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Gas Factfile
Key points
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Gas, or Natural Gas, is mainly methane (CH4).
Gas is used for heating buildings, hot water, cooking and has been used increasingly for
generating electricity.
Background information
Natural gas is formed from the remains of plants and animals that were crushed between layers of
rock and altered by the combined effects of pressure and heat over millions of years.
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Most gas is deep underground – some is under land but a lot is under the sea bed deep in
the ocean. Wells must be drilled at these sites to recover the gas.
Natural gas is highly combustible and is a very useful fuel.
As gas is colourless, odourless, and tasteless, a chemical that smells like sulphur (or rotten
eggs) is added, allowing gas to be detected when leaks occur [1].
Current use in world and UK
World
 Natural gas provides around 25% of global primary energy consumption [2].
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Most gas is used directly, mainly for heating and hot water in buildings and for heat in
industry. However, almost as large an amount is used to generate electricity.
The energy industry also uses large amounts of natural gas, in oil refineries etc [3].
Natural gas is also an important raw material for many products such as paints, fertilizer,
plastics, antifreeze, dyes, photographic film, medicines, and explosives [1].
Like all fossil fuels, the use of natural gas is increasing year on year [2].
Britain
 In the UK, gas provides nearly 35% of our primary energy.
 Most of this gas is used for heating and hot water in homes and other buildings.
 The next biggest use is in power stations to generate electricity.
 A smaller amount is used in UK industry, including the energy industry, such as oil refineries
[4].
 Gas power stations are a major source of electricity, providing about 30% of electricity in
2012 [5,6].
 That percentage could increase in coming years if less coal is used in order to reduce CO2
emissions.
Climate change and impact on nature
Climate change
 Globally, natural gas is the third largest source of CO2 emissions from fossil fuels, behind
coal and oil [19].
 Gas provides less energy but also produces less CO2 per unit of energy compared with the
other fossil fuels.
 Using natural gas to replace higher emission fuels like coal can help reduce global CO2
emissions. There is debate about whether using gas is the best way to lower some
emissions in the short term, giving time to develop the very low or zero carbon energy
sources needed [18]. Others argue that the move should be straight to developing the low
carbon sources.
 Greenhouse emissions per unit of energy for gas are about:
o 185 grams of CO2e per kilowatt-hour for the direct emissions from combustion;
o or 205 gCO2e/kWh if indirect emissions such as those for fuel extraction and
production are included [7].
These figures assume piped gas, for example, from the North Sea.
 If gas has to be transported long distances in tankers it is compressed, forming Liquified
Natural Gas. The energy used to do this means higher emissions per unit of energy – about
250 gCO2e/kWh [7].
 Some natural gas leaks into the atmosphere from gas wells, storage tanks, and pipelines.
Since methane is a powerful greenhouse gas the amount of gas that leaks into the
environment without being burnt is important and must be factored into the above figures.
 For electricity from gas power stations, lifecycle emissions are in the range of 370-500
gCO2e/kWh, depending mainly on the efficiency of the power station and the source of the
gas used.
 For electricity from UK gas power stations the figure is around
400 grams of CO2 or equivalent greenhouse gas per kilowatt-hour (gCO2e/kWh) [8].
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Other environmental impacts
 Apart from greenhouse gas emissions, natural gas is quite a clean fuel, producing much less
air pollution when burnt than coal or oil.
 However:
o Drilling wells produces air pollution and may disturb wildlife.
o Pipelines are needed to transport the gas. This requires clearing land to bury the pipe
but once done it is efficient and inconspicuous.
o Natural gas production can also result in the production of large volumes of
contaminated water, which must be properly handled, stored, and treated so that it
does not pollute land and water [1].
o As harder to access gas is exploited, this brings a range of new environmental
concerns (seeing Fracking factfile).
o There is a great deal of evidence that climate change is having an impact on
biodiversity so energy sources that give off a lot of CO2e damage nature indirectly.
[23]
Risks
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Exploration and extraction of gas can be hazardous and can require operating in extreme
environments, like the North Sea.
Other risks include explosions at production and storage facilities, and when using gas, for
example, in homes.
Gas is clean burning in comparison with other fuels; the impact on human health is limited. A
comparative study places gas as one of the safer energy sources, with around four deaths
per terawatt-hour (TWh), compared with 36 for oil, 25 for coal, and 0.15 for wind [9,10].
Cost now and in the future
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The wholesale price of natural gas is about 60 pence per therm or 2 pence per kWh.
In the last few years a large spread has emerged in the regional prices of natural gas [12].
