no need for a significant or variable-speed gearbox; turning an alternator at comparatively high speeds allows for a smaller and lighter alternator than would otherwise be the case. The superior power-to-weight ratio of the gas turbine and its fixed speed gearbox, allows for a much lighter prime mover than for the Toyota Prius (a 1.8 litre petrol engine) or the Chevrolet Volt (a 1.4 litre petrol engine). This in turn allows a heavier weight of batteries to be carried, which allows for a longer electric-only range. Alternatively, the vehicle can use heavier, cheaper lead acid batteries or safer lithium iron phosphate battery. In extended-range electric vehicles, like those planned by Land-Rover/Range-Rover in conjunction with Bladon, or by Jaguar also in partnership with Bladon, the very poor throttling response (their high moment of rotational inertia) does not matter, because the gas turbine, which may be spinning at 100,000 rpm, is not directly, mechanically connected to the wheels. It was this poor throttling response that so bedeviled the 1950 Rover gas turbine-powered prototype motor car, which did not have the advantage of an intermediate electric drive train to provide sudden power spikes when demanded by the driver. References Gas turbines