Takeover combines electricity generators to become largest independent US power provider, with 2.5 million customers

The US nuclear power giant Constellation Energy has agreed to buy natural gas and geothermal firm Calpine Corporation for $16.4bn, one of the biggest takeovers in the US power industry.

The acquisition would combine two of the biggest electricity generators in the US into the largest independent power provider in the country, with some 2.5 million customers.