There are worries about how the turbines will reach hilly areas
Building work on more wind turbines in rural Wales will bring "significant disruption" because country roads will have problems coping, says a report.
A Powys council study obtained by anti-wind farm activists says narrow roads will have difficulty handling trucks carrying 400ft (122m) structures.
Over 450 turbines may be built in Powys and Ceredigion alone in coming years.
Powys council and the Welsh Assembly Government said they were looking at how to tackle the problem.
Conservation of Upland Powys obtained the draft 86-page Powys council report in a Freedom of Information Act request.
The study, by consultants Capita Symonds, highlighted the logistical problems of transporting a new generation of larger and more powerful turbines to the uplands.
It said the county's narrow country roads would have difficulty coping with the trucks needed for the structures, some standing at 400ft (122m).
Bespoke lorries measuring 180ft (55m) long, 16ft (5m) wide and weighing nearly 130 tonnes, would travel through the county five days a week for five years, making more than 3,000 journeys, said the report.
The turbines are expected to arrive by ship at Ellsemere Port docks in north west England, before being taken to hills above Newtown and nearby Carno and across to the Aberystwyth area and down to the Brechfa Forest in Carmarthenshire.
They would travel the M53, A55, A483 and A458 roads, bypassing Chester and Wrexham but passing through the villages and towns of Four Crosses, Llanymynech, Welshpool and Newtown in Powys.
The report said: "The imminent development of wind farms in rural Wales will result in the largest infrastructure project ever undertaken in Wales.
'Divided public opinion'
"The delivery of components by road has the potential to cause significant disruption to residents along the routes and other road users.
"Media coverage of the planned wind farm developments is already leading to divided public opinion, which may lead to public demonstrations against the scale of planned development, and subsequent use of non-trunk road delivery routes by abnormal load vehicles."
It added that bridges, roads and retaining walls supporting some roads would all have to be assessed to see whether they could handle the heavy loads.
But the report said police forces along the route would not have the resources to escort the trucks for five years, and due to the size of the loads they would not allow haulage companies to escort their own lorries.
A Powys council spokesman said: "We are working with the assembly government and looking at ways of overcoming the serious challenges outlined in the report.
"Further discussions are due to take place."
The Welsh Assembly Government said it was "working closely with affected highway authorities, police forces and the wind energy industry to resolve the transportation issues and develop a strategic traffic management approach to the movement of these loads".
It expects 10% of electricity in Wales to come from renewable sources by 2010.
In August last year, Powys council said planning applications for wind farms had been put on hold amid concerns about the county's "inadequate" road network.