Concerns over the sustainability of certain biofuels have finally reached the biomass power sector after it was revealed that plans to develop a combined heat and power (CHP) plant in Southampton powered by palm oil are being altered.
Solent Sustainable Energy, a not-for-profit company set up by Southampton City Council, is planning to develop a series of 5-20-megawatt CHP plants, having originally considered building a single plant (ENDS Report 376, p 15). The plants will be powered predominantly by waste wood due to concerns over palm oil, according to chairman Michael King.
Solent’s initial plan required any palm oil used to meet standards being developed under the NGO-backed Roundtable on Sustainable Palm Oil. These were finally issued last year (ENDS Report 395, p 24).
However, this was not enough to calm council fears that increased demand for palm oil to make biodiesel will lead to expansion of plantations in Asia and deforestation. Greenhouse gas emissions released during such land-use change could eliminate any emission savings from using biodiesel instead of fossil fuels (ENDS Report 399, pp 30-33).
"There is a debate that needs to be had," said Mr King, "but that needs to be done in a cool and rational manner. In the current climate you can’t have that debate sensibly."
Solent is not the only company planning to use waste wood as a biomass fuel in a new facility. In June, Helius Energy received consent from the Business Department (BERR) to build a 65MW plant near Stallingborough, Lincolnshire, which will initially be fuelled by waste wood, as well as energy crops. This will eventually change to spent grains and glycerol - by-products of biofuel production. Helius has planning permission to build biodiesel and bioethanol plants on the site.
Meanwhile Tilbury Green Power intends to build a 60MW plant by 2011 in Tilbury Docks, near Grays in Essex (ENDS Report 398, p 23). The plant’s main feedstock was originally going to be 300,000 tonnes of wood chip imported from the US, but this could change because of rising transport costs linked to oil prices. The company had intended to burn 50,000 tonnes of locally sourced waste wood, but the quantity could rise.
There are currently four biomass plants in the UK able to burn waste wood and comply with emissions limits set under the EU’s waste incineration Directive. According to the Wood Recyclers Association, last year they burnt 250,000 tonnes of waste wood.
For example, Sembcorp’s 33MW plant in Wilton, Middlesborough, burned 80,000 tonnes supplied by UK Wood Recycling, an aggregator based on the same site. UK Wood Recycling obtains the material from civic amenity sites, construction and demolition projects and waste firms.
And there is significant potential to expand the supply of waste wood, according to a report published in April by the Waste Infrastructure Delivery Programme (WIDP) - part of the Environment Department (DEFRA). Some 10 million tonnes of waste wood is produced annually, most of which is landfilled.1 Only 1.9 million tonnes were recycled or burned in 2007, according to the Wood Recyclers Association. This was mainly clean material, relatively homogenous and free from contaminants. Some 1.2 million tonnes were used to manufacture panel board.
This means there is potentially more wood from biomass available from waste streams than from forestry in the UK. The Forestry Commission’s woodfuel strategy for England aims to put an additional two million tonnes of woodfuel on the market a year by 2020. However, most fuel-grade material now produced goes to other users such as paper mills, a spokesman said.
The drivers to develop a waste wood supply chain are becoming increasingly compelling, with rising landfill tax and local authority targets to divert biodegradable waste from landfill. But Mr King said there are issues that need to be overcome. "There are certain complexities in sorting waste wood - in removing treated timber for example."
This cautious attitude is echoed by Geoff Hadfield, chairman of the Wood Recyclers Association, who warned that there is "a lot of misunderstanding" about the types of waste wood that can be burned in power plant without damaging equipment or exceeding waste incineration Directive emissions limits.
Standards to define grades of waste wood and their contamination levels would overcome this and make it easier for biomass plant developers to specify feedstock needs. The problem was highlighted last year by the Environment Agency, which examined whether ‘clean’ waste wood could be classified as a material rather than a waste and thus become exempt from waste management controls.
For this to happen it said the wood recycling industry would have to develop standards and a certification system (ENDS Report 393, p 47). The standards must specify how companies could be sure that waste wood was free from contaminants.
Even if this problem was overcome, it would take time for supply chains to develop, Mr Hadfield added. For example, UK Wood Recycling only handles some 200,000 tonnes of waste wood annually - less than the volume that could be used at Tilbury alone.