Biofuels: friend or foe?


The concept of using biomass, or biological material, to reduce reliance on the Earth’s natural resources and decrease harmful emissions has been hailed by some as the solution to global warming. But others have rejected it on account of the energy required to produce the fuel and its impact on food prices, as agricultural land once dedicated to growing food crops is switched to the production of crops for biofuels.

The RENEW project set out to establish what the real story is with biofuels, assessing various methods of biomass fuel production and Europe’s potential to produce biomass material. The 31 partners from 8 EU Member States and Switzerland include representatives of the automotive sector, the mineral oil industry, electricity producers, pulp and paper production, process engineering and universities.

The results show that there are ‘multiple opportunities’ in Europe for producing ‘biomass to liquid’ (BtL), a type of biofuel made from ligno-cellulosic biomass such as wood, straw and energy plants. The researchers reached this conclusion after investigating BtLdiesel, as well as two other options: methanol/Dimethyl Ether (DME) and bioethanol.


Renewing what we know about biofuels

RENEW had three objectives: to further our understanding of BtL production methods and BtL’s suitability for current and future vehicles; to assess Europe’s regions’ potential for producing biomass and analyse environmental, economic and technical aspects of production; and to provide recommendations for stakeholders.

The research involved tests at six gasifiers (facilities which convert biomass to gas) around Europe, while BtL was produced in quantities of several thousand litres in Freiberg, Germany. The team looked at the whole life cycle, from well to tank, and the technologies involved at each stage. Researchers assessed the economic costs of production and distribution, as well as the environmental impact of the biofuels. The environmental assessment covered global issues such as climate change and local impacts like the acidification and eutrophication of soils and water and local air quality (summer smog).

‘Substantial’ potential

The RENEW team concluded that synthetic BtL fuels could have a substantial effect on reducing emissions from transport. According to the European Environment Agency (EEA), carbon dioxide (CO2) emissions for the whole of the EU would have fallen by 14 % instead of 7.9 % between 1990 and 2005 if CO2 emissions from transport had fallen along with those from other sectors. Transport is actually the only area in the EU in which emissions are rising.

Tests in passenger cars and heavy-duty diesel engines showed BtL diesel and BtL DME to be the best fuels for use in today’s diesel vehicles, although DME requires engine modifications. Fuel consumption was either equal to or lower than that of conventional fuels, and the RENEW team believes that future research will lead to even greater reductions in energy consumption.

The RENEW scientists also proved that biofuels do not have to be harmful to the environment, and demonstrated that the impact of biomass production on the environment can be reduced if more sustainable production methods are used. The project partners recommend cutting fertiliser use, and increasing yields by using new species of plants.

Where to start?

The regions with the highest biomass density were found to be central France, eastern Germany and western Poland. The team says that Europe has easily enough biomass material to warrant building around 50 industrial sized BtL plants by 2020. These plants could produce enough biofuel to replace 4 % of the road transport sector’s total expected diesel demand.

With the total biomass potential predicted for the year 2020, assuming that only 50 % will be used for transportation, 12 % of the overall fuel demand (17 % of total diesel demand) for road transport could be substituted.

Naturally, government and industry want to know about the overheads involved in producing biofuels. Costs for biomass from short rotation coppice willow, in which shoots are harvested from the willow tree every few years, are in the range of EUR 4.3 to EUR 5.8 per gigajoule (GJ) of energy produced. Costs for straw and forest residues range from EUR 2.4/GJ to EUR 5/GJ. The project predicts a harmonisation of prices across Europe at around EUR 3.5/GJ or EUR 4/GJ. In comparison, energy from crude oil cost around EUR 5.5/ GJ in early 2008, before refinement. Under optimum RENEW conditions, overall BtL production costs could range between EUR 0,5/l and EUR 0,9/l diesel equivalent.

In terms of technology, two production methods met the project’s efficiency, maturity and ecological requirements: the ‘black liquor gasification concept with a DME synthesis’ and the ‘centralised entrained flow gasification with a Fischer-Tropsch diesel synthesis’. The first method involves integrating new technology into an existing pulp mill. The second method involves a stand-alone plant producing synthetic diesel that can be used in unmodified engines. Their conversion efficiency – the amount of biomass that they are able to convert into fuel – is 69 % and 54 % respectively, and both methods are flexible in terms of the category of fuel produced.

First steps first

The next step for the biofuel research community is to set up a demonstration project to test the concepts developed by RENEW at the 50-megawatt scale.

Looking even further into the future, the RENEW team identified the most suitable locations for the first industrial scale BtL plants. The researchers propose west Poland, which offers plentiful, low-cost biomass, and Sweden, which is already home to a well-established forestry industry, residues of which are currently available at relatively low costs.

RENEW’s results provide a solid foundation for the further development of the next generation of biofuels, thereby ensuring that this important energy resource can contribute fully to Europe’s energy supply in the future.