Thanks again to Dr. Max Wallis for the following article:

Under the UK’s system for promoting renewable energy technologies – the Renewables Obligation legislation [1] – subsidies guaranteed for years [2] are granted via Renewables Obligation Certificates (ROCs) and are readily available for energy generation that is far from efficient and, in particular for forms of incineration, waste the majority of the energy which is heat [3].

Waste wood often contains chemical preservatives or is coated with paint, while composite woods like melamine or MDF include chemical glues and coatings.  Modern decking may contain 30% plastic.

Incinerating waste wood receives excessive subsidies because pyrolysis and gasification are classed as “Advanced Conversion Technologies” with no conditions on efficiency or nasty wastes.  Both technologies are defined as ‘incineration’ under the Waste Incineration Directive.

So-called “advanced” gasification or pyrolysis may attract double ROCs for each unit of electricity (although some facilities are experiencing difficulties securing ROCs from the regulator OFGEM), this for gasification or pyrolysis processes that produce very low quality gas and then burn it, in a two stage incineration process.

In numerical terms, pyrolysis qualifies for double ROCs if the gas calorific value exceeds 4 MJ/m3, whereas best technology reaches 11 MJ/m3 (natural gas for comparison is about 70 MJ/m3 ).

The lucrative subsidies are the reason for the rash of planning applications for wood-burners.  One example is the Hudol pilot plant at Rhymney ( and a test plant at Tythegston (Bridgend) that over ten years never worked well with domestic wastes, transgressing NOx and CO limits on several occasions. “Technical problems have prevented the plant from operating to its full potential” they say, and Bridgend Council granted permission last year for autoclaves to be substituted, working on steam from combustion of the output fibre.

Like many such schemes, Hudol’s technology was on the way to fail until a small consultancy called Sedgwick Associates took it on under a “Sunrise Renewables” label.  Their business model aims to attract city finance for docks-based plants, able to import wood wastes as well as take them from the locality.  Sedgwick told the Inquiry into a proposal for a plant in Barry/S. Wales in early June that they have won three permits, in Barrow-in-Furness, Sunderland and Hull [4].

Barry & Vale FoE were their main opponents at the Inquiry and found that Sedgwick have little knowledge of the engineering and the waste wood businesses, and buy in consultants without specific knowledge.  They did not know wood composites contain plastics, claimed the ash would not be hazardous waste if the input wood was ‘non-hazardous’, and produced a mass-flow diagram that they couldn’t explain and was clearly incomplete.  Their claims to CHP were shown up when they hadn’t thought to cope with daily and seasonal variations in demand, or to a back-up heat supply when the incinerator is down.

It seems they had succeeded in England without EIA, but a FoE objection caused trouble at the Welsh government office. The Welsh officials first decided it’s an EIA ‘Schedule 1’ project, as a waste disposal installation handling more than 100 tonnes/day (there’s a ruling that “disposal” covers incinerators that recover energy and/or materials).  Heavy lobbying by the company (uncovered by a Freedom of Information request) got them to reverse that and declare it’s not an EIA project.  They are clearly worried about their contortions – in pursuit of government policy to expand biomass power – and FoE plan to take it to the European Commission.

The consultants made a lot of government policy on biomass, including the Welsh plans for 50% of biomass to be imported, so as to claim that Welsh energy will be all renewable.  This is problematic because the Welsh government also claims to be going for “high efficiency” CHP, but no-one sees the way to using the heat (to avoid the seasonal problems and costs of district heat pipes; officials say airily – industrial users).

FoE also found that the consultants’ air pollution and noise calculations were questionable.  Unrealistic values of background air pollution (low) and of background nighttime noise (high) were taken, and accepted by Council officers – officers who had received the message that these ‘renewable energy’ plants are a good thing, which would win the Council political brownie points.

In fact, these waste wood incinerators can be challenged on CHP, as the Waste Framework Directive (as revised 2008) is specifically worded.  Article 23(4) reads:

It shall be a condition of any permit covering incineration or co-incineration with energy recovery that the recovery of energy take place with a high level of energy efficiency.

Sedgwick omitted any numbers on efficiency, but a mass/energy flow chart released to the Inquiry showed 22% generation efficiency (likely to be an over-estimate).

They can also be challenged on ash.  Sedgwick just asserted their ash/char can be used for block-making, yet no-one would choose material with toxic metals, chlorides and high carbon content.  The EA says incinerator ash is to be presumed hazardous waste [5] until tested, so demand test evidence, including biotoxicity testing under the EA protocol.

