Q-Cells was worth €8bn in 2007 — five years later Hanwha paid €38.7m cash for it

Q-Cells was founded in 1999 in Berlin by four researchers; in 2000 they set a factory on the meadows by Bitterfeld, and in July 2001 the first cells came off the line in Thalheim. The IPO followed on 5 October 2005 in Frankfurt; by the end of 2007 the share stood at around 80 euros and the company was worth almost eight billion. In 2008 it was suddenly the largest solar-cell maker in the world. At Thalheim up to 5,000 people worked behind a gate the region nicknamed Checkpoint Charlie, on a street grandly named Sonnenallee — the heart of what the papers called the Solar Valley.

The boom that built it became the bust that killed it. Der Spiegel later wrote that the subsidy boom of those years became the German solar firms' undoing, as Asian producers left them irretrievably behind. In 2011 Q-Cells piled up a loss of 846 million euros on one billion of revenue. The share that had stood at 80 euros fell to a record low of around 14 cents on 2 April 2012, and days later to nine — leaving the whole company worth 35 million.

The last rescue was a debt-to-equity swap asking bondholders to waive more than 550 million euros of claims. The board abandoned the plan at the end of March 2012, fearing lawsuits after a court ruling in the similar Pfleiderer case, and on 3 April Q-Cells filed for insolvency at the Dessau district court, with 2,200 employees — 500 of them already in Malaysia. On 26 August 2012 South Korea's Hanwha signed the takeover: 250 million euros in all, of which 38.7 million in cash, the rest assumed liabilities, with a promise to keep three quarters of the remaining 1,550 German jobs.

The story is still told as a fairy tale that ended. Süddeutsche Zeitung opened its obituary with 'Once upon a time there was a green dream' — founders who set out to realise humanity's oldest dream of endless clean energy, and did not live happily ever after. Der Spiegel saw a cartoon: a figure runs out over the abyss and hangs in the air until it notices the ground is gone, then crashes down. In Thalheim, twenty-five years on, the local verdict is simpler: 'I hardly use the term Solar Valley any more. That time shaped us, shaped the region — but it is history.'