Biomass Energy Controversy

There is a lot of contention over the sustainability of biomass energy. Some argue that this is a 'carbon neutral' energy source as the uptake of CO2 during regrowth of new biological material equals the CO2 released through the burning of biomass. However, the biosphere is a complex system, therefore, this could be seen as an over-simplified view. 

Abbasi & Abbasi (2009) argue that although biomass production is carbon neutral, it not nutrient neutral, with large scale biomass energy production disrupting the nitrogen cycle, resulting in eutrophication. The study also highlights the large quantity of water required for biomass growth. In Arizona, for example, the rate of groundwater used for corn production is ten times that of aquifer recharge. 

Another key issue, is the replacement of tropical rainforests with monoculture plantations for the energy industry. Danielsen et al., (2008) highlights the importance of tropical regions for carbon sequestration; this is greatly reduced when replaced by monoculture plantations. These areas are also biodiversity hotspots and the removal of natural vegetation results in an immediate loss of flora, fauna and habitats.  As a result, biomass energy production in these regions is unsustainable. Not only is carbon released into the atmosphere through rainforest removal, the plantations are less effective carbon sinks, resulting in a net increase in atmospheric CO2. The study states that preventing topical deforestation is likely to be a better method of combating climate change than biofuel use.

Rainforest clearing for Palm Oil Plantation in Cameroon
Source: Greenpeace

Sulphur oxide, nitrogen oxide and black carbon emissions are another significant impact of biomass burning. Galdos et al., (2013) outlines the environmental and social issues of Brazilian sugar cane ethanol production. The process involves pre-harvest burning of unwanted biomass which releases huge quantities of black carbon. This is not only hazardous to human health, it also absorbs long-wave radiation which has a net warming effect on the Earth. However, the study did state that improving mechanisation of this process is reducing the need for pre-harvest burning. 

Hill et al., (2006) looked at the benefits of biomass, in particular biofuels, finding that biofuel produced by waste and on marginal land is more environmentally beneficial than food-based biofuels. The study also suggests that biodiesel uses less nitrogen, phosphorus and pesticides and produces fewer pollutants per net energy gain than bioethanol. 

There are also political and economic benefits of biomass energy, including reduced dependence on other nations and the potential for biomass energy to be cheaper than fossil fuels. But can't this be said for other the renewable energy options that appear to be more sustainable? 

To conclude...

After my research, I still don't see biomass as a sustainable option, especially when produced in tropical regions where the negative environmental impacts vastly outweigh the benefits. For electricity and heating production, there are more sustainable options, however there is one area where I do see the benefit and that is biofuel. 

Transportation is responsible for circa 13.5% of greenhouse emissions, however, it is difficult to rapidly change this sector due to the high cost of replacing vehicles with green alternatives. The technology behind electric and hydrogen vehicles is now well developed, but the cost is still a barrier. Biofuel, particularly biodiesel, could be a more sustainable option in the short to mid term until there are technological improvements and a price decrease in green transport alternatives.In the longer-term however, focus should be on other more sustainable transport alternatives.