Revenue has opened the portal to allow businesses to lodge claims for energy bills under the extended Temporary Business Energy Support Scheme (TBESS).
It follows the enhanced scheme receiving State Aid approval from the European Commission.
Firms can now claim for bills covering the March 1st to April 30th period, while claims for the month of May will open when the required legislation is passed.
Under the changes, the scheme is being extended to May 31st, while the energy unit cost threshold required to qualify is falling from 50% to 30%.
The level of relief available is also increasing from 40% to 50% in respect of claims for the period from March to the end of May.
"The reduction in the eligibility threshold from 50% to 30% applies from 1 September 2022," said Revenue in a statement.
"Therefore, businesses who did not qualify because their unit cost threshold increased in the range of 30% - 50% are now eligible to register and submit claims."
"They will need to register and enter their reference period details for September 2021 to April 2022 before they can submit claims for scheme."
While from April 24th, Revenue will begin reassessing claims previously made by businesses that registered for the scheme but did not meet the 50% threshold for some or all of the periods.
"Those claims will be automatically recalculated on the basis of the revised 30% threshold and any payments due will be made to the businesses concerned," Revenue said.
"It will not be necessary for businesses to revise claims already submitted for these periods."
"Once claims have been reassessed the business will receive a notification to their ROS inbox confirming the reassessment has occurred, after which the payment due to the business will be processed."
The Government widened the eligibility of the scheme earlier this year after it emerged that many businesses hadn't qualified for the assistance.
As of last Friday, 27,763 firms had registered, with 34,227 claims approved worth €74.86m.
This is despite the Government having set aside €1.25bn in the Budget for the TBESS.
"I am pleased to note that the European Commission has approved the enhancements to TBESS brought forward in Finance Bill 2023," said Minister for Finance, Michael McGrath.
"These changes, in particular the lower entry threshold for the scheme, which is backdated to September 2022, will ensure that additional businesses can benefit from this vital support and I encourage businesses who have not already done so to register for and submit claims under the scheme."
