A few more points on water and power

If we use stored water as a means to supply electricity at night, we will need extra water, unless we're able to have our upper reservoirs at least 100 metres higher (equivalent of 30 storeys) than our lower ones. (The amount of power generated is a function of the height of the water and the rate of flow.) Such variations in elevation are not at all rare, but it would be possible if we haven't thought about this, for us to buy a large, flat area of land, and then find ourselves doing an inordinate amount of earthworks or tower building to create the water heights we want for power storage.

Aside from the planned Stirling Engineering Systems installations that I referred to earlier, another project using dishes to concentrate heat from the Sun is under way in Australia. The town of Whyalla has set in train an AUS$80 million project to build a solar thermal plant that will also desalinate water, which has been dubbed the Solar Oasis (story also here). After a pilot, it is planned that the project will use 200 giant dishes (much bigger than the SES ones), that power steam turbines, which in turn power a conventional thermal power station. According to the design, sufficient thermal energy will be generated by the dishes to keep the electricity generation going throughout the night. The design of this system was developed by a team at the Australian National University. (More details of the technology can be had from Wizard Power, who are commercializing it.)