Experts warn Chinese solar inverters could threaten Swiss grid

Thousands of solar installations in Switzerland could be vulnerable to cyberattacks, posing a risk to the country’s entire electricity network, cybersecurity experts have warned. SRF reported the findings from an unpublished study by the National Test Institute for Cybersecurity, or NTC.

Switzerland already has 338,000 photovoltaic installations in operation. The study focuses on the inverters that control solar systems and convert the direct current produced by solar panels into the alternating current used by the electricity grid.

Most inverters are permanently connected to the internet through built-in communications modules, allowing them to communicate with manufacturers’ servers. Andreas Leisibach, a cybersecurity expert at the NTC, said the devices could be controlled remotely. This could be used for legitimate purposes, he said, but also to switch off or manipulate an inverter.

The NTC examined the cybersecurity of solar inverters in Switzerland for the first time. It identified a particular risk because many of the devices come from a small number of manufacturers, creating what experts describe as a concentration risk.

According to an estimate by the Federal Office of Energy, around 100,000 Swiss solar installations use inverters made in China. The market share of the two Chinese manufacturers Huawei and Sungrow has since risen to more than 60 per cent. Official figures have only been collected recently.

Raphael Reischuk, the NTC’s founder, said anyone controlling the inverter could control the entire solar installation and ultimately affect the electricity grid. If Chinese manufacturers switched off all their devices at full output at the same time, Switzerland’s grid could collapse, he warned.

Reischuk said the manufacturers would have no economic interest in doing so, but could be forced by a state actor or by cybercriminals seeking to extort them. He pointed to a case in which a Chinese manufacturer remotely switched off large numbers of inverters in the United States and other countries during a distribution dispute. The affected devices displayed the message “Not allowed to use”.

More than half of the inverters newly installed in Switzerland come from Huawei. The company Clevergie is also installing a Huawei-equipped system on the roof of the cantonal vocational school in Bern.

Clevergie chief executive Lukas Meister said the products were high-quality and comparatively inexpensive. He added that neither individual customers nor the industry could solve the concentration risk created by thousands of such installations on their own.

Sungrow did not answer SRF’s questions. Huawei declined an on-camera interview but said in writing that cybersecurity was its “highest priority”. It said its systems in Switzerland were operated by customers and could, depending on requirements, use a secure encrypted connection to the manufacturer’s management system or operate offline.

Experts consider offline operation difficult to implement in practice.

United States and EU take measures

The United States is seeking to reduce the risk. President Donald Trump has declared a national emergency for the high-voltage electricity grid. Among other measures, the future installation of grid-connected inverters from countries subject to arms embargoes or sanctions, including China, is to be prohibited. Operators could also be required to remove devices that have already been installed.

The European Union is also taking action. Projects using Chinese inverters are no longer eligible for funding. Siobhan McGarry, a European Commission spokesperson, said risk assessments had confirmed the threat, including the possibility of manipulating electricity production.

In practice, she said, this could allow the remote shutdown of grids and lead to nationwide blackouts. The concern is that Chinese companies, which are legally required to cooperate with state security authorities, could be compelled by Beijing to remotely switch off solar installations in Europe in the event of a conflict.