Plans for hundreds of wind turbines, an electricity substation and dozens of pylons in mid Wales will "totally destroy" the area, says an MP.
Montgomeryshire MP Glyn Davies was leading a Westminster Hall debate in London about wind farms in the region.
The assembly government said its aim had been to preserve the environment.
Energy Minister Charles Hendry called wind cost effective and reliable, but wind farms must be in the right place and need more democratic legitimacy.
Wind turbines have long faced criticism from some locals, but complaints have grown since plans were unveiled for a 19-acre substation and pylons.
They are intended to serve between 600 and 800 wind turbines, which Mr Davies claims are earmarked for his north Powys constituency.
He said he was concerned about their impact on the landscape, on the tourism industry and on property prices in his area.
He claimed they would "totally destroy the place we love by industrialising the uplands with wind turbines and desecrating our valleys with hideous cables and pylons", adding that the scale of it was "almost impossible to comprehend".
Mr Davies said: "Not even the enemies of Britain over the centuries have wrought such wanton destruction on this wondrous part of the United Kingdom.
"Our entire region, the beauty of the landscape of mid Wales, is going to be sacrificed at the altar of a false god."
He added that the authorities were "destroying the one thing that makes that place special", and that tourism in the area was "seriously under threat" because of these plans.
In 2005, Carwyn Jones, then the environment minister, unveiled seven areas across mid and south Wales, known as Tan 8, which had been chosen for the development of windfarms.
At the time, opposition parties accused the assembly government of concentrating too much on wind energy and neglecting other forms of renewable energy, such as solar and hydro power.
Tan 8 was part of the UK government's energy policy to increase the amount of electricity from renewable sources to 10% by 2010, but Wales has exceeded this and produces about 13%.
Concerns in mid Wales about wind farms have grown since the National Grid announced plans for a substation in either Abermule, near Newtown, or Cefn Coch, near Llanfair Caereinion.
Pylons, some measuring 154ft (47m) and spanning 26 miles (42km), are also planned.
ScottishPower also intends to build pylons to carry power from about 10 planned wind farms to the substation.
Several protest meetings have taken place against the proposals and action groups have been formed.
The National Grid has said the electricity infrastructure needs upgrading.
A Welsh Assembly Government spokeswoman said: "Whilst wind energy is currently the most commercially viable technology available, our energy policy utilises the full mix of renewables, including biomass, marine, hydro-electricity, PV (photovoltaics) and energy from waste.
"We recognise the balance that has to be struck between the environmental and economic advantages and disadvantages of wind farm developments and our aim throughout has been to preserve the landscape and environment of Wales and to prevent the proliferation of large on-shore wind farms in an ad hoc manner."