Good practice:

Extended landfill gas treatment by CHP with reservoir – case Lübben

Anaerobic fermentation of municipal waste produces methane. Concentration of CH4 can reach more than 10,000 ppm at the surface of the landfill. CH4 emissions can be avoided by gas collection and treatment systems. Dependent on the methane concentration different systems can be applied to convert CH4 into CO2. Hereby, released energy can be used to produce electricity. The landfill in Lübben is an operating landfill, parts are already closed and remediated and a gas collection system was installed. The currently used gas treatment facility (cogeneration CHP) was reaching its technical limits as the CHP is just capable to operate with CH4 concentration higher than 40 Vol% and a flow rate of approx. 70 m³/h, while in practice methane concentration / flow rate was predicted to be less soon. Thus, the gas flow rate has to be reduced and adjusted to gain a CH4 concentration of >40 Vol%. As gas flow rate was too low now, an additional storage facility for retaining the gas (storage vessel with inflatable film cover) had to be installed. The CHP operates when (i) stored gas volume is sufficient to run adequately the CHP and (ii) demand for energy is high (during daytime).
This practice extends the applicability of the CHP-system to process landfill gases and avoids greenhouse gas emissions while gaining energy and generating income.
The installation of the gas reservoir facility was co-financed by the ERDF fund.

The system works automatically and is controlled by IT-Systems. The human resources need for running the system is equal to the one needed, when conventional flares / CHP are applied.
Financial resources needed for investment to install the gas reservoir is about 100,000 Euro.

This practice extends the applicability of the CHP-system to process landfill gases and reduces greenhouse gas emissions. The systems works with landfill gas which contains much less than 35 Vol% methane. It is quite independent from the amount of gas volume as gas from the landfill is captured intermediately.
The landfill operator benefits financially of the system, as gas to power can be conducted for a longer time span than a CHP without reservoir.

This practice requires a significant knowledge and experience of gas generating potential of the landfill and the adjustment of the needed gas quality by rate of gas volume extracted from the landfill.

In the EU are 500.000 landfills. These landfills develop methane and carbon dioxide. It should first of all be noted that the com-ponents CH4 and CO2 are greenhouse gases. They reinforce the natural greenhouse effect of our atmosphere.In order to avoid these effects it is necessary to build a degassing system.
Thie mentioned practice could be replicable for landfills where municipal waste has been disposed and the gas potential is too low to run a conventional CHP. There has to be a connection to the power supply system, thus produced energy can be transported to the consumers.

The practice contributes to the following articles and annexes in the EU Directive 31/1999 on the landfill of waste, of applicability to landfills throughout the EU.
- Article 16: greenhouse gas emissions