An intense heatwave across Queensland in the early part of February 2018 saw temperatures soar to nine degrees above average in some parts of the State. This ‘heat event’ highlighted how our modern energy system is inextricably linked to the weather now more than ever before. Energy Live spoke to Mike Davidson, AEMO’s Manager of Operational Forecasting, about the lessons learnt from this extraordinary hot spell.
EL: We all know Queensland can be hot and stormy, but was this event truly unseasonal?
MD: This was a remarkable event in that it spread across the whole of Queensland for more than a week, with very high temperatures and humidity. Unfortunately, we also saw severe storms that ripped through the south-east, leaving thousands of customers without power
EL: Just how hot was it?
MD: The picture below shows just how hot it was across northern Australia and Queensland in particular.
Prior to this event there had only been two days on record in February where the Queensland state-wide average maximum temperature had exceeded 40 °C – once in 1935 and once last year. Last week we saw two consecutive days in February averaging over 40C for the first time.
EL: Have we seen new records for power demand because of these weather conditions?
MD: Yes. The previous record operational (or grid) demand for Queensland was 9,412MW set in January 2017. We saw this record literally being smashed every day during the ‘heat event’, and the new record now is 9,796MW. This is an increase of nearly 400 MW, and to put that into perspective, is roughly the energy required to power a mid-sized town of 150,000 customers. If temperatures had reached what had originally been forecast, we would have seen even higher demand.
The chart shows that five days from 12 February to 16 February 2018 exceeded the previous operational demand record set last year. And when you add in roof-top solar generation to the operational demand, you can see that customer demand was even higher still.
‘Operational demand’ refers to electricity that is supplied through the National Electricity Market. ‘Customer demand’ also includes electricity that is generated through roof-top solar panels by customers.
EL: How close is AEMO working with weather forecast providers when it comes to managing extreme events like this?
MD: We take data from three separate weather service providers so that we can get the best information to manage events like this. We also have a meteorologist on secondment in our team from the Bureau of Meteorology and he has been really invaluable in helping us understand what the conditions for the day ahead are going to be. Because events like these are record-breaking, you don’t have history on which to base your forecast. At times like this, having expertise on-hand is absolutely invaluable.
EL: What happens when a storm breaks?
MD: When a storm breaks, it significantly eases demand because the humidity and temperature drop quickly. During the ‘heat event’, we were literally taking one minute observations at peak times to determine what’s going to happen next on the grid. The other thing that became apparent to us was the significant effect of cloud on solar generation. There’s in excess of a 1,000MW of solar generation in Queensland right now, so having this generation ramping up and down is a challenge in its own right.
EL: Is it becoming more complex to plan for extreme weather events?
MD: Demand has always been dependent on the weather, but now because of the growth of solar and wind generation, our supply is equally weather dependent. Growth in solar generation, that is from rooftop PV and large grid-connected solar farms, for Queensland in particular is forecast to be quite phenomenal over the next couple of years - so the impact of weather is only going to become increasingly important in the years to come.