Sustainable certification systems and renewable energy – a growing synergy

As the European building sector continues to grapple with the intertwined challenges of climate change and energy efficiency, green building certifications like LEED (Leadership in Energy and Environmental Design) have become powerful tools for transforming how we design, construct or redevelop, operate and even demolish buildings. Over the past decades, such systems have been continuously improving their guidebooks to set best standards in sustainability, including energy efficiency and the use of renewable energy. LEED v5, the latest iteration of the U.S. Green Building Council’s flagship rating system, launched in April 2025, places even stronger emphasis on decarbonisation and renewable energy integration than its predecessors and competitors, becoming the major global certification with an outlook on reducing greenhouse gas emissions and improving energy efficiency.

When looking closer at the certification’s requirements, it becomes clear that renewable energy is a necessary component of any building striving to achieve it, and here’s why.

Decarbonisation planning supersedes energy modelling

A forward-looking approach to minimise carbon emissions is clearly visible in the system with such strategies gaining the status of required credits. To get the LEED seal, the projects must conduct early-stage design analyses to evaluate energy efficiency, peak load reduction, and come up with decarbonisation strategies. These analyses should inform a 25-year carbon projection, with an intention to guide long-term planning. All this to encourage project teams to use these strategies as genuine design tool rather than a checklist exercise filed away upon certification submission; the teams are required to either design for full electrification or submit a detailed decarbonisation plan outlining retrofit timelines, costs, and readiness strategies, laying the groundwork for the use of low-carbon technologies or, at the minimum, for integrating renewable energy systems over time. This initial analysis can be later supported by CRREM – a tool of growing popularity, enabling projects to assess their transition risks towards Paris Climate Goals. Identifying the stranding year can inform the projects of the ideal timeline of decarbonisation strategies implementation and facilitate informed budget planning.

EU Taxonomy leads the European path to meet energy performance benchmarks

LEED v5 requires compliance with either ASHRAE 90.1-2019 Energy Standard for Buildings Except Low-Rise Residential Buildings or the more stringent 90.1-2022 standard, obligatory for all projects from 2028, both setting the baseline for building energy performance. As they are USA-specific, projects in Europe can use an alternative compliance path aligned with respective national Nearly-Zero-Energy Building (NZEB) standards. In practice, this means that the European projects are no longer required to perform costly energy modelling to the American standards but instead can submit an Energy Performance Certificate (EPC) and demonstrate that their building envelope meets or exceeds national requirements. Easy enough, one may think, and… somewhat controversial, as different countries have adopted different national energy efficiency benchmarks, what can be seen in varying primary energy demand (PED) limits for their national energy classes. For instance, the updated proposal of Polish Regulation of the Minister of Development and Technology on the methodology for determining the energy performance of a building or part of a building, and on energy performance certificates, published on the 6th of June 2025, has lowered the requirement for the class A for the non-renewable PED indicator for public utility buildings excluding healthcare facilities from 63 to 108 kWh/(m²·year), compared to the previous proposal (class G allows the PED to be higher than 338 kWh/(m²·year)), while in France, class A requires primary energy consumption (PEC) to be no higher than 50 kWh/(m²·year) for office buildings, administration, or education buildings, while class G encompasses the PEC higher than 750 kWh/(m²·year), as specified in the Arrêté du 15 septembre 2006, which governs the energy performance diagnosis (DPE) for non-residential buildings. Probably quite rightly, given the discrepancies in the national benchmarks across the European Union, LEED v5 does not consider the EU Taxonomy requirements, based on these, as the highest benchmark for energy performance. To earn extra credits, European projects must prove that they exceed national requirements. While compliance with the EU Taxonomy Climate Mitigation criteria (10% better than NZEB) allows to gain 2 points, 30% improvement is necessary for full points award, encouraging the projects to look for renewable energy sources to minimise PED.

The alignment with the EU Taxonomy’s climate mitigation criteria makes LEED certification a valuable tool for sustainable finance and green investment. 

“LEED is a globally recognized symbol of sustainability achievement for buildings, backed by an entire industry of committed stakeholders paving the way for market transformation through research, collaboration and knowledge sharing. Creating a tool which has to be relevant at a global level is a tall order and we can only do this through active engagement with industry leaders across the world. The energy criteria evolve to continue to raise the bar on efficiency and performance, while remaining relevant to technological advancement, new regulations and the shared goal to decarbonize the built environment.” 

Vessela Valtcheva-McGee, Director Market Development EE, GBCI Europe

Grid-interaction fostering energy resilience

The newest release of the LEED standard promotes projects that secure their energy resilience through strategies focused on grid interactivity and on-site energy storage. Such strategies may include installing electric or thermal energy storage, participating in demand response programs, implementing automated demand-side management or island-mode operation using on-site renewables and storage. Beyond their relevance to reduce peak demand, these strategies support the broader decarbonisation of the energy grid at a national level as well as energy resilience, certainly brought sharply into focus after the blackout event on 28th of April this year on the Iberian Peninsula.

The pursuit of hap… efficiency – thermal load reduction, passive design and air tightness 

The certification targets specific aspects of building design and commissioning to ensure further reduction of energy demand, understanding that mistakes during the construction of the buildings may lead to significant repercussions at the operational stage. One of the key tools, also recognised by the EU Taxonomy’s climate mitigation, is performing air leakage testing. Other key areas related to building envelope design and HVAC systems performance include balancing ventilation schedule, energy recovery systems, thermal bridging mitigation or passive design modelling using tools like PHPP or WUFI.

Improved rules on energy procurement

While even the previous, v4.1 version of the LEED certification recognised the higher value of the on-site generated energy over off-site energy procurement through its tiered point system, more stringent rules govern the purchase of renewable energy certificates (RECs) and energy attribute certificates (EACs) in its latest release. These include matching energy type (electricity or fuel), vintage limits (EACs ≤18 months old), geographic relevance (same country or region) or certification for bulk purchases, ensuring that renewable energy claims are more credible and environmentally meaningful.

LEED v5 classification of the renewable energy sources:

• Tier 1: On-site generation or social impact projects
• Tier 2: New off-site renewable assets
• Tier 3: Certified off-site renewables (e.g., Green-e®)

For decades, green building certification systems have shaped the sustainable development in the built standards. With evolving global and local sustainability goals, advancements in the available technology and the regulatory changes, the certification systems like LEED keep setting new standards for the industry. While quality of life, ecological conservation and restoration impact areas remain valued and appreciated, decarbonisation gains the central place in LEED v5, emphasizing the growing urgency of achieving a climate-neutral future in the construction and real estate industry. This cannot be achieved without turning to the renewable energy that becomes essential in a sustainable world.