General Motors on Monday said it would invest US$336m in its Detroit-Hamtramck assembly plant to begin production of the Chevrolet Volt electric car, with extended-range capabilities, in 2010. The plant initially will also build Opel/Vauxhall Ampera variants for Europe although production of those is expected eventually to shift across the Atlantic, possibly to the Vauxhall plant in Ellesmere Port, north west England, though a final decision has not been made.