Plastics & Injection Moulding: Solar Panels for Manufacturing

Plastics and injection moulding is one of the strongest matches for solar PV in UK manufacturing, and the reason sits in the load profile. Injection and blow-moulding machines, along with the chillers and compressed air that support them, draw a very high, daytime-heavy baseload that runs almost flat through the working shift. Barrel heaters hold temperature, hydraulic and all-electric presses cycle continuously, and the cooling-water and chiller loads that take heat out of the moulds track daylight closely. That combination matters because it sets moulding apart from lighter manufacturing: the plant that consumes the most power is running precisely when the sun is highest. The electricity a rooftop array generates at midday is therefore consumed on site the instant it is produced, rather than spilled cheaply to the grid under the Smart Export Guarantee. On a 24/5 or 24/7 running pattern the result is exceptional self-consumption and one of the faster paybacks we see across the manufacturing sectors. On top of the economics, automotive and packaging customers increasingly require Scope 2 disclosure from their moulders, so on-site generation has become a commercial requirement as much as an energy one, and a rooftop array is one of the clearest ways to evidence a real reduction to a customer audit.

Sizing solar for plastics and injection moulding

A typical plastics and injection moulding installation lands between 300 kW and 1,000 kW, which is roughly 550 to 1,850 panels across 1,800 to 6,000 square metres of roof. A system in that band generates 275,000 to 920,000 kWh a year in UK conditions and displaces around 63 to 212 tonnes of CO2 annually. We do not size from roof area. Moulding sites often carry high rooftop plant density and mixed machine loads, so we pull at least 12 months of half-hourly meter data and model the load shift by shift, then install to 70 to 90 percent of your peak daytime demand so almost every kilowatt-hour is self-consumed. Because large three-phase machine loads and variable-speed drives can affect power quality, we complete a shading and structural study before we fix the final system size and select the inverters.

Costs and payback

A plastics and injection moulding array typically costs £240,000 to £850,000 fully installed, depending on size, roof type and how much rooftop plant has to be worked around. With the site's high, flat baseload driving self-consumption, simple payback usually lands at around 5.5 years, and most of the capital is fully expensed in year one under the Annual Investment Allowance. The figures below summarise the typical range for this sector.

Figure	Typical range
System size	300 to 1,000 kW
Number of panels	550 to 1,850
Roof area required	1,800 to 6,000 square metres
Annual generation	275,000 to 920,000 kWh
Annual CO2 saved	63 to 212 tonnes
Project value	£240,000 to £850,000
Typical payback	5.5 years

We build the business case from your own meter data and share the full discounted-cash-flow model, so your finance team can stress-test it and feed it straight into your capital-appraisal process rather than take a headline number on trust.

Compliance and regulation

The compliance picture for moulding sites is shaped by the electrical and mechanical plant rather than by a single sector regulator. Large three-phase machine loads and drives can raise power-quality and harmonics considerations for inverter selection, so we specify inverters to suit the loads on your site rather than fit a generic package. Chiller and cooling-water plant has to be coordinated during connection works, and because rooftop plant density is often high, a shading and structural study is needed before final sizing. Alongside those sector-specific points, the standard manufacturing regimes apply. MCS commercial certification is required for Smart Export Guarantee eligibility, a G99 application is needed for any connection above 17 kW per phase, CDM 2015 governs the site works, and a structural survey with engineer sign-off is mandatory on most pre-2000 industrial roofs before any rail or ballast loading. Rooftop PV fire-safety design to SPF1981 is now effectively an insurer requirement and we design to it as standard. Where a moulding shop runs older or capacity-limited electrical infrastructure, we also confirm the incoming supply can accept the array before design, since large press and drive loads can leave less headroom than the connection rating first suggests.

A representative project

Consider a moulder in the North West supplying automotive and consumer-goods customers, running energy-hungry moulding machines and chillers on a 24/5 pattern across a trapezoidal metal roof. A Tier-1 customer requirement to disclose Scope 2 emissions is the trigger for the project. From the half-hourly data the site suits a rooftop array of around 410 kW, roughly 760 panels, generating about 375,000 kWh a year. Sized to the daytime baseload, the array reaches around 81 percent self-consumption, so the great majority of the output offsets grid electricity at the full import rate. Funded through asset finance rather than capital, the system is EBITDA-positive from year one and pays back inside six years, and the generation data supports the site through its customer sustainability audit with verifiable on-site renewable disclosure. The numbers here are representative of this sector and every project is modelled from your own metered demand before we quote.

Funding the project

Most moulding installs are funded through a power purchase agreement or asset finance rather than capital, which keeps the money you would otherwise spend free for the production line. A PPA delivers day-one savings against your current tariff with zero capex, while asset finance spreads the cost over 7 to 15 years and is typically EBITDA-positive from year one. Energy-intensive plastics sites may also benefit from the Industrial Energy Transformation Fund and Climate Change Agreement discounts, and the Annual Investment Allowance usually lets you expense the whole system in year one. Our grants and funding page sets out the schemes in detail, and the cost page breaks down the numbers and financing routes.

To see what a system would cost and save on your site, request a free feasibility study and quote or run the numbers yourself with our solar savings calculator. If your operation spans more than one process, our related sector pages may also be useful, including solar for automotive manufacturing and solar for chemical and process manufacturing.