A study conducted by Stanford University confirmed that interconnected multiple wind farms can be used to provide baseload electric power. Interconnecting wind farms with a transmission grid reduces the power swings caused by wind variability and makes a significant portion of it just as consistent a power source as a coal power plant.
"This study implies that, if interconnected wind is used on a large scale, a third or more of its energy can be used for reliable electric power, and the remaining intermittent portion can be used for transportation, allowing wind to solve energy, climate and air pollution problems simultaneously," said Archer, the study's lead author and a consulting assistant professor in Stanford's Department of Civil and Environmental Engineering.
This is an advantage that wind and wave power have over solar power (without storage) unless the geographical diversity of the solar power is so great that there are significant differences in the period of sunlight, which would make the cost of transmission too great using current transmission techniques. High-voltage direct current (HVDC) or high temperature cryogenic transmission could alter this picture. The European super grid described in a previous post depended on both the diversity of wind farms and advanced transmission techniques, but such a large geographical diversity is not required. A previous post reported on an earlier study that came to even more favorable results using a mix of all the renewable technologies. The study found that by combining a diversity of geographical locations and a diversity of technologies, "renewables combined with domestic combined heat and power could ultimately make the following contributions to Britain's total energy supply: wind 35%, wave and tidal 15%, combined heat and power 15%, and solar 5-10%."
An energy storage system, using compressed air storage, here and here, makes wind power dispatchable, but is dependent on suitable geological conditions to store the energy. A vanadium redox battery energy storage system, that stores both solar and wind power as electricity, and thus is not dependent on location, is being planned for an Irish wind farm.
This combined with fact that wind power is less expensive than conventional power in some locations and that solar thermal power should reach that point within a few years, makes utility scale renewable power very possible within a few years and the phasing out of fossil fueled power and energy security realistic goals. Perhaps five years after that PV solar should be competitive opening up another technology for very wide spread use. The limitation at that point will be the production capacity of manufacturers of renewable energy equipment and shortages of some natural resources, such as silicon and vanadium, needed to make the equipment. Alternatives such as non-silicon solar will then be called on to meet the demand. First Solar is already a successful commercial producer of non-silicon solar cells. Market forces will then drive the production capacity without any need for subsidies. In the meantime subsidies may be justified to keep the industries competitive.