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We have already written about Desertec and how it could change the energy scene in Europe. Now the January issue of Scientific American describes a project that aims even higher, by using solar energy to produce up to 3 terawatts of energy and cover 69% of US electricity and 35% of its total energy by 2050. And all on US soil, in the sun drenched states of the southwest.

The numbers might sound optimistic but the whole plan has a firm basis and every one of its aspects is convincing. Geographically, the southwest states are perfect as they provide year-round sunny conditions and have large uninhabited public areas without competing uses. By 2050 and at full deployment, solar stations will require 46,000 square miles of land, a large area by any standard but feasible bearing in mind that the states of interest already have this land available and there would be zero burden on local ecosystems.

The required technologies already exist and are already in small scale use both in the US and Europe. The plan envisages the 50-50 use of photovoltaics for direct electricity production and concentrated solar power for the production of energy via steam turbines. The logic is that both would be sufficiently developed to be efficient enough by 2020 when full deployment would start. Photovoltaics would require a real energy producing efficiency of 14% or better from the current 10%, while concentrated power production would require a molten salt storage period of 16 hours from the current 7.

Apart from energy production itself, the first issue is energy storage for periods without sunshine or high demand. Batteries are out of the question so the proposed method is to use excess energy to compress air in underground mines or reservoirs. When required the air would be released to drive turbines that in turn supply the demanded energy. Natural gas would be used to drive the turbine system flawlessly but would be phased out by 2050 when technical advances make it possible. Molten salt storage will play the same role but on a daily basis.

The second issue is energy distribution, as the current AC grid is inefficient and unable to stand the projected burden. The solution would be the development of a high voltage direct current (HVDC) backbone that would distribute energy with less losses, require smaller scale and be more cheap that current infrastructure. When near consumption points, DC current would be converted to AC to be locally distributed.

The whole key to the project is how to kickstart it into action. Three stages are envisaged:

1. now-2020: Following the example of Germany and Japan, a comprehensive government program of gradual annual subsidy increases as we approach 2020 will help achieve the technical targets already mentioned, guarantee purchase of power and provide much needed price subsidies. The first gigawatt installations of both technologies will provide a taste of clean energy benefits and achieve the economies of scale to make solar financially competitive to current energy sources.
2. 2020-2050: Total cumulative subsidies will reach $420 million by 2050. Solar stations will be deployed in mass and subsidies will be scaled back gradually in the decade leading to 2050. By then, solar will be self-sufficient and natural gas will not be required at all for the storage energy turbines.
3. 2050-2100: Solar will be combined with domestic energy production, wind farms, biomass plants and generally all clean types of energy production to provide all of the US’s electricity and hydrogen for transport. All projections assume a realistic annual increase in energy demand of 1%.

The $420 million will come directly from a carbon tax of 0.5 cents per kWh. Looking and making predictions in a horizon of one century is of course risky but my opinion is that current geopolitical indications and the high price of oil -yesterday the psychological barrier of $100 per barrel was surpassed- are major incentives for technical innovation. As a result the targets of 2050 will be reached even more easily, as 2020 efficiencies are assumed throughout the project and of course we know that nobody will forever stay happy with a photovoltaic efficiency of 14%. Just imagine that oil tankers, trucks, refineries, coal & nuclear plants will be required very little all not at all. It is a reason to live longer to see it all!

For all these wonderful things to happen it is time for governments to look at modern energy and environmental problems in an open and future minded way. The technological and funding scales are absolutely massive and coordinated planning & action are instrumental. Lets hope that large green projects start soon. They will offer employment, energy independence and a chance for the planet to recover. In other words unprecedented high levels of quality of life.

Link 1: Earth2tech

Link 2: Scientific American