Renewable Energy Resources for Irrigation - Practices of Irrigation and On-farm Water Management - page 515

Table 13.1 Typical renewable energy cost (WEC, 2004 )

2001 energy cost Potential future cost

Electricity
Wind 4-8 ¢/kWh 3-10 ¢/kWh

Solar photovoltaic 25-160 ¢/kWh 5-25 ¢/kWh

Solar thermal 12-34 ¢/kWh 4-20 ¢/kWh

Large hydropower 2-10 ¢/kWh 2-10 ¢/kWh

Small hydropower 2-12 ¢/kWh 2-10 ¢/kWh

Geothermal 2-10 ¢/kWh 1-8 ¢/kWh

Biomass 3-12 ¢/kWh 4-10 ¢/kWh

Coal (comparison) 4 ¢/kWh

Heat
Geothermal heat 0.5-5 ¢/kWh 0.5-5 ¢/kWh

Biomass - heat 1-6 ¢/kWh 1-5 ¢/kWh

Low temp solar heat 2-25 ¢/kWh 2-10 ¢/kWh

Note: All costs are in 2001 US$-cent per kilowatt-hour.

Sustainable development and global warming groups propose a 100% renewable
energy source supply, without fossil fuels and nuclear power.
Renewable energy sources are becoming cheap (Table 13.1 ) and convenient
enough to place it, in many cases, within reach of the average consumer. By con-
trast, the market for renewable heat is mostly inaccessible to domestic consumers
due to inconvenience of supply, and high capital costs. Solutions such as geothermal
heat pumps may be more widely applicable, but may not be economical in all cases.
Proponents advocate the use of “appropriate renewables,” also known as soft energy
technologies, as these have many advantages.
Renewable energy technologies are sometimes criticized for being intermittent
or unsightly, yet the market is growing for many forms of renewable energy. Wind
power is growing at the rate of 30% per annum, has a worldwide installed capacity
of over 100 GW, and is widely used in several European countries and the USA. The
manufacturing output of the photovoltaic industries reached more than 2,000 MW
in 2006, and PV power plants are particularly popular in Germany. Solar thermal
power stations operate in the USA and Spain, and the largest of these is the 354 MW
SEGS power plant in the Mojave Desert. The world's largest geothermal power
installation is The Geysers in California, with a rated capacity of 750 MW. Brazil
has one of the largest renewable energy programs in the world, involving production
of ethanol fuel from sugar cane, and ethanol now provides 18% of the country's
automotive fuel. Ethanol fuel is also widely available in the USA.
While there are many large-scale renewable energy projects and production,
renewable technologies are also suited to small off-grid applications, sometimes in
rural and remote areas, where energy is often crucial in human development. Kenya
has the world's highest household solar ownership rate with roughly 30,000 small
(20-100 W) solar power systems sold per year.