Overview
Location: Germany
Asset type: Mixed use, residential, commercial, parking
Built: 2000
Summary: After a prior Net Zero Carbon audit proved unactionable, GreenGen conducted a detailed feasibility study and identified 3 viable solutions that addressed technical, regulatory, and operational constraints. The study enabled the client to defer a planned, multi-million-euro investment.
Background
GreenGen was engaged by a global real estate investment management firm, with over $80 billion in assets under management (AUM), to perform a detailed feasibility study for a mixed-use property in Germany. The property features ground-floor retail, mid-level offices, upper-level residential apartments, and three basement levels housing parking and plant areas, all with varying energy demands and occupancy patterns. This engagement followed a prior audit and implementation project GreenGen completed for the same client in the United Kingdom, which had impressed them with its thoroughness and seamless execution.
Challenge
A prior Net Zero Carbon (NZC) audit for the asset, completed several years earlier, had identified heat pump electrification as the primary decarbonisation strategy. With much of the building’s heating, cooling, and ventilation systems nearing end of life, a failing chiller, and new renewable energy requirements under Germany’s Buildings Energy Act (GEG), the client decided it was time to move forward with implementation. As is often the case, the original assessor didn’t have the expertise to take the project to execution and the client engaged with GreenGen.
Upon review, the earlier report proved unactionable as it failed to consider key asset-specific constraints, including noise limitations, structural and electrical capacity issues, and complex existing piping systems. GreenGen was then tasked with conducting a detailed feasibility study to identify technically viable and cost-effective solutions that would:
- Decarbonize heating and cooling systems while extending the asset’s CRREM stranding date
- Balance low capital expenditure with optimized operational performance
- Address technical and regulatory risks
- Ensure minimal disruption to tenants
Solution
Assessment
GreenGen began with an assessment of the property its systems, surrounding geography, regulatory environment, and all factors influencing the practicality of potential solutions. Key findings included:
- Physical Constraints: A basement plant room with limited space or air access, rooftop weight constraints, complex access routes, and strict noise restrictions due to its residential component presented significant design challenges.
- Electrical Limitations: The existing electrical infrastructure offered limited spare capacity, requiring coordination with Frankfurt’s distribution network operator (DNO) for potential substation upgrades.
- Regulatory Requirements: Under the GEG, heating system replacements after June 2026 must achieve a 65% renewable share, narrowing viable pathways to heat pumps, district heating, or hybrid systems. While no district heating network was immediately accessible, GreenGen identified that the local utility planned to extend district heating access to the property by 2027.
- Building Services Issues: Heating, cooling, and ventilation systems had inefficiencies and performance issues. The building management system (BMS) was outdated, with non-functioning controls and interface errors. A detailed equipment inventory and condition assessment confirmed that most mechanical systems were original and nearing or past end of life. Summarised below:
Engineering
Based on the assessment, GreenGen evaluated 12 potential solutions. Options such as VRF, solar thermal, and ground-source heat pumps were ruled out due to space, noise, and infrastructure constraints. The proposed solution was refined to three feasible decarbonisation pathways, along with a base case scenario:
- Base Case – Like-for-like equipment replacement: This offered the lowest upfront and lifecycle costs but failed to meet decarbonisation objectives.
- Concept 1 – Roof-Mounted Air Source Heat Pump: Delivered strong decarbonisation and energy savings potential, though significant technical and design challenges remained that required further detailed design and assessment.
- Concept 2 – Hybrid Heat Pump & Gas Boiler: Technically feasible and compliant with regulations but retained partial fossil fuel reliance.
- Concept 3 – District Heating: Fully compliant and slightly more cost-efficient than other concepts, though contingent on district heating access in 2027.
For each concept, GreenGen delivered phased implementation plans, conceptual drawings, technical specifications, financial analysis, carbon impact modeling, subsidy reviews, and a CRREM risk assessment to help the client compare options and identify the best path forward. Additionally, ten Energy Conservation Measures (ECMs), including thermostat upgrades, control schedule adjustments, and low-flow fixtures, were presented for future efficiency improvement opportunities.
Results
The study allowed client to progress with an alternative approach than had been originally envisaged in the NZC audit. It resolved potential future decarbonization liabilities and deferred a multi-million-euro investment until district heating access becomes available in 2027. This avoided premature electrification costs and aligned capital deployment with upcoming infrastructure readiness.
By following GreenGen’s roadmap, the client can strategically plan implementation projects that enhance asset performance in alignment with equipment lifecycles, future regulatory requirements, and longer-term decarbonisation goals. The chosen approach reduced uncertainty and ensured readiness to achieve Net Zero Carbon once district heating is operational.
Together, these outcomes provided a comprehensive, data-driven roadmap that supports strategic investment decisions, extends the asset’s lifecycle, and advances the client’s decarbonisation goals across its European portfolio.
Interested in working with the GreenGen team? Reach out to us!