Innovation for the Energy Transition: What Horizon Europe's Cluster 5 Is Funding This Autumn

Three Horizon Europe Cluster 5 calls closing on 1 December 2026 - and why preparation needs to start now.

Horizon Europe is the EU's flagship research and innovation programme, running from 2021 to 2027 with a total budget of €93.5 billion. It funds collaborative projects across six thematic clusters, from health and climate to digital industry and civil security. For universities, research institutes, and SMEs, it remains the most significant source of European public R&I funding. And with the 2026–2027 Work Programme now fully adopted, the last major wave of calls is underway.

Within this landscape, Cluster 5 (Climate, Energy and Mobility) is one of the most strategically significant clusters. With €2.2 billion allocated under the 2026–2027 Work Programme, it covers the full spectrum of the clean energy transition: from renewable energy technologies and grid modernisation to sustainable mobility and climate science. What makes Cluster 5 particularly challenging is the combination of high technical maturity expectations (most calls target TRL 6–8) and the need to bring together research institutions, industry, grid operators, and regulators into a single coherent consortium.

Three calls within Destination 3 (Sustainable, Secure and Competitive Energy Supply) stand out for the depth of interdisciplinary expertise they demand, all sharing a deadline of 1 December 2026.

The Three Calls Worth Your Attention

HORIZON-CL5-2026-11-D3-05 — Demonstration of Solid Biofuel Supply and Conversion to High Efficiency CHP from Fully Sustainable Regional Value Chains

This Innovation Action funds full-scale demonstration projects that close the gap between regional biomass availability and high-efficiency combined heat and power (CHP) generation. Projects must build end-to-end regional value chains that source solid biofuels from upgraded biogenic residues and wastes (in line with the Renewable Energy Directive), convert them through high-efficiency CHP systems, and demonstrate both energy and economic viability at scale.

What makes this call technically complex is the requirement to simultaneously satisfy energy performance targets, sustainability certification under EU regulation, and proof of no negative impact on competing regional bio-based value chains, biodiversity, water balance, and soil carbon stocks. A consortium spanning feedstock logistics, thermochemical engineering, environmental science, and regional policy is not optional — it is the minimum viable team.

HORIZON-CL5-2026-11-D3-14 — Improved System Design for Innovative PV Applications (EUPI-PV Partnership)

This Innovation Action, delivered under the EU PV Industry Initiative (EUPI-PV Partnership), funds large-scale demonstrators for two specific applications: agrivoltaics (agriPV) and offshore or nearshore PV systems. Proposals must focus on one of the two routes — the call applies a portfolio rule guaranteeing at least two funded projects in each category, provided score thresholds are met. Both routes require operational installations of at least 5 MW across multiple EU climate zones, delivering real energy yield, grid integration, and environmental co-benefit data.

Projects must reach TRL 7–8 by conclusion, include social science expertise as a hard condition (not an afterthought), deliver a permitting process as an explicit output, and report KPIs to the EUPI-PV Partnership. The interdisciplinary challenge is significant: agriPV teams need to bridge solar engineering, agronomy, land management, community engagement, and regulatory affairs; offshore teams must add marine engineering, environmental impact assessment, and coordination with shipping and fishing stakeholders.

HORIZON-CL5-2026-11-D3-23 — Data Sharing to Support the Training and Development of AI Foundation Models in the Energy Sector

This Innovation Action funds the development of data governance frameworks and AI foundation models to accelerate the digitalisation of the European energy system. Projects must design and implement scalable, secure strategies for sharing large energy datasets across organisational and national boundaries, using approaches such as data space connectors, federated learning, synthetic data generation, or other innovative mechanisms. The AI models developed must support grid observability, supply and demand forecasting, storage and renewables integration, demand-side flexibility, and energy efficiency - and must be designed to remain FAIR (Findable, Accessible, Interoperable, Reusable) and operational beyond the project's end.

The Commission expects open-source outputs wherever possible. The consortium challenge here is particularly acute: energy data sits with grid operators and utilities who have strong legal and competitive reasons to protect it, yet the call requires them to actively contribute it. Bridging AI research, energy system expertise, data governance, cybersecurity, and the regulatory landscape of the European energy sector in a single partnership is the core difficulty.

What It Actually Takes to Apply

Understanding what a call is asking for is the easy part. The real difficulty begins when you try to turn a research idea into a competitive Horizon Europe proposal.

There are three systematic obstacles that sink even strong proposals:

1. Aligning your concept with grant requirements and expected outcomes. Horizon Europe topics are written with extraordinary specificity. The expected impacts, evaluation criteria, and scope definitions must all be fully reflected (not just addressed) in the proposal narrative. A technically excellent project that fails to map its outputs to the Commission's stated objectives will score poorly regardless of scientific merit. For Cluster 5 calls especially, reviewers expect a clear and measurable pathway from project activities to energy system impact — whether that is GWh of renewable energy demonstrated, tonnes of CO2 reduced, or petabytes of energy data made interoperable. Vague impact claims do not pass.

   
   

2. Finding the right consortium. All three of these calls require partner profiles that most research groups do not have on speed dial. D3-05 needs regional biomass suppliers and CHP operators alongside researchers. D3-14 requires permitting authorities, land managers or offshore engineers, and social scientists embedded from day one. D3-23 requires energy data holders (DSOs, TSOs, utilities) who are willing to share sensitive operational data under a governance framework that does not yet exist. Identifying these partners, convincing them of the project concept, negotiating their roles and budgets, and formalising their commitment in time for submission is a multi-month process that cannot be compressed into the final weeks before a deadline.

   
   

3. Writing a competitive proposal. A winning Horizon Europe proposal must simultaneously demonstrate scientific excellence, technological maturity, operational relevance, impact pathway, project management rigor, and ethics compliance. Evaluation panels expect specific language, trans-section coherency, structured argumentation, and evidence-backed claims. Applicants who underestimate the gap between a well-written research summary and a fundable proposal typically find out only when the rejection letter arrives.

How GrantSpider Can Help

GrantSpider is an AI-boosted platform and fractional grant office that supports European research institutions, universities, and SMEs at every stage of the Horizon Europe lifecycle: from identifying the right call and partners, to writing and submitting a competitive proposal.

Our support covers three areas:

• Grant intelligence and fit assessment — GrantSpider analyses the call requirements and your project concept to give you an honest view of whether your research concept has a realistic path to funding, and how to adjust it before investing in a full proposal.

  
  

• Consortium building and coordination — GrantSpider identifies the partner profiles needed to implement the project concept and provides a curated list of research teams and industry organisations suitable for the consortium. After outreach and negotiations, GrantSpider also manages the collection of inputs from each partner.

  
  

• Proposal development — GrantSpider supports the applicants in the development of the full proposal: excellence, impact, workplan implementation, annex documents — all aligned to the specific grant expectations and scoring criteria.

With five months to the 1 December 2026 deadline, preparation needs to start now.

Get in touch with the GrantSpider team for a free consultation.