The cost of natural gas in the UK is projected to rise by around a third by 2030, to 80 pence
per therm, but could rise to over 100 pence per therm [11].
If carbon taxes are increased in future, natural gas may become more expensive to use but
would also become cheaper relative to other fossil fuels.
Gas power stations also produce cheap electricity – about 6 pence per kWh for gas power
stations started today.
If the expected costs of carbon taxes are included, the cost will increase to about 8.5 pence
per kWh, a similar cost to onshore wind, based on central projections for the future price of
gas. If gas prices rise by more, the electricity from gas power stations will get even more
expensive [13, 14].
World and UK resource
World
 The global proven reserves of natural gas are around 190,000 billion cubic metres (bcm).
 Annual global consumption of gas was around 3300 billion cubic metres in 2012, so supply
could last for over 50 years if we continued using gas at the current rate [2].
 Consumption of gas is increasing and predicted to reach 4000 billion cubic metres by 2020
[15].
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Britain
 Conventional UK natural gas reserves (those proven to be economical to extract) are rapidly
being depleted and are in the order of a few hundred billion cubic metres [2].
 The potentially recoverable conventional gas resources (which could become economic to
extract if gas prices rise) are around 1,500 bcm (billion cubic metres) [20].
 Current annual consumption in the UK is around 85 billion cubic metres.
 Annual production has declined rapidly over recent years, with the UK becoming a net
importer of gas in 2004.
 Current production is around 40 billion cubic metres [5].
 Production at this current level can probably be sustained for less than a decade or two.
However, the UK also has unconventional, shale gas reserves that are currently being
explored (see Fracking factfile).
Reliability/flexibility
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Natural gas has a high energy density by weight at ~54 gigajoule per tonne.
An advantage of gas is that it can be moved around very efficiently by pipeline.
At normal atmospheric pressure the energy density by volume is just ~38 megajoule per m3
[16]. So when gas needs to be transported by vehicles, or used as vehicle fuel, it must be
liquefied or compressed so that a large amount of energy can be carried in a reasonable
space.
Liquified Natural Gas has an energy density of 22 gigajoule per m3.
The low energy density of gas by volume also presents problems for storage, as large
volume containers are required to store lots of energy. On the plus side, natural gas is very
stable and can be stored in containers, or appropriate spaces underground, for months or
years.
Gas fired power stations:
 are a very reliable way to produce electricity, so long as a fuel supply can be maintained.
 can be very flexible in their output of electricity, and
 can change their output speed (known as the ramp rate) very fast.
This makes them very useful to have alongside intermittent sources of electricity such as
wind turbines. The gas turbines can respond to changes in output from renewables and help
balance supply with demand for electricity [17].
Wales
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There is no source of gas in Wales unless fracking is accepted. Gas is the main fuel for
electricity generation, with 39% in 2011 coming from eight large gas fired power stations. At
least 3 more are planned, at Abergelli and Hirwaun, Swansea, due to come online after 2019
[24], and at Port Talbot. [25]
Wales has a higher proportion of industry demand for heat than the rest of the UK and a lot
of this is met by gas [21].
Piped (mains) gas is used by 79% of homes in Wales but there are large areas of Wales that
are not connected to the gas network so quite a lot of houses use bottled gas, oil, electricity
or wood for heating. [22]
There have been concerns about the replacement Pembroke power station dumping waste
heat into the Pembrokeshire Marine Special Area of Conservation posing a threat to marine
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life, with suggestions that the wasted heat is equivalent to 40 per cent of Wales' electricity
demand. [26]
Gas is regarded by the Welsh Government as a key transitional fuel to a low carbon future.
Pembroke gas power
station – the biggest in
Wales – 2000 MW
References
[1] EIA (2013). Natural Gas Explained. United States Energy Information Administration.
http://www.eia.gov/energyexplained/index.cfm?page=natural_gas_home [accessed 13/1/2014].
[2] BP (2013). BP Statistical Review of World Energy June 2013. BP.
http://www.bp.com/en/global/corporate/about-bp/energy-economics/statistical-review-of-world-energy2013.html [accessed 8/1/2014].
[3] IEA (undated). ETP 2012 data visualisation. International Energy Agency. http://www.iea.org/etp/explore/
[accessed 8/1/2014].
[4] DECC (2013). Energy Flow Chart 2012. Department for Energy and Climate Change.
https://www.gov.uk/government/publications/energy-flow-chart-2012 [accessed 8/1/2014].
[5] DECC (2013). Statistics at DECC. Department for Energy and Climate Change.
https://www.gov.uk/government/organisations/department-of-energy-climate-change/about/statistics
[accessed 8/1/2014].
