With countries now committed through the Paris Agreement of 2015 to limiting the maximum global average atmospheric temperature rise to 1.5-2.0°C, the question arises as to the role of natural gas in achieving this very challenging objective.
The issue is not straightforward, because, on the one hand, compared to coal and oil, gas produces relatively low carbon emissions but, on the other, it is very far from being carbon-free, and the Paris Agreement is clear that the temperature target effectively requires zero net carbon emissions in the second half of this century. This article explores the options for gas in the UK and globally in the intervening decades.
Globally, work by the UK Energy Research Centre (UKERC) showed clearly that, in some parts of the world, gas has the clear potential to play the role of a transition fuel, or a ‘bridge’ to a low-carbon future. Figure 1 comes from a UKERC Research Report. It shows global gas consumption out to 2050 in three model runs, which result in average global warming of 2°C (2DS), 3°C (3DS) and a Reference case (REF) with very weak climate policy that results in average global warming of around 5°C. The modelling clearly shows that, in the 3DS scenario, gas consumption is higher than in REF throughout the modelling period, and in the 2DS scenario it is higher than in REF through to 2035, falling below it thereafter. Globally, gas consumption clearly can act as a ‘bridge’ to a low-carbon future.
The reason for this is that, as noted above, gas is much less carbon-intensive than coal, and substitutes for coal in the 2DS scenario up to 2035, but then the increasingly stringent emissions constraint causes gas consumption to fall, ending up 20% below REF by 2050.
It might be expected that the opportunity for coal-gas substitution would vary in different regions of the world, which led UKERC then to examine whether such an opportunity existed for the UK. Figure 2 from another UKERC Research Report shows results from this research.
Figure 2 shows three different scenarios. The two Maintain scenarios both meet the UK’s carbon emissions target of an 80% reduction by 2050, with the difference between them being that in the Maintain (Techfail) variant CCS is not deployed, so that more gas can be used in Maintain. The Abandon scenario shows what happens if the UK abandons its carbon emission reduction targets after 2020.
It can be seen from Figure 2 that gas consumption in the Maintain scenarios very briefly rises slightly above that in Abandon, but after 2020 quickly declines and falls below it. The role of gas as a ‘bridge’ to a low-carbon future in the UK is therefore much more limited than it is globally, almost to the point of non-existence.
The reason for this is not hard to fathom. In the UK the substitution of gas for coal took place in the residential sector in the 1970s, when natural gas replaced town gas (made from the gasification of coal) for heating and cooking in homes. In industry, natural gas and electricity replaced much coal in the 1980s. And in the 1990s the ‘dash for gas’ caused much coal in power generation to be replaced by natural gas. The coal-gas substitution in the UK has already largely taken place. The scope for further such substitution is therefore rather limited.
This does not mean, of course, that there is no role for natural gas in the UK energy mix in the 2020s and 2030s. But it does mean that the consumption of natural gas will be falling from 2020, if the UK is to meet its carbon targets in a cost-effective way.
Any new gas plant in power generation, which may be required to balance the grid as the quantity of intermittent renewables increases, will increasingly be operated at low load factors to fulfil this role, which has implications for how such a plant is to operate profitably. The capacity market undoubtedly has a potential role here, even if to date it has been singularly ineffective in bringing forward new investment in CCGT gas plants.
The second implication is for UK shale gas production. Should this prove commercially viable at scale, more and more of the production will need to be exported for consumption abroad, if the UK is to meet its carbon emission reduction targets. But other countries will also presumably be seeking to decarbonise. If this shale gas substitutes for German or Polish coal consumption, then emissions could indeed fall overall. But UK shale gas is not needed for this to happen.
There are plenty of other currently available sources of gas that could play this role, and if it is not happening it is because it is being prevented by economic or political factors which presumably would apply equally to UK shale gas. ■
Professor Paul Ekins
Professor of Resources and Environmental Policy
From Adjacent Oil & Gas 5, November 2016