Energy efficiency in warehouses: a long journey that began before regulation

Accounting for 10% of national GDP, €200 billion in revenue and 1.8 million jobs, logistics is on the front line of the national effort to improve energy efficiency. Starting with its warehouses, which did not wait for the tertiary-sector decree to take effect (which provides for energy-consumption reductions in existing warehouses over 1,000 m2 of at least 40% by 2030, 50% by 2040 and 60% by 2050) to scale back their consumption.  

Compared with residential and office real estate, logistics real estate has lower actual final energy consumption (that is, the total energy consumed by end users). Residential properties rank first at 202 kWh(final energy)/m2/year, ahead of offices (160) and logistics facilities (141), according to the OID’s 2021 barometer of building energy and environmental performance*. Although “comfort” requirements are lower in these buildings, certain constraints weigh heavily on energy bills: warehouse air conditioning, and even refrigeration for certain “cold-storage” warehouses, the energy used by handling machinery and equipment, lighting, and more. These figures nevertheless remain well above the average primary-energy consumption level of 50 kWh/m2/year set out in the 2011 Grenelle 1 law on thermal regulations applicable to new construction.

However, in terms of final energy—that is, energy actually consumed—the logistics sector is a top performer according to the same OID study, having reduced its consumption by 2% in one year (compared with +5% for shopping centers and -0.5% for residential properties, despite substantial budgets allocated to home energy renovations). New-generation warehouses (built after 2020) must also be “positive-energy” buildings and outperform much older, far more energy-intensive warehouses, despite significant energy-renovation efforts. Beyond small everyday actions, more advanced solutions are beginning to emerge, particularly to lower warehouse temperatures during hotter periods, thereby reducing reliance on highly energy-intensive air conditioning. One solution gaining wider adoption is reflective white roof coating, which can deliver energy savings of up to 40% by limiting air-conditioning use while improving comfort, with indoor temperatures up to 6°C lower. EDF, E. Leclerc, Intermarché and Renault have all taken the step. These same roofs can also be used to generate renewable energy.

To reduce their draw on electricity grids, some warehouses are betting on generating their own energy by making use of roof space to install photovoltaic panels. These are “prosumer” warehouses—both producers and consumers of their own energy—in the sense used by economist Jérémy Rifkin, author of The Zero Marginal Cost Society. In his view, electricity generation should no longer be organized according to a centralized model, but rather a “distributed” one in which energy flows through a so-called “smart” grid, much as information flows over the internet. Each warehouse, for example, would generate its own energy, which would then be distributed in a decentralized manner.

And the theory is being put into practice through the reciprocal commitments between the French State and members of the AFILOG association, which provide for photovoltaic panels to cover, on average across all permits filed between January 1, 2022 and January 1, 2025, 50% of usable roof area. This ambition goes beyond the requirements set by the 2019 Energy and Climate Act and the 2021 Climate and Resilience Act, which require 30% photovoltaic coverage. In this respect, the French State undertakes to facilitate installation of such panels during the review of applications for environmental authorization or ICPE registration. Indeed, the electricity generated by these panels can not only meet warehouses’ needs, but can also supply neighboring buildings that are too old to accommodate this type of structure. In Saint-Ouen-l’Aumône (Val-d’Oise), Groupe Panhard covered a building with 30,000 m2 of photovoltaic panels as early as 2009, creating at the time the largest photovoltaic power plant north of the Loire. It has proved an economically sound bet for these logistics real estate players, which are cutting their energy expenditure and diversifying their operations, like property company Argan, which has specialized in self-consumption power plants. From small actions to major transformations, logistics facilities truly have everything they need to succeed in their energy transition.

* OID 2021 Barometer of Building Energy and Environmental Performance