Tag Archives: Natural gas grid

Biomethane – The Green Gas

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Biomethane, also known as the green gas, is a well-known and well-proven source of clean energy, and is witnessing increasing demand worldwide, especially in European countries, as it is one of the most cost-effective and eco-friendly replacement for natural gas and diesel.

Advantages of Biomethane

The key advantage of biomethane is that it is less corrosive than biogas which makes it more flexible in its application than raw biogas. It can be injected directly into the existing natural gas grid leading to energy-efficient and cost-effective transport, besides allowing natural gas grid operators to persuade consumers to make a smooth transition to a renewable source of natural gas.

Biogas can be upgraded to biomethane and injected into the natural gas grid to substitute natural gas or can be compressed and fuelled via a pumping station at the place of production. Biomethane can be injected and distributed through the natural gas grid, after it has been compressed to the pipeline pressure.

The injected biomethane can be used at any ratio with natural gas as vehicle fuel. In many EU countries, the access to the gas grid is guaranteed for all biogas suppliers.

A major advantage of using natural gas grid for biomethane distribution is that the grid connects the production site of biomethane, which is usually in rural areas, with more densely populated areas. This enables biogas to reach new customers.

Storage of Biomethane

Biomethane can be converted either into liquefied biomethane (LBM) or compressed biomethane (CBM) in order to facilitate its long-term storage and transportation. LBM can be transported relatively easily and can be dispensed through LNG vehicles or CNG vehicles. Liquid biomethane is transported in the same manner as LNG, that is, via insulated tanker trucks designed for transportation of cryogenic liquids.

Biomethane can be stored as CBM to save space. The gas is stored in steel cylinders such as those typically used for storage of other commercial gases.

Applications of Biomethane

Biomethane can be used to generate electricity and heating from within smaller decentralized, or large centrally-located combined heat and power plants. It can be used by heating systems with a highly efficient fuel value, and employed as a regenerative power source in gas-powered vehicles.

Biomethane, as a transportation fuel, is most suitable for vehicles having engines that are based on natural gas (CNG or LNG). Once biogas is cleaned and upgraded to biomethane, it is virtually the same as natural gas.

Because biomethane has a lower energy density than NG, due to the high CO2 content, in some circumstances, changes to natural gas-based vehicle’s fuel injection system are required to use the biomethane effectively.

Biomethane Industry in Europe

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Biomethane is a well-known and well-proven source of clean energy, and is witnessing increasing demand worldwide, especially in European countries. Between 2012 and 2016, more than 500 biomethane production plants were built across Europe which indicates a steep rise of 165 percent. The main reasons behind the growth of biomethane industry in Europe is increasing interest in industrial waste-derived biogas sector and public interest in biogas.  Another important reason has been the guaranteed access to gas grid for all biomethane suppliers.

Biomethane production in Europe has swiftly increased from 752 GWh in 2011 to 17,264 GWh in 2016 with Germany being the market leader with 195 biomethane production plants, followed by United Kingdom with 92 facilities. Biogas generation across Europe also witnessed a rapid growth of 59% during the year 2011 and 2016. In terms of plant capacities, the regional trend is to establish large-scale biomethane plants.

Sources of Biomethane in Europe

Landfill gas and AD plants (based on energy crops, agricultural residues, food waste, industrial waste and sewage sludge) are the major resources for biomethane production in Europe, with the predominant source being agricultural crops (such as maize) and dedicated energy crops (like miscanthus). In countries, like Germany, Austria and Denmark, energy crops, agricultural by-products, sewage sludge and animal manure are the major feedstock for biomethane production. On the other hand, France, UK, Spain and Italy rely more on landfill gas to generate biomethane.

A large number of biogas plants in Europe are located in agricultural areas having abundant availability of organic wastes, such as grass silage and green waste, which are cheaper than crops. Maize is the most cost-effective raw material for biomethane production. In many parts of Europe, the practice of co-digestion is practised whereby energy crops are used in combination with animal manure as a substrate. After agricultural biogas plants, sewage sludge is one of the most popular substrates for biomethane production in Europe.

Biomethane Utilization Trends in Europe

Biomethane has a wide range of applications in the clean energy sector. In Europe, the main uses of biomethane include the following:

  1. Production of heat and/or steam
  2. Power generation and combined heat and power production(CHP)
  3. Replacement for natural gas (gas grid injection)
  4. Replacement for compressed natural gas & diesel – (bio-CNG for use as transport fuel)
  5. Replacement for liquid natural gas – (bio-LNG for use as transport fuel)

Prior to practically all utilization options, the biogas has to be dried (usually through application of a cooling/condensation step). Furthermore, elements such as hydrogen sulphide and other harmful trace elements must be removed (usually trough application of an activated carbon filter) to prevent adverse effects on downstream processing equipment (such as compressors, piping, boilers and CHP systems).

biomethane-transport

Biomethane is getting popularity as a clean vehicle fuel in Europe. For example, Germany has more than 900 CNG filling stations, with a fleet of around 100,000 gas-powered vehicles including cars, buses and trucks. Around 170 CNG filling stations in Germany sell a blend mixture of natural gas and biomethane while about 125 filling stations sell 100% biomethane from AD plants.

Barriers to Overcome

The fact that energy crops can put extra pressure on land availability for cultivation of food crops has led many European countries to initiate measures to reduce or restrict biogas production from energy crops. As far as waste-derived biomethane is concerned, most of the EU nations are phasing out landfill-based waste management systems which may lead to rapid decline in landfill gas production thus putting the onus of biomethane production largely on anaerobic digestion of food waste, sewage sludge, industrial waste and agricultural residues.

The high costs of biogas upgradation and natural gas grid connection is a major hurdle in the development of biomethane sector in Eastern European nations. The injection of biomethane is also limited by location of suitable biomethane production facilities, which should ideally be located close to the natural gas grid.  Several European nations have introduced industry standards for injecting biogas into the natural gas grid but these standards differ considerably with each other.

Another important issue is the insufficient number of biomethane filling stations and biomethane-powered vehicles in Europe. A large section of the population is still not aware about the benefits of biomethane as a vehicle fuel. Strong political backing and infrastructural support will provide greater thrust to biomethane industry in Europe.