Underground Coal Gasification (UCG)

Underground Coal Gasification (UCG) is a process for exploiting coal that cannot be mined because the seams are too deep, thin or fractured. Exploratory licenses have been granted for the Dee Estuary (Cluff Natural Resources) and Liverpool Bay (Riverside Energy).

The Purple Area Shows the License Block Granted to iGas for CBM exploration on the Wirral.

The Grey Area Shows the License Block Granted for UCG exploration in the Dee Estuary and Liverpool Bay.


The process involves using the same sort of drilling technology usually used for fracking to get air/oxygen into the coal seam and then set the seam on fire. By controlling the amount of oxygen injected it is then possible to only partially burn the coal and bring the gases produced to the surface where they can be burned to produce energy.

The Underground Coal Gasification Process


A brew of toxic and carcinogenic coal tars are produced in the burn cavity. The process is associated with serious groundwater contamination and massive carbon emissions. In the UCG area proposed under the Dee Estuary and Hilbre Island it could also have the effect of raising the water temperature which will have serious consequences for the delicate marine ecosystem.

A UCG Plant

Small scale tests of UCG have been taking place on and off since the 1930’s, particularly in the Soviet Union and United States, and have usually resulted in contamination of groundwater. In the 1960s a coal seam was set on fire below a town in Pennsylvania, USA, and is still burning 50 years later. This has resulted in the population of the town dwindling as toxic fumes, damage to the environment and subsidence has turned it into a wasteland.

More recently there have been three tests in Australia, two of which have resulted in the plants being shutdown. After only a five day burn the well at the Cougar Energy plant in Kingaroy, Queensland exploded and subsequently benzene and toluene were detected in groundwater and in the fat of animals grazing on the surface.

Full scale UCG would likely involve huge plants connected to multiple gasifiers, and might be similar to tar sands extraction in its scale and impact. Given that Hilbre Island is a Special Area of Conservation and a Site of Special Scientific Interest we are extremely concerned about the proposals to destroy this. It may also effect protected wildlife species in the area.


