In another apparent blow to the solar industry, Queensland regional electricity utility Ergon Energy has effectively imposed a 3.5kW limit on rooftop solar system, making it more difficult and potentially more costly for households and businesses to install rooftop solar.

The new limit – down from 5kW previously – is the level at which Ergon will demand a “network assessment”, and it could include limits on how much, if any, solar can be exported back into the grid.

The limit applies to grid-linked inverter systems and is expressed in kVa – which roughly translates into the size of the solar system in kilowatts.

The restrictions in remote areas will be even more severe. Technical assessments will be required for any inverter system above 2kVa on so-called SWER networks – the single line networks that operate in remote areas – and any system above zero kVa in isolated grids.

The solar industry says the decision means that it will become more costly to install solar on households, and comes after a change in tariffs that hikes fixed rates, lowers volume charges, and makes it less attractive to install solar in Queensland.

Businesses will also be affected, with any solar 3-phase inverter above 10kVa on the main network requiring an assessment. The assessments do not apply if the system does not intend to export to the grid.

Ergon says the new thresholds are forecast to “quadruple” the current volume of assessments. It says it will allocate more assessors, but there could be delays in July and August.

Ergon Energy has also flagged in the past that assessment fees will be introduced as part of the move to the new regulatory period. “While we do not plan to introduce fees at this time, should this change, we will communicate the new fee structure to you prior to its introduction.”