Renewable Futures: the Sustainability of Biomass
Professor Tony Bridgwater, Director of the European Bioenergy Research Institute, shares his thoughts on the sustainability of biomass, carbon capture and storage and how EBRI is advancing bioenergy technology processes.
Biomass is quite amazing. Take some carbon dioxide out of the air, some water out of the ground, shine a bit of sunlight and what have we got? Lots of weeds in the back garden.
We also get trees for timber, grass for cattle and many food crops. All of these contain energy. Energy to live by and energy to benefit from.
Biomass is unique in fixing carbon from the atmosphere into plants. No other energy source can do that. And carbon is at the heart of our society for transport fuels and many consumer goods such as plastics and clothing.
So biomass is the only renewable source of many of the goods we take for granted today. And we must not forget wastes – municipal solid waste, commercial waste, food waste and crop waste.
For every 2 tonnes of biomass we process into useful forms of energy, approximately 1 tonne of oil or gas, or 1½ tonnes coal is left in the ground unused. That means a reduction in manmade carbon dioxide and potentially contributes enormously to meeting our greenhouse gas commitments.
We can do even better than this by using carbon capture and storage where CO2 is removed from flue gases in biomass combustion, liquefied and buried deep underground in old oil and gas wells. This is called bioCCS and turns a carbon neutral situation into a carbon negative opportunity. That doubles the benefit of replacing oil or gas by biomass.
So how is biomass used? It is increasingly used for power generation to replace coal. Drax for example, is converting half its coal fired power generation into biomass fired power generation.
In biofuels, there is increasing use of bioethanol in petrol and biodiesel in diesel in most of the industrialised world. But this raises issues over competition between food and fuel. First generation ethanol comes from corn, wheat and sugar, all of which are also food for many people. That is why second generation biofuels from non-food crops are increasingly being researched and developed. Here the UK, including the European Bioenergy Research Institute at Aston University, is making extensive contributions in both basic science and applied research to start building advanced technology processes such as biorefineries.
A key question is where the biomass comes from. At best the UK has the potential to produce around half our land transport fuel needs from biomass with nothing left over for electricity or any other purpose. We will therefore need to import a significant amount of biomass, and this is already being done with pellets from USA and Canada for co-firing. Drax for example will import 90% of its biomass needs when conversion is complete. And most new projects are sited near major ports to facilitate importation.
Wastes can supplement these imports and the European Bioenergy Research Institute is researching and developing a wide range of waste as well as biomass technologies for our bioenergy and biofuels needs for the future.
While it is not difficult to measure and control the sustainability of home grown biomass, imports are a different matter and there is still no consensus on how this can be done reliably on a global basis. But the UK is driving this through the SUPERGEN Bioenergy Hub.
Biomass is predicted to be the largest single source of renewable energy up to 2050 and its unique quality as renewable carbon guarantees this dominance.
So when you go into your gardens this summer and curse the weeds growing there, remember what they stand for – a sustainable and environmentally friendly future.