Bioelectricity
for transport
A wide range of biomass resources can be used as a fuel in Combined Heat and Power (CHP) plants for the generation of bioelectricity. Biomass may be co-fired in coal power plants or in smaller dedicated biomass energy plants, where there is a reliable local supply of feedstock.
Typically 10% of biomass can be used for co-firing [Source: IEA Clean Coal] - avoiding issues such as slagging and fouling. High percentages of biomass in co-firing may be enabled by Torrefaction [Source: Torrefaction for biomass co-firing in existing coal-fired power stations; Bergman et al 2005). Torrefaction is a thermochemical process typically at 200-300 °C in the absence of oxygen, at atmopsheric pressure with low particle heating rates and a reactor time of one hour. The process causes biomass to partly decomposes, creating torrefied biomass or char - or "biocoal".
Note: 700m tonnes of coal are used in Europe every year and there are only 300m tonnes of wood produced. So even if every piece of wood was used for biocoal production, this would still not meet current energy demand. As in other areas of bioenergy, feedstock availability (rather than technology issues) may ultimately be the limiting factor.
In 100% biomass energy plants, typically wood wastes are dried and combusted to generate heat for district heating, and to power steam turbines to generate electricity.
CHP plants are often built into the design of biorefineries, which can be used for production of biofuels and/or other products. Bioeletricity can be used within the production process (i.e. to power the biorefinery) and/or be exported to the grid, potentially for use by electric vehicles.
Recent links and reports on combustion, pyrolysis and gasification of biomass are provided by the ThermalNet project. The final report of ThermalNet - Thermal Biomass Conversion - was published in November 2009.
Higher efficiency power generation via gasification of biomass
Biomass integrated combined cycle gasification (BIGCC)-gas turbine technology (BIG-GT) potentially offers much higher efficiences than conventional CHP, and was investigated in the late 1990s and the early 2000s. Several demonstration plants were built. However, at the current time, biomass gasification technologies for heat and power are not considered competitive with combustion (i.e. the costs for generating bioelectricty via gasification are higher). Hence biomass gasification research is focused on production of synthetic biofuels (e.g. BioSNG). [Source: ThermalNet].
The Värnamo plant in Sweden was the world's first IGCC plant and was designed to generate 6 MW of electricity and 9 MW of heat for district heating from wood chip. Further information is available from the Växjö Värnamo Biomass Gasification Centre (VVBGC) (which now focuses on gasification R&D for production of liquid biofuels).
In 2001, a demonstration plant was comissioned in Brazil with support from the EU-BRIDGE (EU-Brazil Industrial Demonstration of Gasification to Electricity) project. This demonstrated that the power output of biomass to energy plants in the Brazillian sugar industry could potentially be greatly increased via gasification. IGCC was also the basis of the Arable Biomass Renewable Energy (ARBRE) project in the UK. However this project was halted due to a combination of technical and financial issues.
The Biomass CHP Plant Güssing, which started operation in 2002, has a fuel capacity of 8 MW and an electrical output of about 2 MWel with an electrical efficiency of about 25 %. Wood chips with a water content of 20 – 30 % are used as fuel. The plant consists of a dual fluidized bed steam gasifier, a two-stage gas cleaning system, a gas engine with an electricity generator, and a heat utilization system.
Use of an Externally-Fired Gas Turbine EFTG allows a wider range of biomass resources to be used, and has been investigated for decentralised production of power at a smaller scale.
In Canada, Nexterra has developed a proprietary fixed-bed, updraft gasifier for generating decentralised heat and power from biomass with high efficiency (up to 10 MW). The technology is being implemented in a number of niche projects in North America.
In the United States, several biomass gasification plants were demonstrated in the late 1990s (e.g. Vermont Gasifier). However, as in Europe, the technology has not been widely developed.
The $2billion Clean Coal Power Initiative is (among other activities) developing IGCC technology for coal power. A number of US DoE awards have been made for research into biomass-coal gasification, as well as hydrogen production.
