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Are we installing rooftop solar panels to produce the best outcome for our households?

Traditionally solar panels including residential, commercial and industrial scale have been orientated to catch the sun to produce as much solar energy as possible. This has resulted in solar panels being installed facing north in the southern hemisphere, to face the equator. The north facing panels would then produce the most energy from the sun when it passes the zenith in the middle of the day. This results in the most amount of energy being produced, usually when a majority of households are not using electricity, resulting in excess energy being exported or stored in batteries. The returns from the export credits are lower than the cost of electricity during the peak times of use and the capital cost of batteries, which are currently high.

We are all aware, the export of excess solar energy during the middle of the day is causing issues for the National Energy Market (NEM) and can result in negative spot prices during these times. There are currently 20% of households with rooftop solar installed and this is expected to grow in the coming years. The issue of excess solar energy being exported will worsen over time.

The University of South Australia (UniSA) is comparing rooftop solar installations compared to the usage patterns of consumers. UniSA see “the real challenge now facing the solar industry is finding ways to balance production and consumption by maximising self-consumption for the solar panel owner”. This has led to researchers exploring the orientation of rooftop solar panels, rather than to match the times of best generation but to meet patterns of consumption. Matching consumption will result in a reduction in overall energy generation but exports will be minimised.

The UniSA research found “by orienting panels in different directions rather than just facing the equator, it’s possible to minimise the shortfall between load and generation for a community precinct…This benefits the end-user by decreasing the amount of electricity required to be imported, and the stability of the grid by decreasing the amount of variability between peak and low loads.” The research found it was better to face the panels North West to match the afternoon loads. To optimise for the morning and afternoon consumption, by placing panels North East and North West, the load in the middle of the day was still met, but a greater proportion of the morning and afternoon load was also delivered from the solar panels.