US energy officials are reassessing the risk posed by Chinese-made devices that play a critical role in renewable energy infrastructure after unexplained communication equipment was found inside some of them, two people familiar with the matter said.

Power inverters, which are predominantly produced in China, are used throughout the world to connect solar panels and wind turbines to electricity grids. They are also found in batteries, heat pumps and electric vehicle chargers.

While inverters are built to allow remote access for updates and maintenance, the utility companies that use them typically install firewalls to prevent direct communication back to China.

However, rogue communication devices not listed in product documents have been found in some Chinese solar power inverters by US experts who strip down equipment hooked up to grids to check for security issues, the two people said.

Over the past nine months, undocumented communication devices, including cellular radios, have also been found in some batteries from multiple Chinese suppliers, one of them said. Reuters was unable to determine how many solar power inverters and batteries they have looked at.

The rogue components provide additional, undocumented communication channels that could allow firewalls to be circumvented remotely, with potentially catastrophic consequences, the two people said. Both declined to be named because they did not have permission to speak to the media.

‘Distorting, smearing’

“We know that China believes there is value in placing at least some elements of our core infrastructure at risk of destruction or disruption,” said Mike Rogers, a former director of the US National Security Agency. “I think that the Chinese are, in part, hoping that the widespread use of inverters limits the options that the West has to deal with the security issue.”

A spokesman for the Chinese embassy in Washington said: “We oppose the generalisation of the concept of national security, distorting and smearing China’s infrastructure achievements.”

Using the rogue communication devices to skirt firewalls and switch off inverters remotely, or change their settings, could destabilise power grids, damage energy infrastructure and trigger widespread blackouts, experts said. “That effectively means there is a built-in way to physically destroy the grid,” one of the people said.

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The two people declined to name the Chinese manufacturers of the inverters and batteries with extra communication devices, nor say how many they had found in total. The existence of the rogue devices has not previously been reported. The US government has not publicly acknowledged the discoveries.

Asked for comment, the US department of energy said it continually assesses risk associated with emerging technologies and that there were significant challenges with manufacturers disclosing and documenting functionalities. “While this functionality may not have malicious intent, it is critical for those procuring to have a full understanding of the capabilities of the products received,” a spokesman said.

Work is ongoing to address any gaps in disclosures through “software bill of materials” — or inventories of all the components that make up a software application — and other contractual requirements, the spokesman said.

As US-China tensions escalate, the US and others are reassessing China’s role in strategic infrastructure because of concerns about potential security vulnerabilities, two former government officials said.

In February, two US senators introduced the Decoupling from Foreign Adversarial Battery Dependence Act, banning the department of homeland security from purchasing batteries from some Chinese entities, starting October 2027, due to national security concerns. The bill was referred to the senate committee on homeland security & governmental affairs on 11 March and has yet to be enacted.

It aims to prevent homeland security from procuring batteries from six Chinese companies Washington says are closely linked to the Chinese Communist Party: CATL, BYD, Envision Energy, EVE Energy Company, Hithium Energy Storage Technology and Gotion High-tech. None of the companies responded to requests for comment.

Utilities are now preparing for similar bans on Chinese inverter manufacturers, three people with knowledge of the matter said.

Some utilities, including Florida’s largest power supplier, Florida Power & Light Company, are attempting to minimise the use of Chinese inverters by sourcing equipment from elsewhere, according to two people familiar with the matter. FPL did not respond to requests for comment.

Huawei is the world’s largest supplier of inverters, accounting for 29% of shipments globally in 2022, followed by Chinese peers Sungrow and Ginlong Solis, according to consultancy Wood Mackenzie. German solar developer 1Komma5 said, however, that it avoids Huawei inverters, because of the brand’s associations with security risks.

‘Bigger issue’

“Ten years ago, if you switched off the Chinese inverters, it would not have caused a dramatic thing to happen to European grids, but now the critical mass is much larger,” 1Komma5 CEO Philipp Schroeder said. “China’s dominance is becoming a bigger issue because of the growing renewables capacity on Western grids and the increased likelihood of a prolonged and serious confrontation between China and the West.”

Since 2019, the US has restricted Huawei’s access to US technology, accusing the company of activities contrary to national security, which Huawei denies. Chinese companies are required by law to cooperate with China’s intelligence agencies, giving the government potential control over Chinese-made inverters connected to foreign grids, experts said.

While Huawei decided to leave the US inverter market in 2019 — the year its 5G telecommunications equipment was banned — it remains a dominant supplier elsewhere. The company declined to comment.

In Europe, exercising control over just 3-4GW of energy could cause widespread disruption to electricity supplies, experts said. The European Solar Manufacturing Council estimates over 200GW of European solar power capacity is linked to inverters made in China — equivalent to more than 200 nuclear power plants.

At the end of last year, there was 338GW of installed solar power in Europe, according to industry association SolarPower Europe.

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“If you remotely control a large enough number of home solar inverters, and do something nefarious at once, that could have catastrophic implications to the grid for a prolonged period of time,” said Uri Sadot, cybersecurity programme director at Israeli inverter manufacturer SolarEdge. — Sarah McFarlane, with Andrius Sytas, (c) 2025 Reuters

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