A collapse in the spot price for electricity in Queensland on Wednesday morning to as low as minus $1000 a megawatt-hour has rattled the industry and raised questions as to who will bear the losses triggered by a flood of solar generation from rooftop panels and large-scale farms.

The wholesale price slumped to the market floor for several five-minute periods on Wednesday morning on an unseasonably hot early spring day when an outage on a transmission line prevented surplus electricity being exported south to NSW.