The Costs of Decarbonisation: System Costs with High Shares of Nuclear and Renewables


Under the Paris Agreement, OECD countries agreed to aim for a reduction of their greenhouse gas emissions sufficient to hold the increase in the global average temperature to well below 2°C above pre industrial levels. This commitment requires a massive effort to decarbonise energy and electricity generation, a radical restructuring of the electric power sector and the rapid deployment of large amounts of low-carbon generation technologies, in particular nuclear energy and renewable energies such as wind and solar PV. This study assesses the costs of alternative low-carbon electricity systems capable of achieving strict carbon emission reductions consistent with the aims of the Paris Agreement. It analyses several deep decarbonisation scenarios to reach the same stringent carbon emission target but characterised by different shares of variable renewable technologies, hydroelectric power and nuclear energy.


  • Limiting the rise of global temperature to less than 2°C represents an enormous challenge for the whole electricity sector. 
  • Decarbonising the electricity sector in a cost-effective manner while maintaining security of supply requires the rapid deployment of all available low-carbon technologies.
  • System costs are not properly recognised by current market structures and are currently borne by the overall  electricity system in a manner that makes it difficult – if not impossible – to make well-informed decisions and investments.
Publications and reports