Leave carbon price, speculators alone, say traders

* Panel says prices should stay unregulated

* Argues that fear of high prices triggers investment

* Estimates half of open interest comes from speculators

By Michael Szabo

BARCELONA, May 29 (Reuters) - Carbon prices and the speculators who trade the underlying emissions permits should remain unregulated, despite wild volatility in the nascent market, a panel of emissions traders said on Friday.

Prices for European Union carbon permits traded under the 27-nation bloc's $92 billion emissions trading scheme have fluctuated wildly, touching a 2-year high of 30 euros ($42) last July before dropping to record lows of 8 euros in February.

"It's tempting to regulate prices, but it would be a counterproductive measure," said Adrien Assous, chief carbon market economist at investment bank Natixis, referring to suggestions that price floors or ceilings should be imposed to curb volatility.

"None of the emissions reductions spurred by a carbon price above 50 euros would be explored ... also it's the sheer fear that prices will go up this high that triggers investment (in clean energy)."