DEVA, Romania (Reuters) - “I pollute to death,” said the message projected by Greenpeace activists onto the Mintia coal-fired power plant in central Romania late on Thursday.

Slideshow ( 3 images )

More than half of Romania’s 28 coal-fired plants, including Mintia, are operating without environmental permits or lacked upgrades that would make them less polluting, according to a Greenpeace report released earlier in the day.

Aging coal-fired plants produce more than a third of the European Union state’s electricity and the energy ministry says they will continue to do so for some time because clean energy takes time to develop.

The European Commission imposed stricter limits on emissions this year, giving power stations and district heating plants until 2021 to comply. It said pollution was the EU’s biggest environmental cause of premature deaths, responsible for roughly 400,000 per year.

“The government should refocus towards investing in renewable energy, which is the investment of the future and which certainly doesn’t damage our health and the environment,” said Greenpeace Romania director Patricia Puschila.

Investment needs need to be reassessed in the light of the new EU rules, deputy energy minister Doru Visan told Reuters.

“For those coal-fired power plants that do not conform to environmental and energy efficiency requirements the result can be only one: either they conform or they shut down,” Visan said.

Romania uses a mix of coal, gas, hydro, nuclear and renewable energy. It has both hard coal and lignite.

Visan said maintenance and upgrade works were under way at several coal-fired units. The ministry planned to fully retrofit a unit at its Rovinari power plant by 2020 and was also in talks with a Chinese company to jointly build a new plant.

“The thermal energy sector must be understood as belonging to a market where there already are strong competitors,” said Ana Otilia Nutu, an energy and infrastructure expert from Romanian think tank Expert Forum.

“It will need to somehow keep up with technology advances made in the rest of the European Union.”