Consisting of 76 wind turbines, the 299MW facility will be located between Neath and Aberdare, and is expected to generate enough power for up to 206,000 homes a year.
"Onshore wind plays an important role in enhancing our energy security," said Hendry. "It is the cheapest form of renewable energy and reduces our reliance on foreign fuel. This project in South Wales will generate vast amounts of home-grown renewable electricity and provide a significant benefits package for the local community."
Swedish energy giant Vattenfall said the project would require a capital investment of about £300m and could create more than 300 jobs while pumping up to £1bn into the Welsh economy during the three-year construction period and anticipated 25 years of operation.
The company said it will review the letter of consent from the secretary of state in detail before committing to a forward programme for the proposal. However, a final decision is expected in the near future, with the firm signalling it could begin construction work from next year, with the first energy from the site coming online from 2016.
Both the Department of Energy and Climate Change and Vattenfall stressed that a number of steps were taken to minimise the impact of the project on the environment and secure local community support for the facility.
Vattenfall has pledged to deliver a "community benefits package" that could be worth more than £55m over the lifetime of the development, including £3m for habitat management and £6,000 a year per megawatt that will be paid in to a community trust fund.
Moreover, neither of the affected local authorities objected to the wind farm, while concerns about the impact on local mining activity have been addressed in the planning consent, which requires the developer to take steps to ensure future coal extraction from beneath the site can be undertaken.
"This project shows what onshore wind energy investments can offer Wales over the short and long term," said Piers Guy, Vattenfall’s head of Onshore Wind Development in the UK.
"Through this project we will be supporting the delivery of national and local priorities – from creating local jobs, supply chain opportunities and apprenticeship schemes, to supporting tourism initiatives, community services and facilities. Our 25-year investment makes us one of the most significant wind energy investors in the country."
The move will be welcomed by the wind energy industry, which yesterday released a report demonstrating how onshore wind farms were worth £548m to the UK economy last year.
However, the consent is also likely to further fuel the on-going row over the government’s wind energy strategy, which in recent months has seen more than 100 backbench Conservative MPs write to the prime minister calling for a significant watering down of support for wind energy.
Last month also saw the launch of a new campaign group opposed to all new wind farm developments, while there have been calls from a number of right wing think tanks for the government to reduce the level of subsidy available to renewable energy developers through imminent electricity market reforms that are expected to be included in tomorrow’s Queen’s Speech.
As with a number of other wind energy firms, Vattenfall’s final decision on whether to move forward with its investment is likely to be determined on the government’s ability to confirm in the next few months that it will move forward with anticipated changes to the Renewables Obligation subsidy scheme and its electricity market reform programme in a way that makes wind farm projects financially viable.