20 impacts UCG

  • Toxic Waste
    Coal is the dirtiest of the fossil fuels containing many highly toxic materials. The process of Underground Coal Gasification (UCG) involves the partial burning of coal underground. This produces even more toxic and carcinogenic hydrocarbons including benzene, toluene, ethyl-benzene and xylene. Large volumes of these compounds are brought to the surface by the process.
  • Waste Disposal
    Large volumes of highly contaminated water will be produced and the industry has not publicly addressed what will happen to it. The water used to control the process will emerge along with other liquids and particulates drawn up with the exhaust gasses. Vast volumes of liquid and solid waste will require treatment if companies are going to gasify billions of tonnes of coal as they are proposing here in the UK.
  • Air Pollution & Flaring
    Trials have shown that significant quantities of toxic and carcinogenic hydrocarbons (e.g. phenols and benzene) are produced as by-products of the gasification process. Much of this will be carried to the surface by the product gas. Large volumes of carbon dioxide and other combustion products will be emitted from sites and power stations. Emergency flaring and uncontrolled emissions will inevitably occur.
  • Pollution of Aquifers
    Previous trials have consistently resulted in contamination with toxic and carcinogenic materials. The heat and pressure produced by the burning coal provides a mechanism to spread this pollution. Perfectly controlling the reaction to prevent this is impossible when it is happening deep underground. However the most common paths to the surface is via the wells themselves. Of three recent tests projects in Australia two have been shut down following these compounds being released into the biosphere.
  • Pollution of Sea & Coastline
    UCG has never been tested offshore or near shore (under the sea). This targeting of sub-sea locations appears to be a tacit admission of the threat of water contamination, but UCG licencing is now creeping onshore due to industry pressure, with a proposed licence in the Warwickshire countryside.
  • Toxic Residues
    Large volumes of partly burnt coal will be left underground by the process. The industry claims that they will flush out these residues but this would not be consistently possible on an industrial scale, due to collapses in the burn cavity. Over time toxic materials will be leached out by groundwater flows and follow the path of least resistance up leaking wells to the surface.
  • Subsidence
    As the fire burns along the coal seams the space created will collapse. This can cause collapse of the overlying geology and could lead to subsidence and damage to buildings and infrastructure including the UCG boreholes themselves.
  • Underground Coal Fires
    The geology of the British Isles is littered with faults and abandoned mine workings. If a supply of oxygen from an uncontrolled source reached the burning coal, the coal seam could continue to burn indefinitely. An uncontrolled fire would not be confined to the offshore coal seam.
  • Explosions & Poisoning
    Hydrogen and methane gas are produced by the UCG process. Both are colourless, odourless, and highly explosive. Large volumes of carbon monoxide are also produced. It is a colourless, odourless gas that can kill humans and animals at very low concentrations. The process also produces waxes and tars that gradually build up in wells and pipes and make the process unstable. A significant number of test projects have been terminated by explosions in wells and pipes.
  • Dangerous Work Environments
    The jobs created by the UCG industry are small in number for the size of the investment. Employment would be in high risk areas/occupations. These workers are at increased risk of industrial disease and accidents.
  • Corporate Profit vs Community Cost
    The more the coal and gas industry invest in drilling and gasification equipment, the more drilling and gasification will happen. The dangers are acute and borne by the local community. The rewards go to an elite of shareholders, directors and investors. Stopping this industry in the UK will send a clear message to other countries that the impacts and dangers are unacceptable.
  • Industrialised Coastline
    The equipment at surface will include the drilling rigs, wellheads, connecting pipework, and process plant for handling the injection/production gases. A commercial UCG scheme will require permanent connections to power stations. This industrialisation will change the character of our coastal areas. Placing infrastructure in areas at risk from tidal surges, coastal erosion and sea level rise is reckless and irresponsible.
  • Toxic Pipelines
    The industrialisation required for this industry will spread beyond the limits of the main sites into urban and residential areas. As sections of the coal seams are burnt, drill rigs will leave a trail of sites along the coast. Pipelines carrying toxic and explosive gas at high pressures and temperatures will follow the rigs, linking the wells to the processing plant.
  • Damage to Other Industries
    Fishing, tourism and recreation will suffer at all stages of UCG exploration, production and legacy. An areas reputation and landbase are exposed to long term dangers that exist long after the UCG industry has gone.
  • Boom & Bust
    Many areas of the country bear the scars of previous industrial development. Extractive industries destroy long term sustainable jobs and create unsustainable booms and busts. Any short term gains are far outweighed by the long term losses and resulting regional instability.
  • Heavy Vehicle Traffic
    Just removing drilling mud and waste from wells will require many tanker/truck movements for each site. Waste disposal traffic will become a common sight on local roads. This is in addition to construction vehicles and drilling equipment when the sites are commissioned and pipelines are constructed through rural and suburban areas.
  • Road Damage, Subsidence & Earthquakes
    Road damage is an inevitable consequence of UCG exploration due to intensive transportation of materials and machinery. Subsidence and earthquakes may be caused by the process and are quite common in conventional coal mining.
  • Property Blight
    Home owners in UCG areas can find themselves trapped in a house they can not sell, re-mortgage, insure or develop. An area already suffering from a decline in existing industries is further impacted by industrialisation (sites & pipelines), air and water pollution and the resultant health impacts.
  • Direct Threat to Renewable Energy Investment
    Further investment in fossil fuel extraction and a new wave of extreme energy undermines investment in energy efficiency and renewable energy technologies. It perpetuates our dependence on finite resources and sabotages the life chances of future generations.
  • Climate Change
    The Underground Coal Gasification process alows companies to access coal that has previously been considered unminable. By developing this new energy extraction technique we are expanding global reserves of hydrocarbons and increasing emissions. The chemistry of the atmosphere is changing and due to drought, flood and starvation the death toll already stands at 450,000 annually.

See Underground Coal Gasification: Hellfire and Damnation for more details about this process.

One thought on “Underground Coal Gasification (UCG)

  1. Pingback: Watch our Short Film | Wirral Against Fracking

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