The King continues to put the environment and sustainability at the heart of his reign, as his vehicle fleet shifts towards becoming fully electric and the first royal residence has installed solar panels, annual accounts have revealed.

His two State Bentleys are due to undergo refurbishment this year to enable them to run on biofuel, meaning they’ll produce fewer emissions.

This will be an interim measure before transitioning to a fully electric motor vehicle fleet.

Gas lanterns at Buckingham Palace, which were switched off during the recent energy crisis as a cost-saving measure, are being repurposed with specially-designed electrical fittings to improve their energy efficiency while preserving their historic look and glow.

Other measures as part of the Palace’s roadmap to Net Zero include installing solar panels on the roof of Windsor Castle.

“Out went the leaking roof and in came the Castle’s first solar panels”, said Sir Michael Stevens, Keeper of the Privy Purse, as he revealed the Palace’s accounts covering the first full financial year of the King’s reign.

The installation of heat pumps at Windsor is also on the cards.

Proactive work has also been taken to improve the efficiency of royal flights, with the acquisition of two AW139 helicopters which can operate with 50 percent Sustainable Aviation Fuel (SAF).

To support this, a temporary SAF tank has been installed at RAF Odiham.

But despite Sir Michael highlighting the Palace’s “determination to place sustainability at the heart of our operations… inspired by His Majesty’s leadership in this sphere” the total greenhouse gas emissions increased by four percent due to an increase in travel and electricity use.

But natural gas and heating emissions dropped three percent after last year’s drive to increase efficiency.

The financial report, published today, also revealed that the monarchy will receive a boost of more than £45million, after huge yields from offshore wind farms result in record earnings for the Crown Estate.

Soaring profits from the Crown Estate to £1.1 billion means the taxpayer-funded Sovereign Grant, which supports the official duties of the royal family, will increase from £86.3 million in 2024/2025 to £132 million in 2025/2026.

Officials said the boost in funding will help fund the final two years of the £369million renovation of Buckingham Palace, ensuring it stays on time and budget.

The increase will be reviewed through legislation in 2026/27 to keep funding of the royal family at a “more appropriate” level, a Palace spokesman said.

The Sovereign Grant is funded by the taxpayer in exchange for the King’s surrender of the revenue from the Crown Estate.

The rundown of royal finances – from April 1 2023 to March 31 2024 – covers the months following the King and the Princess of Wales’s double cancer diagnosis, with both away from public-facing duties from January onwards.

As a result, the number of engagements dropped, with 2,327 undertaken this year, down from 2,710 last year

The King undertook 464 official engagements despite his cancer diagnosis and ongoing treatment, with the Queen carrying out 201, of which 103 were joint engagements.

Sir Michael added: “Behind the scenes, the work of the Royal Household continued apace, even throughout the latter course of the financial year, with His Majesty still performing his full state duties, Her Majesty taking on a greater share of public engagements, and their support teams adapting swiftly to the changing circumstances.”

The King and Kate received some 27,000 messages from well-wishers.

Official travel costs for the monarchy rose marginally by £0.3 million from £3.9 million to £4.2 million.

The most expensive travel was the King and Queen’s visit to Kenya by charter flight in October, along with the related separate staff planning visit by scheduled flights, which came to a total of £166,557.

Housekeeping and hospitality came in at £2.6 million, up from £2.4 million last year.

But overall expenditure fell by 17 percent or £18.4 million from £107.5 million in 2022/23 to £89.1 million, with the drop due to an anticipated decrease in expenditure on the Palace renovation programme.

The report also showed £600,000 from the Sovereign Grant was spent on the coronation and events surrounding it last year, with the total cost to the Sovereign Grant overall coming to £800,000.

The figure covered internal costs such as staffing, Palace receptions, plus any furnishings or costumes which be reused later on, including the readjusting of the Imperial State Crown and the King and Queen’s coronation robes.

In separate accounts, the Duchy of Cornwall reported profits of £23.6million, down from £24million the previous year.

The money is spent on the cost of the official, charitable, and private lives of the Prince and Princess of Wales and their children.

William pays tax on the profits after official costs have been deducted.

It comes as Kensington Palace announced the heir is taking on several new patronages, including becoming Patron of the Welsh Guards Charity and moving from President to Patron of the Football Association and Fields in Trust.

The Duchy of Cornwall also revealed that Will Bax will take over from Alastair Martin as Secretary and Keeper of the Records when he steps down from the role in Autumn 2024.