The Bartlett


Economic modelling of long-term decarbonisation pathways: policy impacts of the MARKAL-TIMES model

MARKAL-TIMES energy models developed at UCL have underpinned every major UK government energy policy document on long-term decarbonisation.


The MARKAL-TIMES model family is an integrated energy system, technology-rich optimisation framework. 

Since the key researchers, Professor Neil Strachan and Professor Paul Ekins, joined the UCL Energy Institute in 2009, they have led the generation of a rich diversity of insights, including about the interactions between:

  • technological and behavioural change
  • geographical drivers
  • multi-regional impact
  • decision-making under uncertainty
  • life-cycle analysis
  • global drivers. 

Most recently, the model platform has evolved from MARKAL to the successor TIMES model, plus the development of EU and global model versions.

The groundbreaking research has taken the UK’s energy systems analytical capacity from near zero to world-class. The models have underpinned every major recent UK government energy policy document on long-term decarbonisation pathways. 

These models generate the key numbers and insights that form the backbone of debate and resultant policy. The researchers regularly provide expertise to policymakers and inform political debate.

The 2011 Carbon Play

The MARKAL-TIMES model has had a continual influence on UK government policy-making by demonstrating the economic feasibility of decarbonisation pathways. UK MARKAL-TIMES constituted the key technical reports on this topic for the 2011 Carbon Play by the Department of Energy & Climate Change (DECC).

The DECC accepted the MARKAL elastic demand model’s finding of the critical role of the electricity generation sector in enabling wider decarbonisation efforts in buildings and transport. Based on this, electricity decarbonisation policy mechanisms have been implemented as a key government priority.

Committee on Climate Change targets

The quantification of electricity sector decarbonisation using MARKAL models is also an essential step in meeting the targets set by the Committee on Climate Change (CCC). 

The CCC’s carbon budget reports (2009–2013), which outline the framework for legislated UK carbon budgets, draw on successively commissioned MARKAL-TIMES modelling projects to provide long-term energy and emission scenarios. 

In 2011, the UK government accepted the CCC’s fourth budget period recommendation for a 50% reduction (from 1990 levels) in carbon emissions by 2025, with underpinning technical appendices from the UK stochastic MARKAL model.

Non-governmental organisations

The models have also been used to produce alternate decarbonisation scenarios for a consortium of non-governmental organisations including the:

  • World Wildlife Fund
  • Institute for Public Policy Research
  • Royal Society for the Protection of Birds.

International contributions

MARKAL-TIMES was channelled through a Japan–UK research project on international modelling on low carbon societies. It contributed to the declaration and reaffirmation through 2009–2013 of a global long-term target of a 50% reduction in greenhouse gas emission by 2050. This led to input to the G8/G20 Gleneagles Dialogue.

Other uses

The models produced by the team are also widely used by stakeholders themselves, and the research team has also been instrumental in developing complementary energy modelling tools, including:

  • Professor Strachan serving as a strategic advisor on the development of the ESME energy systems model of the Energy Technologies Institute from 2010, illustrating how UK industry has adopted an energy systems modelling approach
  • Professors Ekins and Strachan successfully arguing for the incorporation of cost metrics (derived explicitly from MARKAL) to be incorporated into the DECC Calculator – the UK government’s highly popular policy engagement tool, which is downloaded by 10,000 UK users each month.