German independent power producer Clearvise AG (<a href="https://www.boerse-frankfurt.de/equity/clearvise-ag-inh-o-n" target="_blank">ETR:ABO</a>) has extended its turbine maintenance contracts with Denmark’s Vestas Wind Systems A/S (<a href="https://www.nasdaqomxnordic.com/aktier/microsite?Instrument=CSE3258&name=Vestas%20Wind%20Systems&ISIN=DK0061539921" target="_blank">CPH:VWS</a>) aiming to optimise its portfolio of wind farms in France.