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Using OSeMOSYS as part of a World Bank study to assess the climate vulnerability on Africa’s Energy Infrastructure

The objective is to study the interactions of a constrained and aging system under future climate uncertainties. It will produce a quantified network infrastructure performance for four Power Pools and 7 Water Basins to enable identification of Robust Adaptation Strategies. This study will serve to update previous GAMS based PIDA and AICD models and reports. Most importantly, it will provide actionable recommendations for policy makers to ensure enhanced system resilience, forming the basis for safer and sustainable economic growth.

Global CLEWs Model - An Integrated Assessment Model as part of a UN report on Sustainable Development

Developed in collaboration with UNDESA, an OSeMOSYS model has being developed to study the interactions,trade-offs and synergies between Climate Change, Land-use, Energy and Water (CLEWs) and material sectors on a global level. The open-source nature of the OSeMOSYS ensures transparency and accessibility of the study. This allows for open collaboration, extensions from any user, and easy adaptation to other user’s needs and interests. The collaborative effort will lead to a greater detail of the model – on a global, regional and national scale. This study will form an input to UNDESA’s forthcoming report on Sustainable Development.


Shortening of OSeMOSYS core code

The OSeMOSYS development team reduced the total number of equations in the OSemOSYS code by integrating them into the existing inequalities. This eliminated the need to calculate and store intermediate values. The reduction in the number of equations translates into the generation of a smaller matrix to be solved. This significantly reduces the memory usage (~10x) and the processing time (~5x)

This version of the OSeMOSYS code contains only the essential equations required for running the model. However, all the previous equations have been left as before, and "commented out" to better understand the methodology followed to shorten the code.

        OSeMOSYS Version

Matrix size before pre-processing

(Rows x Columns)

Matrix size after pre-processing

(Rows x Columns)

Memory used



174379 x 173379

25587 x 26652



8749 x 8841

3751 x 5839


It is important to note that the shortening of the code does not change any aspect of the functionality of OSeMOSYS. Furthermore, there are no special formatting requirements of data file required to run this version instead of the regular version. The short version of OSeMOSYS only serves to reduce the memory usage as well as the processing time for finding the model solution. In the future, both the regular and the short versions of OSeMOSYS will be developed and released simultaneously. This effort was led by Abhishek Shivakumar, a member of the OSeMOSYS development team. The following table gives the specifications of the respective  memory and matrix size reductions.

Reordering of Indices

A new version of OSeMOSYS was released with re-ordered arguments of parameters, variables and constraints, to be compatible for use with the ANSWER interface which is currently being developed by Noble-Soft Systems Pty Ltd. Henceforth, this reordered indexing will be applied to all future versions of the OSeMOSYS model.



is now


Following the above index order,


is now


Previous News



Peer reviewed OSeMOSYS publication on smart grids

Another peer reviewed OSeMOSYS publication is available online. Here the modular nature of the code allowed the authors to include smart grid attributes note easily included in similar modelling tools, such as MARKAL or MESSAGE

OSeMOSYS to include short term capacity constraints

KTH-dESA with University College Cork is finalizing modules that allow OSeMOSYS to simulate long term futures together with short term (capacity, operation and regulation reserve) constraints. This gives insights into optimal mixes of intermittent RE, nuclear as well as the value of ancillary markets in the longer term.

South Africa’s national IEP ( Integrated Energy Planning) to use OSeMOSYS

OSeMOSYS is actively being used for South Africa’s country’s national IEP (Integrated Energy Planning). Current tests have it replicating electricity expansion plans, with non-electricity sectors now being added.

OSeMOSYS to be linked with LEAM tool for land use evaluation

An initiative has begun with the University of Chicago and KTH-dESA to link OSeMOSYS with GIS-based city planning infrastructure tool  LEAM.  The model can provide the demand side input (primarily related to land use) to a rasterized city.

World Bank to use OSeMOSYS

The World Bank will be using OSeMOSYS modules for planning activities in Africa in a new effort to update their infrastructure outlooks.

Lithuanian Energy Institute uses OSeMOSYS

The Lithuanian Energy Institute is using OSeMOSYS to examine distributed energy deployment

UNDESA to develop global economic models in OSeMOSYS

The United Nations Department of Economic and Social Affairs (UN-DESA) will be using OSeMOSYS to create global economic models based on Global Sustainability Development (SD) report, which is currently being developed.

OSeMOSYS used for Master thesis Study at Aalborg University

OSeMOSYS was used for a study on long term expansion plan for the electricity generation system of West Java, Indonesia. This work was performed as a master thesis study at Aalborg University in Denmark.

Swedish energy model in OSeMOSYS

A Swedish Energy model is currently being developed at KTH-dESA for long term planning objectives.


OSeMOSYS- GAMS translation

The OSeMOSYS code was translated into the General Algebraic Modeling System (GAMS). This will enable flexibility for folk familiar with that environment. Also a thumbs up for the notion of the layers of abstraction, allowing OSeMOSYS to be easily exported. A data file to test the model installation is available for download under “Publications” at

ANSWER-OSeMOSYS user interface

Added to the excellent LEAP efforts, ANSWER-OSeMOSYS (from popular ANSWER-TIMES/MARKAL family of interfaces) has been developed. More details on the ANSWER interface will follow in a couple of months.

New Staff

At KTH-dESA two new staff (Vignesh and Abhishek) have been added to the OSeMOSYS team and will be – amongst other things - developing the community support of the project.


OSeMOSYS workshop - organized as a parallel event during the International Energy Workshop 2012 in Cape Town, the following elements were demonstrated

  • Expansion of OSeMOSYS to include MIP( mixed integer programming)

  • The importance of flexibility in energy system modelling and the possibilities of increasing flexibility by including capacity credit of wind and optimizing system reserve for unpredictable variations were discussed

  • The ANSWER-OSeMOSYS and the South African-Department of Energy (SA-DOE) interface for OSeMOSYS were demonstrated
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