Solar PV isn’t just about yield

Inspired by the lively discussion that resulted from Gavin Mooney‘s recent post on what direction to point roof-top solar systems, we crunched a few numbers to help inform the conversation.

The analysis looks at a single commercial load shape (I picked an office building) & how the financials might play out if it was equipped with solar PV oriented either 0° North or 270° West. We virtually located the office in 4 different jurisdictions, each with its own network tariff & wholesale market & of course with different solar yield.

We then added a 200kWh battery with either 50kW or 100kW of output & simulated a range of control modes. Finally we threw in a couple of different solar system sizes, 99kW & 200kW.

The outputs are quite complex to display graphically but I’ve had a crack. The first two charts show NPV (y-axis) & avoided grid consumption (x-axis) for each potential scenario. Icon colour indicates the site’s location, icon shape represents the orientation of the solar system. The label identifies whether the system is co-optimised with a battery and if so what the spec & control mode is.

The final chart is just an indicative week for the Perth site to demonstrate how W facing solar performs and the residual site load shape. I’ve used the IRCR days for illustration.