Two billion seeds stored at Kew's Millenium Seed Bank in West Sussex are to be kept cool by solar panels.
A total of 270 panels have been installed on the roof of the facility at Wakehurst Place in Ardingly, near Haywards Heath.
Tomorrow, the longest day of the year, they are expected to produce up to 400 kWh of electricity.
More top news
Rain will arrive through the early hours for a wet start to Monday. It will eventually brighten up by the afternoon.
Rain on the way tonight, then a wet start to Monday, but it will brighten up through the day with sunny spells for the afternoon.
One of nine dogs dumped on the streets of Winchester, unable to see or stand properly, is fighting for its life.