Electric heavy-duty truck developer Nikola Motor has announced that it's refunding 9000 deposits so far paid for its highway tractor units.

Nikola CEO and founder Trevor Milton says that the move is in response to "a lot of people" asking if Nikola was using the deposit money to fund its operations.

The company announced its move on its Facebook page, with the message: "Great news! All reservations will be refunded 100% and you won't lose your place in line. We don't use your money to operate our business. We want everyone to know we have never used a dollar of deposit money to operate the company on – like other companies do."

The last bit is clearly a shot at Tesla, which is taking $US20,000 reservations for its electric tractor unit.

Nikola says that orders from here on require no deposits and those already paid – an estimated $US13.5million worth – will be refunded within two months, says Nikola: "How awesome is that!!!!!! Over 8 billion in pre-orders, so who needs deposits."

The Nikola One and Two tractor units will reportedly use electric motors powered by 320 kWh battery packs…..which in turn will be replenished via a hydrogen fuel cell system, which Bosch is designing.

When the etruck was launched two years ago Nikola said it had 7000 orders (which until now required a $US1500 deposit), for $US2.3billion worth of trucks. The announcement of the refunds now claims that it has $US8bn worth of trucks ordered.

Nikola says it's building a $US1bn R&D centre in Arizona and will be in production with its etrucks in 2021.