Solar panels could be added to Edinburgh Castle after Scotland’s heritage group found the historic structure was causing as much pollution as 348 homes.
The carbon footprints of five Edinburgh historic sites were revealed by Historic Environment Scotland in an attempt to track their impact on the environment and how changes to the environment affect them.
Edinburgh Castle was found to use an “incredible” amount of energy, amounting to as much carbon as nearly 350 UK homes generate per year - or approximately 1,155 tonnes of carbon dioxide emissions.
Plans have now been unveiled to place solar panels on the roof of the castle, which is home to the Scottish National War Memorial building.
Historic Environment Scotland, which manages the maintenance of property, has submitted a planning application to City of Edinburgh Council.
This comes despite a 30 per cent decline in the castle's total energy since 2008/09, along with a 40 per cent reduction in its emissions, with new boilers and sheepskin insulation introduced to better control loss of heat.
The new plans involve the installation of solar panels on the roof of the memorial building and cabling, which will run from the roof into the Palace Block, to help power the castle complex.
However, the council's planning department has expressed concern that the panels could affect the city's iconic skyline and pave the way for similar projects on other historic buildings.
Historic Environment Scotland has acknowledged the plans could be viewed as "contentious", given the castle's status as the country's "most significant Scottish royal castle".
Despite this, they said that the benefits outweigh any concerns and that the panels will only be visible from the air.
In a design statement submitted to the local authority, Historic Environment Scotland said: "Such an extensive intervention could be viewed as contentious given the role of the building as a place of national memorial.
"However, the design is sufficiently sensitive and unobtrusive so as not to be visible to visitors to the memorial and it will not detract from the sense of place."
In pre-application feedback given to Historic Environment Scotland, the local authority said: "The iconic and the roofscape of the city centre of Edinburgh is frequently viewed and photographed from the air and is defined as the 'fifth elevation'."
It added that there is "concern that allowing this form of proposal on the castle would (in effect) weaken our position with regard to similar proposals for our heritage assets within the city".
Members of the public have until December 3 to comment on the proposals before the council makes a decision.
The Scottish National War Memorial was built between 1924 and 1927, designed as the nation’s tribute to all those who sacrificed their lives during the First World War.
The new Climate Change Explorer app, launched by Historic Environment Scotland, also includes carbon mitigation methods for the historic sites Charlotte Square, Scott Monument, General Register House and Calton Hill.