FRANKFURT (Reuters) – Shares in German wind and solar park operator CHORUS Clean Energy opened flat in their stock market debut on Wednesday. CHORUS started trading at the offer price of 9.75 euros a share, which had been set at the low end of a 9.75-12.50 euro range in the 119 million euro ($133.71 million) deal, including an over allotment option. Wind park operators such as CHORUS and larger peer Capital Stage, have benefited from rising demand for energy assets, most of which offer stable returns in times of record-low interest rates. ($1 = 0. …