California: the installation of a battery and solar panels, mandatory in new businesses

California has reformed its Building Code which now requires new commercial buildings to be equipped not only with a photovoltaic installation, but also with a storage battery. In addition, new residential constructions, which were already subject to the obligation to install solar, must now be ready to accommodate electricity storage.

At the forefront of the energy transition in the United States and probably also in the world, California was, in 2018, the first state to prescribe the mandatory installation of solar panels on all new homes. Today it is taking a further step towards its objective of carbon neutrality in 2045 by requiring the mandatory integration in new commercial buildings of electricity storage and a photovoltaic installation. The battery must have a capacity greater than 5 kWh and a charge-discharge efficiency of at least 80%. In addition, the installer must guarantee a residual capacity greater than 70% after 10 years or 4,000 cycles.

A virtual power plant

The Building Code now requires new homes to be designed in such a way that they can also welcome the installation of a domestic battery. To do this, they must now be equipped with a 225 amp bus bar, four backup circuits that can be powered by the battery (including one for the fridge and another for a socket in the bedroom) and a secondary electrical panel or a main panel with a division for these circuits.

The new regulations require the coupling of the solar installation and the battery and the latter must be programmable remotely. This requirement aims to create a kind of “virtual power plant” that can intervene to support the network in the event of a risk of congestion or blackout. Like the one launched by Tesla with its customers' Powerwalls.

As a reminder, California is regularly confronted with catastrophic fires which, in addition to the deaths and the significant damage they cause, also cause repeated power cuts.