Effect of quarter-hourly trading on the need for reserves in Germany, 2012-2017 Openexpand Created with Highcharts 9.3.3Power (MW)Trading Volume (MW)Jan-2012Jul-2012Jan-2013Jul-2013Jan-2014Jul-2014Jan-2015Jul-2015Jan-2016Jul-2016Jan-2017Jul-2017Jan-201805010015020025030035002505007501000125015001750