On Thursday, Hawaiian Electric issued a long-awaited request for proposals for about 900 megawatts of renewable energy and energy storage projects. It’s the utility’s second major round of contracts in the past year seeking to marry variable solar and wind power with the capacity and flexibility of batteries. But the Variable Renewable Dispatchable Generation and Energy Storage RFPs that opened on Thursday are a bit more complicated than their headline figures — seeking “technologies equal to 594 megawatts of solar for Oahu, 135 megawatts for Maui and up to 203 megawatts for Hawaii Island” — might indicate.