Session: 09-02 Pumped Thermal Energy Storage

Paper Number: 101892

101892 - Techno-Economic Assessment of Co2 Based Power to Heat to Power Systems for Industrial Applications 

Nowadays about 50% of the worldwide energy consumption is spent on heating purposes, and about 44% of this is devoted to the industrial sector. Technically efficient and cost-effective solutions targeting the industrial heat demand are largely needed. By exploiting thermal energy storage (TES) based power-to-heat and power-to-heat-to-power systems the industrial sector could largely cut its dependency on fossil fuels, minimize its operational costs, whilst providing a source of flexibility to the overall grid and facilitating the integration of fluctuating renewable energy sources.

This work presents the techno-economic assessment of a molten salts (MS) TES and CO₂ based power-to-heat-to-power system storing thermal energy at about 450°C and aimed at providing both electricity and saturated steam between 150°C and 180°C to the industrial sector. Paper and cardboard production industries and their typical consumption patterns, accounting for an average steam and electricity consumption per ton of paper of 1.5 MWh_th and 0.7 MWh_e respectively and limited load variability based on work shifts scheduling, are considered.

This study investigates and compares the techno-economic performance of different pumped CO₂ cycles as charging units benchmarking them against direct heating via resistive electric heaters and different discharge units (MS-based steam generators for heat production, recuperated supercritical and transcritical CO₂ cycles for power generation). Key trade-offs between power and heat production, the specific levelized costs, and efficiency are explored identifying the most suitable system based on different industrial requirements and market conditions. Also, the relevance of different capital and operational costs, commercial readiness, and thermodynamic performance is investigated. Optimal system configurations and dispatch strategies are identified based on typical load curves and considering various EU and US electricity markets, having different electricity price fluctuations and fuel costs. Scalability and sizing criteria are presented highlighting the suitability of different technical solutions for small and large scale industrial sites. This study focuses on KPIs such as the levelized cost of storage (LCoS), heat (LCoH) and electricity (LCoE), and operational costs (OPEX).

The results show that the elevated system flexibility, short commitment periods and rapid operation switches provided and ensured by CO₂ based power cycles are essential to ensure cost-effective technical solutions. Within EU, the Nordic markets (i.e. Finland, south of Sweden, Denmark), thanks to the low electricity prices and high price fluctuations, guarantee the most cost-effective installations. For the Finnish market, small scale power-to-heat-to-power systems including a supercritical CO₂ cycle (providing an average daily 50 MWh_t and 20 MWh_e) could attain electricity prices reductions of about 42% with respect to average daily price and LCoE of about 100 €/MWh. The introduction of power units comes at the expense of a limited increase of about 9% of the LCoH (with specific values between 75 and 80 €/MWh) with respect to only power-to-heat systems

Presenting Author: Silvia Trevisan KTH Royal Institute of Technology

Presenting Author Biography: Silvia is a Postdoctoral researcher working on thermal energy storage looking into cost-effective solutions for materials and components and aiming at optimizing the storage integration into different energy systems providing heat and power.

Authors:

Silvia Trevisan KTH Royal Institute of Technology
Syed Safeer Mehdi Shamsi University of Genoa
Simone Maccarini University of Genoa
Stefano Barberis University of Genoa
Rafael Guedez KTH Royal Institute of Technology