Subsidy for heat storage in heating networks via WIS scheme

The Heat Networks Investment Subsidy (WIS) , part of the National EZK and LNV Subsidies Scheme, supports companies in the construction and expansion of energy-efficient heat networks in the Netherlands. With a budget of €200 million, available from 1 August 2025 to 16 January 2026, the scheme stimulates the transition to sustainable heating and cooling, with the aim of accelerating natural gas-free solutions for existing buildings. The WIS focuses on projects that reduce greenhouse gas emissions to less than 25 kg CO₂ per GJ of heat supplied.

An important innovation in the scheme is the explicit support for thermal storage (heat storage). This includes systems that store excess heat for later use, which increases the efficiency of heating networks. Subsidies are available for investments in thermal storage as part of an energy-efficient heating network, provided that proven techniques are used. The subsidy for thermal storage falls under a maximum support intensity of 30% of the investment costs, with a cap of €4,000 per small consumer connection in existing buildings. Small and medium-sized enterprises can receive an increased support intensity of 50% and 40% respectively.

The successful integration of heat storage in the WIS underlines the importance of storage technologies for the energy transition. In a recent letter to parliament (December 2024), the Dutch government already emphasizes that heat storage is essential to match fluctuating supply of sustainable sources such as solar thermal, geothermal and residual heat with heat demand. Short-term storage, such as hot water buffers, and seasonal storage, such as heat-cold storage (WKO) or aquifers (ATES), play a crucial role in this. Innovative techniques, such as thermochemical storage and phase change materials, are also being investigated, although these are still in the development phase.

In addition to the WIS, the government is working on additional incentive measures for heat storage. This includes better anchoring storage in legislation and regulations, such as the revision of the Heat Act, and investigating additional subsidy options through schemes such as the SDE++. The National Local Heat Transition Programme (NPLW) obliges municipalities to include heat storage in local heat plans. In addition, the government is investing in pilots and collaborations to reduce costs and scale up promising technologies.

Energy Storage NL has been advocating for the integral inclusion of heat storage in heating networks for some time now. In the study “ The costs and benefits of heat storage in heating networks ”, Energy Storage NL and Invest-NL previously investigated the social added value of the combination of heat storage in heating networks. The study showed that heat storage not only reduces the costs of supplied heat by €0.70 to €3.20 per gigajoule, but also makes the construction of heating networks more financeable. ESNL sees the addition of heat storage to the WIS as a nice result of this study.