Renewables and energy efficiency are the two sides of the same coin in the heating sector.
For instance, solar thermal works best when combined with other energy efficiency measures. It is not just a technology issue, it is also about synergies in the financing, planning and cost efficiency of projects.
Indeed, when renovating a building, it is important to combine traditional energy efficiency measures, such as insulation, with the decarbonization of the remaining heating demand, through switch to renewable heating technologies such as solar thermal. Otherwise, the risk is locking in for decades the existing fossil fuels appliances. Moreover, when combined into energy efficiency projects, the costs of installing renewable heating technologies decreases, and cost-optimal solutions can emerge.
While we take all the necessary steps to reduce our energy consumption, we also need to fully decarbonise the remaining energy production. And that is renewable energies’ job! With a 46% share of our energy system, of which 82% still fuelled by fossil energy, decarbonising heating & cooling is our most critical challenge. We will need well insulated buildings, which will greatly reduce -but difficultly eliminate- our needs for space heating, but we will always need domestic hot water!
Combining solar thermal with energy efficiency measures in buildings, as well as in industry is a win-win for consumers, for project developers, and for the environment!
Efficiency must be applied also at systemic level: the efficient allocation of different technologies and fuels to different needs is crucial. Using high quality electric energy for low temperature domestic hot water needs through direct electric appliances is a waste, while in other sectors (such as high temperature industrial heat, which cannot be covered yet by renewable heat), electricity would be more efficient than currently used fossil fuels. The 2050 heating sector might include an increasing share of electricity, but only if in an efficient way and only using highly efficient appliances powered by renewable electricity, mostly leaving the low temperature heat consumption to be met by direct, efficient and renewable heat production such as solar thermal.