FINGERS CROSSED: Victorians are being warned to brace for possible extended power outages over the approaching summer period as sources of base-load power become stretched during peak periods.
By JOHN DOOLEY
MORE than one million Victorian households are at risk of being without power this summer during extreme heat events if full capacity is not restored to all coal and gas plants operating in the State, a recent report has revealed.
The report, penned by the Australian Energy Market Operator (AEMO), also stated that more than 375,000 households were without power for an hour in Victoria and South Australia in January this year due to extreme temperatures – exacerbated by several coal units in the Latrobe Valley not being in operation.
The closure of the Hazelwood power station some years ago saw a major depletion of the State’s power-generating capacity – a large source of dispatchable energy.
It’s been reported that this summer Victoria is at the highest risk of blackouts, particularly if two power stations, AGL’s Loy Yang A2 in Gippsland and Origin’s gas plant in Mortlake, which have been out of service due to maintenance issues, are not back online in time for the summer peak.
AEMO’s report warned that “If both power station outages were extended over the summer, and if no additional supply was secured, involuntary load-shedding may be experienced in Victoria during extreme weather events, potentially over multiple-events, equivalent to between 260,000 and 1.3 million households being without power for four hours”.
AEMO chief executive, Audrey Zibelman, said the continued reliance on back-up generation from other States was unsustainable.
“We are finding this type of reactive action is imposing higher costs on consumers and risks to reliability which are not sustainable over the longer term,” she said. “Longer term, NSW’s energy reliability will decrease as Liddell (NSW coal-fired power station) gradually closes, if no alternative is built in the interim.”
AEMO said Australia needs targeted investment in dispatchable power (coal, gas, battery and pumped hydro) to meet the expected shortfall during peak demand as older coal plants, such as Liddell, close in the coming decade.
Adding to concerns, Energy Australia has warned the Andrews Government of “dire consequences” in pursuing Victoria’s proposed 50 percent renewable energy target, calling their actions “a reckless drive towards renewable energy”.
The energy company has told the Government that this course of action will “put more coal-fired power stations out of business”.
They believe this will also result in power prices climbing, and will “expose Victoria to worsening and more frequent blackouts”.
Solar and wind power are seen as the renewable energy sources to fill the gap in the energy generation sector. However, it was reported in ‘The Australian’ newspaper recently that output from five solar farms in Victoria and NSW have been ‘sliced’ in half by the market operator, citing concerns over voltage issues potentially hitting the power grid.
What that means is that the current poles and wires are unable to handle the increased fluctuations in the energy that is attempting to be fed into the State’s power grid.
Victorian solar farms affected are at Bannerton, Karadoc, Wemen and Gannawarra near Kerang.
New generation standards and system strength requirements have been put in place to ensure solar and wind maintain grid stability.
AEMO said that until these fluctuations are resolved, they will need to restrain the affected generators to maintain system security.
The regulator said that urgent transmission investment in western Victoria was needed to cope with a surge in ‘clean energy’ supplies which could potentially see a long-term price increase for consumers.
BayWa r.e. Global Director Solar Projects, Dr Benedikt Ortmann, whose company operates the solar farm at Karadoc, said that AEMO’s latest modelling of their grid in North Western Victoria and South Western NSW indicates there may be some issues with stability under very specific, but rare, events.
“As a consequence, the generators in the region have been temporary restricted until the modelled issues have been solved. We expect this process to be completed by the end of the year,” Dr Ortmann said.
“As a matter of fact, photovoltaic solar farms can add very valuable ancillary services to assist with grid stability and quality, simply by programming the inverters in a certain way.
“Fortunately, all solar generators in the affected area are equipped with SMA inverters which will streamline AEMO’s process.
“SMA is currently working very closely with AEMO to adjust the parameters of the inverters to assist AEMO model an improved scenario.”
The BayWa r.e. Karadoc farm has more that 330,000 individual solar panels, which at their peak are rated to produce 112 megawatts (MW) of power.
As wonderful as solar power sounds, surprisingly solar panels perform worse as the temperature rises! On days of extreme heat, their efficiency output falls off quite dramatically.
In fact, when the temperature climbs above 25ºC, the output begins to reduce, and on days when the mercury breaks 40ºC, the efficiency reduces by more that 20 percent.
Heat is a challenge
Solar panels work by using incoming photons to excite electrons in a semiconductor to a higher energy level. But the hotter the panel is, the greater the number of electrons that are already in the excited state.
This reduces the voltage that the panel can generate and lowers its efficiency. The other issue that will be faced one day is the replacement of the panels and the disposal of the redundant ones.
Dr Benedikt said that his company has made provision for this eventuality.
“Photovoltaic cells are not physically, chemically or mechanically changed by the sun. The photovoltaic effect simply enriches the electrons within the cell with energy and makes them assemble at the sunny side of the cell,” Dr Ortmann said.
“They flow back to the backside of the cell after they have been used for electrical power. So you can say a solar cell is not more burdened by the electricity than any other electrical cable.
“This leads to the assumption that the lifetime of photovoltaic installations are far longer than 20 years. Panels which get destroyed by hail or accidents are fully recycled, as they contain mainly glass, aluminium and silicon.”