[6] Elexon (undated). Neta - Electricity summary page. Elexon. http://www.bmreports.com/bsp/bsp_home.htm
[accessed 8/1/2014].
[7] DEFRA (2012). 2012 Guidelines to Defra / DECC's GHG Conversion Factors for Company Reporting.
Department for Environment, Farming and Rural Affairs.
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/69554/pb13773-ghgconversion-factors-2012.pdf [accessed 8/1/2014].
[8] CCC (2013). Reducing the UK’s carbon footprint and managing competitiveness risks. The Committe on
Climate Change. http://www.theccc.org.uk/publication/carbon-footprint-and-competitiveness/ [accessed
14/1/2014].
[9] Starfelt, N. and Wikdahl, C (undated). Economic Analysis of Various Options of Electricity Generation Taking into Account Health and Environmental Effects.
http://manhaz.cyf.gov.pl/manhaz/strona_konferencja_EAE-2001/15%20-%20Polenp~1.pdf [accessed
14/1/2014].
[10] Unnamed (undated). Deaths per TWh for all energy sources. http://nextbigfuture.com/2008/03/deathsper-twh-for-all-energy-sources.html [accessed 14/1/2014].
[11] DECC (2013). DECC Fossil Fuel Price Projections. Department for Energy and Climate Change.
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/212521/130718_decc-fossilfuel-price-projections.pdf [accessed 9/1/2014].
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[12] BP (undated). Natural gas prices. BP. http://www.bp.com/en/global/corporate/about-bp/energyeconomics/statistical-review-of-world-energy-2013/review-by-energy-type/natural-gas/natural-gas-prices.html
[accessed 9/1/2014].
[13] CCC (2010). The Fourth Carbon Budget – reducing emissions through the 2020s. The Committee on
Climate Change. http://www.theccc.org.uk/publication/the-fourth-carbon-budget-reducing-emissions-throughthe-2020s-2/ [accessed 9/1/2014].
[14] DECC (2012). Electricity Generation Costs. Department for Energy and Climate Change.
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/65713/6883-electricitygeneration-costs.pdf [accessed 9/1/2014].
[15] WEC (2013). World Energy Resources 2013 Survey: Summary. World Energy Council.
http://www.worldenergy.org/wp-content/uploads/2013/10/WEC_Resources_summary-final.pdf [accessed
9/1/2014].
[16] http://en.wikipedia.org/wiki/Energy_density
[17] Ray, R. (2013). Gas Turbine Innovations: Increasing Flexibility & Efficiency. Power Engineering.
http://www.power-eng.com/articles/print/volume-117/issue-5/features/gas-turbine-innovations-increasingflexibility-efficiency.html [accessed 14/1/2014].
[18] Kirkland, J. (2010). Natural Gas Could Serve as 'Bridge' Fuel to Low-Carbon Future. Scientific American.
http://www.scientificamerican.com/article.cfm?id=natural-gas-could-serve-as-bridge-fuel-to-low-carbon-future
[accessed 14/1/2014].
[19] Sato, M. and Hansen, J. (undated). Updating the Climate Science. What Path is the Real World
Following? Columbia University Earth Institute. http://www.columbia.edu/~mhs119/ [accessed 8/1/2014].
[20] Houses of Parliament (2013). UK Shale Gas Potential. UK Houses of Parliament.
http://www.parliament.uk/documents/post/ShaleGas_POSTbox.pdf [accessed 8/1/2014].
[21] National Assembly for Wales, 2013
[22] http://www.energyefficiencywales.org.uk/targetwales.php?mopt=1&pid=gas_areamap
(Map of areas in Wales that are not connected to gas grid)
[23] http://jncc.defra.gov.uk/page-5145 http://jncc.defra.gov.uk/PDF/Pub10_Bio_&_CC_IACCF_2010_Web.pdf
2014 [accessed 28.1.15]
[24] 11.6.14 http://www.walesonline.co.uk/business/business-news/revealed-plans-new-gas-fired-power7250001 Accessed 11.12.14
[25] 22.9.14 http://www.southwales-eveningpost.co.uk/Power-station-approved-Port-Talbot-steelworks/story22961296-detail/story.html Accessed 11.12.14
[26] ITV News 19.9.12 http://www.itv.com/news/wales/2012-09-19/1bn-new-pembrokeshire-power-station-toopen/ (Friends of the Earth Cymru) Accessed 11.12.14
– background information for Energy Trumps cards. Full resource available as free download at
http://learning.cat.org.uk/en/resources
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