

Methane is an example of a greenhouse gas that is emitted when we use biomass to generate energy. It is 30 times more capable of storing heat energy than carbon dioxide. Others include carbon monoxide and nitrous oxide. The emission of these gases contributes to global warming, and implies that biomass energy is not perfectly ‘clean’.

2). Biomass Energy is Not Carbon-Neutral

Biomass (especially plants) all contain carbon, which is accumulated from the atmosphere during the process of photosynthesis [7]. When used as a fuel to produce energy, this carbon is released into the atmosphere.

Because biomass is renewable, it is generally assumed that it continues to recycle carbon in the environment, without significantly increasing the amount of atmospheric CO2 at any point in time.

However, this concept is an idealization. The dynamics of atmospheric CO2 is controlled by different factors within the natural carbon cycle. One of these is the storage potential of biomass with respect to carbon.

Because different types and species of biomass have different carbon storage capacities, biomass energy cannot always be carbon-neutral.

This can be explained using an instance where plant biomass which has a low carbon storage capacity is used to replace higher-storage-capacity biomass in a bioenergy farm. Such a replacement will ultimately lead to a rise in the volume of atmospheric CO2, since the storage capacity of the existing biomass is less than required.

Also, biomass which has been used to generate energy, is not always replaced. In such cases, the carbon which has been released into the atmosphere will not likely be reabsorbed or sequestered. In the long-term, such imbalances can contribute to climate change.

3). High Prospect of Deforestation

Without doubt, plant biomass is the most used organic material for producing bioenergy.

What this implies also, is that plant biomass must be available if any large-scale or significant biomass energy project is to be executed successfully.

Forests have always served as a natural source of large volumes of biomass. However, they also contribute to the atmospheric balance on Earth, by acting as a natural carbon sink [9] which sequesters or stores away much of the carbon which would have been released into the atmosphere. Forests also shelter a vast number of important organic species, and protect soils from erosion.

Biomass energy production increases the risk of dependence on forests to provide the needed biomass. This means that relying on biomass energy might lead to a higher rate of deforestation, which will have negative environmental, social and economic consequences.

4). Seasonality of Biomass Supply

While biomass in general is always available, some of the important species like switchgrass and sugarcane may vary in their abundance through the year.

This means that the supply of biomass may not always be consistent, and biomass energy is not perfectly reliable.

5). Relative Inefficiency

Compared to energy sources like fossil fuels, biomass does not stand out as a very efficient option.

One of the reasons for this is the fact that biomass has a relatively low energy density compared to fossil fuels [8]. For example, the average energy density of woody biomass is about 19.8MJ/kg2 [1], whereas that of natural gas is about 55MJ/kg2.

In combustion engines, most fossil fuels perform with an efficiency of 60-80%. This is not the case for biomass-driven engines, which may perform with efficiencies of as low as 10% or less. What this implies is that more than 70% of the energy from biomass is often lost.

The results of these limitations include the fact that biomass is not usually used solely to provide energy, especially in combustion engines and other elaborate systems. Rather, it is more often used in combination with fossil fuels like coal and diesel. Also, the low efficiency of biomass implies that it might nor be able to effectively replace fossil fuels as a source of energy.

6). Waste Production

While biomass energy-generation is an avenue for managing organic waste, it is also often an avenue through which waste is produced.

Some of the by-products of burning and converting biomass (to produce energy) include sulfur dioxide (SO2), carbon monoxide (CO), carbon dioxide (CO2), volatile organic compounds (VOCs), mercury, arsenic, lead, chromium, and cadmium.

7). Exhaustion of Natural Resources

On of the key demands of biomass energy generation is space. This includes the land space required to grow crops which can be used as biofuel, and the space required to carry out the processes by which energy is derived from biomass.

Land is itself an important natural resource, and the extensive production of biomass energy implies that this resource will be heavily relied upon.

Water is yet another natural resource which is significantly needed in order to harness biomass energy. It is estimated that for each liter of biofuel produced, about 1,400 liters to 20,000 liters of water may be consumed [6]. This is a notable challenge, since water is a very important natural resource on Earth.

Water itself can be used as a source of renewable energy, which is much cleaner than biomass energy. It is therefore not always beneficial to use this resource as an ingredient to facilitate the production of biomass energy.

8). Biomass Energy is Relatively Expensive

In spite of the fact that biomass itself is a renewable resource, the production of biomass energy is often expensive relative to other forms of energy.

One of the reasons for this is that biomass energy plants are generally expensive to build. They also generally require a high level of maintenance. Compared to other renewable energy options like hydro, wind and solar, biomass energy projects are not always economically profitable.

Also, while the extraction of biofuels is much less expensive than the extraction of fossil fuels, the low energy density and low efficiency of biofuels in comparison to fossil fuels, almost appears to close the gap of cost between both options. An increase in demand for biofuel may as well increase the cost of accessing it.

9). Still Undergoing Development

Unlike several other established forms of energy, biomass energy is still in its developmental stage.

