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Bio-energy with carbon capture offers potential for 'negative emissions'
The use of carbon-based materials to produce energy mainly relies on the heat emitted by the carbon as it oxidises to carbon dioxide. We have been doing this for tens of thousands of years - since man first learned how to use fire for heating and cooking. For much of the time, this use ofto produce energy (bio-energy) has been a sustainable process as the carbon dioxide generated was used by trees and plants to grow.
However, once we started to use fossil fuels - oil, gas and coal - we started to generate more carbon dioxide than nature could use. This lead to a build up of carbon dioxide in our atmosphere - slowly at first, but accelerating as populations and their demand for energy increased. As a result of the "greenhouse effect" of carbon dioxide, we now have global warming and the resulting changes in our climate.
But we can use chemical or physical processes to actually remove carbon dioxide from the atmosphere. These methods can be expensive and energy consuming, and we have to try to find a use for the massive quantities of products. This is where the use of bio-energy with carbon capture and storage (CCS) emerges, creating the possibility of decreasing the level of carbon dioxide in the atmosphere in a more economic way.
This is the main finding of recently released Global Status of BECCS Projects 2010, commissioned by theand carried out by AB, a Swedish energy consultancy.
The report finds that bio-energy with CCS (BECCS) is a very useful tool for tackling climate change, as it is the only technology by which we can actually reduce the level of CO2 in our atmosphere. What sets BECCS apart as a climate mitigation measure is that if it is widely deployed it can result in permanent reduction in in this level of CO2 - in other words we can produce energy with "carbon negative" emissions.
The process works because trees and crops, when they grow, remove CO2 from the atmosphere. Using this biomass to produce energy or feed industrial processes, then capturing and permanently storing underground the CO2 released during conversion, leads to a "carbon negative" technology.
BECCS combines the natural CO2 capture process in trees and plants with the benefits of geological carbon storage. In other words, nature - in the form of sunlight - provides the energy required to collect and convert the carbon dioxide into a fuel or other material we can use to produce energy or energy products (such as biofuels).
The report finds that BECCS can be done at a reasonable cost. This is good news, as it means we can reach globally agreed climate targets (atmospheric levels of greenhouse gases) at a cost much less than required for mitigating climate change, while creating opportunities for more ambitious levels of emission reductions.
BECCS could be applied to a range of biomass related technologies, such as power stations, combined heat and power plants, a range of flue gas streams from the pulp industry such as from recovery boilers and lime kilns, fermentation inproduction and refining processes.
At the moment, there are only 16 projects worldwide aiming to install a BECCS process. Most of these are in Europe and North America.
The potential climate impact of combining biomass with CCS in BECCS systems is large, with negative emissions in the order of billions of tonnes. BECCS could also be a cost-effective technology for meeting ambitious climate targets. However, BECCS is still a new technology and the biomass it consumes must be produced in a sustainable way, without negative impacts on food production.
If we are to tackle climate change as comprehensively as needed, technologies like CCS and more encompassing processes like BECCS are urgently needed. Policymakers should be educated about these options, which should then lead to an increase in BECCS projects around the world.