17 Jan 2023

A new study on Renewable heat

Carbon 4, a French consulting firm specialised in carbon strategy, has recently published a report on renewable heat and pictures it as the “forgotten giant” of national renewable support schemes in Europe.

Newheat, and EHP members, partly financed this study, which mainly focuses on the French market, but some key outcomes are relevant for many European countries.

The study describes the advantages and limitations of the non-combustion renewable heat sources (geothermal, solar thermal and heat pumps) compared to the solutions using combustion (biomass and biomethane). The first ones are pinpointed to meet low temperatures needs (<100°C) which cover 67% of the global heat needs of humanity, the real needs of the residential and tertiary sectors, and 30% of industrial heat needs. In contrast, the second one should be favoured for higher temperature requirements. It is noteworthy that a barrier to exploiting non-combustion heat sources are existing unoptimised installations; this is to say that district heating networks or industrial heat loops with higher set point temperatures are required. To overcome these technical hurdles, design specifications must be adapted and operating temperatures lowered; a couple of case studies illustrate the successful implementation of solar thermal and geothermal projects on district heating networks in France. 

Furthermore, the report pushes planners to select the right solution for the correct requirements. It suggests, for example, limiting the use of biomass for energy to when it is locally available as a coproduct, even more so if it is a residue of long-life wood products (e.g. construction materials, furniture manufacturing..). Heat pumps which seem easy to implement in principle must be considered within a long-term energy sourcing strategy, where competition with other new electricity needs will arise, namely in the transport and mobility sectors. The rapid increase in demand for decarbonated electricity raises questions about the feasibility of large-scale electrification of heat needs concerning the electricity grid and the clean power generation capacity.

The study closes on the fact that in an energy and geopolitical context that is pushing us to accelerate the transition to low-carbon energy, these local low-temperature non-combustion heat production solutions are relevant for gaining energy sovereignty and can, in the case of solar thermal and geothermal offer long term price stability.

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