It can be said that this is partly caused by the fact that biomass energy itself presents several drawbacks and challenges. The relative inefficiency of biofuels, for example, has negatively impacted the level of interest and research in this area.

Because it is yet to be fully developed, biomass energy does not yet deliver its full potential like some other energy alternatives.

10). General Environmental impact

It has already been pointed out that biomass energy leads to the emission of some greenhouse gases and pollutants. However, it is still necessary to assess the overall environmental impact of this form of energy.

Deforestation is one of the most significant (potential) environmental consequences of biomass energy generation. Deforestation exposes the environment to higher risk of climate change and soil erosion [5].

By-products of biomass conversion and energy generation can pollute the soil, air and water. Also, the need for plant biomass may place a strain on the environment.

For example, private forests, and biomass-producing agricultural areas, are usually cultivated monoculturally (with one or a few species of crops). Monoculture is not generally good for the environment and the ecosystem. It reduces biodiversity and can decrease soil fertility [2].

With regards to soil fertility, biomass-production projects often require the application of large amounts of fertilizer to make crops grow faster and larger. This is not always good for the environment. Excessive fertilizer application has several, potentially-adverse environmental effects.

One of these is the release of greenhouse gases into atmosphere. Many mineral fertilizers contain nitrogen, ammonia, carbon dioxide and methane, which can be emitted as the fertilizer is broken down by heat and microbes in the soil.

Another environmental effect of fertilizers is the growth of algal blooms in water bodies [4].

When nitrogen from fertilizer is washed into water bodies, it provides a bountiful supply of nutrient to algae, thereby causing the formation of large algal blooms.

This leads to a gross decrease in the volume of oxygen in water bodies. Several of these algal blooms are also harmful, and may release toxins into the water. Consequences of these occurrences include water pollution and a loss of aquatic life.

11). Land-use Challenges

This is a closely related problem to the issue of natural resource depletion.

Biomass energy production often requires that large expanses of land be used to cultivate energy-dense and suitable plant biomass like sugarcane.

However, food insecurity is a major challenge in the world today. This means that agricultural land is in high demand. Biomass energy production raises the debate on land-use priorities. Clearly, such a debate is hardly in favor of biomass energy production, as food is one of the greatest necessities for human survival.

The move to extend the development of biomass energy may affect the food supply chain, such that food prices may increase as the production and use of biofuels. Biomass production may also reduce the availability of agricultural land for food production. These are all negative potential impacts.

12). Potential Health Problems

Obviously, when biomass like firewood is burnt to produce energy, large volumes of gaseous by-products (otherwise referred to as ‘smoke’) are also produced.

Long-term exposure to such emissions can have health implications. Some of these include bronchitis, asthma attacks, stroke, heart failure and heart attack [3]. These illnesses are prone to become more rampant on the event that the use of biomass energy becomes more intensive and widespread.

13). Biomass Energy is Not Scalable

Because of the continuous increase in energy demand on Earth, scalability is one of the most critical attributes of any energy resource. It refers to the ability of energy to adapt easily (i.e. to be up-scaled) to meet increased demand.

Unlike many alternatives, biomass energy is not scalable. This is because the amount of energy output directly depends on the amount of biofuel which is being burnt. Because it is not scalable, biomass energy is a less-flexible option than several of its counterparts.

14). Low Energy Density

This is the main reason why biomass energy is not as efficient as fossil fuels.

Low energy density directly translates to low fuel quality, which means that biomass is a low quality fuel compared to several alternatives. It also means that we cannot expect nearly as much energy from biomass as that which can be obtained from fossil fuels.

As a result of these issues, the use of biofuel is not generally economical, especially when given other options. It is also not generally economical to transport biofuels over long distances using fossil-fuel driven vehicles. In some cases, the energy used to burn these biofuels is nearly equal to (or even more than) the energy which is produced eventually.

Conclusion

Many of the drawbacks of biomass energy are environmental. Although it is conceptualized as a clean and environment-friendly option (and is indeed cleaner than fossil fuels), biomass energy is associated with greenhouse gas emission.

It is also not perfectly carbon-neutral. This is because the carbon which is emitted when we break down biomass to produce energy, is not always re-absorbed by other organisms.

Biomass energy generation also leads to the production of large quantities of waste, which is potentially hazardous to the environment.

Fertilizer application in plant biomass cultivation poses the risk of greenhouse emission, water pollution, and toxic-algal-bloom growth.

Similarly, biomass energy demands the use of natural resources like land and water. Land itself is a crucial resource for agriculture, especially in the face of a growing population and rising food insecurity. Water is very critical for survival on Earth, and can be used to generate hydro-energy, which is much cleaner than bioenergy.

There are a few health challenges that are likely to arise as a result of producing and using biomass energy. One of these is bronchitis, and others include asthmatic attacks and heart failure.

Because biomass has a generally low energy-density compared to fossil fuels, it is a less-efficient option, and biomass energy production may not always be economical.

Lastly, biomass energy is not scalable. This implies that it cannot be adjusted in a flexible manner, to adapt to changes in energy demand.

References

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