(ShareCast News) - Windfarm investment trust Greencoat reported a fall in net asset value per share over the last six months, from 105.5p in the six months to December 2014 to 104.2p to June 2015.It said the relatively weak NAV was due to lower forecast power prices and the July budget announcement of cuts to climate change subsidies.Greencoat said its investments had generated 408.0 GWh of electricity, which was 10% above budget thanks to high wind resources.Chairman Tim Ingram said substantial growth in the UK wind farm secondary market would enhance investment opportunities in a market which was anticipated to reach £60bn."As an investor in up and running UK wind farms, we are not significantly affected by the closure of the Renewables Obligation for new onshore wind farms from March 2016, and remain encouraged by the outlook for investment opportunities," Ingram said in a statement.At 1408 BST shares in Greencoat fell 0.18% to 112.55p.