Demonstration of thermal energy storage solutions for solar thermal plants and systems

This EU funding opportunity is part of the Horizon Europe program, specifically under Cluster 5, with the topic HORIZON-CL5-2026-02-D3-05, focusing on the Demonstration of thermal energy storage solutions for solar thermal plants and systems. The action type is categorized as a HORIZON Innovation Action with funding structured under a grant budget framework.

The submission period is set to begin on September 16, 2025, with a deadline for proposals by February 17, 2026, at 17:00 Brussels time. This process is a single-stage submission. The total budget allocated for this initiative is 15 million euros, with expectations that approximately two grants will be awarded, each estimated at around 7.5 million euros.

The primary aim of the projects funded under this grant is to significantly reduce the Levelized Cost of Heat Storage (LCOHS) and/or Levelized Cost of Energy (LCOE). The initiative targets the demonstration of innovative thermal energy storage technologies applicable to concentrated solar power (CSP) systems. Successful projects are expected to enhance the dispatchability of solar thermal plants, improve access to financing for technology providers, and offer grid operators reliable options to manage variability in renewable energy sources.

Each project must include a defined go/no-go milestone prior to entering the demonstration phase, ensuring that projects deliver comprehensive engineering plans, techno-economic assessments, and all necessary permits. Sustainability assessments encompassing environmental and socio-economic impacts are also required, following the Safe and Sustainable by Design (SSbD) initiative.

Proposals must present a robust business case, with plans for scalability, commercialization, and deployment alongside assessments of funding sources, notably the Innovation Fund. Additional criteria, such as admissibility and evaluation processes, are outlined in the Work Programme.

Eligible participants typically include universities, research institutes, SMEs, large enterprises, and public-private partnerships, primarily from EU member states and associated countries. Non-EU countries may participate if they meet specific provisions.

Overall, this funding opportunity seeks to promote innovative thermal energy storage solutions, enhancing the reliability and integration of solar thermal energy into the European energy landscape. Successful applicants will demonstrate substantial improvements in technological performance while ensuring commercial viability and sustainability.

This EU funding opportunity is part of the Horizon Europe program, specifically under Cluster 5, Call 02-2026 (WP 2025) with topic HORIZON-CL5-2026-02-D3-05. It aims to support the Demonstration of thermal energy storage solutions for solar thermal plants and systems. The action type is a HORIZON Innovation Action (HORIZON-IA) with a budget-based HORIZON Action Grant (HORIZON-AG).

The planned opening date for submissions is September 16, 2025, and the deadline for submissions is February 17, 2026, at 17:00 Brussels time. This is a single-stage submission process. The total budget allocated to this topic is 15,000,000 EUR for the year 2025, and it is expected that around two grants will be awarded. The estimated contribution per project is around 7,500,000 EUR.

The expected outcomes of the projects funded under this topic include: a significant reduction of the Levelised Cost of Heat Storage (LCOHS) and/or Levelised Cost of Energy (LCOE); technology providers profiting from successful demonstration and de-risking of thermal energy storage solutions that improve the dispatchability of solar thermal plants and/or systems; improved access to financing for technology providers through a better understanding of the bankability of dispatchable solar thermal solutions; electricity grid operators having access to reliable options to cope with the increase in the share of variable-output renewables and reduce curtailments; support and facilitation of the execution of the solar thermal implementation plan of the Strategic Energy Technology Plan (SET Plan); and support and facilitation of the execution of the solar energy joint research and innovation agenda.

The scope of this funding opportunity is to support the demonstration of innovative thermal energy storage solutions in concentrated solar power (CSP) and/or solar thermal heat and/or cold. The proposed solutions must achieve substantial improvements in performance, cost-effectiveness, and lifespan compared to the current state of the art.

Each project must include a clear go/no-go milestone before entering the demonstration phase. Prior to this milestone, the project must deliver detailed engineering plans, a techno-economic assessment, and all necessary permits for the demonstrator. The project proposal should present a clear and convincing pathway and timeline for obtaining these permits.

Projects must assess the sustainability of the proposed solutions in environmental and socio-economic terms. The Commission initiative for Safe and Sustainable by Design (SSbD) should be considered as a reference for project proposals, providing a framework for assessing the safety and sustainability of chemicals and materials.

