By Suzanna Hinson
Clean energy is essential for a sustainable and secure future. But the clean credentials of some energy technologies are increasingly thought to be compromised by negative externalities. This is leading to the pursual of certain clean options being widely questioned and the future components of a sustainable energy mix being cast into doubt.
Large-scale hydropower for example often causes huge social and environmental consequences. The controversial Three Gorges Dam originally highlighted these limitations of large hydropower and we are regularly reminded of the balancing act of good and bad effects of the recent cancellation of the Amazon dam and on-going project in the Congo. The unanswered questions of whether the negatives outweigh the positives mean many clean energy scenario reports seek to avoid this compromised technology, focusing on small hydro instead.
Bioenergy too, once a clean energy panacea, appears now to be falling from favour. Currently the world’s main renewable, producing 10% of global energy supply, bioenergy is used in power stations for heat and electricity, in transport as biofuels, and largely in cooking stoves across the developing world. There are multiple types or “generations” of bioenergy, with the current main source being cropped such as sugar beet and soy. Despite being an established and renewable option, to some it has lost its value as a clean energy technology amid issues over deforestation, food insecurity and carbon neutrality, with the consequential erosion of support for the entire industry.
Using land to grow non-food crops is a key compromise to biofuel’s sustainability credentials. Direct land use change, with land grabs or deforestation to grow bioenergy crops, is associated with driving starvation and forest loss, with the consequential loss of biodiversity and carbon sinks, especially when the deforested land exposes peat bogs. Indirect land use change adds to the issues, with a transition from food to fuel crops, meaning the displaced food crops drive deforestation elsewhere.
In addition to the sustainability of production, the sustainability of combustion is also questioned. The fuels are generally considered carbon neutral as they release the carbon they took in with photosynthesis as they grew, but concerns over emissions from production, and land use change, suggests they can be more negative than neutral.
Bioenergy can also negatively impact air quality. Simple wood biomass, used in stoves across the developing world, is the cause of many premature deaths. Biofuels used in transport in developed cities have mixed results. Modelling in the UK has predicted a switch to biofuels in transport would cause a reduction in particulate matter, carbon monoxide and PM, CO and VOCs but small increases in NOx which has impacts on ozone. The issue of biofuels and air quality remains debated however based on the biofuel used and the engine adaptions.
With so many questions over sustainability, pursuing bioenergy can seem like opening a Pandora’s box of problems. But it is important not to homogenise the vast and diverse bioenergy sector. Though there is undoubtedly bad bioenergy, produced through poor practice that must be combatted, there is also good bioenergy, which is not only a truly clean energy option but also a vital one for decarbonisation.
The issue of land use change is severe but also complex. Attributing the issue to bioenergy is simplistic and incorrect. The main driver of deforestation is agriculture, with soy and palm oil key cash crop culprits. These are both used in biofuels (though there is no palm oil used in the UK) but also, widely used in animal feeds and for the cosmetics industry. The meatification of diets worldwide is hugely increasing demand for animal products, with some now concerned that meat agriculture is the main cause of global warming as well as a contributor the obesity issues we face. Beef production alone is thought to use 60% of the world’s agricultural lands. Similarly, palm oil, is used widely in processed food but also cosmetics and bioenergy is a relatively small sector of demand. It is easy to see if biofuels were banned, these other sectors would quickly absorb their land share. Deforestation is complex and bioenergy is but one part of the problem.
Nevertheless, any bioenergy that contributes to deforestation, directly or indirectly, should not be encouraged. Forests are an essential carbon sink as well as a critical resource for biodiversity and their loss at the hands of the meat, cosmetics and other industries should not be exacerbated by an energy industry seeking to reduce carbon. But not all bioenergy contributes to deforestation. In many places marginal land, unsuitable for food crops or much else, can be used to grow bioenergy crops. Additionally, some crops can have dual uses, where the protein can be used for animal feed whilst the carbohydrates go to bioenergy. As bioenergy crops often have stricter sustainability criteria than food crops, such dual uses can drive up production standards across the agriculture industry. There is also the option of sustainable forest management, in countries such as Sweden and Finland where there is plentiful forest, centuries old management can be applied to sustainably harvest resources without deforestation.
Bioenergy can, therefore, be produced in ways that maintain its clean credentials. Advanced bioenergy offers, even more, possibilities. As we have deduced, there are multiple types or generations of biofuels and so far we have only dealt with one, the first generation. There are great opportunities for the second generation of biofuels, produced from non-food crops or from waste recycling to eliminate any displacement arguments. TFL claims almost one-third of London’s buses already run on these biofuels from waste such as cooking oil and tallow from meat processing. The third generation of biofuels, produced from algae has even greater promise. Though this technology is very much in a research phase at present, it offers the potential for carbon-neutral fuel grown on the sea, which also provides waste products for medical and cosmetics industries and simultaneously helps to rejuvenate and cleanse ocean environments of excess carbon and nitrogen, limiting acidification. With so much potential in the highly diverse bioenergy sector, it is unreasoned that the entire industry is often homogenised, its flaws emphasised and used to argue for an end to bioenergy.
An end to bioenergy, however, would, at present, prevent complete decarbonisation. Energy demand comprises multiple sectors; electricity, heat and transport. Electricity can make great advances with renewables such as solar, wind and tidal power. Similarly, industrial and domestic heat can be supplied with electric heat pumps, advanced nuclear and carbon capture and storage instead of biomass, though sustainable biomass could be an important bridge technology to heat decarbonisation whilst the alternatives are developed and deployed. Transport, however, is the sector where bioenergy is indispensable. There are approximately 36 million cars in the UK of which only 76,000 are electric (0.2%). In personal transport, biofuels are an essential bridge allowing the decarbonisation of the transport sector whilst electric vehicles and better batteries are developed and the electricity grid is adapted to provide sufficiently and decarbonised energy. In aviation, there is currently no other realistic decarbonisation option than biofuels. Essentially, with transport being such a significant part of the global energy mix, it will be impossible to decarbonise energy without biofuels under present technology. Those arguing for an end to bioenergy are inadvertently arguing against the greater need for an end to fossil fuels.
As well as reducing demand for fossil fuels, bioenergy also has the potential to be part of a technology that reverses the damage that years of fossil fuel combustion has wrought on the global climate. Such negative emission technologies are based largely on the promise of carbon capture and storage (CCS). CCS technology has had the whole chain demonstrated is under development around the world and offers great opportunities for decarbonising power and heavy industry. Combining bioenergy, which absorbs carbon as it grows through photosynthesis, with CCS, which captures and permanently stores carbon in the Earth’s crust, will allow carbon to be actively removed from the atmosphere. This, in essence, would allow a partial reversal of the rise in carbon emissions at a time when climate change is accelerating and efforts to keep warming to safe limits of 1.5°C or 2°C look doubtful. Although there is much to be done in making this idea a reality, it certainly is a promising, and potentially necessary option, in which the role of bioenergy is essential.
Bioenergy is a broad term, encompassing energy fuels that are both good and bad. Often these are homogenised to make damning judgements against the whole industry. But bioenergy, particularly biofuels, are vital to decarbonisation. They are far from a panacea but it is unjust to dismiss them as a Pandora’s box. We cannot do it without them.
 Title credit from: Ransom, P. (2014). Ecotourism in Munduk Village, Bali: Panacea or Pandora’s Box? Bachelor of Arts, Cambridge: University of Cambridge.
 It is important to note that whilst alternatives, such as electric cars, produce no emissions or pollutants, if the electricity used to power the cars was produced from fossil fuels elsewhere then the pollution has only been displaced, not removed.