Western Power faces a payout bill that could run into tens of millions of dollars after a record number of customers were left without power for extended periods in the wake of Sunday's storm.
As WA's peak business group warned about the effects of blackouts on its members, Western Power said it would be liable for thousands of claims through its extended outage payment scheme.
Under the scheme, any Western Power customer whose electricity has been out for more than 12 hours is eligible for an $80 payment.
About 100,000 households and businesses were without power for 12 hours or more after the storm struck, meaning the utility could have to fork out more than $8 million in extended outage payments.
The State-owned utility could also be subject to a series of costly compensation claims by businesses seeking to recover losses or damages caused by a long blackout.
Western Power is bracing for a big bill to repair its network after saying damage caused by the storm was the worst in WA's history.
Donna Anderson, who owns a Lenard's chicken franchise in Baldivis, said the blackout would cost her business up to $17,000 in lost stock and sales.
Like many small businesses in her position, Ms Anderson said she would seek compensation from Western Power for the losses.
Having gone through a similar experience three years ago, she held out little hope of a quick and adequate outcome.
"The heart-wrenching part of all this, is there's nothing you can do about it," Ms Anderson said.
A Western Power spokeswoman said it was too early to say how many customers would be eligible for extended outage payments.
She said the final figure would be hard to calculate because the number of customers whose power was affected fluctuated wildly in the hours after the storm.
She also said that although Western Power would consider compensation claims, people should contact their insurers first.
WA Chamber of Commerce and Industry chief executive James Pearson said many businesses would have suffered "significant disruption and costs".
Emergency Services Minister Troy Buswell said the scale of the damage was testing Western Power's ability to restore supplies.