London, UK [RenewableEnergyWorld.com] Material of recent biological origin – such as wood which can be either be burnt directly or further processed to provide heat, electricity or fuel – is defined as biomass or biogas in the context of renewable energy systems.
There are five basic categories of biomass material: virgin wood from forestry, arboricultural activities or from wood processing; energy crops, both high yield and grown specifically for energy applications; agricultural residues from harvesting or processing; food waste from manufacture, preparation/processing, and post-consumer waste; and, industrial waste, including co-products from manufacturing and industrial processes.
Thus, aside from major sources of timber and wood waste, the sector also includes energy crops and less obvious sources such as animal fats. Specialist crops include short rotation coppice (SRC), with willow and poplar the most common types. The wood is then dried and burnt, though may also be converted to biofuels or biogas by further processing.
In September 2008, the Department for Environment, Food and Rural Affairs (Defra) launched a £1.5 million (€1.7 million), three-year research project to examine the feasibility of SRC as a viable renewable energy source. The project aims to establish a number of sites where intensive research will be carried out and operational-scale plots will be planted. The species will include both native and naturalized broad-leaved trees along with other species with the potential to be used for biomass, such as eucalyptus.
Miscanthus, or elephant grass, is another specialized energy crop being grown in the UK. This is a perennial crop similar to bamboo. It grows to about 3 metres in height per annum and can produce very high yields with little by way of secondary inputs like pesticides or fertilizer. As a perennial it also sequesters more carbon to the soil than most annual crops.
The variety of biomass systems and the diversity of technologies involved makes it hard to come up with a simple definition, but there are, nonetheless, several common factors. Foremost among these, most biomass is considered to be broadly carbon-neutral and, on combustion, only releases the carbon that the living material absorbed during its growth. This is a key part of its categorization as a renewable fuel.
However, while at face value this simple equation holds true, its complexity is increased with the use of modern agrochemicals and processes which can affect the carbon balance by increasing the quantity of fossil-fuels used to produce the biomass and convert it into a usable fuel. Another factor, which also affects biofuels, is the potential for increasing carbon emissions through land use changes related to the mass production of biomass crops.
Conversely, the use of waste streams not only provides a valuable source of biomass that can be used for energy, it also provides an additional environmental benefit and is growing in importance in the wake of increasingly stringent legislation concerning the use of landfill in waste disposal. Conventional disposal of waste streams into landfill often results in unwanted anaerobic degradation, a biological process which releases methane, a greenhouse gas far more potent than carbon dioxide.
Biomass is not only renewable and generally low carbon, it is also very versatile and can be used as fuel across the energy spectrum for both electricity and heat.
At current usage levels, biomass can largely be considered as an untapped resource for the UK, and the government’s strategy for biomass is intended to realize a major expansion in its supply and use. At present, biomass provides around 3.5% of UK electricity and 0.6% of heat demand, but has a realistic potential to supply some 6% of UK electricity by 2020. Demand for renewable heat could also potentially increase to about 6% by 2020.
The government believes there is significant scope to expand the UK supply of biomass, without any detrimental effect on food supplies and in a sustainable manner, by sourcing an additional one million dry tonnes of wood per annum from currently unmanaged woodland in England alone, and from increasing the recovery of wood for energy from managed woodland and other sources of wood waste products across the UK. In addition, perennial energy crops produced in the UK have the potential to use up to a further 350,000 hectares across the country by 2020, bringing the total land availability for biofuel and energy crops to around a million hectares, equivalent to 17% of total UK arable land.
By expanding biomass supplies, the government estimates the future resource in the UK to be a total of approximately 96.2 TWh. However, imports are estimated to account for some 54 TWh, a figure expected to grow.
Incentives are already in place to support the use of biomass as a renewable fuel source for heat, electricity, and transport. The nature and level of incentives vary between the different sectors, and include the Renewables Obligation (RO) for electricity supply, and grants towards the capital costs of heat and CHP (combined heat and power), including the Bio-energy Capital Grants Scheme. Now in its fifth round, around £12 million (€13.6 million) in funding is available under the scheme in 2009, which will fund up to £500,000 (€568,000) for up to 40% of the difference in cost between a biomass boiler and its fossil fuel alternative. So far, some £55 million (€63 million) has been allocated to help set up biomass power stations, biomass-fuelled CHP plants and biomass heating systems under the programme, the government says.
However, a key policy driver for the development of biomass installations, the Low Carbon Buildings Programme (LCBP) is due to be phased out in June 2009, ahead of the introduction of a feed-in tariff scheme – to the widespread consternation of the bioenergy industry. The government has, however, introduced modest interim measures along with reforms of the 2008 Energy Act to support heat production from renewables – a key market for biomass and biogas.