Opponents may need some idea of alternative processes for contaminated waste wood.  The WRAP guidance [6] has high status.  Re-use comes before ‘energy recovery’ – chipped clean wood for chipboard manufacture or animal bedding, otherwise for rural paths and mulches, or for land reclamation.  For waste wood contaminated with PCP and CCA, carbon sequestration could be a better environmental option than burning, with the worst contaminated material (if a long term threat in landfill) treated by thermal desorption to recover the contaminants.   The Annex below (or jump to) outlines this and gives references on waste wood.

A second WRAP report [7] on options for treated wood waste gives little guidance, but interestingly does cite stronger efforts overseas over waste woods, particularly citing Switzerland as specifying  wood which is glued, painted, lacquered or surface coated with preservative is categorised as used timber. This must be disposed of in special waste wood incinerators, cement kilns or waste incineration plants. Waste wood which has been impregnated with preservatives under pressure, or that has been heavily coated with preservatives such as PCP, or has been coated with products made from halogenated organic compounds is identified as problematic wood waste.

If people want to run the arguments on dioxin production, potentially high in waste wood combustion, do make use of the FoE statement (available upon request) to the Barry Inquiry.  Note that pyrolysis and gasification may not produce as much dioxin as the waste wood boilers of the UNEP guidance we cited, but insist the onus is on the applicant to produce evidence.

Max Wallis, July 2010


[1] The Renewables Obligation 2009: a new order  <>.  Definitions of advanced and standard pyrolysis or gasfication are given at and UK WIN’s information on the new RO is at

[2]  One ROC is currently valued at £37, planned to inflate with prices, but floats around this level depending on the ROC market.  Banding is to be reviewed every 5 years, with option for an emergency review if a cheap technology emerges in a band and might knock out the others; the whole system is promised to last till 2027.

[3] ROCs are approved for heat energy from April 2010, but the system proposed would allocate them for heat output, with nothing to ensure the heat is used efficiently or even beneficially.  Heat pipes could be poorly insulated and the heat be piped to an uninsulated warehouse plus air-cooled heat dump for summer use.

[4] a) 20MW plant at Anchor Basin, Barrow-in-Furness, Cumbria
Says intended to use wood that is refined for reuse –  covering up that it’s waste wood from the neighbouring Bennett Bank landfill operator. No EIA; no condition on heat use.

b) 9MW biomass plant to generate electricity from reclaimed timber at Hudson Dock East, Barrack Street, Sunderland 08/04526/FUL
The Officers’ report fails to mention EIA or ‘waste’ except saying that Process Guidance Note 1/12(04) using waste fuel is used for emissions and WID will apply.

c) renewable wood fueled energy plant (9MW) King George Dock, Kingston Upon Hull  00030735A
No EIA.  Objections made on grounds of contamination (railway sleepers; no use of waste heat.
Conditions set on waste arising within Hull and East Riding; on energy efficiency under Local Plan policy

see particularly the Annex from ENDS report, March 2009.

[6] WRAP Guidance for Mixed Wood Waste Producers on End Markets

[7] WRAP Options and Risk Assessment for Treated Wood Waste, TRADA Technology & Enviros Consulting Ltd  (2005) /Options_and_Risk_Assessment_for_Treated_Wood_Waste.bb71f367.2237.pdf

Annex   Combustion of Wood?
Extract from Friends of the Earth Cymru Response to “Towards Zero Waste– One Wales: One Planet”, July 2009

WAG, like DEFRA and DECC, appears enthusiastic to increase the level of combustion of waste wood (both in this consultation and in the renewable energy route map for Wales [41]. Little or no consideration seems to have been given to the implications of the contamination of significant parts of this wood with industrial wood preservatives.
Since the 1970s sawn timber treated with water-borne preservatives has totally dominated the industrial preservation market (Krook et al., 2006b). Most of this wood has been treated with CCA-preservatives (containing copper, chromium and arsenic).

In 2002 wood containing hazardous substances was classified as hazardous waste according to the Swedish waste decree [73]. This legislation requires that such waste should be separately handled by operators who have permission to manage hazardous waste. Whilst the types of wood waste which should be classified as hazardous is, to some extent, open to varying interpretations the Swedish Environmental authorities have interpreted that wood treated by CCA and creosote preservatives is most likely to be regarded as hazardous waste [73]. This legislation has resulted in most Swedish combustion plants not having permission to handle industrial preservative-treated wood (Krook et al., 2006b).

Incineration of wastes containing CCA is likely to be problematic for several reasons:
•    Incineration and subsequent ash disposal greatly concentrates the chromium, often oxidizing it to the more toxic and mobile Cr(VI) form [74].
•    The copper is a potent catalyst for dioxin formation in incinerators [75-77]

Some older wood treated with Pentachlorophenol (PCP) such as railway sleepers can have extremely high levels of dioxin contamination. Asari [78] reported 21,000 ng/kg which exceeds the Stockholm Convention and EU levels at which the wastes are POPs wastes.

