Optimal Energy Joule
A South African team imagined an electric family car before most big carmakers had one on sale.
2008 Optimal Energy Joule concept · Rutger van der Maar · CC BY 2.0
Research pending
A matching completed auction sale has not been verified for this exact year, body, trim, engine, transmission and market.
Joyride shows this gap instead of substituting an asking price, unsold bid or mismatched special vehicle.
More than a set of wheels.
Cape Town startup Optimal Energy unveiled the Joule at the 2008 Paris motor show. The first show concept was described as a six-seater with flexible motor and battery choices. Engineers later built four roadworthy, five-seat prototypes and tested them, but the funding needed for mass production never arrived. The Joule remained a prototype, not a car customers could buy.
Look a little closer.
Joule is also the scientific unit of energy, making it a very fitting name for an electric car.
Photos show an example of the model or generation. The pictured vehicle’s year, equipment, or modifications can differ from the specification described here.
A show promise is not a production specification
In Paris, Optimal Energy discussed one or two removable battery packs and front-, rear- or all-wheel-drive possibilities. Those were concept plans. By 2010 the roadworthy development cars were five-seaters with a 36 kWh pack and a 75 kW peak motor, so this page does not quietly paste those later numbers onto the 2008 show car.
Source: Gerhard Swart · Innovation lessons learned from the Joule EV Development ↗Building prototypes was only the middle
The former chief technical officer records four roadworthy prototypes and more than 38,000 test kilometres. The team still needed final design, suppliers, a factory, sales and service systems. When industrial funding did not materialise, Optimal Energy closed in June 2012 before those last steps.
Source: Gerhard Swart · Innovation lessons learned from the Joule EV Development ↗Where these facts come from
- Gerhard Swart · Innovation lessons learned from the Joule EV Development
- Wired · South African Electric Car the Crown Joule of Paris Auto Show
Selected facts checked for this edition. Some source pages link to broader model families. Last reviewed September 30, 2026.