NOTE: EXPANSE is no longer used at UCL.  This page is made available here for legacy reasons.

Bottom-up, technology-rich energy system models, that optimise the total system costs under emissions constraint, have been extensively used to derive energy system transition pathways. While these pathways are optimal, given the costs and emissions dimensions, they may not be optimal if further dimensions, such as supply security or stakeholder preferences, are added. The EXPANSE (EXploration of PAtterns in Near-optimal energy ScEnarios) model has the same structure of a bottom-up, technology-rich model. In addition to the optimal transition pathway, EXPANSE generates a large number of near-optimal pathways and systematically mines patterns in these pathways. As a result, EXPANSE shows several plausible transition pathways that are nearly cost-optimal, but differ substantially in the technologies used and investment patterns.

Currently, there are two versions of this model: EXPANSE and D-EXPANSE. EXPANSE is used for generating the optimal and multiple near-optimal energy mixes for the specific year in the future, without analysing the pathway from the current situation to the future energy mix. It has been applied for analysing the near cost-optimal energy mixes in a Swiss region in order to quantify the economic potential of renewable energy sources. In addition to the cost-focused analysis, EXPANSE can also be used with different types of optimality functions, e.g. optimization of supply security or stakeholder consensus.

D-EXPANSE model is the dynamic version of EXPANSE and analyses the cost-optimal and near-optimal transition pathways from the current system to that of the future. In the Realizing Transition Pathways project, D-EXPANSE is currently used for understanding the plausible investment patterns into the UK power system until 2050. The first application of D-EXPANSE shows that investment strategies, that are nearly optimal with respect to the total system costs, are at the same time poles apart in terms of technologies and temporal distribution of investment.

Model summary

Type: Bottom-up, technology rich cost optimization, including the exploration of near- optimal transition pathways
Purpose: Energy system transition pathways, decarbonisation pathways, economic appraisal, stakeholder engagement
Spatial scale: UK single region
Temporal scale: Annual
Main contact: Evelina Trutnevyte
Other contacts: Neil Strachan


For the EXPANSE documentation, please see the publications below.


Journal papers

Trutnevyte, E. (2014) The allure of energy visions: are some visions better than others? Energy Strategy Reviews 2:211-219

Trutnevyte, E. (2013) EXPANSE methodology for evaluating the economic potential of renewable energy from an energy mix perspective. Applied Energy 111: 593-601.

Trutnevyte E., Stauffacher M., Schlegel M. and Scholz R. W. (2012) Context-specific energy strategies: Coupling energy system visions with feasible implementation scenarios. Environmental Science & Technology 46; 9240-9248.

Trutnevyte E., Stauffacher M. and Scholz R. W. (2012) Linking stakeholder visions with resource allocation scenarios and multi-criteria assessment. European Journal of Operations Research 219: 762-772.

Conference papers

Trutnevyte, E. (2014) Does cost optimisation approximate the real-world energy transition? Retrospective modelling and implications for modelling the future. Paper for the International Energy Workshop 2014, 4-6 June 2014, Beijing, China.

Trutnevyte E. and Strachan N. (2013) Nearly perfect and poles apart: investment strategies into the UK power system until 2050. Paper for the International Energy Workshop 2013, 19-21 June 2013, Paris, France.