Glenn Pure wrote a letter in The Canberra Times on Saturday that sparked some discussion.

This page did some analysis on the subsidies and effectiveness of Solar Hot water and PV technologies – particularly payback periods and the effect of subsidies.

The bottom line is that you can get a return on investment for solar hot water in 2-5 years in Canberra if you are an average user of hot water. If you use a lot of hot water then you get a pay back quicker. There is almost no need for boosting because we have clear skies and the Evacuated Tube technology is so efficient at converting diffuse sunlight to heat.

Subsidies for solar hot water are low compared to the benefits that Government gets in terms of saving the need for building more generating capacity and from carbon emission reductions.

So the question is whether it is good Public Policy to provide large subsidies (~$A8,000) for PV electricity generation or to provide small subsidies (~$A2,400) for solar hot water where the benefits to Government and the consumer are actually higher for the smaller subsidy. If Procurement guidelines were followed then there is no doubt that the Value for Money requirements would not be met, technically putting the Government in breach of its own guidelines.