Demand charges and peak load penalties are a significant portion of a factory’s electricity bills.

The good news?

Solar power – and battery storage during non-daylight operations – can help you manage and reduce these costly charges.

This post explains how demand charges work, why they matter to factory owners, and practical strategies to lower them using solar energy.

1. What Are Demand Charges and Peak Load Penalties?

Unlike simple energy consumption fees, these charges are fees based on your maximum electricity usage during peak times, usually measured over a 30-minute window.

These charges incentivise factories to smooth out spikes in electricity demand.

In the UK, many industrial tariffs include:

❌ Red-band Distribution Use of System (DUoS) charges: Often highest during late afternoon and early evening.

❌ Capacity charges: Based on the maximum load your factory places on the grid.

If your factory suddenly powers up several large machines at once, you create a peak demand spike – and your bill increases accordingly.

2. Why Demand Charges Matter for Factories

Demand charges can account for 30 – 50% of your total electricity bill.

For factories running heavy equipment or multiple shifts, peak loads often occur unpredictably, driving up costs.

Managing these peaks can deliver significant savings, directly improving your factory’s bottom line.

3. How Solar Reduces Demand Charges

✅ During the day, solar panels generate electricity, decreasing the power you need from the grid.

✅ By supplying some or all of your factory’s load, solar reduces the size and frequency of peak demand spikes.

This effect is most powerful during daylight hours but limited once the sun sets.

4. Boosting Impact with Battery Storage

✅ Batteries store excess solar power during the day.

✅ During peak tariff hours (often late afternoon/evening), the battery discharges, supplying power and reducing grid demand.

✅ This peak shaving strategy flattens demand spikes, lowering your demand charges significantly.

Factories using solar and storage have reported demand charge savings of up to 25% or more.

5. Practical Considerations for UK Factory Owners

❓Analyse your tariff structure: Understand your demand charge components and peak periods.

❓Assess your energy profile: Identify when peak loads occur and how solar production aligns.

❓Invest in battery storage: Consider if your factory’s demand patterns justify the additional cost.

❓Work with experts: Specialist factory solar providers can design tailored systems to optimise demand charge savings.

Conclusion…

Demand charges and peak load penalties are often overlooked opportunities for cost savings in factory energy management.

By reducing peak grid demand through solar and battery, your factory can lower bills, improve sustainability, and gain more predictable energy costs.