Alkane Energy reported an increase in half-year electricity output boosted by the acquisition of Greenpark Energy. In the first six month of the year, the group achieved a 44% rise in electricity output to 94 gig watt hours (GWH) compared to a year earlier, according to a trading update on Tuesday.The company said the increase reflected the contribution of Greenpark Energy, which was acquired in April 2012.It also reflected a first time contribution from the Maltby coal mine methane assets acquired on May 24th. "Our investment strategy has continued to deliver strong growth in our core coal mine methane business and we are encouraged by progress in power response which has seen higher call levels from National Grid," said Chief Executive Officer, Neil O'Brien."Ofgem has recently again highlighted the risks facing the UK of an energy gap in the electricity market, which underpins our investment plans."Shares rose 5.15% to 35.75p at 14:55.RD