* To start consultations in 2016

* Coal provided a third of UK electricity in 2014

* Gas plants and nuclear must be built -minister (Updates with speech details, Drax shares)

LONDON, Nov 18 (Reuters) - Britain aims to close its coal-fired power plants by 2025 under plans announced on Wednesday, becoming the first major economy to put a date on shutting coal plants to curb carbon emissions.

Instead, the country will look to nuclear and natural gas-fired power plants to complement intermittent renewable energy, Secretary of State for Energy and Climate Change Amber Rudd said.

“It cannot be satisfactory for an advanced economy like the UK to be relying on polluting, carbon-intensive 50-year-old coal-fired power stations,” she said at the Institution of Civil Engineers.

Around a third of Britain’s electricity came from coal-fired plants last year but many of the 12 still operating are old and due to close over the next decade under tightening European Union environmental standards.

Rudd said the government would begin a consultation next spring setting out proposals to close by 2025 all coal-fired power stations which are “unabated” - plants not equipped to capture and store their carbon emissions - and restrict their usage from 2023.

British power producer Drax announced in September it would halt investment in the country’s only coal power station carbon capture and storage (CCS) project when it is completed.

A spokesman for the Department of Energy and Climate Change said details would need to be ironed out after consultation with industry.

Drax Group, operator of one of Europe’s largest coal and biomass-fired power plants, could see the remaining coal units close two years earlier if the government sticks to the 2025 closure date, analysts at Jefferies said.

Shares in Drax, down by almost two-thirds in the past year, were down 4.6 percent at 216 pence by 1236 GMT.

German utility E.ON operates a 2 gigawatt (GW) coal-fired plant in Nottinghamshire, England, which is fitted with pollution-reducing technology that means it could still be running in 2025 under current legislation.

“We firmly believe that coal-fired power stations which meet rightly rigorous UK and European standards should remain an important part of the UK’s energy mix,” a spokesman for E.ON UK said.

Rudd said the government is committed to meeting a legally binding target to cut carbon dioxide emissions by 2050 to 80 percent below 1990 levels.

“One of the greatest and most cost-effective contributions we can make to emission reductions in electricity is by replacing coal-fired power stations with gas,” Rudd said.

Gas plants emit almost half the amount of carbon dioxide per megawatt of power generated as coal plants.

The move away from coal was welcomed by climate change campaigners seeking a reduction in carbon emissions blamed for global warming.

“The UK is demonstrating the type of leadership that nations around the world must take in order to craft a successful agreement in Paris and solve the climate crisis,” said former U.S. vice president and climate change campaigner Al Gore.

This month, world leaders will gather in Paris for U.N. negotiations to seek an accord to curb greenhouse gas emissions.

However, some campaigners criticised the new emphasis on burning gas instead.

“Phasing out coal is essential for the climate. But switching from coal to gas is like an alcoholic switching from two bottles of whisky a day to two bottles of port,” said Simon Bullock of the environmental group Friends of the Earth.

The government on Wednesday committed to hold three more auctions offering support for renewable power generation but did not set out how much funding would be available. (Additional reporting by Nerijus Adomaitis in Oslo and Karolin Schaps in London; editing by Greg Mahlich and Jason Neely)