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Science shop: inconsistent law on biomass gasification harms energy company Essent

01 March 2007

In the policy agreement of the Dutch government and the Dutch energy sector, it is stated that by 2008-2012 the coal-fired power stations in the Netherlands need to have reduced their fossil CO2 emission. Half of this reduction should be accomplished by co-incineration of biomass.

Essent installed a gasifier next to its coal fired power to produce fuel from biomass for its powerplant. However, Essent had to stop the gasification of waste wood and the subsequent use of the resulting gas as fuel when the BVA (Besluit Verbranden Afvalstoffen) entered into force. This Dutch measure seems however to be incompatible with the European treaty it originated from, the WID (Waste Incineration Directive). This was discovered bij researchers of the Science Shop and the Energy Delta Research Centre (EDReC). They also formulated recommendations for Essent how to keep living up to the standards of green electricity.

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The central question is: can power plants which use fuel derived from gasified biomass be regarded as green electricity generation or as waste incineration? The gasifier of Essent produced from demolition wood - i.e. polluted biomass and can be defined as waste – a purified gas to burn in its power plant. Essent asked EDReC and the Science Shops of the RUG whether its plant, which is treated as a co-incineration plant by the Dutch BVA, is regarded as a co-incineration plant by the European WID as well. Students Murat Duman and Christiaan Boelens showed that it is not a co-incineration plant under the WID and that the BVA therefore is incompatible with the EC treaty.

Two conditions of the WID
According to the BVA, any power plant co-incinerating products of thermal treatment of waste is regarded as a co-incineration plant irrespective of the quality of the product. According to the WID, the decisive condition is that the substance used as fuel or thermally treated for the purpose of disposal must be waste. But, if a gasifier (1) thermally treats waste for the purpose of recovery and (2) the resulting gas has lost the waste status prior to being co-incinerated as fuel in the connected plant, the whole plant –i.e. the gasifier and the power plant - falls outside the definition of co-incineration plant.

Useful purpose
To comply to the first condition, the waste must substitute a non-waste material, which would have been used if the waste was absent and this substitution must lead to conservation of natural resources. This is the case for Essent, because the gas derived from demolition wood replaces the fuels used. Furthermore the principal objective of the operation must be serving a useful purpose through replacing other materials, and thereby protecting natural resources. This condition is highly likely to be satisfied if the company processing the waste pays the holder of the waste. Fact is that Essent pays the holders for the demolition wood.

Do what it claims to do
The WID also dictates that the conditions in which the operation takes place must give reason to believe that the operation does indeed what it is claimed to do. According to the researchers there is sufficient ground to believe that the gasification process of Essent does what it is claimed to do. Essent uses a single type of waste, namely demolition wood. The waste is subject to quality criteria and Essent monitors the compliance with the quality criteria on a weekly basis. The gas is capable of being used instead of other fuels. Furthermore the benefits exceed the costs of producing it.

Analogous to clean biomass
Waste ceases to be waste the moment it is transformed into a material analogous to a raw material with the same characteristics as that raw material and capable of being used in the same environmental conditions unless it is discarded. The gas of Essent is analogous to clean biomass, which it intends to replace and it is capable of being used under the same environmental conditions as clean biomass. Accordingly, the producer gas of Essent may not be regarded as waste.

The quality monitoring of Essent, which entails weekly analysis of samples taken from the shipment of demolition wood, is not sufficient to guarantee the quality and comparability of the producer gas to clean biomass. There may be large differences between different shipments meaning that the producer gas may not always be comparable to clean biomass. However, it is imperative that the comparability of the gas be constantly maintained. Thus, Essent should increase the sampling frequency of the delivered demolition wood to guarantee the comparability of the gas prior to its co-incineration in the power plant.

- M. Duman and L. Boels, The Waste Incineration Directive and its Implementation in the Netherlands: Assessment of Essent's Waste Wood Gasification Process, University of Groningen, EDReC, 2007.
- For more information: contact Elise Kamphuis, co-ordinator Science Shop Economics, Management & Organization tel. (050)363 7182, e-mail:

Last modified:31 January 2018 11.51 a.m.

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