The UK’s ‘peak gas’. The rate
of North Sea gas production
in gigawatts or GW. 1 GW
equals one million kilowatts.
Source: reference .
The UK’s oil, coal and gas production continue to decline steadily. Precipitate could be a better word for the rate in decline of North Sea gas output, see the chart above.
The main action visible from the government has been a second ‘dash for gas’, but this time a rush to award various subsidies for ‘unconventional gas’. Unlike North Sea gas, this new natural gas resource is tied up in shale deposits and is only extractable via the process of hydraulic fracturing or ‘fracking’.
Fracking-type processes have a very long history and have sometimes been used in ‘conventional’ oil or gas extraction without apparent fuss. The recent earthquakes from the Gröningen gas field in the Netherlands have been larger than from fracking . So maybe some intrinsic problems are less than the worst scare stories suggest.
But we lack basic answers to many questions. Government answers so far to these six seem to risk misleading us as much as they inform us:
- How much higher are greenhouse gas emissions from shale gas vs. conventional natural gas? The government estimated that shale gas has similar emissions to imported liquefied natural gas from Qatar but it has probably underestimated the methane leaks .
- The theoretical amount of shale gas in place under various regions of the UK, as cited by the British Geological Survey, is very high. But no-one ever expects to extract all the oil or gas which is present. It is much more useful to estimate the recoverable amount of gas. Was the larger figure so widely quoted by accident or was it an attempt to mislead?
- How much of the theoretical amount is recoverable at an acceptable energy return on energy invested (EROEI)? EROEIs are crucial to the viability of new energy sources. Shale gas may be less good than conventional gas fields and better than a few other sources which the government is subsidising. But one would like to base energy policy on hard evidence. There seems to be uncomfortably little.
- Why the apparently low level of interest from four of the world’s five main oil companies? It is not exactly a vote of confidence on a par with their enthusiasm to drill the North Sea for conventional oil 40 years ago.
- How many wells per year must be drilled in order to supply gas at a significant rate in relation to UK consumption? Production from a shale well falls off quite quickly. If developers want the most rapid return, other wells must soon be drilled nearby. Is the answer ‘too many for comfort in a small, very densely-populated country’?
- If this is a ‘last gasp’ of the natural gas industry, the gas may not be particularly cheap. So why is it apparently to go on being wasted in heat-only boilers ?
Re the last point, it strains credulity to call shale gas ‘a bridge to sustainable energy’ if it is to be burned off as fast as possible in one of the most wasteful ways possible. By taking this approach to conventional gas, we exhausted the North Sea in 40 years flat. But nothing very decisive on implementing energy efficiency seems to have happened since DECC issued a ‘strategy’ on it in November 2012  and an ‘update’ on it in 2013 .
I still hope that an effective policy is maturing behind the scenes, benefiting from the approaches which were found to work or not work elsewhere around the world. But at times I fear that the modern meaning of ‘strategy’ or ‘update’ could be the same as the old Civil Service phrase: ‘The matter is under review’. This was a euphemism for: ‘File it and forget about it’.
 Historical Gas Data: Gas Production and Consumption and Fuel Input 1920 to 2013. DECC (31 July 2014)
 UK gas power stations reject enough cooling water to heat the domestic sector. Denmark, just across the North Sea, uses the bulk of its natural gas considerably more efficiently in combined heat and power plants. The heat piped to houses is two to six times less CO2-intensive than heat from a gas condensing boiler. These figures refer respectively to heat from a small 500 kW(e) reciprocating engine and from a 300 MW(e) or larger combined cycle gas turbine.
Using reject heat from power stations is as much an energy efficiency measure as insulating buildings. The first measure uses less fuel to provide heat; the second uses less heat to provide comfort. We need an astute combination of both, especially for historic buildings in UK cities.