Power-to-heat for the industrial sector: Techno-economic assessment of a molten salt-based solution

Abstract

The industrial sector is a major source of wealth, producing about one-quarter of the global gross product. However, industry is also a major emitter of CO2 and it represents a key challenge towards achieving the worldwide CO2 emission reduction targets. Nowadays, about 22 % of the overall energy demand is heating for the industrial sector, generating about 40 % of the global CO2 emissions. Solutions to decarbonize the industrial sector are needed. This work presents the techno-economic assessment of a molten salts based power-to-heat solution aiming at decarbonizing the industrial sector, requiring medium temperature heat (150–450 °C). The system is studied under different electric markets considering electricity prices of 2021, future electricity market price modifications are assessed via sensitivity analyses. Dispatch strategies and system sizing are identified to ensure optimal techno-economic performance. The main performance indicators investigated are the levelized cost of heat, the operational expenditure, and the attainable savings with respect to traditional solutions. The system scalability and sizing criteria are investigated accounting for different typical industrial load profile curves and nominal thermal power demands. The results highlight that nominal levelized cost of heat as low as 55 €/MWhth are attainable in cheap electricity markets (i.e. Denmark) and 80 €/MWhth in more expensive scenarios (i.e. United Kingdom). The proposed system can provide operational cost savings between 0.5 and 3 M€/y against traditional non-flexible electric boilers and even wider benefits if fossil fuels-based boilers are considered. Future electricity markets, subjected to higher renewable penetration causing cheaper average electricity prices and higher price volatility, could lead to further reductions of the levelized cost of heat of more than 20 % achieving values below 45 €/MWhth in markets such as Denmark. This study sets the ground for further power-to-heat techno-economic investigations addressing different industrial sectors and identifies main system design strategies.