TEDOM, a supplier of packaged CHP systems based in the Czech Republic, installed its first coalmine methane-fuelled unit in 2004. Energy generated from this ‘waste’ gas is used on-site to operate buildings and exported to the local electricity grid. Richard Choleva reports.
Green Gas DPB is the largest company in the Czech Republic concerned with mining, and the supply and utilization of coalmine methane. It is also one of the most significant companies in the country.
Many CHP units are installed at coalmines within the Ostrava-Karvinàƒ¡ district of the Czech Republic
The company is based in the southern part of the Upper-Silesian coal basin, in the Ostrava-Karvinàƒ¡ district. Its main activities include: mining, treatment and sale of black coal; coke production; and other products related to coal mining and treatment.
In recent times (due to increased environmental issues) Green Gas DPB has intensified its efforts to reduce the effects of mining at the surface, and has focused on the sanitation of old mines and solving the problem of coalmine methane emergence. With respect to coalmine methane, mining always requires a guarantee of work security and safety and the air and coalmine methane combined forms an explosive mixture which is dangerous for miners. The geological process of biological substance carbonization means the coal and methane was formed in sealed underground strata.
However, coalmine methane is not just a source of danger, it provides a significant source of energy. Its main element, methane, has a significant heat value à¢€” 34 megajoule per cubic metre (MJ/mà‚³) à¢€” and Green Gas DPB quickly realized the significance of this potential energy source and started to extract methane from closed rock strata. Using a 150 km long pipeline system, the company started transporting the gas from mines to places of utilization. Both abandoned mines and currently operating mines are now connected through this gas pipeline system. Initially the coalmine methane was used as a substitute for natural gas, but now the gas is viewed as a full-value energy source.
In 2004, Green Gas DPB decided to expand its coalmine methane utilization project to include combined heat and power. The pilot project used coalmine gases from closed strata in the Vrbice coalmine and from the Paskov operational coalmine in the Chlebovice region of the Czech Republic.
In autumn 2004, the company prepared a tender for the supply of a cogeneration unit (running on coalmine methane) in Vrbice à¢€” an abandoned mine in the Ostrava district. The most important criterion was the ability to burn the gas with a low calorific value (percentage of methane as low as 40%).
TEDOM was the successful tender for the CHP unit. They suggested the installation of an engine, generator, cooling equipment, and the power and control switchboard à¢€” all in an external container à¢€” as a suitable solution. This container design also included its own pump unit with a gas pump, whereby the gas is drained from the abandoned mine and supplied to the engine. All units were equipped with remote monitoring of data for Green Gas DPB.
The supply of the first their CHP unit ‘QUANTO D580 SP CON’ (container version) took place in May 2005 and was soon put into operation. The ‘waste’ gas feeding the unit is 3 million mà‚³ of coalmine methane mixture per annum.
In 2006 a unit was installed at the Chlebovice mine in the Frydek-Mistek district. The unit was a QUANTO D770 SP CON type, also in a container. It was delivered and put into operation in spring 2006. The parameters of both pilot project units are outlined in Table 1.
THE 2007à¢€”2008 PHASE
Following the successful installation of the pilot project, Green Gas DPB started to consider options for more comprehensive coalmine methane utilization. A subsequent contract, signed in November 2006, covered the delivery of 11 TEDOM CHP units running on coalmine methane, with an output range of 770 kW to 2000 kW. The next ten CHP units, with a total electrical output of 12.6 MW, were installed by the end of 2007. During nine months of operation, 12 GW of electrical energy was generated, see Table 2.
The 2008 tender stage for the delivery of TEDOM CHP units (running on coalmine methane) was successfully finished at the end of February 2008. This stage included the supply of 17 CHP units in container version, equipped with DEUTZ engines, with a total output of 27 MW. The CHP unit deliveries continued through 2008 with the installation of the next five CHP units, with an electrical output of 1600 kW. These latest installations are at the Lazy operational coalmine and the Frantià…¡ek abandoned coalmine in Horni Sucha. The units running on coalmine methane, with a total installed output of more than 20 MW, are now up and running in the Ostrava-Karvinàƒ¡.
TEDOM CHP units are used for recovering heat and energy for Green Gas DPB in the Ostrava-Karvinàƒ¡ coalmining district of the Czech Republic. Generated heat and power is supplied to the OKD mine buildings (Green Gas merged with OKD in 2007) and generated power is distributed through the OKD grid. Company offices are heated by the generated heat, which is also utilized for heating water.
This project illustrates companies working together to increase safety measures during the mining processes while working towards environmental protection (based on emission decreases in the atmosphere) and, not least, a significant increase in energy efficiency by the utilization of a secondary energy source.
OTHER COALMINE METHANE PROJECTS
In co-operation with a Slovakian business partner, Intech Slovakia, a similar project utilizing coalmine methane was carried out in 2006. This project included the installation of three TEDOM CHP units at Hornonitrianske coalmines in Slovakia.
CHP units installed at an iron and wire company at Bohumàƒn, Czech Republic
In autumn 2004, TEDOM was contracted by the Moravia Energo company to install the CHP unit for Bohumàƒn à¢€” the iron and wire company (Moravia Energo is an electricity dealer in the Czech electricity market). They became the successful tender for the project, with a total output of 1 MW. The CHP unit was equipped with Caterpillar engines as these best matched the CHP unit delivery term requirements.
Other important considerations included the non-stop service, reliability guaranteed by experience with long-term CHP unit production/operation, guarantee of output according to technical specifications, and a strong background of warranties. The first unit was put into operation in December 2004, followed by another in December 2005.
In 2006, another unit, equipped with a DEUTZ engine, was installed and one of the Caterpillar engines was replaced with a DEUTZ engine. See Table 4 for more details.
Soon, a new project on coalmine methane will be carried out in Poland à¢€” and we certainly don’t expect this to be the last CHP project using coalmine methane.
Richard Choleva works with TEDOM s.r.o., Trebàƒc, Czech Republic.
- Annual CHP operation of each unit: 8000 hours per year
- Total output: 320 terrawatt hours of electricity (TWhe) per annum
- Total number of installations: 28 TEDOM CHP units
- Total emission reduction per year (in terms of CHP unit operation): 1.3 million tonnes of carbon dioxide
- Electrical output for the 2007 stage: 11.7 MW
- Electrical output for the 2008 stage: 27.2 MW
- Scheduled installation of the next 17 CHP units: within four years (2008-2012)
- Total electrical output, after completion: around 40 MW.
Methane in coal seams
Coal seams contain large quantities of gas which is held in place until it is released during mining. If conditions allow, it can be pumped to the surface through boreholes.
The main component of coalmine gas is methane à¢€” one of the more harmful gases whose emissions contribute to global warming. Each country must pay attention to reducing its methane emissions. This requirement is outlined in the Kyoto Protocol à¢€” governed by the UN Framework Convention on Climate Change with the objective of reducing greenhouse gases in an effort to prevent anthropogenic climate change.
A significant source of methane can be found in active coalmines where methane is blown out through the mining ventilation system. Methane can also be deliberately recovered through mining degasification, where it is subsequently utilized for power generation. The second largest source of methane is from areas where mining operations have ceased and so-called remnant reserves of coalmine methane are released and accumulate in underground spaces created by the mining process.
The composition of coalmine methane is different to natural gas. The methane content varies from 30% to 70% of volume, and also includes other components like CO2, N2, and O2 (in operating mines).