Clouds add layer of concern for solar

CLOUDS have become an issue for Queensland’s electricity system.

According to the Australian Energy Market Operator, Queensland now has more than 1000MW of solar power generation, about the size of a major generator, and passing clouds can cause a drop in capacity which needs to be found elsewhere.

The February heatwave, which smashed temperature records, showed AEMO how power generation “is inextricably linked to the weather now more than ever before”.

AEMO’s manager of operation forecasting Mike Davidson said electricity demand had always been weather- related but now a significant portion of the supply was equally dependent.

Large banks of moving clouds such as storms cause rapid changes in rooftop solar power generation that must be replaced from conventional grid connected generation.

“Growth in solar generation, that is from rooftop photovoltaic and large gridconnected 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.”

AEMO said it now had to determine whether grid demand at any time was being reduced by rooftop solar.

“When the sun shines, rooftop solar generators reduce demand on the network. If there is cloud present then the PV generation is reduced.

“Because AEMO doesn’t get real- time data from rooftop PV output we have to estimate the PV generation ….

“This is why real- time observations are so important.’’

AEMO now has an analyst from the Bureau of Meteorology embedded within its forecasting team and uses satellite imaging showing where clouds are every 20 minutes.