Plans for the exploitation and dissemination of results should include a strong business case and a sound exploitation strategy. These plans should include preliminary plans for scalability, commercialisation, and deployment, such as feasibility studies and business plans, indicating potential funding sources, particularly the Innovation Fund.

Regarding admissibility conditions, proposal page limits and layout are described in Annex A and Annex E of the Horizon Europe Work Programme General Annexes, and in Part B of the Application Form available in the Submission System.

Eligible countries are described in Annex B of the Work Programme General Annexes. Specific provisions are available for non-EU/non-Associated Countries, as detailed in the Horizon Europe Programme Guide.

Other eligible conditions are described in Annex B of the Work Programme General Annexes. Financial and operational capacity and exclusion criteria are detailed in Annex C of the Work Programme General Annexes.

The evaluation and award process includes specific criteria, scoring, and thresholds, as described in Annex D of the Work Programme General Annexes. To ensure a balanced portfolio, grants will be awarded to proposals that are highly ranked within the areas of concentrated solar power (CSP) and solar thermal heat and/or cold, provided they meet all thresholds and are subject to available budget. A proposal addressing both areas will also satisfy this condition.

Submission and evaluation processes are described in Annex F of the Work Programme General Annexes and the Online Manual. The indicative timeline for evaluation and grant agreement is also described in Annex F of the Work Programme General Annexes.

The legal and financial setup of the grants is described in Annex G of the Work Programme General Annexes. Specific conditions are described in the specific topic of the Work Programme.

Application and evaluation forms, as well as the model grant agreement (MGA), are available in the Submission System. The standard application form is HE RIA, IA, and the standard evaluation form is also HE RIA, IA, with necessary adaptations. Guidance is provided in the HE Programme Guide, and the Model Grant Agreement is the HE MGA.

Additional documents include: HE Main Work Programme 2025 – 1. General Introduction; HE Main Work Programme 2025 – 8. Climate, Energy and Mobility; HE Main Work Programme 2025 – 14. General Annexes; HE Programme Guide; HE Framework Programme 2021/695; HE Specific Programme Decision 2021/764; EU Financial Regulation 2024/2509; Decision authorising the use of lump sum contributions under the Horizon Europe Programme; Rules for Legal Entity Validation, LEAR Appointment and Financial Capacity Assessment; EU Grants AGA — Annotated Model Grant Agreement; Funding & Tenders Portal Online Manual; Funding & Tenders Portal Terms and Conditions; and Funding & Tenders Portal Privacy Statement.

There are 22 partner search announcements available for collaboration on this topic. LEARs, Account Administrators, and self-registrants can publish partner requests after logging into the Portal.

The submission system is planned to open on the date stated on the topic header.

Applicants are encouraged to read all provisions carefully before preparing their application. The Online Manual serves as a guide for procedures from proposal submission to grant management. The Horizon Europe Programme Guide provides detailed guidance on the structure, budget, and political priorities of Horizon Europe. The Funding & Tenders Portal FAQ answers frequently asked questions on proposal submission, evaluation, and grant management. The Research Enquiry Service can answer questions about European research in general and the EU Research Framework Programmes in particular. National Contact Points (NCPs) offer guidance and practical information on participating in Horizon Europe. The Enterprise Europe Network (EEN) provides advice to businesses, especially SMEs, including guidance on EU research funding. The IT Helpdesk addresses technical questions related to the Funding & Tenders Portal. The European IPR Helpdesk assists with intellectual property issues. CEN-CENELEC Research Helpdesk and ETSI Research Helpdesk advise on standardisation in project proposals. The European Charter for Researchers and the Code of Conduct for their recruitment outline the roles, responsibilities, and entitlements of researchers, employers, and funders. Partner Search helps find partner organisations for proposals.

In summary, this Horizon Europe funding opportunity seeks to support innovative projects that demonstrate advanced thermal energy storage solutions for concentrated solar power and solar thermal systems. The goal is to improve the performance, cost-effectiveness, and lifespan of these storage solutions, contributing to a more reliable and sustainable energy landscape. Successful projects will reduce the cost of heat storage and energy, improve the dispatchability of solar thermal plants, and provide grid operators with reliable options for managing variable renewable energy sources. Applicants must present a strong business case, a clear exploitation strategy, and a convincing plan for obtaining necessary permits, while also addressing the sustainability and safety of their proposed solutions. The call aims to foster innovation, de-risk thermal energy storage technologies, and facilitate the broader adoption of solar thermal energy in the European energy mix.

