Hydrogen-based Sector Coupling: the Role of Heat Capture, Usage, and Storage
Completion date: 5.6.2023 Abstract
The transition towards a carbon-neutral society by 2050, or the ambitious target set by Finland to achieve it by 2035, requires a shift towards generating electricity and producing heat from renewable energy sources and the electrification of consumption. Due to the intermittent nature of renewable sources, challenges are posed for grid integration of them. Sector coupling is seen as an approach and strategy to replace fossil fuels with renewable energy sources in all energy-consuming sectors and achieve a net-zero carbon energy system, and hydrogen technologies play a crucial role in enabling this approach. Clean hydrogen can be produced through water electrolysis, and the efficiency of this process is typically less than eighty percent, with the remaining energy primarily being converted to heat and released into the atmosphere. The capturing and utilisation of this byproduct heat in hydrogen production are being investigated in this project. Initially, a comprehensive review of hydrogen-based sector coupling was conducted, followed by an exploration of different hydrogen production and compression methods to assess the potential and role of heat capturing. Then, a detailed examination of the combined heat and hydrogen system was carried out, analysing the individual components of this system. Moreover, different applications and utilisation options for the captured heat, including injecting it into the district heating network and utilising it for energy storage, were studied. Additionally, the utilisation of excess heat through thermoelectric generators for electricity generation was investigated. Moreover, to provide practical insights into the feasibility and benefits of heat capture and utilisation technologies, a comprehensive techno-economic analysis of a hydrogen plant was performed as a case study. This analysis considered key factors such as cost, efficiency, and environmental impacts.