The Flynn IT specialist and public servant has designed and hand-built what is surely the ACT's hardest-accelerating electric vehicle, a sports racing motorcycle powered by an engine capable of developing 20 kilowatts and fuelled by 120 lithium ion phosphate batteries.

Mr Castley, who described the machine which took three years to design and construct as a labour of love, says it costs him about 41¢ in electricity to complete his 37km daily commute to and from the city.

''Normal bikes are quite economical, but this is an order of magnitude cheaper again,'' he said.

The bike is one of many transport devices featuring at the Electric Vehicle Festival this Saturday, an annual event on the Canberra calendar. This year it is an integral part of Spin, the Centenary of Canberra's month-long celebration of the city's love affair with everything on wheels.

Mr Castley, the treasurer of Electric Vehicles Canberra, attended the inaugural festival in 2009 and has been hooked ever since.

''I like motorbikes and I like electric vehicles,'' he said. ''This seemed a natural progression.''

The high-voltage commuter, built around the frame and superstructure of a 1985 Suzuki RG250 two-stroke racer, shares shed space with the inspired designer's weekend fun machine, a Suzuki GS 650.

''Before anybody complains that I've wrecked a classic bike [making his commuter] I need to point out that it had already donated its engine and gearbox to a go-kart project before I got hold of it,'' he said.

That left the frame, made partly from cast and partly from extruded aluminium, a clean slate for the electric project. His engine is in the usual position and most of the sophisticated electronics nestle out of sight under the dummy fuel tank. The end product is five kilograms lighter than the original piston-engined bike, and needs no gearbox. ''A petrol-engined bike delivers its maximum torque at about 9500 rpm,'' Mr Castley said. ''The electric motor produces its torque from start-up, giving a seamless power curve and smooth, constant acceleration.

''The horsepower limits the top speed to about 110km/h but the acceleration is on a par with a 200cc motorbike (which makes it quicker than most cars).''

Mr Castley, a motorcycle enthusiast from an early age, said he wanted to build an electric motorbike, not anything like a plug-in scooter or moped.

Numerous Canberra and interstate mechanical and electrical specialists helped, and he said staff at the Dickson Motor Registry had been very supportive when it came to getting the machine road-compliant.

The Canberra International Electric Vehicle Festival

Where: Garema Place.

When: Saturday, 10am to 3pm.

On the web: electricvehiclefestival.com.au