PV can give electricity for 2.1 ยข/kWh
Large networks allow much cheaper electricity
PV can give electricity from decentralized installations. That is helpful for many locations, in particular in poor countries without grid were often petroleum is used in generators for generating electricity. In highly developed countries PV installations, if connected to the grid, allow decrease of use of fuels during periods of good sunshine.
Present costs of this electricity are about 10 ¢/kWh in locations with low insolation, e.g. the north of Germany or Alaska Panhandle (insolation per year about 1000 kWh/m2/year) or 6 ¢/kWh in southern Europe (1500 kWh/m2/year) or 4.5 ¢/kWh (large areas between 30° North and 30° South with 2200 kWh/m2/year).
Roadmaps for the further development of PV until 2020 also predict that these electricity costs will decrease to half beginning after 2020.
However, that is intermittent electricity subject to day and night, the seasons and clouds. But it is still very cheap electricity so that PV installations pay for providing electricity from early spring to late autumn. If installations are so big that they allow to meet most of the electricity demand during this period of time, they give a lot of excess electricity during the summer and during very sunny days.
Electricity storage, here in particular lithium-ion batteries, can provide electricity during the nights and also during periods of cloudiness. However, very large and thus expensive amounts of storage would be necessary to overcome the effects of the seasons.
Very extended grids have become possible through high-voltage DC lines, as described by Chatzivasileiadis, S., D. Ernst, G. Andersson in their paper from 2013, "The Global Grid", published in Renewable Energy. Andersson in professor at the ETZ Zurich and was at Asian Brown Bovery before joining the ETH. These authors calculate costs per kWh of 1.3 ¢ /kWh for transmission between Europe and the U.S. Some new-laid cables cut these costs to half.
The figure shows electricity costs for dispatchable electricity (i.e. electricity that always meets the load calculated with the weather over the last 20 years), from decentralized locations (here for Styria in Austria) and for grids of different extension. A global grid with an optimal selection of 60 locations would give dispatchable electricity at 2.1 ¢/kWh plus transmission costs which according to our calculation would be about 0.8 ¢/kWh after 2020.