Eligible Applicant Types: The eligible applicant types are not explicitly stated in the provided text. However, based on the nature of Horizon Europe calls for proposals, eligible applicants can include a wide range of entities such as universities, research institutes, SMEs, large enterprises, and other organizations. The specific eligibility criteria are detailed in Annex B of the Work Programme General Annexes and the Horizon Europe Programme Guide.

Funding Type: The primary funding mechanism is a grant, specifically through HORIZON Innovation Actions (HORIZON-IA), HORIZON Research and Innovation Actions (HORIZON-RIA), HORIZON Pre-commercial Procurement (HORIZON-PCP), and HORIZON Coordination and Support Actions (HORIZON-CSA). The type of Model Grant Agreement (MGA) is HORIZON Action Grant Budget-Based [HORIZON-AG].

Consortium Requirement: The text does not explicitly state whether a single applicant or a consortium is required. However, Horizon Europe projects often involve consortia to bring together diverse expertise and resources.

Beneficiary Scope (Geographic Eligibility): Eligible countries are described in Annex B of the Work Programme General Annexes. The opportunity is primarily targeted towards EU member states and associated countries. Non-EU/non-Associated Countries may also be eligible if they have made specific provisions for funding their participants in Horizon Europe projects, as detailed in the Horizon Europe Programme Guide.

Target Sector: The program targets the energy sector, specifically focusing on solar energy and thermal energy storage solutions. This includes concentrated solar power (CSP) and solar thermal heat and/or cold technologies.

Mentioned Countries: The text mentions "EU" and "non-EU countries", but does not list specific countries. It refers to "EU member states and associated countries" and "third-countries".

Project Stage: The project stage is primarily demonstration, as the call focuses on the "Demonstration of thermal energy storage solutions." Projects should aim to demonstrate innovative solutions and achieve substantial improvements in performance, cost-effectiveness, and lifespan compared to the current state of the art. The project must include a clear go/no-go milestone ahead of entering the demonstration phase.

Funding Amount: The funding amounts vary depending on the specific topic. The budget overview provides the following ranges:
HORIZON-IA: typically between €7.5 million and €11 million per project, with total topic budgets ranging from €12 million to €33 million.
HORIZON-RIA: typically between €4 million and €6 million per project, with total topic budgets ranging from €8 million to €18 million.
HORIZON-PCP: €20 million total budget, with one grant of around €20 million.
HORIZON-CSA: around €2 million per project, with a total topic budget of €6 million.

Application Type: The application type is an open call with a single-stage submission process.

Nature of Support: Beneficiaries will receive money in the form of grants to support their projects.

Application Stages: The application process is single-stage.

Success Rates: The success rates are not explicitly mentioned, but the indicative number of grants for each topic provides some insight. For example, a topic with a €33 million budget might fund around 3 projects, while a topic with an €8 million budget might fund around 2 projects.

Co-funding Requirement: The text does not explicitly mention a co-funding requirement. However, Innovation Actions typically require the beneficiary to cover a percentage of the total project costs.

Summary: This Horizon Europe call, part of Cluster 5, focuses on "Demonstration of thermal energy storage solutions for solar thermal plants and systems." It aims to support projects that demonstrate innovative thermal energy storage solutions in concentrated solar power (CSP) and solar thermal heat/cold, leading to significant reductions in the Levelized Cost of Heat Storage (LCOHS) and/or Levelized Cost of Energy (LCOE). The call is structured around different types of actions, including Innovation Actions (IA), Research and Innovation Actions (RIA), Pre-commercial Procurement (PCP), and Coordination and Support Actions (CSA), each with varying budget allocations and expected outcomes. Projects must demonstrate substantial improvements in performance, cost-effectiveness, and lifespan compared to existing technologies, and must include a clear go/no-go milestone before entering the demonstration phase. Eligible applicants include a wide range of entities from EU member states, associated countries, and potentially non-EU countries with specific funding arrangements. The application process is single-stage, with a planned opening date in September 2025 and a deadline in February 2026. The funding supports the broader goals of the Strategic Energy Technology Plan (SET Plan) and the solar energy joint research and innovation agenda, contributing to a more reliable and dispatchable solar energy sector.