Losses in the future grid: rooftop solar, EV charging and network transparency

Generation and consumption are metered well. What happens between them, in the distribution network, is poorly visible — especially at 0.4 kV. New kinds of load and generation make this blind spot more expensive.

How does distributed generation change the network?

Rooftop solar and small wind at consumers feed energy into a 0.4 kV network designed for one-way flow — from the substation to the consumer. In hours when generation exceeds consumption, the voltage at remote consumers rises and can go beyond permissible limits. Power quality suffers, and one consumer’s export can overload a section designed for a different load.

How does EV charging change losses?

Networks were built for a short consumption peak. Charging an electric vehicle draws high power for hours. Technical losses grow with the square of the current: double the current and the losses on a section quadruple. So several chargers on one line multiply losses and lower the neighbours’ voltage — without formally breaking any rule.

Why should the network become transparent?

Loss norms are set from regional averages. They do not show where energy is lost or who is responsible. An honest consumer on a good network pays for losses on other people’s poor sections, and a distribution company has no reason to cut losses below the norm. For market participants to be interested in reducing losses, it must be known where and how much energy is lost on every section of the network.

What can be done already?

GRID-IN takes into account both energy taken by a consumer (A+) and energy fed back to the network (A−): at a consumer with rooftop solar the flow goes towards the network in generation hours, and this enters the calculation. From AMI data and the network diagram, GRID-IN calculates for every overhead and cable section:

• technical losses — for the period and by hour;
• loading against the continuous current rating;
• voltages at nodes and at consumers;
• and it finds non-technical losses at specific addresses.

This shows which section is overloaded by evening charging, where consumer voltage rises in generation hours and where losses exceed technically justified ones. More — Technical loss calculation for 0.4 kV networks.

Our view

Settlements in the electricity market of the future should rest on a network model: a digital diagram and a calculation of its state from meter data. Then only technically justified losses go into the price, generators gain from siting closer to consumers, and consumers gain from flattening their load. No new hardware is needed for this — the profiles meters already collect are enough.