Bioenergy and Carbon Storage (BECS)
The concept of Bioenergy and Carbon Storage (BECS) has been suggested as a means of producing carbon negative power. However commercial carbon capture and storage (CCS) technology is currently at a demonstration phase, and current research is focused on reducing the costs of CCS so that it can be applied to a new generation of clean coal power stations.
The concept of very large biomass energy power plants (of a size that makes CCS viable) has caused some concerns among sustainability organisations, who fear that it could lead to deforestation of diverse habitat to make way for extensive monocultures of energy crops. Such issues are addressed on the sustainability section of this website, and covered by a number of global initiatives on production and certification of sustainable biomass feedstocks.
Co-gasification of biomass and coal with CSS is another option that has been investigated by the US National Energy Technology Laboratory.
Further information on CCS is available from:
ZEP - Zero Emmissions Platform
Electric passenger vehicles
Extensive links to information on electric vehicles are available on the EurActiv website.
In addition to existing hybrids, such as the Toyota Prius and Honda Civi Hybrid, an increasing number of motor manufactures are launching innovative plug-in and hybrid vehicles in 2010/2011 including:
Renault Z.E. - a range of electric vehicles
Peugeot 308 Hydrid HDi - the world's first diesel hybrid due to go on sale in 2010
Peugeot iOn - plug-in electric vehicle
Mercedes S400 BlueHybrid - 'mild hybrid' with a 20-hp electric motor and a compact lithium-ion battery pack, integrated in the cooling system
Electric HGVs
In the UK, the retailer TK Maxx has introduced the "largest electric vehicle In Europe". The aerodynamic, battery-powered ten-tonne delivery truck has a range of over 120 miles. The retailer plans to introduce 10 further trucks to deliver to its stores in the UK, Germany and Poland. The company also uses biodiesel blends (based on WVO).
© TK Maxx
For
improved efficiency, the TK Maxx electric delivery lorry features the
aerodynamic "teardrop
design",
a registered design of Don-Bur
European Green Cars Initiative
The European Green Cars initiative is one of the three PPPs included in the Commission's recovery package. The envelope for this initiative is foreseen at €5 billion to boost to the automotive industry in a time of economic hardship, and support the development of new, sustainable forms of road transport. Of this financial envelope, €4 billion will be made available through loans by the European Investment Bank (EIB), and €1 billion through support to research, with equal contribution from the Seventh Framework Programme for Research (FP7) and from the private sector.
Research on electric and hybrid vehicles, within this initative, includes:
- High density batteries
- Electric engines
- Smart electricity grids and their interfaces with vehicles
Plug in Hybrid Electric Vehicle (PHEV) technology and Smart Grids
Looking to jointly develop new plug-in hybrid vehicle (PHEV) technology and accelerate its consumer acceptance and commercialization, the U.S. Department of Energy (DOE) and Sweden signed a Memorandum of Understanding (MOU) in July 2008 for a one year, $1 million cost-sharing agreement to be equally funded by DOE and the Swedish Energy Agency (SE-US PHEV Program). [Source: Argonne National Laboratory]
Bioelectricity vs. Biofuels?
A widely publicised study by the University of California published in Science in May 2009 suggested that bioelectricity produces an average 81% more transportation km and 108% more emissions offsets per unit area cropland than cellulosic ethanol.
These findings do not address the issue that electricity needs to be stored in batteries, which are not yet widely available for long distance road freight or possible for aviation, or the requirements for upgrading of the electricity infrastructure to enable large scale recharging of electric vehicles at regular intervals (or in millions of homes overnight). However, electric vehicles and electrified public transport may be the preferred option for urban transport strategies, where journeys are much shorter and where congestion and air quality are also important considerations.
A wide range of advanced technologies are being developed for second generation biofuels. However, as these are not yet commercially available, any direct comparison of bioelectricity with current 2G biofuels may be considered as premature. However, it is clear that both sustainable biofuels and plug-in and hybrid vehicles will have a vital role to play in the future of sustainable transport in Europe.