Powering Belgium’s energy transition with battery storage

As Belgium accelerates its transition toward renewable energy, integrating variable energy sources such as wind and solar into the electricity grid poses significant technical challenges. Battery Energy Storage Systems (BESS) have emerged as a key solution, absorbing surplus energy and compensating for shortfalls, thereby stabilising the grid and ensuring supply security.

To that end, Kallima launched its most significant initiative to date: the 50 MW / 100 MWh Tihange BESS. Located in the Liège region, this flagship project is designed to deliver critical grid stability services, in line with Belgium’s nuclear phase-out strategy and long-term renewable energy goals.

The challenge: ensuring bankability for utility-scale BESS

The project was awarded a Capacity Remuneration Mechanism (CRM) contract in Belgium’s capacity remuneration auction, ensuring a fixed 15+1-years revenue stream in return for reliable grid capacity. This award confirms that the asset meets the fundamental requirements for deliverability, availability and grid compliance as defined by Elia, Belgium’s transmission system operator (TSO).

However, to secure financing and gain investor confidence, Kallima needed to further validate the technical and contractual soundness of the asset. 3E was therefore commissioned to conduct a comprehensive Technical Due Diligence.

The solution: Technical Due Diligence for battery energy storage

As Lender’s Technical Advisor, we provided a comprehensive technical due diligence scope designed to ensure the project’s technical robustness, contractual soundness, and long-term bankability. Our work covered the full value chain of the BESS development, including:

• Vendor evaluation: Evaluation of battery integrator, PCS/EMS vendors, equipment and O&M providers based on experience, bankability, track record and warranty offering.
• System design & technology review: Verification of BESS/PCS sizing, auxiliary systems, cooling/fire safety design, layout planning and compliance with Elia’s requirements.
• Performance and availability risks: Analysis of system round-trip efficiency, degradation rates and contractual KPIs (e.g., availability, throughput and response time) in light of CRM obligations.
• Contract assessment: In-depth review of EPC, BESS supply, EMS license, warranty and O&M agreements, including responsibilities, liability caps, LDs and performance guarantees.
• Warranty and guarantees review: Ensuring component and system warranties align with industry best practices and provide adequate protection for the client.
• CRM compliance check: Validation of system readiness for CRM obligations.
• Business model validation: Confirming technical and contractual assumptions underpinning the project’s financial viability.

Our deliverables included a red flag reportand a final bankable due diligence report.

The result: securing investor confidence for Tihange BESS

Thanks also to 3E’s rigorous technical due diligence, the Tihange BESS project successfully secured lender confidence and moved forward toward financial close. By identifying and mitigating key technical, operational and contractual risks early on, 3E ensured that:

• The BESS design is technically robust, with appropriate redundancy and thermal/fire safety systems in line with industry standards.
• CRM prequalification is confirmed, with a design fully compliant with Elia’s grid code, control requirements and availability KPIs.
• Contracts fairly allocate technical and commercial risk according to market standards, with recommendations made to improve warranty terms and system throughput guarantees.
• Fire risks are addressed though adequate drainage, clearance and fire suppression design.

As a result, the 50 MW / 100 MWh Tihange BESS is on track to become a cornerstone of Belgium’s energy transition, contributing to grid stability, renewable energy integration and the decarbonisation of the power sector.

Why Kallima chose 3E for battery storage Due Diligence

Kallima was particularly pleased with 3E’s ability to streamline the whole process while maintaining clear, proactive communication with investors, an essential factor in securing project confidence.

Paul-Hadrien, Project Engineer and Manager at Kallima:

3E’s thorough and expert technical due diligencegave us full confidence in the quality and reliability of the Tihange BESSproject. Their deep understanding of storage technology and rigorous contractreview were instrumental in securing financing and ensuring a successfulintegration with the Belgian grid. We highly value their professionalism andpartnership throughout the process.

Beyond this, Kallima chose to partner with 3E for several key reasons:

• Local presence and multilingual expertise: Our strong presence in Belgium and our team’s ability to communicate fluently in the local language ensured a smooth coordination and efficient project execution
• Proven BESS expertise: Our extensive experience in Battery Energy Storage Systems (BESS) was key to addressing both technical and regulatory challenges with precision.
• Flexibility & professionalism: We easily adapted to the project's evolving needs, while maintaining stakeholders informed and delivering outputs on schedule.

This combination of technical depth, local knowledge and client-centered delivery enabled Kallima to move forward with confidence and to keep investors aligned at every step.

Looking for trusted advisors in battery energy storage projects?

With over 25 years of experience providing technical, financial and strategic advisory services in the renewable energy sector, 3E offers expertise that supports projects at any location and at every stage of their lifecycle. By leveraging our insights, clients like Kallima are able to make more informed decisions and drive stronger project outcomes.

For other examples of our work, you can find more project references and client testimonials at our resource page. Or if you request our capability statement via this contact form, we’ll be happy to send you a comprehensive overview of our past projects.