Salvador Guerra i Salamo can't sleep at night. "I fear that I can't pay back the bank loan. And this after I've honored my debts all my life," he says as he walks through the 2.1-megawatt Riudarenes II solar park near the Catalan city of Girona, in which his family owns a stake.

His family has invested €7m in solar parks, but now Spain's cash-strapped government is contemplating steep cuts to subsidies for renewable power, even for plants already producing power. Investors in these plants thought subsidies had been guaranteed by the government. Such cuts could push small businesses like Guerra's over the edge.