Are the savings as good as they look?

How much solar will your school actually need?

The key question is around self-consumption — how much of the electricity generated by your panels will be used by the school rather than exported to the grid. 

It’s important to ask: 

• Has the calculation used your school's actual consumption data, based on at least a year’s worth of the school’s energy bills?  

• Has it accounted for weekends and school holidays?  

• Has it used data from comparable schools?  

• How accurate have the provider's previous forecasts been?  

A shopping centre may consume electricity seven days a week. A school does not. A factory may operate throughout the year, while a school has significant periods when demand is much lower.

What happens if the forecast is wrong?

This matters particularly with a Power Purchase Agreement (PPA). 

If self-consumption is lower than predicted, the school may still benefit from lower bills, but the PPA provider may not generate the expected income to repay the cost of the system. 

If the school buys the system outright, an overly optimistic forecast could mean spending more capital than necessary. 

And finally, don't forget about exports...

Ask how the proposal treats electricity exported to the grid and whether it includes REGOs or similar credits. 

Export contracts are currently reasonably attractive, but as more solar connects to the grid, daytime electricity exports could become less valuable. 

Don't just compare the headline saving. Ask to see the assumptions behind it.