Solar thermal power rating: Guidance for developing installation and energy credit programs for solar hot water systems

Solar Hot Water (SHW) systems that displace grid electricity are being considered for inclusion into installation and production credit programs. However, SHW systems normally have only energy production ratings, not power ratings, creating difficulties in including them into credit programs. Dave Menicucci, Sandia National Laboratories, USA describes the current issues surrounding this key area for solar thermal and presents a simple methodology that can estimate an effective power rating for SHW systems.