The UK energy system in 2050: Comparing Low-Carbon, Resilient Scenarios

Phase 1 of the UK Energy Research Centre (UKERC) facilitated the development of a state-of-the-art MARKAL model of the UK energy system. MARKAL is a well established linear optimisation, energy system model, developed by the Energy Technology Systems Analysis Programme (ETSAP) of the International Energy Agency (IEA) in the 1970s, and was until very recently used by it for its annual Energy Technology Perspectives (ETP) reports. It is also used by many other research teams round the world, and has been regularly updated and improved over the years through the ETSAP Implementing Agreement.

Towards the end of UKERCs Phase 1, in 2007-8, UK MARKAL was used for a major modelling exercise of different projections of the UK energy system to 2050, the results of which were published in Skea at al 2011. In the ensuing years, UK MARKAL was again used for major 2050-focused modelling projects: for the Committee on Climate Change (CCC) in 2010 (CCC 2010), for the Department of Energy and Climate Change (DECC) in 2011 (HMG 2011), and again for UKERC to update the Energy 2050 scenarios in 2012. This UKERC Research Report presents the main results of each of these modelling exercises, with a view to drawing out any key messages from the set as a whole.

Comparisons between such model runs, even of the same model, need to be drawn with care. Various assumptions, including cost and other data inputs to the model, were changed between the model runs, to reflect policy and other developments, and to incorporate new information. Some of the technology representations in the model were also improved. These changes have two implications for comparisons between such model runs. The first is that detailed conclusions about the cost-preferability of particular technologies, unless they emerge as clear favourites across the whole set of runs, are unlikely to be robust. This is because the cost uncertainties of possible developments in these technologies and their competitors over four decades are very great. Where, as will be seen in these cases, the costs between the major low-carbon technologies are, or may be, of the same orderof magnitude, then there are no strong grounds on the basis of these runs of preferring one over the others on cost grounds.

The second conclusion is more positive. Where consistent patterns of development of the energy system emerge across the different runs, despite the different inputs and the fact that the runs were carried out by different modellers and modelling teams, then more confidence may be placed in these patterns as likely features of the future UK energy system under the constraints applied, theprincipal constraint being reductions in greenhouse gas (GHG) emissions, or carbon dioxide (CO2) emissions in the case of the UK energy system, according to the provisions of the UK Climate Change Act of 2008. It is these consistent patterns that inform the main conclusions of this report, which are summarised here under a number of headings. The numbers on which these broad conclusions are based appear in the main report.