A tiny German firm brought its solar mirror into one of the world’s most closed energy markets and beat every performance target set for it
Image generated with artificial intelligenceChina builds almost everything in its renewable energy supply chain itself. Foreign companies rarely get a seat at the table — and almost none have managed to license core solar technology at scale inside the country’s borders.
sbp sonne is an exception. The small German engineering firm has done what most Western companies haven’t: placed two distinct solar technologies — a parabolic trough design and a ten-faceted heliostat — into operating concentrated solar power plants across Chinese provinces from Inner Mongolia to Tibet.
How a firm of its size broke through one of the world’s most closed energy markets is a story that starts, unexpectedly, in Spain.
“Our experience with Chinese partners has been positive for both technologies.” That outcome runs counter to what many Western firms assume going in.
A wall most Western companies never climb
China’s concentrated solar power supply chain is, by design, almost entirely domestic. Government policy and procurement preferences push projects toward Chinese manufacturers at every stage — mirrors, receivers, control systems, structural steel. For a Western firm to license core technology into that ecosystem isn’t just difficult. It’s nearly unprecedented.
sbp sonne has done it twice. The Munich-based engineering firm holds active licenses for two distinct solar technologies operating inside China: EuroTrough, a large parabolic trough design deployed at projects in Inner Mongolia and Tibet, and Stellio, a ten-faceted heliostat now running at multiple tower CSP plants. Both have delivered strong annual performance results and won SolarPACES Technology Innovation Awards — EuroTrough in 2010, Stellio in 2015.
From a Spanish test site to Chinese deserts
The Stellio story begins at the Plataforma Solar de Almería in southern Spain. Working with partners Ingemetal and Masermic, sbp sonne built and tested a prototype heliostat there, with evaluation carried out by the German Aerospace Center (DLR). What sets Stellio apart is its ten-facet design: all mirror segments are controlled from a single central point, giving it strong optical efficiency and notable resistance to wind loads.
Chinese representatives visiting PSA saw the prototype in action, drawn specifically to its efficiency and wind performance. That encounter set the partnership in motion. Prototype to commercial deployment in China took just 30 months — a timeline Oschatz describes as unprecedented. “We were probably the most advanced technology provider at that time,” he said. “Therefore, we were chosen for both projects.”
The partnership that made it possible
Technology transfer at this scale doesn’t happen through contracts alone. It requires a local partner genuinely willing to invest in understanding, adapting, and improving what it receives — not simply executing a spec sheet.
For sbp sonne, that partner was Dongfang Boiler, one of China’s major state-owned equipment manufacturers. Dongfang established intelligent, semi-automated manufacturing lines in Tibet and Xinjiang, and engineered the Stellio design to withstand high-elevation conditions and harsh wind environments. “We found with Dongfang that they invested in learning and, by delivering projects, improving elements of the Stellio technology,” Oschatz said. His formula: find a partner interested in mastering the technology, not just producing it.
Navigating IP and open-source control systems
One significant compromise came in control systems. Outside China, sbp sonne uses Masermic’s proprietary software — a closed system containing algorithms the firm doesn’t want disclosed. China required something different, classifying CSP control systems as critical infrastructure and mandating an open-source setup.
Oschatz is candid about the trade-off. “The control system currently used for Stellio is, in our opinion, probably less optimal but more transparent,” he said. That concession on software, though, didn’t extend to sbp sonne’s core intellectual property. “We didn’t have any trouble getting our IP respected and protected,” he said. “Our experience with Chinese partners has been positive for both technologies.” That outcome runs counter to what many Western firms assume going in.
Costs falling, performance rising — but market logic still has gaps
Five Stellio deployments have now been completed or are underway. Costs have fallen with each production run — a direct result of learning-curve effects. Even the first commercial production line at Hami exceeded DLR’s optical accuracy targets. “In production, these are even beyond our targets in optical quality,” noted sbp sonne technology developer Thomas Keck.
Not every market dynamic works in the company’s favor. Some Chinese tenders price heliostats purely by mirror area, attaching no performance criteria whatsoever — a structure that disadvantages precisely the kind of engineering sbp sonne specializes in.
Still, Oschatz speaks positively about China’s broader policy approach. “Overall, I think it’s been a kind of well-structured approach for supporting new technology and implementing it on a country level,” he said.
That balance — between policy coherence and market imperfection, between IP protection and necessary compromise — is perhaps what makes sbp sonne’s experience worth examining. It doesn’t offer a clean blueprint. But it does suggest that the wall around China’s energy supply chain, while real, isn’t entirely without doors.
Carlos is an engineer with strong expertise in technical and industrial topics. He previously worked at international companies such as Siemens and is multilingual.
