The owners of the former Aberthaw power station have been granted a High Court injunction against trespassers.
It follows a spate of online videos by 'urban explorers' who managed to enter the coal-fired plant, which was decommissioned in March 2020.
CCR Energy, which brought the site for £8 million in 2022, says the injunction covers land within the construction design and management boundary and runs until March 2027.
Demolition work is currently taking place at the former power station, which has been earmarked for a green energy hub.
But the energy firm stressed it does not affect the nearby section of the Wales Coast Path, which remains open to the public.
A CCR Energy spokesperson said: "This supports our continued commitment to ensuring the highest standards of safety and security on the site while demolition and remediation works continue."
"The injunction will help prevent unauthorised access and trespassers, safeguarding both the public and on-site workforce. Warning notices will be displayed around the boundary to make the restrictions clear."
"The injunction applies exclusively to CCR Energy owned land within the CDM boundary and does not affect the coastal path - which remains open and fully accessible to the public."
CCR Energy is a subisdary of the Cardiff Capital Region, a group of ten local councils in South East Wales, including the Vale of Glamorgan.
They plan to transform the former Aberthaw power plant, which dates back to the early 1960s, into a "cutting-edge" low carbon destination.
A spokesperson added: "Beyond energy, the vision extends to delivering economic regeneration for the region - supporting new, high-value jobs, attracting investment, and fostering a hub for sustainable technologies."
"We remain committed to transparent engagement with local communities and stakeholders throughout the entire redevelopment journey and will continue to provide timely updates as work at Aberthaw progresses."
Earlier this year, it emerged CCR had settled a legal dispute for £5.25 million after the High Court ruled a contract to demolish the power station had been awarded unfairly - with the findings of an independent review due to be published by the end of the year.
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