The rate at which costs reduce with deployment is referred to as the 'learning rate', that is 'the percentage reduction in costs for each doubling of installed capacity' (EASAC, 2011, p.
Many other countries are likely to reach grid parity by 2020 for solar PV-generated electricity (Bazilian et al., 2012; Bony, Doig, Hart, Maurer, & Newman, 2010; Branker et al., 2011; BZE, 2010; EASAC, 2011; EERE, 2010a; IEA, 2010a; Jablonski, Tarhini, Touati, Gonzalez Garcia, & Alario, 2012), with prices continuing to fall strongly after that (EERE, 2010b; IEA, 2010a).
EASAC states that 'incorporating thermal storage capacity can extend the operating period of the CSP [CST] plant by a few hours after sunset up to 24 hour, base-load operation' (2011, p.
There are other forms of CST beside the solar tower shown in Figure 7; for example, the parabolic trough, Linear Fresnel Reflector (LFR) and dish (for descriptions see BZE, 2012; EASAC, 2011; IEA, 2010b; Wyld & MMA, 2008).
According to EASAC, Worldwide in 2011, 1.3 GW of CSP [CST] were operating and a further 2.3 GW were under construction' (2011, p.
Hence CST plants with storage can complement the variable generation of other renewable energy technologies (Dunn et al., 2012) and effectively enable greater penetration (i.e., higher percentages) of wind and solar PV in the electricity grid (Denholm & Mehos, 2011b; IEA, 2010b; EASAC, 2011).