The remarkable growth in deployment of grid-connected photovoltaics (PV) in recent years has, in large part, been driven by its rapidly improving economics. System costs have fallen almost fourfold in some markets over the past five years. The future success of the technology will, however, depend on the value that it can contribute toward delivering affordable, reliable, secure, and sustainable ... [Show full abstract] energy services to end users. PV has some highly valuable characteristics in this regard. It can be deployed at almost any scale from household to utility plant, typically generates at times of higher demand and hence higher value, and has very low adverse environmental impacts. However, its variable and somewhat unpredictable generation does raise some challenges within an industry aspiring to ensure that supply must meet demand, at appropriate levels of quality, at all times and locations across the electrical network. These challenges become greater as the penetration of PV increases.