Formula E chief Alejandro Agag believes the all-electric series could be the only viable form of motorsport left by 2040, overtaking Formula One in the process.

The all-electric championship is currently in its fourth season of racing around street circuits at major world-wide city locations, and continues to go from strength to strength as electrification production increases on the road with global companies keen to embrace greener and more sustainable routes for the future.

Major car manufacturers including the likes of Renault, Audi and Jaguar Land Rover already compete in the series, while German giants Porsche and Mercedes have revealed plans to join the Formula E grid in the coming years. Formula E also boasts partnerships with global companies such as Swiss bank Julius Baer, German insurance company Allianz and Visa, while fashion brand Hugo Boss recently announced it would end its long-term F1 presence in favour of a switch to Formula E.

Mercedes motorsport boss Toto Wolff previously predicted that Formula E will emerge as a "serious motorsport player" in the near-future, and Agag insists the series will only continue to grow.

"I think Formula E is going to get really, really big. I believe that in 20, 30, 40 years, we will be the only motorsport out there," Agag told ESPN at a Formula E event in London. "There may be others but we will be probably the main motorsport because the world will be electric. If the world is not electric in 20 or 30 years, we are in trouble. So, even if that happens, then Formula E will be the championship of the cars."

Alejandro Agag (right), who has spearheaded Formula E's rise, welcomed new title sponsor ABB at an announcement in central London on Tuesday. Sam Bloxham/LAT Images/FIA Formula E via Getty Images

At the end of the inaugural Formula E campaign in 2015, former F1 team owner Sir Richard Branson -- who owns the DS Virgin squad -- said Formula E could surpass F1 as the top motorsport series by 2020.

When asked if he agreed with Branson's vision, Agag replied: "We never like to put ourselves in competition with F1. We love F1, we think F1 is great. But I never disagree with Richard Branson, he's a very clever man and he gets it right most of the time."

Agag's comments came after Formula E announced a multi-year title sponsorship partnership with Swedish-Swiss industrial technology company ABB to be renamed as the 'ABB FIA Formula E Championship' from this weekend's race in Marrakesh. The deal is understood to be worth in the region of $15 million per year to Formula E and will last until at least 2025, reflecting another huge boost for the series.

The Spanish businessman admitted he has been surprised by the vast growth rate Formula E has enjoyed since its conception in 2014, adding it has already surpassed the goals set in the initial project proposal.

"I have been surprised. We are far beyond our expectations from when we launched the project. To sign a title partnership like this, with a company like ABB, it's another huge step. We wouldn't have imagined this when we started the project, so we keep getting good surprises so I think that probably means that we are moving in the right direction."