Why are so many warehouse spaces going to wasteby not using solar? Amy Wilson, Chief Marketing Officer at Wattsor, explains.
With geopolitical events causing two major price shocks in five years, it is no wonder that energy has become a major operational and financial concern for logistics providers. As the sector looks at ways to reduce its reliance on volatile wholesale energy prices, the idea of generating renewable energy on-site has moved from a ‘nice-to-have’, or purely environmental initiative, to an increasingly attractive strategy for securing a stable and predictable energy supply.
Despite the government pushing a ‘solar revolution’ for both businesses and households, thousands of warehouse rooftop spaces remain untapped potential for solar generation. A report from Cushman & Wakefield estimates that UK logistics and industrial buildings of 50,000 square feet or more account for 1.5 billion square feet of roof space, with the potential to generate over 36GWh of electricity each year. With the government targeting 45 to 47GW of solar capacity by 2030, warehouse rooftops could make a substantial contribution to national targets.
At a time when logistics operators need greater control over energy costs and to be demonstrating credible carbon reductions, they should look to roofs as a valuable asset.
Several barriers can prevent a promising project from being reduced or even abandoned. Most of the time, technology isn’t the blocker. Developers sometimes design warehouse solar schemes around present demand, so an ambient warehouse with an enormous roof may receive only enough panels to serve its modest daytime load. Much of the available space then remains untouched, even when automation or vehicle charging will increase electricity use later down the line.
In addition, complex property arrangements can make the calculation harder. For example, the occupier pays the electricity bill while the landlord controls the roof, meaning that the lease may not align with the expected payback period. Furthermore, supporting equipment may require planning permission.
Grid constraints often present the biggest obstacle to a large rooftop solar project. Solar panels on a warehouse roof may be able to generate more electricity than the business can use, but the local electricity grid may not have room to take the excess. This can lead to either installing fewer panels or paying for an expensive grid upgrade.
While the UK needs a costly, decades-long grid investment as logistics sites electrify, it must also use the existing network more effectively. Battery storage and smart energy management systems may provide a more immediate solution.
A battery can store solar electricity that the warehouse cannot use straight away, preventing too much power from being sent to the grid at once. If a project can show that it will stay within the grid’s existing limit, the need to pay for an upgrade to handle electricity that the site will never send is avoided. Grid constraint then becomes a design or engineering challenge, rather than the end of the project.
Pharmaceutical distributor Mawdsleys faced this challenge at its warehouse in Doncaster. The site needed a 1,700-kilowatt rooftop solar system to match its expected annual electricity use, but the grid operator would only allow a much smaller limit. Wattstor linked the panels to a battery so surplus solar electricity could be stored on site rather than sent straight to the grid. Controls limited how much power reached the grid, allowing Mawdsleys to install the larger solar system while staying within the permitted connection limit.
Similarly, our work with Big Yellow Self Storage shows how one project can establish a repeatable approach. Its Slough store combined rooftop solar panels with a battery that can power the site for up to ten hours. The installation has helped set the requirements for future stores, allowing it to include solar and storage in new developments from the outset.
This is a model that can be repeated. Warehouse operators should begin with the site, not a predetermined quantity of panels. Half-hourly demand data and the condition of the roof show what is possible, while expected growth and grid limits reveal what the system must handle.
New warehouses should now plan rooftop solar and battery storage together, with energy management built in from the outset. Retrofitting the existing estate remains a vast opportunity, but completing a logistics building without considering the power it could generate, and how it will use that power, creates wasted space from its first day.
The rooftop revolution no longer needs a technological breakthrough, but it does require more than panels. The logistics sector must stop treating roofs as leftover space and use solar plus battery storage and smart energy management to turn them into working energy assets. Operators that act now can reduce costs while preparing for rising electricity demand. The rooftops are ready. The sector should be too.
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