As an extremely convenient heating source, based on a simple concept enhanced by cutting edge technology, solar thermal energy has the potential to be a major source of heating and cooling in Europe. Technological advancements have seen solar thermal become not only a better option for more traditional applications, such as domestic hot water production, but also a promising solution for new and more advanced applications such as industrial process heat.
However, despite this potential, the share of solar thermal in Europe’s supply of heating and cooling is still far below 1%, and European solar thermal markets are stagnating or declining. The market in 2014 amounted to 2 GWth (approximately 2.9 million m²), down 7.1% from the previous year. In the same year, the total installed solar thermal capacity registered a net increase of 1.6 GWth to reach 31.8 GWth (45.4 million m²), up 5.3% from 2013.1 This poor performance is largely a result of the fact that the European market continues to suffer from declining sales in its largest national markets, where sales are currently at the level of 2007.
There are several reasons behind this sluggish performance, such as low gas prices, difficult access to finance for consumers, a slow-moving construction sector, fewer public support schemes for solar thermal and competition from other energy sources, (sanitary hot water heat pumps, condensing gas boilers, and so on) that are also eligible for incentives and offer cheaper installation costs. According to the EurObserv’ER Solar Thermal and Concentrated Solar Power Barometer 2015, the solar thermal sector also has to contend with ‘internecine competition’ from solar photovoltaic, which is also addressing the domestic hot water segment2.
Europe is making good progress towards its 2020 targets for electricity, but the heating and cooling sector risks missing the indicative target for 2020 by 19.5%3. If this trend is to be reversed, then a number of challenges will have to be overcome, including increasing the competitiveness of solar heating and cooling by reducing the price for solar heat by 50% compared to 2013. It will also be necessary to simplify thermal heating systems by developing easy-to-install compact solar hybrid heating systems that are more user-friendly. The solar fraction will also have to increase from about 25% to 60% in solar active houses. Finally, the market for solar thermal applications will have to extend into new segments, such as industrial processes.
Production of heating and cooling from RES-H&C technologies in the EU-28 for 1995-2012 (actual) and 2013-2020 (projections)5
Reflecting these priorities, in its Solar Heating and Cooling Technology Roadmap , the European Technology Platform6 on Renewable Heating and Cooling (ETP-RHC) identifies three pathways to meet the main short to mid-term challenges for a significant increase in the solar thermal market share. These are the development of Solar Compact Hybrid Systems (SCOHYS), the development of Solar-Active-Houses (SAH) and the development of systems for Solar Heat for Industrial Processes (SHIP).
SCOHYS are compact heat supply systems that include a solar heating source and a backup (e.g. based on bio energy or heat pumps). In the case of domestic hot water (DHW) systems, which deliver only domestic hot water, these have a solar fraction of at least 50%, while combi SCOHYS systems, which deliver both, domestic hot water and space heating, have a solar fraction of at least 25%. By 2017, SCOHYS is expected to be available as prototype for single family homes (DHW and combi systems) and for multifamily homes (DHW) with solar heat costs reduced by 35% in comparison to 2013, leading to fossil fuel parity in southern Europe (<10 €ct/kWh).6 By 2020, it is planned that SCOHYS for multifamily homes will also be available as combi systems and the SCOHYS systems should be ready for broad market deployment with solar heat costs reduced by 50% compared to 2013, reaching the fossil fuel parity target for Central Europe.
Solar Active Houses offer a nearly zero energy solution for new buildings and buildings undergoing major renovations. Based on improved insulation standards for buildings and improved solar heating technology, the Solar-Active-House with a solar fraction of about 60% (SAH60) has been developed with a good combination of high solar fraction and acceptable storage volume. In Central Europe a typical single family Solar-Active-House needs a collector area of 30 to 40 m2 and a water storage tank of only 5 to 10 m3. More than 1300 of these Solar-Active-Houses have already been built and, by 2017, SAH60 for new-build single-family homes should be available as a standardised solution that can be used by all planners and construction companies. By 2020, a standardised SAH60 solution for small multifamily homes and refurbished buildings is also expected to be available. The SAH60 aims to be cost-competitive with other nearly zero-energy buildings and will provide solar heat at costs comparable to today’s combi systems in Central Europe (between 15 and 20 €ct/kWh).6
Solar Heat for Industrial Processes (SHIP) is a collaborative project that aims to provide the knowledge and technology necessary to foster the installation of solar thermal plants for industrial process heat. The project is currently at a very early stage of development - fewer than 120 operating SHIP systems are reported worldwide, with a total capacity of over 40 MWth (>90,000 m²). Most of these systems are relatively small pilot plants. However, there is great potential for market developments based on innovations, as 28% of the overall energy demand in the EU28 originates in the industrial sector and the majority of this heat demand is in the temperature range below 250°C. By 2017, the SHIP roadmap pathway should achieve solar heat costs in the range of 5-9 €cent/kWh for systems with 10-20% solar fraction, by reducing the investment costs to 350 €/m2 for low-temperature SHIP systems including storage and 400 €/m2 for medium-temperature SHIP systems without storage. By 2020, it is expected that the solar heat costs will be further reduced to 3-6 €cent/kWh for low-temperature applications below 100°C and 4-7 €cent/kWh for medium-temperature applications below 250°C.6
Another obstacle to the advancement of solar thermal heating and cooling identified by EurObserv’ER is the fact that, for several years there has been a dearth of communication on the solar thermal sector with no national institutional promotion campaigns. If the targets set in the ETP-RHC roadmap are to be achieved, communications campaigns will be essential, as they will imply public authority advocacy of solar thermal technology and help guide consumers in their investment choices, allowing solar thermal to reach its potential as reliable supplier of competitively-priced heating and cooling in Europe.
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