SEB Bulletin October 2007
Plant Power - Background and Policy
Driven by the need to reduce carbon emissions worldwide1, a depletion in the world's fossil fuel supplies and accompanying increase in the price of crude oil, major moves are under way for governments to seek alternative sources of energy for the future. Bioenergy development is seen as the major alternative to fossil-based fuels and much research will be undertaken in the next two decades to move over to new and viable energy sources including biofuels2.
In its Strategy for Biofuels paper 2006, the European Commission states: “In the EU, transport is responsible for an estimated 21% of all greenhouse gas emissions that are contributing to global warming, and the percentage is rising. In order to meet sustainability goals, in particular the reduction of greenhouse gas emissions agreed under the Kyoto Protocol, it is therefore essential to find ways of reducing emissions from transport. This is not the only challenge. Nearly all the energy used in the EU transport sector comes from oil. Known oil reserves are limited in quantity and restricted to a few world regions. New reserves exist, but will mostly be more difficult to exploit. Securing energy supplies for the future is therefore not only a question of reducing import dependency, but calls for a wide range of policy initiatives, including diversification of sources and technologies… The EU is supporting biofuels with the objectives of reducing greenhouse gas emissions, boosting the decarbonisation of transport fuels, diversifying fuel supply sources and developing long-term replacements for fossil oil”.3
The US Department of Energy in its Biomass Program Plan 2007 - 2012 states: “Over the next 20 years, energy consumption in the U.S. is projected to rise by 30 percent; yet domestic energy production is only expected to grow by 25 percent. Petroleum imports already supply more than 55 percent of U.S. domestic needs, and they are expected to grow to more than 68 percent by 2025 as worldwide oil demand continues to rise and domestic oil production continues to decline. This increased reliance on imported sources of energy threatens our national security, economy and future competitiveness. Biomass is the only domestic, sustainable and renewable primary energy resource that can provide liquid transportation fuels and organic chemicals and materials currently produced from fossil sources. Biomass also supports a technology transition to a hydrogen economy through either gasification or the production and reforming of liquid intermediates such as ethanol, methanol, or bio-oil”.
DEFINITIONS
Bioenergy is energy derived from biomass, which is organic material such as wood, plants, or animal wastes.5
Biomass is any plant material which can be used as a fuel, such as energy crops, wood, agricultural waste and vegetable oils. Biomass can be burned directly to generate power, or processed to create gas or liquids to be used as fuel for production of power, transport fuels and chemicals6.
Biofuels are fuels made from biomass which can be used instead of traditional fossil fuels. Biofuels are most commonly used for transport, but are also used for small heating applications5. The three most common biofuels are:
Biodiesel - derived from vegetable oils, and can either replace diesel completely or be mixed in different proportions) - already available at the pumps.
Bioethanol - produced from a variety of agricultural feedstock, including starch crops, sugar crops and woody crops. By-products from the sugar industry, such as molasses, can also be used. The most typical feedstocks are wheat and sugar beet (Northern Europe) and sweet sorghum (Southern Europe). Bioethanol can be used in existing petrol engines, although some petrol is needed in addition to the fuel when cold starting.
Biomethanol - produced from wood but not as common as biodiesel and bioethanol.
'First generation' biofuels are derived from crops (generally food) such as maize, oil seed rape, wheat, sugar beet and sugar cane which convert the energy of the sun into simple carbohydrates such as sugar and starches. 'Second generation' biofuels are less easy to synthesise as they come from woody (generally non-food) crops such as Trees (willow and poplar) and Grasses (giant elephant grass, Miscanthus) which produce complex carbohydrates such as cellulose, wood and lignocellulose.
Science and Research
Large collaborative research programmes around the world are investigating the optimum biomass sources and their method of conversion to different energy outputs in order to establish a basis for large scale production of biofuels which are acceptable at an economic, environmental and social level. They work in cooperation with the IEA Bioenergy7, an organisation set up in 1978 by the International Energy Agency (IEA) with the aim of improving cooperation and information exchange between countries that have national programmes in bioenergy research, development and deployment. These programmes are national and international and serve a variety of research needs which will lead towards determining the most workable and sustainable bioenergy programmes for the long and short-term future. For example EPOBIO8 is a European Network in partnership with the USA whose aim is “to design new generations of bio-based products derived from plant raw materials that will reach the market place 10-15 years from now”. SUPERGEN9 on the other hand represents an interdisciplinary partnership in the UK which brings together people at all stages of bioenergy production including farmers, scientists and suppliers. Professor Tony Bridgewater (Aston University) who heads the programme says, “We are studying the production of different types of biomass and investigating their behaviour in thermal conversion processes to improve their performance. Bioenergy products are being expanded to include transport fuels and renewable chemicals within the context of a biorefinery. A wide range of system studies are included to evaluate the performance, cost, and socio-economic benefits of a wide range of bioenergy chains”.
