Could one of the biggest eco-innovations in warehouse property be dead before it even got going? That is what some observers are saying about installing solar panels on warehouse roofs, discovers David Thame.
Acres of warehouse roof-space was touted as the next big opportunity for the solar energy business. The reason was simple – compared to domestic solar panels, which have a capacity of 4kW or less, commercial scale installations are typically in the 50kW to 500kW range. And the UK is unusual in generating more solar energy from residential homes than on commercial and industrial buildings.
Government ministers have called for a greater increase in the proportion of the UK’s solar energy generated from panels mounted on commercial and industrial buildings and has set up a task force to get industry professionals, landlords and occupiers together to try to address the differences between landlords and tenants that are preventing the exploitation of solar energy.
But getting the panels from the drawing board to the roof is likely to be hard work, say experts. Mat Lown, sustainability partner at property consultant Tuffin Ferraby Taylor, says few warehouses have yet to take up the potential of solar panels: “It’s an active minority, but it’s starting to change as the cost of panels comes down. Returns for owners are around 8%, sometimes as high as 15%, even given the changes in the Feed-In Tarrifs, so its quite an attractive investment.”
If that wasn’t enough there could also be scope for argument over who gets the benefit of the electricity the panels generated, and who pays the (relatively low, compared to domestic houses) installation costs. According to Lown, disagreement between landlords and tenants is often getting in the way of new installations.
“It’s the classic landlord and tenant confrontation,” he says. “Tenants need the consent of landlords to put panels on the roof, and getting consent can be a barrier. Landlords worry about insurance issues because sometimes the panels get hot, and it worries them, and there are also issues about leasehold warranties.”
Change in law
A change in the law in 2011 should have made it easier to make energy-saving changes to buildings, but in practice it hasn’t had much effect, says Lown. He concludes that there needs to be strong leadership from either the landlord or the tenant to get things moving.
The next big problem is the physical problem of putting extra weight on often light-weight warehouse roofs. “You need to check the condition of the roof, and do any repairs that are needed. And you need to check the structural capacity of the roof, because that could be a concern. Today, efficient building techniques mean structures aren’t engineered with as much scope for extra loading,” he says.
If extra roof insulation has already been added, then the solar panels could be the straw that breaks the camel’s back. Supposing the attempt to put panels on a warehouse gets this far, it could still be undone by competing efficiency measures. For instance, it is now standard for 15% of a roof to be transparent roof lights. This is hard to accomplish if your roof is covered in panels, or the panels are in the wrong place. Some experts say the risk of the roof not being up to the job is easy to over-state. James Kelway, director of building consultancy at surveyor Savills, says: “Obviously you need to check that the loading on the roof is right, but if you are retrofitting solar panels the impact on loading is likely to be minimal because the panels themselves are now a lot lighter than they used to be.”
For now, solar energy derived from commercial buildings accounts for just 20% of the solar energy generated in the UK. The government hopes to push that figure up to 30%. But getting there could be harder work than ministers suppose. Heat up, costs down
For the UK’s warehouses, the onset of winter means a surge in the heating and lighting bills that inflate supply chain costs and eat into profit margins.
Keeping the heat up but the cost down is often about common sense. But it is also about how the building is built – and according to property experts, there’s plenty of scope to engineer warmth and light. Both new-build and retrofitted older properties can benefit from a specialist’s eye, they say. New developments in LED lighting are the main opportunity to make smart savings. But it might involve an upfront capital cost.
“The best approach is to design your lighting with your racking layout, mezzanines and marshalling areas in mind, ideally before you even build the warehouse,” says James Kelway, director of building consultancy at surveyor Savills and an expert on how to get heat and light into warehouses. “That’s the best way to make it efficient. But you can upgrade from fluorescent to LED lighting and that can mean real cost savings.” Kelway cites the example of a 400,000 sq ft cross-docked warehouse in Lancashire he visited in September: “It cost around £70,000 to upgrade to LED lighting, and they reckon they will have paid that back in energy saving within two-to-three years. Logistics is a business with narrow margins, and there’s a tendancy to look at the revenue figures - where £70,000 could make a big difference - instead of the capital figures. But any investment that pays back so quickly has to be worth considering, especially if the warehouse operator has a lease of, say, 15 years. What’s two or three years compared to 12 years of savings?”
Finding energy-efficient heating is more complicated. Gas-fired high velocity duct systems remain standard, and it’s hard to make them more efficient. A good modern high-efficiency boiler will help, says Kellway. Otherwise the answer is simply to use it less. “Maybe you don’t need the warehouse heated to 14-15°C and can get away with frost protection only, and staff wearing nice warm jackets?“ he suggests.