Solar panels for manufacturers: Metalworking, Engineering & Fabrication

Load profile: spiky single-shift daytime load, with CNC, welding and compressed-air baseload.

Metalworking, engineering and fabrication shops have a load profile that suits rooftop solar almost perfectly, because the power-hungry equipment runs in the very hours the sun is up. CNC machining, press brakes, welding sets, induction heating and laser or plasma cutting are all daytime-heavy, and underneath them sits a steady baseload from compressed air and fume extraction that never really stops during a shift. That combination of spiky daytime process demand and a firm background load is why solar panels for engineering works generate a return most sub-contract firms are surprised by.

The single-shift daytime match

Most engineering and fabrication shops run one strong daytime shift, occasionally two. That is a slightly harder self-consumption case than a 24/7 food plant, but it is still a good one, because your peak demand coincides with peak generation. A well-matched array on a single-shift metalworking site typically self-consumes 60 to 80 percent of what it produces, and payback lands around 6.5 years. The compressed-air system is the quiet hero here: it draws a continuous load through the working day that solar can offset directly rather than exporting, and fume extraction and LEV add to that firm base.

We size from your half-hourly meter data, not from your roof area, because the shape of a fabrication load matters more than its annual total. A typical project runs from 150 kW to 600 kW, roughly 275 to 1,100 panels across 900 to 3,600 square metres of roof, generating around 140,000 to 550,000 kWh a year. Portal-frame workshops usually have clean, clear-span roofs that suit straightforward rail-fix installation, which keeps the cost per kW down.

Power quality is not an afterthought

A fabrication shop is not a warehouse with a flat load; it has motor-start surges, welding loads and, on some sites, induction furnaces that introduce harmonics. That shapes the inverter selection. Where induction or foundry equipment is present, inverters are specified to hold up under those conditions rather than fitting a standard commercial unit and hoping. The G99 grid-connection application must also account for large motor-start and welding loads, because inverter sizing has to reflect the real power-quality characteristics of your plant, not an annual average. LEV extraction ducts and any crane rails are coordinated with rooftop access so the install does not fight your production layout. This is exactly the kind of detail a generalist contractor prices out and a specialist prices in.

Building the number for the board

Engineering firms live and die on job margins, so any capital has to earn its place. We give you the full model, not a sales figure: simple payback, IRR (typically 12 to 22 percent), NPV at your own discount rate, and an LCOE that for a metalworking site usually sits at 4 to 7p/kWh against the 22 to 32p you pay the grid. That is the comparison that matters, because every unit you generate and use is a unit you are not buying at retail.

Funding follows the same three routes we model for every manufacturer, compared against your current tariff:

• Outright purchase for the best lifetime return, with the Annual Investment Allowance expensing 100 percent of the first £1m of qualifying spend in year one (solar is special-rate plant and machinery, so it is the AIA that applies, not full expensing).
• Asset finance or a lease to keep the capital off your production budget and spread it over 7 to 15 years, typically EBITDA-positive from year one.
• A power purchase agreement for zero-capex, off-balance-sheet solar with a day-one saving.

Our cost guide works these through with figures, and the grants and funding page covers the Annual Investment Allowance and, for eligible energy-intensive sites, Climate Change Agreements.

Older supplies and older roofs

Many established engineering works occupy buildings from the 1970s to the 1990s, and two things commonly come up. First, the electrical supply may be capacity-limited or ageing, which can cap the array size unless a supply upgrade is undertaken; we assess this early and, where it is needed, the upgrade can often be funded inside the same project envelope. Second, the roof itself: pre-2000 industrial roofs usually need engineer sign-off before any ballast or rail loading, and asbestos-cement roofs cannot take rooftop PV and must be replaced first. We start every project with a structural survey precisely so these do not become surprises after contract.

A representative metalworking project

A sub-contract engineering firm in the West Midlands ran CNC machining, press brakes, welding bays and a large compressed-air system on a single daytime shift in a portal-frame workshop. Their demand was spiky, the three-phase supply was ageing, and an automotive Tier-1 customer had begun flowing net-zero requirements down the supply chain. A 2,400 square metre clear-span roof suited rail-fix PV. We installed 265 kW, about 490 panels, with inverters specified for welding and motor-start harmonics. First-year generation reached 244,000 kWh at 78 percent self-consumption, saving around £57,000 a year with simple payback at 6.2 years. The supply upgrade was funded inside the project envelope, and the renewable share was reported to the customer’s supplier scorecard.

What to do next

Send us twelve months of half-hourly meter data and your roof drawings and we will model your self-consumption, payback and IRR, and return a sized, priced feasibility study within seven working days. Our engineers then visit for a single day before we issue a fixed-price proposal with full yield modelling and a financial model you can own. Try the savings calculator or request a free feasibility study; if your load or roof does not suit solar, we will tell you before you commit a penny.