A University of South Australia (UniSA) study has found that simply increasing solar penetration is not good enough, the panels need to be orientated so as to minimise the discrepancy between the times of peak use and peak production.
As UniSA solar researcher Kirrilie Rowe makes clear, “Solar panels on residential dwellings are typically installed facing the equator to maximise the energy collected, but the power generated by an equator-facing panel peaks at around midday, whereas residential loads typically have peaks in the morning and afternoon.”
Working to our home ground advantage, as it were, “it is possible to minimise the shortfall between load and generation. 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 Western Australian Government has already heeded the rationality of Rowe’s argument. The McGowan Government’s recently launched Distributed Energy Buyback Scheme encourages the uptake of solar on west-facing rooftops which receive sunlight at times when demand is highest and therefore most profitable to export to the grid.
Panel orientation may sound like solar basics, but it is solar basics that Australians need to work on. Electricity isn’t in high demand at midday, when a north-facing panel is at its peak. “The real challenge now facing the solar industry,” Rowe says, “is finding ways to balance production and consumption by maximising self-consumption for the solar panel owner.”
Solar orienteering
Of course, as solar penetration continues to increase, the returns on “feed-in tariffs” will necessarily reduce. One easy way to stem this reduction is to install solar in an orientation that plays to your rooftop’s geographic strengths.
For those considering installing solar panels on their rooftops there is an increasingly diverse solar toolkit at their disposal. For instance, OpenSolar, a partner of Nearmap, or alternatively, through the use of drones such as with DroneDeploy, potential solar customers can determine the optimal orientation of solar panels in their rooftops in a matter of minutes.
By incorporating access to Nearmap imagery, OpenSolar provides a purpose-built digital toolkit to streamline the design-and-quote process for installers by generating professional quotes, incorporating Nearmap imaging of home owner’s roofs as they will appear with solar installed.
Speaking at Navig8 last month via livestream video, OpenSolar co-founder Andrew Birch (Birchy) said he was excited about the next iteration of Nearmap in the OpenSolar app, which will create a 3D immersive experience that allows solar installers to view a digital surface map of a property and its surroundings. Using the orientation of the roof and its dimensions, they’ll be able to automatically calculate roof pitch; and use “ray tracing” of the sun as it moves across the roof and is filtered through nearby trees, to accurately estimate what solar output will be.
Putting it to the test
Rowe and fellow researcher Associate Professor Peter Pudney, worked out the optimal orientation of solar panels for a community of 29 individual dwellings and a residential block of 42 apartments. “Our analysis uses detailed load data and detailed irradiance data and shows that optimal panel placement for self-consumption is rarely towards the equator,” Rowe concluded.
Of course, if your rooftop is small and you’re only producing for you’re own household, then facing the panel north is best. “But as the panel area increases, it becomes better to face the panels acing north-west to meet the afternoon loads, and if even more panel area is available, then panels should be aced north-east and west.”
Rowe’s research demonstrates that solar panel orientation is one elegantly simple solution. “By orienting panels in different directions rather than just facing the equator,” says Rowe, “it’s possible to minimise the shortfall between load and generation. 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.”
Of course, says Rowe, future work will “incorporate energy storage into the model,” but as batteries remain expensive for many, “the real value of solar self-consumption will continue to rise” and this simple orientation strategy can be easily adopted for new installs or remodelling existing systems.
This content is protected by copyright and may not be reused. If you want to cooperate with us and would like to reuse some of our content, please contact: editors@pv-magazine.com.
I thought everyone knew this…
I would have thought, minimising any mismatch between PV generation and electricity demand whether by PV design or load shifting is common sense, I know that’s how I’ve always approached things for the last 10 years but more recently BESSs make this a much more interesting exercise.