Nottinghamshire Police say a protest by 15 campaigners, staged inside two chimneys at West Burton power station near Retford, is costing £20,000 a day to police.
The campaigners say they plan to camp inside the chimneys for a full week and this morning have taken to flying kites and tweeting pictures.
More top news
Passengers have been warned to expect disruption on East Midlands Trains this weekend because of work on the main line into St Pancras.
A cold and mostly dry day, with wintry showers becoming more confined to coasts. Brisk winds, especially near coasts.
A mostly dry day with sunny spells. Wintry showers from late afternoon in the west and north, perhaps falling as snow to lower levels.