To help promote the use of dedicated feedstocks, the Renewable Obligation dictates that from 2010 all power stations using co-firing must source an increasing proportion of their biomass from dedicated energy crops if they wish to qualify for ROCs (25% in 2009, 50% in 2010 and 75% in 2011). Furthermore, the ROC banding proposed by the government distinguishes between various types of biomass, with bands ranging from 0.25 ROCs/MWh for established technologies, such as co-firing and landfill gas, to 2 ROCs/MWh for certain types of advanced dedicated biomass and second generation ligno-cellulosic technologies.
In addition, farmers, foresters and biomass producers have been able to apply for up to £200,000 (€227,000) each under the Bio-energy Infrastructure Scheme, designed to support the biomass industry in England by helping those supplying biomass fuel for use in heat and electricity generation – one of a number of measures instigated to encourage the growth of feedstocks.
Measures also include a £10 million (€11 million) scheme announced in 2008 to make more use of AD to produce biogas.
Another valuable source of support for biomass projects comes from the UK’s major utility companies, many of which have launched grant support schemes designed to support community-scale energy projects, including the use of biomass-fired boilers and such like.
Biomass for heat & Power
Planning and construction of large biomass-fuelled power plants has gathered pace across the UK over recent years. Often maximizing the environmental benefits through the use of CHP, such facilities are typically located on industrial sites with a significant demand for both process heat and electricity, although this component is sometimes sold back to the grid. Furthermore, biomass developments at industrial sites more easily accommodate the relatively large storage areas required for biomass materials and the regular heavy goods traffic necessary to deliver large volumes of biomass material to the site.
Several high profile biomass developments have been announced in the UK over the past twelve months. For instance liquor company Diageo, which produces spirits such as Johnny Walker, Tanqueray and Smirnoff, is to develop a biomass/biogas-fired on-site energy facility at a new distillery in Roseisle, on Speyside, Scotland. The plant is designed to utilize spent wash – a mixture of wheat, malted barley, yeast and water – from the distillation process to supply heat to the plant.
To be designed, built and operated by Dalkia, the Roseisle Distillery will use a bubbling fluidized bed boiler to combust both biogas – produced from an on-site AD process – and solid wastes. The £40 million (€45 million) distillery is due for completion as the UK Renewables Guide goes to press, and follows the August 2008 announcement of plans by Diageo for a similar bioenergy CHP installation at Scotland’s largest distillery, Cameronbridge in Fife, believed to be the largest single investment in renewable technology by a non-utility company in the UK.
In a similar development due to come on stream in 2009, brewing company Scottish and Newcastle (S&N) awarded two contracts to Finland’s Wärtsilä for the supply and installation of two biomass-fuelled CHP plants to be located on the premises of the company’s UK breweries in Manchester and Tadcaster. The facilities will use a mixture of spent grain and wood chips from local sources.
Meanwhile, supermarket chain Tesco has been given the go-ahead to build Britain’s first straw-powered CHP plant to meet the electricity and heating needs of its Goole Distribution Centre. The new plant will generate 5 MWe with any excess sold back to the grid. The straw will be supplied from local farms. Tesco estimates that it will have recouped the £12 million (€14 million) set- up costs within six years. David North, community and government director for Tesco, said: ‘We’ve identified five sites that would be suitable for further biomass technology.’
In another indication of utility engagement with the biomass sector, RWE Innogy has announced plans for a 73 MWe biomass power plant that is to be developed in north east Lincolnshire after the company acquired Helius Energy Alpha Ltd. Helius owns the rights for the development and operation of the Stallingborough biomass power plant, consent for which has already been granted. RWE Innogy will invest some £229 million (€260 million) in the 430,000 tonnes per year wood-fired project, which is due to be operational by 2011.
Fritz Vahrenholt, RWE Innogy CEO said: ‘This transaction enables RWE Innogy to enter the UK biomass market. Overall, we intend to increase the generation of electricity and heat from solid biomass almost five-fold to 600 MWe in Europe by 2011. The UK is an extremely important market for these growth plans.’
In July 2008, its UK subsidiary RWE npower also announced plans for a 45 MW biomass CHP plant at Tullis Russell Papermakers in Markinch, Scotland.
Topping the scales as the UK’s largest power station, the 4 GW Drax plant in North Yorkshire, is also increasingly turning to co-firing biomass along with coal. The company has signed a £10 million (€11 million) contract with Doosan Babcock to supply direct injection biomass systems to all six units at the site. On completion, the biomass co-firing facility will be the largest of its type in the world, Drax says, providing a total of 500 MW of renewable electricity.
Installation of the direct injection systems is scheduled to be complete towards the end of 2009. Other coal-fired plants such as Eggborough and Ferrybridge also co-fire biomass.
