The European Union and its Member States have committed themselves to increasing the share of renewables in energy use to 20% by 2020. As heat accounts for 49% of the overall final energy demand of the European Union, the renewable heating sector will need to provide a major contribution in order to reach this renewable energy target.
Given the fact that just three renewable sources (biomass, geothermal and solar) generate heat, it is essential to show how these different sectors can contribute to the renewable energy target. Since deep geothermal sources are limited to a few locations in Europe and shallow geothermal is considered as energy efficiency technology; biomass should also be used for transport fuels, electricity generation and medium to high temperature applications, it is apparent that solar thermal systems need to provide a substantial share of the low temperature heat.
To support the European Union and its Member States with substantiated information on solar thermal energy’s contribution to the 20% renewable energy target and its long term potential, detailed investigations were conducted of a representative sample of five European countries and an extrapolation for the EU-27 countries. Both the technical and the economic potential for solar thermal technologies were investigated for different applications.
To determine the potential of solar thermal’s contribution to the heat demand in the selected reference countries, a model for the future demand - taking also energy efficiency measures into account - was developed. Based on this model, the future heating and cooling demand was calculated for the years 2020, 2030 and 2050.
The model includes three scenarios and is focused on the following sectors:
- space heating of residential buildings
- hot water preparation in the residential sector
- space heating in the service sector
- industrial low temperature heat (<250°C)
- air conditioning and cooling in the residential and service sectors
The three scenarios are a “Business As Usual scenario” (BAU), an “Advanced Market Deployment scenario” (AMD), which includes financial and political support mechanisms such as subsidies and obligations, moderate energy efficiency measures and improved research activities, and a “Full R&D and Policy scenario” (RDP), which includes substantial financial and political support mechanisms, energy efficiency measures and research activities.
Contribution of Solar Thermal to the EU 20% Renewable Energy Target
Assuming a 9% reduction of the overall final energy demand due to energy efficiency measures by 2020 compared to the year 2006, the contribution of solar thermal to the EU 20% Renewable Energies Goal would be 6.3% under the RDP scenario and 2.4% under the less ambitious AMD scenario. Related to the necessary 11.5 percentage points increase of renewable energies (reference share of renewables in 2005 was 8.5%) in the EU-27 countries by 2020, the contribution of solar thermal would be 12% according to the RDP scenario, 4.5% according to the AMD scenario and 2.9% in the BAU scenario.
To reach the goals of the RDP scenario a 26% average annual growth rate of the European solar thermal market is needed until 20201. The goals of the AMD scenario require a 15% average annual growth rate and the goals of the BAU scenario a 7% growth rate. The resulting total collector area by 2020 would be between 97 million m² (BAU) and 388 million square meters (RDP). The total installed collector areas correnspond to total installed capacities of 67.9 GWth and 271.6 GWth.
According to the RDP scenario the effect on employment would be considerable. In total, 470.000 jobs would be related to the solar thermal sector in 2020. This number is for the European Union domestic market only. The total investment needed in the solar thermal sector to reach the 2020 goals of the RDP scenario would be EUR 214 billion. This includes production, engineering, trade and installation of solar thermal systems installed from 2006-2020.
Contribution of Solar Thermal to the Energy Supply and CO2 Reduction
The solar yield according to the RDP scenario is 155 TWh in 2020. This corresponds to an oil equivalent of 22 billion tons. Taking this oil equivalent into account the annual contribution to the CO2 reduction by solar thermal systems is 69 million tons.
In 2050, the contribution of solar thermal to the low temperature heat demand of the European Union (EU 27) ranges from 47% in the RDP scenario and 8% in the BAU scenario. The corresponding annual solar yields are 1552 TWh (RDP) and 391 TWh (BAU). The specific collector area needed to reach these goals is between 2 m² (BAU) and 8 m² (RDP) per inhabitant in the EU-27. The resulting total collector area is between 970 million m² (BAU) and 3.88 billion square meters (RDP).
If solar thermal is to contribute significantly to the long-term heating and cooling demand in EU-27 countries then the primary focus in central and northern Europe must be on systems for space heating (solar combisystems) and in the Mediterranean on combined systems providing space heating, hot water and air conditioning. If the focus remains solely on solar thermal systems for domestic hot water preparation then solar thermal’s contribution to the long-term final energy demand will be limited because by 2030 the full potential for these applications will have been nearly exploited and the market reduced mainly to the replacement of old systems. Another important sector with considerable potential is low temperature process heat for industry.