Formula E has not had an easy time winning over its sceptics since the all-electric championship was launched four years ago.

This is due in no small part to the gulf in performance between Formula E’s relatively immature electric technology and Formula 1’s vastly quicker cars.

“They are two completely different categories” FIA president Jean Todt stressed earlier this year. “Formula E has not the performance of Formula 1 at the moment.”

That much is clear. But there is one crucial respect in which even Formula E’s staunchest detractors must give it credit. And it explains why manufacturers like Mercedes and Porsche are queuing up to join in.

Most branches of motorsport have closed off avenues for development. Junior championships are almost exclusively single-make series. IndyCar has a spec aero kit and tightly-defined engine rules.

In GT racing, Balance of Performance regulations ensure no one can innovate their way to an advantage. And some series which do encourage competitive car development have suffered because of it: Look at the state of the World Endurance Championship’s LMP1 category, reduced to a single, dominant manufacturer.

But Formula E, like Formula 1, is intended to push car development forward. And, arguably, it fulfils this at least as well as F1 does.

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While F1 teams pour huge sums into aerodynamic developments which are of little benefit to real-world motoring, Formula E’s spec chassis means the development budget goes on the power train.

F1 has boxed itself into a set of regulations which allow only a certain configuration of V6 turbo with hybrid energy recovery systems, and found no new manufacturers are interested in joining in the near future. Formula E has gradually opened up its power train regulations and this seems to be part of its appeal to manufacturers.

So what has Formula E achieved in this time? Have Renault, Audi and the rest pushed forward the development of battery technology? Have lap times tumbled over the first four years?

Measuring this is not entirely straightforward. While F1 tracks tend to change only occasionally, Formula E has moved between many different venues during its first four years. And the configuration of some tracks have changed too.

So much so there is no single unchanged track the championship has raced on in all four seasons. Here’s how its lap times compared at those tracks which have remained the same for two or three different seasons:

For its first season, Formula E used a fixed-specification powertrain supplied by Spark. From the 2015-16 championship manufacturers were allowed to develop their own parts including the EMotor, differential and gearbox, though not the traction battery.

They responded with a range of solutions. This differentiation has been credited with creating better racing and more variety between winners than in F1, where only three teams have won races in the last five seasons.

The development also led to a substantial drop in lap times between the first two seasons, when lap times improved by around 1.4%. This may not seem like much compared to F1, but keep in mind there is no aerodynamic development in Formula E.

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This is not to say that the progress made in Formula E has entirely been down to powertrain development. Michelin has reduced the weight of its tyres, as motorsport director Pascal Couasnon told RaceFans: “To give more weight to put batteries [in] we – in two generations of tyres – decreased the weight of the tyre by 10 kilos over the set.”

Formula E’s rate of development slowed in its second season but in its most recent championship the lap times dropped by almost 1% year-on-year. The net effect is by the end of their life the first generation cars were around 2.6% quicker than at launch. James Rossiter, who sampled a show car when the championship launched and Venturi’s car last season, said the latter “feels totally different.”

Differences in tyre development mean only the broadest possible comparisons can be made with F1. However consider that in 2015, the second year of its V6 hybrid turbo regulations, F1 lap times fell by around 1.3%, and another 2.5% the following year (when softer compounds were used at several tracks).

But Formula E’s biggest step forward is yet to come. The new season begins in exactly two months’ time and tomorrow the teams begin testing the championship’s second-generation chassis.

Significant gains in efficiency, range and outright performance are expected. Peak power output in qualifying trim will increase by 25% to 250kW. This may prove not merely a step forward for electric racing, but a leap.

Quotes: Dieter Rencken and Hazel Southwell

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Formula E