The inquiry, which is expected to last at least six days, was prompted after Scottish Power Renewables appealed against the former Carrick District Council's decision to reject the plans, days before the council was disbanded to make way for the unitary authority.
Energy giant Scottish Power wants to replace its 15 turbines at Carland Cross, between Truro and Newquay, with 10 new ones that, at 100m from base to blade tip, are double the height of existing machinery.
But concerns have been raised locally over the effect on the character and appearance of the landscape, and the implications on living conditions of residents due to possible noise and visual intrusion.
Such is the strength of feeling surrounding the issue, Cornwall Council decided on a last-minute change of venue for the inquiry, to cater for the number of members of the public who wished to attend.
The new venue, at Hendra Holiday Park in Newquay, was described by planning inspector David Lavender as "better suited to disco dancing than a planning inquiry", after complaints from the 30-40 members of the public that they were unable to hear due to echo and microphone feedback in the room, which had a disco ball suspended above Mr Lavender's head.
After a short delay, Scottish Power launched into their opening statement, outlining how the 10 new turbines would be split between the existing land at Carland Cross and on additional land at nearby Newlyn Downs.
John Houghton, Scottish Power's legal representative, said how the new turbines would have a generating capacity of 20MW, more than three times the current capacity.
He said: "A repowering of an existing location not only has the advantage of making use of a site already characterised by wind farm development, but also the enhanced [wattage] capacity can be achieved relatively quickly. In our submission, the need for this project decisively outweighs any landscape visual or residential amenity impacts which the project may have."
Barrister Graeme Keen, on behalf of Cornwall Council, said there was "a considerable amount of common ground" between the main parties involved. But he said the turbines would have "significant adverse impacts" on the landscape character and residential property in Fiddlers Green, St Newlyn East and other areas.
Mr Keen said: "The significant adverse impacts substantially outweigh the benefits associated with the production of energy from the proposed renewable source."