King Charles’s property management company has made more than £1bn for the third consecutive year thanks to the boom in offshore windfarms paid for through energy bills.

The crown estate, the royals’ portfolio of land and property, reported £1.2bn in profit for the last financial year, almost three times the amount it made three years ago. Two-thirds came from the offshore wind industry.

Wind developers paid £875m in option fees last year to secure areas of the seabed from the crown estate, which is considered the legal owner of the ocean floor around England, Wales and Northern Ireland.

The windfall marks the third year in which the property manager – which partly funds the monarchy – was able to capitalise on Britain’s booming offshore wind industry after introducing an auction for windfarm developers hoping to lay claim to a seabed lease.

The income from the wind industry fell by £198m from the year before as two offshore windfarms began construction, allowing the developers to pay a lower rate to the crown estate. Once the windfarms begin generating low-carbon electricity the developers will be required to pay the crown estate 2% of the revenue they collect from energy bills.

Investor appetite for UK offshore windfarms, which earn guaranteed rates from energy consumers, has helped transformed the financial fate of the crown estate, which also includes a portfolio of London properties and rural real estate.

A portion of the crown estate’s earnings are returned to the Treasury, which uses the funds for public spending and also pays a percentage to the monarch. The property manager returned £487m to the Treasury in the last financial year, of which £132.1m was paid to the king to support the official duties of the royal family, up from £86.3m the year before.

The crown estate also plans to increase the annual pay packet of its chief executive, Dan Labbad, by almost 20%, the fourth consecutive hike. Labbad will take home almost £2.33m for the last financial year, up from almost £1.95m the year before, and more than four times the £517,000 he received in 2019 when he stepped into the role.

He expects the crown estate’s profits to normalise in the years ahead as more windfarm developers move forward with construction and become eligible to pay a lower rate to the property company.

The prospect of a government led by Reform UK, which has vowed to end subsidies for renewable energy, would not end the wind industry’s growth or income for the crown estate, Labbad said. “We will course correct as we need to, moving forward.”

This could include working with industry players to help set up direct energy supply deals between developers and buyers to provide a similar guarantee of future earnings to support investment. “We’ve seen some pretty big shocks to this industry over the years, [but] there are other things you can do,” Labbad added.

He said the windfall profits from the current leases were the result of a very competitive first auction in 2022, which helped the crown estate earn a return on “investing with the government for 20 years in getting the offshore wind sector in this country to scale”.

“What we’re effectively doing is leasing a very scarce resource to market, and in this case the taxpayer benefited,” Labbad said.