A PowerPoint (in PDF) by RENEW Wisconsin’s Executive Director Michael Vickerman presents the preliminary conclusions of a forthcoming white paper on solar hot water system:
When energy prices rise above $1.00/therm and incentives are available to reduce system cost by half, the internal rate of return (IRR) on investment in a commercial SHW system will surpass those of traditional investments. Moreover, it is as risk-free an investment as one can make.
Natural gas price volatility will invariably impart a herky-jerky pattern to annual returns and installation activity.
To ensure the steady of expansion of SHW technology, governments should consider policy options to provide some buffer against fuel price volatility and reduce front-end costs.