PLEA Network

29 March 2017, The Conversation, Hazelwood closure: what it means for electricity prices and blackouts. Victoria’s Hazelwood power station will be shut down this week after nearly 50 years of supplying electricity. The imminent closure has led to concerns about blackouts, raised most recently by Deputy Prime Minister Barnaby Joyce, and rising electricity prices. So what does the evidence suggest? Blackouts ahead? Last week The Age reported that Victoria is facing “72 days of possible power supply shortfalls over the next two years”. While that sounds bad, it does not mean the state is facing imminent blackouts. This was based on a report from the Australian Energy Market Operator (AEMO), which is in charge of making sure that Australia’s energy markets work. Every week, AEMO produces something called the Medium Term Projected Assessment of System Adequacy. This report assesses the expected supply and demand of electricity for the next two years. In a recent report, AEMO did indeed forecast a “reserve shortfall” for 72 days in Victoria in the coming two years. AEMO has actually been forecasting many days of reserve shortfall, since early November last year when Engie announced the closure of Hazelwood. AEMO has also been forecasting an even greater number of days of reserve shortfalls in South Australia for well over a year. The shortfall forecast is based on a combination of factors. This includes the amount of local energy supply, the import and export of electricity from other states, the maximum daily demand for electricity, and the “reserve requirement”. The reserve requirement is essentially “spare” capacity that can be used to maintain a reliable supply if something goes wrong. If there is not enough supply to meet this requirement, there is a reserve shortfall. Forecasting maximum demand is incredibly challenging and uncertain. AEMO does it by using probabilities. This gives us a measure of the probability of a particular demand forecast being exceeded in a year. For example, a 10% chance would be expected to be exceeded one year in ten. A 50% chance would be expected to be exceeded one year in two. To illustrate the point, AEMO forecast that demand over the past summer in Victoria had a 10% chance of exceeding 9,900 megawatts. In reality, the maximum demand was only 8,747MW. That’s not to say the forecast was wrong, but rather that it was not an exceptional (one year in ten) summer. Read More here