The ESB is planning to convert its Dublin headquarters into the most energy efficient office block in the State with nearly all the building’s energy needs coming from on-site renewable sources.

The seven-storey building planned for the company’s Fitzwilliam Street site in Dublin 2 will be heated and cooled by a series of ground- and air-sourced heat pumps, while an extensive rooftop garden of solar photovoltaic panels will generate much of the residual electricity requirements.

The ESB said the aim was to create a building with a near-zero energy rating, which means the total energy used by the building is roughly equal to the amount of renewable energy generated on site.

The €150 million redevelopment, which is expected to take up to two years to complete, will also deploy a rainwater harvesting system, which will reduce water consumption by up to 70 per cent.

The building is expected to use 52 per cent less carbon than a traditional office building, which the ESB said was the equivalent of planting “26 Merrion Squares in trees”.

Exemplar

The company wants the new development to be “an exemplar in sustainability” while sensitively respecting and enhancing the surrounding Georgian streetscape.

The new development will double existing capacity with 50 per cent occupied by the ESB and the balance, capable of accommodating an additional 1,400 workers, available for letting.

The original ESB headquarters, designed in the 1960s by architects Sam Stephenson and Arthur Gibney, was mired in controversy after 16 Georgian houses were demolished to make way for the building, a move that effectively dismantled the longest unbroken stretch of Georgian housing in Europe.

The plan for the new headquarters got the green light from An Bord Pleanála in 2015 despite appeals to the board that the 1960s building should be preserved as a unique example of 20th century architecture.

The plan involves the demolition of the existing building, the retention and refurbishment of a number of protected Georgian structures and the construction of a new seven-storey office block designed by Grafton Architects and O’Mahony Pike.

The development will cover an area of 45,000sq m, including 36,917sq m of office space. Some 440 bicycles will be accommodated, along with 110 car-parking spaces.

An ESB spokesman said the project was progressing well, with demolition almost complete and construction works due to be completed in 2019.

While construction is under way, the ESB has temporarily moved its headquarters to Two Gateway and Three Gateway on East Wall Road in Dublin 3.