A reality check on biomass ambitions
To combat climate change and reduce petroleum imports, some countries have started to adopt strong targets for renewable energy. For example, European Union law requires 20% of energy to be from renewable sources by 2020, and is targeting 27% renewable energy by 2030. So far, biomass is by far the largest contributor to meeting this target, and the use of biomass energy is expected to keep growing. Generating energy from some types of biomass (like cellulosic wastes and residues and sustainably grown energy crops) can deliver high emission reductions, but could there be enough of these resources to go around if the entire world looked to deliver 20% of its energy needs from biomass?
Resource Media, a non-profit communications firm based in the US, have created a handy infographic on biomass targets based on a study we published earlier this year. This infographic puts this kind of aggressive bioenergy target in perspective by illustrating the area that would be necessary to replace 20% of global energy from biomass in 2050. Biomass production takes land – a lot of land! The area that would have to be devoted to biomass energy crops would as large as the United States, Central America, the Caribbean, and a sizeable chunk of Canada combined. It would be equal to almost the entire area used to produce food crops today. Assuming that food production could be protected and that therefore dedicated energy crops like switchgrass, Miscanthus, or short rotation trees would be grown on non-agricultural land, these biomass crops would have to expand to use up all available grassland around the globe and encroach on 10% of the world’s forests.
What effects would this level of disturbance have on our environment? Digging up all that natural grassland would severely impact biodiversity, with massive disruption to existing ecosystems. If fertilizer is used on energy crops it could pollute waterways. Large quantities of water would be sucked up by these crops, even if we didn’t irrigate them. If we actually started cutting down forests to make way for energy crops, large amounts of carbon would be released. Even though using the wood from deforestation for bioenergy would to some extent mitigate the carbon release due to land use change, our lifecycle research has shown the payback time can be many decades long).
There’s a real opportunity for biomass energy to contribute to reducing climate change, but there’s also a very real risk that excessive targets could drive perverse outcomes. What’s a smarter path forward? An important start would be making sure that bioenergy targets are focused to what can reasonably be achieved without driving a level of environmental damage that is unacceptable to the public. Energy crops can be ecologically restorative as well as carbon negative when grown on degraded land – but there’s only so much of this kind of land, and we should temper our expectations of how much biomass we’ll get from it (see our recent review on energy crop yields on marginal land).
The environmental risks of high bioenergy targets highlight the importance of reducing energy demand overall. The above data and infographic are based on business-as-usual fuel use patterns. We can dramatically reduce fuel use with more efficient vehicles including electric vehicles, and many governments now have 2020, and even 2025, efficiency standards for new cars and are working on truck efficiency standards. There’s plenty of room for vehicle technology, as well as improving efficiency of appliances, to greatly reduce overall energy demand, reducing the need to convert so much of the planet’s land to biomass production.
We should also prioritize bioenergy from wastes and residues that would not otherwise be used, including corn stover, wheat straw, small branches from harvesting wood, and garbage that would go to landfills. Even if a relatively small fraction of crop and forestry residues is collected on each acre, it can add up to a considerable and clean resource. Bioenergy from wastes and residues like these can deliver more carbon savings than what’s available from most first generation biofuels (again, see our lifecycle work).
We’re currently working on expanding some of our previous research on waste and residue availability in the EU to estimate how much biofuel could be produced from these low carbon sources in each Member State. As a whole, the EU should have no problem meeting and exceeding the proposed 0.5% advanced biofuel target from a resource perspective. Italy has already adopted a 0.6% advanced biofuel blending target for 2018, and other Member States like Germany are working on broader policies that offer more support for lower carbon biofuels. Hopefully the other EU Member States, and countries around the world, make similar policy moves in the near future. Steps like these go in the right direction towards bioenergy production that is both smart and sustainable