Suzuki has unveiled a plug-in hybrid version of the Suzuki Swift and a hydrogen-powered SX4.
The green concept cars will be the company's main attractions at the Tokyo motor show later this month.
The hybrid Swift is the closest to making it into production. It has a 660cc petrol engine and an electric motor powered by lithium-ion batteries.
On electric power alone, the car has a range of 20km (around 12.5 miles). The batteries are recharged by plugging into the domestic mains, but the petrol engine also has a generator to charge the batteries, while on the move.
The car could make it to production within a couple of years, initially for the Japanese domestic market, but Suzuki may consider selling it further afield if it proves to be successful.
The SX4 uses a hydrogen-powered fuel cell that's been developed by General Motors. The car has been on test in Japan for the past year on public roads.
Any moves to put the fuel cell vehicle in to mass production would first require the infrastructure to support hydrogen-fuelled cars.