Solar for Factories With High Daytime Electricity Use

Why the timing of consumption matters

The benefit of daytime demand is the opportunity to use solar electricity immediately, reducing purchases from the grid under the applicable arrangement. This explains why the timing of consumption matters as much as the monthly total. A factory with heavy night-time use may have a large bill but less demand that coincides with generation.

Separate daytime and night-time consumption. A factory can have a large monthly bill while using most electricity after sunset. Only demand that occurs while the system is generating can use that solar electricity directly.

Ask for a chart showing factory demand and expected solar output at the same times. It should show when solar can replace grid purchases and when generation may exceed the factory’s demand.

Identify equipment that runs regularly during daylight hours

Not all daytime machinery use provides the same opportunity. Cooling or circulation pumps that run steadily can absorb output differently from equipment drawing power in short bursts. Separating those patterns helps the provider size around demand that is actually present, rather than assume every listed machine runs continuously.

Some equipment cycles on and off. Other equipment draws heavily only during start-up or a brief process. Adding rated equipment power together can therefore exaggerate the demand available to absorb generation.

Use meter records alongside the production schedule. If records are missing, ask what the provider has estimated and whether more measurement is needed before choosing capacity. The final size should not depend on an unverified claim that machinery runs all day.

Include low-production days

The strength of the weekday match can hide a weaker one at weekends or during shutdowns. Panels may continue generating when production stops, reducing the share of electricity used directly. Those quieter periods are part of the annual return and need to be included even where normal working-day demand is high.

The calculation should show what happens to surplus under your proposed programme. Do not count the same unit as both directly used and exported. Check any limits on export credits instead of assuming every surplus unit receives the same value.

Include regular festive closures and annual maintenance in the forecast. If the factory normally shuts for those periods, the savings calculation should account for the lower demand rather than assume year-round weekday consumption.

Shift flexible tasks only when it helps the business

A factory may be able to improve direct use by moving a necessary but flexible task into daylight hours. Charging or pumping could offer that option where timing is not critical to production. The saving is only worthwhile if the change remains workable for staff and equipment, rather than requiring the business to run differently just to use more solar.

The production team should decide what is practical. Changes must respect process quality, staffing, delivery commitments and any applicable tariff arrangements. Running unnecessary equipment simply to consume solar does not create a saving.

Ask the provider to distinguish benefits from the current operation and benefits that require a schedule change. Management can then see whether the forecast depends on a practice the factory has actually agreed to adopt.

Calculate demand-charge savings separately

Using fewer grid units does not necessarily reduce demand charges by the same proportion. Those charges may depend on a measured peak, and solar only affects that peak if generation and demand coincide in the relevant interval. This is why an energy-saving estimate needs a separate check before being used to promise demand-charge savings.

If the site’s highest demand occurs when solar output is low, the billed demand may remain substantial. Even during daylight, changing cloud conditions and production peaks can affect the result.

A proposal should therefore assess demand-related benefits separately where applicable. Avoid accepting a single percentage applied to every bill component. The calculation needs to follow the account’s current tariff and the measured operating profile.

Compare sizes using electricity consumed directly

Strong daytime use does not identify one automatic system size. Several capacities may serve the factory, with the larger options increasingly producing surplus at quieter times. Comparing their extra costs with their extra savings helps decide whether additional panels are worth buying, even when the smaller option already looks attractive.

For each size, list expected generation, electricity used directly, surplus, purchase cost and operating costs. Then calculate what the larger option adds to annual savings and whether that justifies its extra cost.

A larger system may generate more overall but export a higher share on quiet days. Use the applicable export value in the calculation instead of valuing those units as direct consumption. Compare the resulting additional benefit with the additional investment.

Ask Verdant Solar to use your actual shifts and meter records

Verdant Solar’s commercial proposal includes projections for different consumption levels. Ask the team to calculate savings using your current shifts first, then show any separate result that depends on changing working hours.

The proposal should state the working hours, meter records and planned business changes used for each calculation. Ask how missing records were estimated and whether those estimates could materially change the recommended size.

The project scope should also address applications, equipment, testing, handover and ongoing support. High self-consumption does not remove the need for clear delivery and maintenance responsibilities. Those items affect both implementation and the long-term value of the system.

Have operations and finance check the same calculation

The forecast depends on information held by different teams. Operations can judge whether the assumed machinery use and working hours are realistic, while finance can assess the rates, payments and costs applied to them. Reviewing the same calculation together avoids approving savings that rely on a production schedule nobody has agreed to follow.

Use one summary showing working days, shutdowns, expected generation and the share used directly. Include the assumed production changes and whether the system is purchased or supplied by a third party. Both teams should review the same version before approval.

This shared picture prevents a financial forecast from depending on operational changes that nobody has approved. It also makes later performance reviews easier because the business retains a record of what it expected at the investment stage.

Measure the effect of changing a work schedule

If a task can move to daylight hours, test a change that operations can maintain. For example, reschedule necessary charging only if equipment remains available when needed and staffing is suitable. Record the old and new times, then check whether electricity costs changed as expected.

After changing a task’s schedule, compare electricity use and cost before and after the change. Separate the effect of solar from any tariff change, and do not count the same saving twice. Review the schedule again if orders or staffing change; the task still needs to serve production, not just consume solar output.