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.
A number of large-scale bioenergy CHP plants are now being constructed in Europe. For example a 69MW plant based at a Smurfit Kappa Group paper facility in France commenced operation in September 2012.
Typically 10% of biomass can be used for co-firing [Source: IEA Clean Coal] - avoiding issues such as slagging and fouling (although these issues also depend on the feedstock type). Higher 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 decompose, creating torrefied biomass or char, also referred to as 'biocoal'.
Biocoal has a higher energy content per unit volume, and torrefaction followed by pelletisation at the harvest sites facilitates transport over longer distances. It also avoids problems associated with decomposition of biomass during storage. Hence the benefits of torrefaction may outweigh the additional cost in many cases.
FP7 Project SECTOR - Production of Solid Sustainable Energy Carriers from Biomass by Means of Torrefaction started in 2012 and runs for 42 months.
Torrefaction is also being developed in the US. For example, in May 2012 Vega Biofuels (VB) announced plans to build a new bio-coal manufacturing facility in Georgia, US. Timber waste will be used as the feedstock.
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 June 2010, the EUwood project published a report that examines the potential availability of wood in Europe: Real potential for changes in growth and use of EU forests.
Also in June 2010, the world's largest biomass co-firing project was commissioned at the Drax coal power station, which has an installed power cpacity of 4000 MWe and provides 7% of the UK's electricity. The plant aims to use 10% biomass (1.5m tonnes per year).
The rising demand for wood from the bioenergy sector led to a 30% increase in wood price in the UK in the 3 years up to 2010. Energy generator subsidies for wood fibre is causing concern for other industries, for example, chipboard manufacturers, who have seen sharp rises in costs.
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 - recent history
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 generally considered to be competitive with combustion. Hence biomass gasification research tends to be 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. The Växjö Värnamo Biomass Gasification Centre (VVBGC) was upgraded under the EU CHRISGAS project in 2004-2010 and there were plans for it to continue as a "centre of excellence" on biomass gasification, supporting the development of industrial scale biomass gasification in Sweden. However in February 2011 funding partners withdrew.
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.
However development of biomass gasification technology continues (as detailed below). See also the Bio-SNG page for details of new industrial-scale gasification projects.
Biomass CHP Plant Güssing
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.
CHO Power (Europlasma) plsma gasification projects
In December 2011, CHO Power SAS (a subsidiary of Europlasma) and Sunrise Renewables announced plans to build 4 high temperature plasma gasification facilities at UK docks to convert waste wood into clean syngas. The Syngas will be cleaned further and the tar removed, prior to power production via gas engine generators. The company is also developing a demonstration facility in Morcenx, France that will gasify 37,000 tonnes of ordinary industrial waste and 15,000 tonnes wood chips per annum, generating power for EDF.
Andritz Carbona Skive CHP demonstration plant
The demonstration plant at Skive Fjernvarme in Denmark converts wood to combined heat and power (CHP) production via gasification, generating 120k MWh of district heating and 22k MW of electricity.
"A single bubbling fluidized bed (BFB) gasifier and related equipment converts wood pellets to fuel gas for three reciprocating engines in a combined heat and power (CHP) in the CHP plant. The engines generate electrical energy (two MW each) from which the heat is recovered for the community’s district heating needs. Two gas boilers in the facility can also utilize the biomass-derived gas providing additional district heat."
The DEBCO project on biomass/coal co-firing
The FP7 DEBCO project - DEmonstration of large scale Biomass Co-firing and supply chain integration - will develop and demonstrate innovative approaches to the co-utilisation of biomass with coal for large-scale electricity production and/or CHP, at more competitive costs and/or increased energy efficiency. The aim is the development, demonstration, and evaluation of innovative and advanced co-firing technologies.
Biomass CHP in North America
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 Systems 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 September 2012 a commercial demonstration of a CHP system using Nexterra's technology (with wood waste as a feedstock) was launched at the University of British Columbia. The system combines Nexterra’s gasification and conditioning technologies with a GE Jenbacher internal combustion engine.
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 Capture and Storage
The concept of Bioenergy and Carbon Storage (Bio-CCS or BECCS) has been suggested as a means of producing carbon negative power (i.e. removing carbon dioxide from the atmopshere via biomass conversion technologies and storage underground). 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. However, CCS could potentially be appled to a wider range of energy plants, including those incorporating co-firing or co-gasification of sustainable biomass feedstocks (agricultural and wood wastes and energy crops), or even 100% biomass energy plants, biofuel production facilities or biorefineries.
The potential for future synergies between CCS and bioenergy/biofuels production is the focus of the Bio-CCS Joint Task Force led by the Zero Emissions Platform with contributions by EBTP.
Electric passenger vehicles
Extensive links to information on electric vehicles are available on the EurActiv website. Many countries offer tax incentives and grants to promote electric cars.
In addition to existing hybrids, such as the Toyota Prius and Honda Civi Hybrid, an increasing number of motor manufactures have launched innovative plug-in and hybrid vehicles in recent months including:
Renault Z.E. - a range of electric vehicles.
The purchase price of many electric vehicles, such as the Renault Fluence Z.E., excludes monthly battery hire (which can amount to several hundred Euros per year). However, it is suggested that this is mitigated by lower servicing costs over the life time of the vehicle and guards against potentially expensive battery issues, which may affect performance.
Opel (Vauxhall) Ampera includes the battery in the price and has a 4 hour charging time. It is a hybrid with a petrol driven generator/engine.
Peugeot 308 Hydrid HDi - the world's first diesel hybrid went on sale in 2010
Peugeot iOn - plug-in electric vehicle (Citreon C-Zero and Peugeot iOn are both essentially rebadged versions of the Mitsubishi i-MieV - see below).
Mercedes S400 BlueHybrid - 'mild hybrid' with a 20-hp electric motor and a compact lithium-ion battery pack, integrated in the cooling system
Nissan Leaf - All electric, 5 door
Chevrolet Volt - all electric vehicle with lithium-ion battery, and on-board high-efficiency petrol generator
The Wikipedia page on Plug In Electric Vehicles provides a good overview of the current models and compares the LCA, lifetime running costs and efficiency of various vehicle types (the page includes a long list of refernces, and we advise that all technical information should be verified with the original sources and the vehicle manufacturers).
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
improved efficiency, the TK Maxx electric delivery lorry features the
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 crop land than cellulosic ethanol.
These findings do not address the issue that electricity needs to be stored in batteries, which currently have limited capacity 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 local congestion and air quality issues are also important considerations. Electricty is not an option for aviation, which requires liquid fuels.
A wide range of advanced technologies are being developed for second generation biofuels. However, as these are not yet widely available at commercial scale, 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.