Professor Gail Taylor10 (University of Southampton) runs the Bioenergy Research Programme of the UK Energy Research Centre11. Her research focuses on the use of Second generation crops such as Poplar and Willow with the aim of improving disease resistance and productivity to improve their growth across Europe as a bioenergy and timber crop. “My research is aimed at understanding how we can manipulate and improve fast growing trees for bioenergy - that isn't just liquid transportation fuel such as bioethanol and bio-oils, but also for heat and power”, says Professor Taylor. “We need higher yield because trees for energy are largely undomesticated and have not been selected and improved over centuries as have traditional food crops like wheat and maize. We may do this through traditional breeding but this will take too long and so we are using biotechnological routes to crop improvement that do not necessarily involve producing GM (genetically modified trees). We need trees that use water efficiently, have low nutrient inputs and are resistant to pests and disease”.
Professor Steve Long12 at the University of Illinois is the Deputy Director of the newly built BP-funded, Energy Biosciences Institute (EBI) alongside the University of California at Berkeley and the Lawrence Berkeley National Laboratory. As part of the EBI, some 340 acres of farmland at the Urbana campus will be devoted to the study and production of feedstock for biofuel production. Researchers will explore the potential benefits of using corn crop residues, switchgrass, Miscanthus and other plants as fuel sources. The initiative will explore how adequate supplies of high quality plant biomass can be sustainably produced and utilised in facilities that convert the biomass to fuels.13
Meanwhile, Shell has partnered with Iogen Energy to build and operate the first cellulose ethanol demonstration plant in Ottawa, Canada, that entered production in 2004.14 Unlike with other bioethanol fuel sources, cellulose ethanol is made from second generation plants such as corn stalks, straw and potentially from woodchips and does not compete for the world's food supplies. New powerful enzymes are used to separate the cellulose from the rest of the plant. The plant's lignin is burned to drive the entire process by generating steam and electricity. In the US, where GM crops are not banned as they are in most of Europe, a group of scientists from the Agricultural Research Service in Lincoln, Nebraska15 are releasing genetically modified sorghum which has a low lignin content and so is favourable as cattle feed and also as a biofuel since it is more easily digested by the cow as well as in the biofuel production process.
As well as large collaborative research programmes, smaller projects are investigating more basic and specific aspects of plant physiology and biochemistry which aim to underpin technological improvements in the future such as the productivity of plants to be used as biomass for bioenergy. For example, fundamental research in the laboratory of Professor Christine Raines16 (University of Essex) has shown that by increasing photosynthetic carbon fixation, plant yield can be increased by up to 30%. This work provides clear evidence that improvement of photosynthetic efficiency is a potential target to increase the yield of crop plants in order to improve their energy outputs, i.e. this would lead to a greater biomass per hectare of first generation crop planted. Professor Taylor (Southampton University) is also working at the fundamental research level: “There is a strong link between leaf size and biomass in Populus”, says Professor Taylor, “so an understanding of the genetic mechanisms controlling leaf development as well as the effects of CO2 concentration on Populus will help us to select more favourable varieties for biofuels in the future.
And what of the future? How will the large scale production of plants to be used for bioenergy affect agriculture and landscapes? “There is the issue of food versus fuel”, says Professor Taylor. “Do we have enough land to grow biofuel crops globally? Probably the answer is yes, but we need strict certification procedures and environmental assessments to ensure that these crops do not displace precious plant resources such as tropical rainforests. Geopolitics is complicated and nations must work together to address this problem”.
Sarah Blackford
Education & Public Affairs
References
1. http://en.wikipedia.org/wiki/Kyoto_protocol
2. http://www.epobio.net/overview.htm
3. http://ec.europa.eu/energy/res/biomass_action_plan/doc/
2006_02_08_comm_eu_strategy_en.pdf
4. http://www1.eere.energy.gov/biomass/
publications.html#vision
5. http://www.bioenergywm.co.uk/bioenergy
.aspx
6. http://www.eia.doe.gov/kids/energyfacts/
sources/renewable/biomass.html
7. http://www.ieabioenergy.com/
8. http://www.epobio.net/
9. http://www.epsrc.ac.uk/ResearchFunding/Programmes
/Energy/Funding/SUPERGEN/BiomassAndBioenergy.htm
10. http://www.soton.ac.uk/~taylor/projects.htm
11. http://www.ukerc.ac.uk
12. http://cropsci.uiuc.edu/faculty/long/index.cfm
13. www.bp.com
14. www.shell.com
15. http://www.ars.usda.gov/is/AR/archive/sep07
sorghum0907.htm
16. www.essex.ac.uk/bs/staff/raines/rainesb.shtm#res
