A Victorian parliamentary inquiry on apartment energy issues has recently reported and identified several issues that require urgent attention to address the failures of energy policy.
One interesting issue that relates to both high rise apartments, and plug-in ‘balcony solar’, is where solar fits into apartment occupant energy costs.
High rise apartment buildings have very limited roofspace. Individual apartment occupants may wish to install plug-in balcony solar that is near vertical. But how does that impact on energy bills?
Just looking at annual PV output, near vertical PV doesn’t look great. But that’s not the whole story. A kilowatt-hour generated in winter can be worth far more than one generated in sunny weather over the rest of the year.
I used the PVWATTS calculator to look at monthly generation at Tullamarine, near Melbourne. This suggests that a vertical (or near-vertical) PV system facing between north-east and north-west produces similar output to a rooftop PV system from April to August. Reflection from a balcony could improve the story as shown below.
