The creator of the first ever commercial fuel pump to accept bitcoin has revealed a plan to add Lightning Network functionality to his design.

The original machine, designed and built by Andy Schroder in 2014, allows users to scan a QR code and send bitcoin instead of more traditional means of payment. Schroder now wants to adapt his design to incorporate the Lightning’s off-chain payments, he announced on the Lightning-dev mailing list yesterday.

However, Schroder pointed out some issues he has with Lightning – which he hopes will provide “real-time micropayments” – including that its invoice protocol BOLT 11 does not appear to accommodate refunds. Refunds are a necessity for the bitcoin fuel dispenser, because it runs on a fixed prepayment, and immediately returns any unused credit at the end of sale, he said.

Schroder is currently using bitcoin improvement protocol (BIP) 70, a user-friendly payment protocol that creates a receipt for the customer, as well as automatically providing a refund address to the seller.

He stated in the mailing list:

“I don’t really see an option for a refund address like is present in BIP 70. Is this intentional? If so, why do you not see that people would possibly want to receive a refund?”

He also speculated about a possible fix for this problem that would involve fitting cars with an onboard digital wallet, though he conceded this is not a short-term solution.

Fuel pump image via Andy Schroder