The UK Department of Energy & Climate Change (DECC) has rejected four planned onshore wind farms in Powys, Mid-Wales.
The rejected projects include Llanbadarn Fynydd, Llaithddu, Llanbrynmair and Carnedd Wen onshore wind farms.
DECC has rejected these proposals following a combined public inquiry, called by the Secretary of State for Energy and Climate Change, which closed in May 2014.
A DECC spokesperson said: "Careful consideration has been given to each application, and the planning and energy issues involved."
Renewable energy trade association RenewableUK Cymru said that Mid Wales will lose £50m investment the rejected wind farms were set to bring to the area.
However, the government has given its consent to to upgrade the existing Llandinam onshore wind farm.
DECC Spokesperson said: "Careful consideration has been given to each application, and the planning and energy issues involved."
RenewableUK Cymru director David Clubb said: "Given the blows the UK government are raining down onto the renewable energy sector on both consents and subsidies, ministers will be heading to the Paris climate discussions with their credibility in tatters."
The Llandinam to Welshpool Substation Overhead Power Line connection was also refused by the government.