There are already a number of independent firms that will retro-fit solar panels to the roofs of hybrid vehicles like the Toyota Prius to help extend the car’s electric-only driving range, however, from next year onwards the Prius will be available with the panels direct from the factory. The new Prius is set to be revealed at next year’s Detroit Auto Show before going on sale around April.

According to latest reports, high-end versions of the car will be fitted with solar panels to power ancillary features such as the air conditioning system. The news comes from Japan’s Nikkei economic daily, which also reported that up to 450,000 units of the new Prius will be manufactured next year.

Toyota refused to comment on the report.

Retro-fitting solar panels to the current Prius can yield fuel savings of up to 29% depending on driving style. However, the costs of installing the panels can range from anywhere between $2,000 and $4,000.

Toyota’s next-generation Prius is expected to also receive a larger and more powerful 1.6L engine and will eventually be offered with a plug-in hybrid powertrain. Despite being bigger and more powerful, fuel consumption will be improved. Toyota will do this by installing a more efficient powertrain with improved batteries for longer electric-only driving plus a lighter body thanks to extensive use of advanced composites in its construction. The lightweight construction concept was first previewed by the 1/X concept (pictured) from last year’s Tokyo Motor Show.