An increasing proportion of the wood now used in decking and outdoor applications (22% in 2006 and estimated to be 30% by 2011 [79] )is a wood plastic composite .  The plastics used are polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC).  Any energy recovered from combustion of this composite would be largely fossil based  and would add, in the case of PVC based composites, significantly increased risks of dioxin and similar compounds if burned.

Rather than burn this contaminated wood the contamination it contains should ideally be treated.  Alternatively engineered landfill sites are a more appropriate disposal route than combustion.  In no circumstances should the wood be landfilled in unlined landfills [80] or open-burned. The Consumer Safety Information Sheet for Inorganic Arsenical Pressure-Treated Wood (14) cautions that CCA treated wood “should not be burned in open fires or in stoves, fireplaces, or residential boilers because toxic chemicals may be produced as part of the smoke and ashes”.  The Environment Agency does not appear to have taken this issue seriously to date and still permits the burning of contaminated wood on construction and demolition sites.  Open burning is banned in several US states [81] and should not be tolerated in Wales.

41.    Welsh Assembly Government, Renewable Energy Route Map for Wales consultation on way forward to a leaner, greener and cleaner Wales. 2008.
73.    Krook, J., et al., Swedish recovered wood waste: Linking regulation and contamination. Waste Management, 2008. 28(3): p. 638-648.
74.    Jambeck, J., et al., CCA-Treated wood disposed in landfills and life-cycle trade-offs with waste-to-energy and MSW landfill disposal. Waste Management, 2007. 27(8): p. S21-S28.
75.    Stanmore, B.R., The formation of dioxins in combustion systems. Combustion and Flame, 2004. 136(3): p. 398-427.
76.    Shibamoto, T., A. Yasuhara, and T. Katami, Dioxin formation from waste incineration. Rev Environ Contam Toxicol, 2007. 190: p. 1-41.
77.    Hatanaka, T., A. Kitajima, and M. Takeuchi, Role of copper chloride in the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans during incineration. Chemosphere, 2004. 57(1): p. 73-9.
78.    Asari, M., et al., [3] Environment International, 2004. 30(5): p. 639-649.
79.    Klyosov, A.A., Wood-Plastic Composites. 2007: Wiley-Interscience 698.
80.    Jambeck, J.R., T.G. Townsend, and H.M. Solo-Gabriele, Landfill Disposal of CCA-Treated Wood with Construction and Demolition (C&amp;D) Debris: Arsenic, Chromium, and Copper Concentrations in Leachate. Environ Sci Technol, 2008. 42(15): p. 5740-5745.
81.    Wasson, S.J., et al., Emissions of chromium, copper, arsenic, and PCDDs/Fs from open burning of CCA-treated wood. Environ Sci Technol, 2005. 39(22): p. 8865-76.

Waste Wood pyrolysis plant permitted at Barry, South Wales

Barry & Vale FoE deplore the decision of the Planning Inspector, quickly made after a curtailed 3-day inquiry where the voices of local people and businesses were hardly heard.

Allowing this major industrial plant pays little regard to neighbouring businesses and goes against aspirations for upgrading this part of the Dock for housing and light industry.

The permit as written by the Inspector goes against Welsh policies on the proximity principle for dealing with waste locally and on high energy efficiency, since he deleted the Council’s proposed conditions that were uselessly weak.  We believe this leaves it open to legal challenge.

The Barry & Vale group are lobbying for the Council to decide to challenge this shocking decision.

The evidence at the inquiry disclosed that similar plants have been permitted in Hull, Sunderland and Barrow-in-Furness, all without Environmental Impact Assessment, which FoE point out is mandatory for waste incineration plants over 100 tonnes per day (these burn 200 to 500 tonnes per day).

The company disclosed they are only interested in taking waste wood which allows them to earn ROCs (Renewable Obligation Certificates) as the business model relies on claiming this subsidy for being “advanced technology” even though they would be only 20% efficient.

2 Responses to “Excessive Subsidies for Waste Wood Incineration”

  1. In New England US subsidies are reported to be $80 million for a Federal stimulus and about $25 million in annual public subsidies. What are the figures in the UK?

  2. Difficult to give an exact figure Graham. A large amount of money is set aside to support Private Finance Initiatives (PFIs), and landfill of incinerator bottom ash is subsidised by virtue of a £2.50 per tonne charge instead of the usual landfill tax of £48 per tonne (about $100), rising to £80 per tonne in a few years.

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