Can a commercial solar system export unused electricity?

Unused electricity is normally handled in three ways: it powers equipment on site, charges a battery, or passes through the meter for export. The right balance depends on the business’s demand pattern, the battery capacity and the export limit agreed for the site.

Using the electricity on site comes first. Solar generation can supply lighting, refrigeration, machinery, computers, pumps and other equipment while the panels are producing power. A business that uses electricity during the day may use much of its generation directly. That reduces the amount available for export and means the system is designed around actual operating patterns rather than roof size alone.

Where generation exceeds immediate demand, a battery can store some of it for later. It may then discharge when the site is using electricity after solar production has fallen. Battery sizing needs care: a larger battery does not automatically improve the financial case if the business has little evening or overnight demand. We compare the proposed battery capacity with the site’s load profile and expected solar generation.

Electricity that cannot be used or stored can be exported. The import meter must be able to record electricity flowing back to the grid, and the business needs an export arrangement with its electricity supplier. The supplier’s tariff, contract terms and meter requirements determine how exported electricity is recorded and paid for.

For an eligible installation, MCS certification provides the evidence needed for a Smart Export Guarantee application. We explain the paperwork and the information the supplier requires, so the export arrangement is considered as part of the installation rather than left until the panels are producing.

The grid may not accept unlimited export. The local network operator can set an export capacity for the property. This depends on the connection and the condition of the surrounding network. If the approved capacity is lower than the system could produce, the inverter may need to limit export at certain times. That does not necessarily prevent solar installation, but it affects the system design and the amount of generation that can be sent away.

We check the proposed array, inverter, battery and connection requirements together. If an application or technical approval is needed, we account for the agreed export limit before equipment is specified. This avoids designing a system that depends on exporting more power than the connection allows.

Export income is only one part of the assessment. We look at when the business consumes electricity, how much roof space is usable, whether a battery can shift generation to a useful time and what the supplier will pay for exported power. The result is a clearer view of how much electricity is likely to be used on site and how much may leave the property.

Export arrangements can also change if the business changes supplier, adds equipment or alters its electricity connection. The monitoring system continues to show generation, on-site use, battery activity and export, helping identify whether the system is working as expected.

Before work starts, we provide a written quotation covering the equipment, connection requirements and installation work. The design is based on the business’s demand and the permitted grid connection, not on the assumption that every unit of generated electricity will be exported.