Such new facilities for biomass generation join a host of other well-established sites which amply illustrate the range of biomass resources available. For example, Thetford, in Norfolk, which produces close to 40 MW from chicken litter; the 30 MW Wilton 10 at Teeside, which uses wood waste, imported wood pellets (from companies such as Talloil) and SRC from local farmers; in Lockerbie is the 44 MW Steven’s Croft plant which runs largely on wood waste; and the world’s largest straw-fired power plant, the 36 MW facility at Ely in Cambridgeshire.
Furthermore, a number of large biomass projects are also on the horizon. In November 2008 a 350 MW woodchip-fired biomass plant proposed by Prenergy for Port Talbot in South Wales, was granted consent by the government. The £400 million (€454 million) project, if commissioned, will be the UK’s largest biomass facility to date and will be larger than the country’s entire existing biomass-fired capacity. The company says the project will be fuelled by sustainably grown wood supplied into Port Talbot’s deepwater facilities from the US and Canada.
If completed at the turn of the decade, the plant will contribute around 70% of the Welsh Assembly government’s 2010 renewable electricity target.
Biogas can be produced in dedicated biogas plants, which handle specific organic waste streams (such as farm waste or sewage sludge), but can also be captured from decomposing organic material in landfills – landfill gas.
As well offering the potential to produce electricity and heat, controlled anaerobic digestion (AD) produces high-quality organic fertilizer as a by-product. If the digestate (the compost left over at the end of the process) is determined to be free of harmful contaminants, this can replace energy-intensive fossil-based fertilizers. Digestate which passes the new standard, the PAS110 and Quality Protocol will be de-classified as a waste, increasing its value to farmers. In addition, there is potential to use the biogas directly as vehicle fuel similar to the LPG widely available in the UK, or to further process it into liquid biofuel.
By far the largest source of biogas in the UK is the digestion of organic wastes in landfill sites. Indeed, in the last few years landfill gas has been one of the largest earners of Renewable Obligation Certificates in the UK, although this is set to change with the proposed revisions to band the ROC scheme. The UK’s Department of Environment, Farming and Rural Affairs (Defra) also released a guidance document on facility design for the biomass and energy-from-waste sectors in 2009, in partnership with the Commission for Architecture and the Built Environment (CABE).
Other legislative changes, such as the EU Landfill Directive, will reduce the amount of organic waste being sent to landfill. Despite this, the quantity of methane being produced in landfills is still enormous. Within the UK there are a number of landfill gas operators, with one of the largest being Infinis, which has over 250 MW of landfill gas generation under management.
Nonetheless, companies involved in the sector have diversified and a significant number of digester and gasifying projects and developments have been announced so far in 2009.
A gasification project on the Isle of Wight that converts the biomass portion of municipal waste into biogas has been awarded preliminary ROC accreditation by regulators Ofgem, for example. Part of UK-based ENER-G plc, Energos, which is commissioning the thermal conversion technology, expects to achieve full accreditation. Plans for a second energy-from-waste gasification CHP plant in Knowsley, Merseyside, have also been unveiled by Energos. The £40 million (€45 million) plant will take two years to build and is expected to supply 9 MWe and 32.8 MWth.
The company has further been appointed as technology provider to United Utilities and Interserve for a joint venture to build a similar facility in Derbyshire. Water company Northumbrian Water has also announced a series of advanced anaerobic digestion plants at several water treatment centres in its operational area, the first one of which was commissioned in spring 2009.
Municipal authorities are also exploring energy-from-waste biomass developments. For example, Prosiect Gwyrdd, a joint initiative between five South Wales councils looking at energy from municipal waste, is to receive extra government funding of up to £7.8 million (€8.8 million) in a full year of operation, depending on the final costs of the project.
In the last four years 14 new anaerobic digestion plants have been built, ranging from small farm projects to merchant plants processing 40,000 tonnes of food waste and with 1MW electrical capacity. Many more plants are awaiting planning decisions and the industry is set to expand exponentially in the next few years. The REA’s UK Biogas Group reflects this expansion with 75 members and rising.
The growing season?
As with biofuels, aside from energy-from-waste, biomass and biogas developments have been dogged by the food versus fuel debate and questions over sustainability and carbon balance. Nonetheless, while this – coupled with a lack of early government support – has hampered the industry, further evidence of growth drivers is encouraging. The government decision to include biogas and heat in the RO, ever tougher restrictions on landfill and the issue of waste disposal, and the wider European renewables legislation, are all strong policy measures pushing development.
There are also signs of a growing supply chain in evidence. For example, the last year has seen Biojoule join forces with the Energy Crops Company to produce and market biomass pellets in the UK, near Retford in Nottinghamshire. The plant will be operated in conjunction with Coppice Resources Ltd, which has recruited local farmers to grow SRC. Another new wood pellet manufacturing plant is being developed in the UK by LandEnergy in Yorkshire.
Such key market developments, together with continued on-going commercial expansion across a range of sectors, indicates a buoyant interest in biomass and biogas and prospects that such interest will be reflected in significant growth.