Growth and fluctuations in the Dutch PVT and solar thermal markets

October 14, 2025

The Netherlands, though small in size, is one of Europe’s most densely populated countries and a long-standing member of the IEA Solar Heating and Cooling Programme. Renowned for its innovation and strong environmental consciousness, the country has become a leader in the adoption of solar thermal energy. This progress was showcased last year through two significant projects. First, a groundbreaking solar district heating plant was inaugurated in Groningen. Second, one of the few solar process heat plants featuring PVT collectors began operation at De Hoop Pekso, a manufacturer of concrete products (see photo). Despite these advances, the development of the solar heat market remains highly sensitive to fluctuating subsidy conditions. Nevertheless, the IEA Solar Heating and Cooling Programme continues to benefit from the expertise of Dutch specialists at TNO (Netherlands Organisation for Applied Scientific Research), who contribute to various research platforms within the programme.
Photo: R&R Systems

“The Dutch PVT market is becoming increasingly mature, with not only PVT heat pump systems for individual homes but also larger installations for newly built neighbourhoods or renovated multi-family buildings,” confirmed Corry de Keizer, Deputy Research Manager for Solar Energy Applications at TNO. She is actively involved in IEA SHC Task 73 on PVT Heating Systems. “Our goal is to collect and share data on applications, collector types, and system configurations, including field data for water-based PVT collectors,” explained de Keizer, outlining one of the objectives of the task. Another key aim is to compile a catalogue of frequently asked questions and answers from market participants regarding PVT systems. This information will be integrated into a newly developed PVT chatbot, which will provide automated responses to inquiries from potential customers.

Fluctuations in the heat pump market influencing PVT sales

In 2024, the Netherlands ranked as the second-largest PVT market globally, with 14,466 m² of newly installed PVT collector area. This represents a 39 % increase compared to 2023 (10,411 m²) but is 28 % lower than the 2022 total of 19,588 m². The data comes from an annual survey conducted by the Austrian research institute AEE INTEC, with results published in the Solar Heat Worldwide report. Seven Dutch PVT collector manufacturers and suppliers participated in the most recent survey. We spoke with one of them, Cees Mager, CEO of Triple Solar, to gain insight into the market’s fluctuations.

Mager observes a general increase in interest in PVT collectors in the Netherlands. He attributes the recent market fluctuations more to changes in the heat pump market than to a decline in interest. For example, in 2023, supply chain issues in the heat pump sector led to fewer units being installed. Despite these shifts, subsidies for heat pump systems have remained stable over the years. These are provided through the ISDE (Investering Subsidie Duurzame Energie en Energiebesparing) programme, administered by the Netherlands Enterprise Agency (RVO).

The ISDE programme subsidizes the installation of heat pumps and solar thermal systems but does not extend subsidies to PVT collectors themselves. However, at the start of 2024, the subsidy rates for air-source heat pumps and solar thermal collectors were significantly reduced, while the subsidy for brine heat pumps remained unchanged. The exact subsidy amounts depend on the type of heat pump and are detailed in the list of eligible equipment available on the RVO website.

Figure 1: Market development for residential solar thermal systems between 2010 and 2024. PVT collectors and large solar district heating systems are not included in these statistics. Source: Statline open-source data

Dramatic drop in sales due to halving of subsidy rate

“Solar thermal collector sales have averaged around 35,000 m² per year over the past 15 years,” emphasized Martijn van Elburg from RVO, the Dutch representative on the Executive Committee of the IEA SHC Programme. However, the market closely follows subsidy changes, a trend clearly evident in 2024. The halving of subsidy rates for solar thermal energy within the ISDE programme led to a dramatic drop in demand (see Figure 1).

According to provisional data, only 20,559 m² of solar thermal collectors were installed in the Netherlands last year. The official subsidy notification dated 11 December 2023 states: “To prevent overstimulation, the subsidy amounts for solar water heaters with an aperture area of 5 m² or more will be reduced. For solar water heaters with an aperture area between 5 and 10 m², the subsidy will decrease from 1.02 to 0.55 EUR/kWh of annual solar energy contribution. For solar water heaters with an aperture area exceeding 10 m², the subsidy will drop from 0.45 to 0.28 EUR/kWh.”

The programme’s administrators at RVO explained: “Based on a cost price analysis of solar water heaters conducted within the ISDE scheme, we have concluded that the subsidy amounts were not fully aligned with the intended subsidy percentage for solar water heaters.” While the exact subsidy percentage was not disclosed, it is known that for heat pumps, the target subsidy rate was around 30% of the investment costs, so it can be assumed that the same percentage may apply to solar thermal systems.

Figure 2: Top markets in terms of the number of new SHIP plants commissioned per year between 2020 and 2024. Source: Annual surveys of the companies listed on the SHIP Supplier World Map link to https://www.solar-payback.com/suppliers/

Flagship projects using PVT collectors for solar process heat

The continued ISDE subsidy for commercial customers buying solar thermal systems is the reason the Netherlands has also taken a leading position in the field of solar process heat (SHIP). In 2024, the country was again just ahead of Mexico with 24 systems (see Fig. 2), although significantly lower than in previous years due to the reduction in subsidy rates. “Our sales fell by 50% last year compared to 2023,” confirmed Gijs van Houtum, Account Manager at R&R Systems, a Dutch PVT collector manufacturer and project developer.

A distinctive feature of the Dutch SHIP market is the use of PVT collectors by industrial heat consumers. The project at De Hoop Pekso, mentioned earlier in the article, serves as a prime example. 720 m² of PVT collectors provide heat to a 120 kW brine heat pump to power the drying process for concrete construction products.

A second heat source is the nearby canal. “We have remote access to the heat pump system, allowing us to monitor and adjust all settings,” said van Houtum. “When the temperature of the PVT collectors drops below 7°C, the heat source for the heat pump switches to the canal.” This multi-source heat pump system achieves an annual COP of 3.6, relative to the 24/7 drying process at 60°C.

Strategic partnerships driving the implementation of the world’s 6th largest solar heat plant

The Netherlands also holds a place in the ranking of the world’s largest solar heat plants. A 37 MW collector field in Groningen, in the northern part of the country, supplies heat to 2,600 households. Situated on a former sludge depot, 24,000 evacuated flat-plate collectors generate heat up to 93 °C, which is then fed into the Warmtestad district heating network. The collector field was supplied and installed by the Swiss company TVP Solar, which also handled the EPC (Engineering, Procurement, and Construction) for the solar plant. A 30-year heat delivery contract was signed between Warmtestad and Zonthermiepark Dorkwerd, the special-purpose vehicle that owns and operates the plant. TVP Solar partnered with a local renewable infrastructure developer, Novar, and a landscaping specialist, K3, for project development and project financing.

Collector field	48,800 m²; 37 MWth
Collector type	Evacuated flat plate collectors of the type MT-power v4 from TVP Solar
Operating temperature of collector field	69 to 93 °C
Delivered solar energy	23 GWh/a or 471 kWh/m²a
Targeted annual solar fraction	50 %
EPC of collector field	TVP Solar, Switzerland
Owner of the solar plant	Zonthermiepark Dorkwerd, Special purpose vehicle with three shareholders: Novar and K3 from the Netherlands and TVP Solar
Project CAPEX including collector field, tank installation and permit applications in 2022	EUR 23 million or 479 EUR/m²