Introduction

There are nearly 2000 GW of coal power plant capacity in operation globally today and more than half are less than 14 years old.  This makes them prime candidates for repowering, as they can continue to be utilized efficiently with new low-carbon technologies rather than being prematurely decommissioned. Repowering these newer plants can maximize their remaining lifespan, ensuring continued power generation, minimizing economic losses and job retentions in the local communities while transitioning to cleaner energy sources.  Conservatively, around 1300 GWe of coal power units globally could be applicable for Repowering by the early 2030s.

‍

"In an era where phasing out coal is essential, RepowerScore serves as a straightforward and effective scientific decision-making tool. It enables quick assessments of which coal plants can be repowered by clean energy sources while still utilizing existing grids and infrastructure, thus preventing stranded assets." - Bob S Effendi, Repower Indonesia Project Manager.

‍

Many factors influence the suitability of a coal power plant to be repowered. Broadly, these factors can be categorised into seven groups:

• Technical –E.g.,Age of the unit, power plantcapacity, carbon emission intensity
• Pathway Specific –E.g., Geothermal, Nuclear, Thermal Energy Storage
• Geographical –E.g.,Flood risk, seismic activity risk, water stress index
• Logistical/Infrastructure –E.g., Highway/railway availability fortransport, mine infrastructure, grid constraints
• Regulatory –E.g., Rules and regulations within power generation,emergency plans
• Political/Policy –E.g., Attitude towards new or existing technologies(nuclear, next-gen geothermal)
• Economic –E.g.,Subsidies, tariffs, investments, profitability

Not every factor is of equal importance, and the relative importance can and will change depending on the pathway for repowering.

The process of understanding these factors and how the interact for any given site is a long one involving many different stakeholders. From choosing a site, to performing feasibility studies, to surveying the political landscape, a lot of effort can be undertaken for little reward. That is why it’s so important to give utilities, technology providers, financial institutions, and academics a guide to quickly and systematically find the most promising pathways for the most promising sites. That is what RepowerScore aims to be.

‍

So, what is RepowerScore?

RepowerScore is an open platform designed to help utilities, asset owners, investors, technology providers, academics, and policymakers in assessing the suitability of a coal power plant to be repowered by clean alternatives such as next-generation geothermal, advanced nuclear or concentrated solar power.

‍

‍

RepowerScore is actively being developed and its current state is in no way final. We encourage interested individuals and organisations to contact us with feedback on factors, either existing or new, weightings, new or improved data sources, pathways, as well as any other enquiries you may have.  

Which pathways do we include in Repowering?

While our approach is technology agnostic, only Repowering with geothermal, nuclear and concentrated solar power pathways are currently included in RepowerScore. In our future updates we will be adding Thermal Energy Storage and renewable interconnect points.  

While other technologies such as PV and Wind are fundamental in the shift towards a 24/7 decarbonised power system, due to their reduced energy density (Nuclear and Geothermal range up to 25-50 MWh/m²/year compared to 0.04 MWh/m²/year for wind and Solar) they are not included for on-site repowering. They also cannot provide other services coal plants currently provide such as heating for nearby residential areas or process heat for industrial processes.

Types of Repowering?

• Full Repowering. For new plants, often the coal boiler can be replaced with a low-carbon heat source, likely a Small Modular Reactor or Geothermal, then the full steam cycle, condenser cooling system, grid connection, and all auxiliary buildings can be reused with minimal retrofitting requirements.

• Partial Repowering. For modern coal plants (effective age of under 15 years) the condenser cooling system, grid connection and all auxiliary buildings can be reused, and even with a new steam cycle, the costs are likely to be significantly lower than any comparable greenfield site.

• Site Repurposing. The sites of old, already decommissioned or fully depreciated units can be repurposed for low-carbon energy generation or storage, in many cases these sites still have an active grid connection.

Validation

"The DEsire project in Poland is going to be instrumental in assessing the technical and economic potential, social acceptability, and human resource readiness for Coal-to-Nuclear repowering. By thoroughly evaluating these factors, we are developing a comprehensive modernization plan for our national power plants. Our findings have significantly contributed to the calibration of the RepowerScore tool, ensuring it accurately reflects real-world conditions and challenges. This collaboration underscores the critical importance of tailored, data-driven approaches in transitioning to sustainable energy solutions." - Łukasz Bartela

Daniel Cox, a senior developer at QuantifiedCarbon, has been leading the development of RepowerScore. Describing the project, Danny explains:
‍

"RepowerScore can truly highlight the potential of repowering by showing how each coal plant in the world could be repowered, while identifying the most sensible pathway. Building on the elegant and clever idea from DEsire, we've developed RepowerScore into a powerful tool for demonstrating repowering feasibility. Over the last year, we've added numerous features to RepowerScore, and now with V5, we are introducing concentrated solar power as a pathway option, which holds great potential in many areas around the world."

‍