System strength issues take toll on renewable plants in Queensland, NSW and Victoria

Constraints imposed on large scale renewable energy plants are taking an increasing toll on wind and solar farms in three states, with nearly affected facilities in north Queensland suffering cut-backs around one quarter of the time.

The Australian Energy Market Operator has imposed restrictions and constraints on a range of solar and wind farms along the eastern seaboard because of what it has identified as “system strength” issues.

Four out of the five solar farms operating in Victoria, plus the Broken Hill solar farm in NSW, have had their output cut in half since September, and hope to have at least some of their capacity restored if tests on new inverter “firmware” being conducted this week prove successful.

The latest facilities to be affected are two solar farms – Sun Metals and Haughton – and the Mt Emerald wind farm in norther Queensland, due to newly identified system strength issues. Like those solar farms in Victoria and NSW, the constraints have been imposed despite the facilities operating in some cases for more than two years.

The latest Quarterly Energy Dynamics report released by AEMO shows that the constraints in north Queensland were imposed 25 per cent of the time since being imposed in mid March. (The three wind farms are largely dependent on two local hydro plants operating to avoid constraints, and can be dialled back to zero in some circumstances).

Output at the Haughton solar farm  was cut by around 18 per cent over those two week because of the curtailment – see graph above – and Mt Emerald by 7 per cent. A figure for Sun Metals was not provided, but that solar farm is having unrelated “performance issues” which have reduced its output to less than half of its capacity.

Across the grid in the first quarter, curtailment of wind and solar reached 7 per cent of total output – their highest on record (in green in graph below).

Most of this was because of the separation event that forced South Australia to operate as an energy island – and six wind farms were curtailed to zero because they either had no transmission lines (blown down by a storm) or due to system security issues).