Italian independent power producer ERG SpA (<a href="https://www.borsaitaliana.it/borsa/azioni/scheda/IT0001157020.html?lang=en" target="_blank">BIT:ERG</a>) has issued a six-year EUR-500-million (USD 536.2m) green bond as part of its EUR-3-billion medium-term note programme, the company said on Wednesday.