DESERTEC and INDUSTRIAL PROCESSES
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Given the enormous quantities of energy available in deserts, it is
natural to consider whether it might be used to support energy-intensive
industrial processes such as the production of aluminium, iron, steel, cement,
- The large quantities of heat and electricity that are needed to convert bauxite into aluminium could, in principle, be provided by CSP plants in the Australian desert, close to where the bauxite is mined.
- The production of iron from iron ore requires a combination of large amounts
of heat and a chemical reducing agent such as carbon. In conventional smelting,
coke provides the heat and serves as the reducing agent—and large amounts of CO2 are released into the atmosphere. In principle, large reductions in CO2 emissions may be achieved by using solar concentrators or solar electricity instead of coke as the source of
- It is possible that hydrogen produced by the electrolysis of water (using electricity from CSP plants) might be used as the reducing agent in the production of iron, thus avoiding the use of coke.
- In processing iron to make steel, the main requirement is heat. In principle,
this could be provided by solar concentrators or solar electricity thus eliminating the emissions of CO2 that might otherwise result from burning coal.
- The production of ordinary 'Portland' cement requires large amounts of heat
combined with chemical processing of limestone. Some CO2 comes from
the limestone itself but if the heat is provided by burning something like coal,
this may be an additional large source of CO2. In principle, that
second source of CO2 can be eliminated by using heat from solar concentrators or solar electricity instead of
coal. And if geopolymeric
cement is produced instead of Portland cement, this would eliminate most of
the first source of CO2 as well.
- Steam generated by CSP could become widely used for industrial processes in the future (see, for example, A solar-powered oil field?).
- Given that:
it is natural to consider whether the glass that is needed for CSP plants
(and other purposes) might, with advantage, be made using the heat from CSP
- The mirrors of CSP plants are often made from glass,
- Glass is made from sand,
- Sand is often plentiful in the desert regions where CSP plants work best,
- And the production of glass from sand requires quite a lot of heat.
Social and political dimensions
Although, from a technical perspective, it may make sense to move some energy-intensive industries to desert regions, social and political aspects are clearly relevant too. A good balance needs to be found amongst the several aspects, and that balance may vary, depending on specific industries, specific technologies, and the interests of relevant stakeholders.
CSP and the synthesis of fuels
Electricity is a very versatile form of energy and can be transported very efficiently over long distances using HVDC transmission lines. But, despite lower efficiencies, energy in chemical forms such as hydrogen, alcohol or
hydrocarbons may be better for
- They can be stored and this can be useful for ironing out
variations in supply or demand or as strategic reserves of energy.
- They provide an alternative vehicle for transporting
energy and this may be useful as a means of increasing the security of energy
- Although railways and road vehicles (electric and hybrid) can be powered by
electricity, aircraft need chemical fuels and the same is true of ships that
have an engine and do not rely exclusively on the power of the wind.
So although there will be losses of
energy, there may be good reasons to convert CSP energy into chemical
form. Here are the main options:
- Solar electricity may be used to generate hydrogen by the electrolysis of water. It
is also possible split water into hydrogen and oxygen using heat from a CSP
plant (see Clean Hydrogen Producers Ltd. (CHP)).
- Another possibility, somewhat more speculative, is
to capture solar energy as finely powdered metal (iron,
aluminium etc) or boron (see an
article from the New Scientist and letters in the New Scientist). Surprising as it may seem, powdered metal or boron
may be used as fuel in a Diesel engine, Stirling engine, or gas turbine engine.
The oxide of metal or boron that results from combustion may be collected and
recycled (at solar power plants) back into powdered metal or boron. Instead of ‘the hydrogen economy’ we
should, perhaps, be aiming for ‘the powdered boron economy’!
- It appears to be feasible to use solar
heat or solar electricity (or both) to synthesise hydrocarbons or alcohol from
CO2 (extracted from the air) and water. Some of the possibilities are
outlined in the following sources:
- What Obama meant by "converting sunlight into liquid fuel" (MIT Technology Review, 2015-01-21).
- Nanoparticles make steam without bringing water to a boil (MIT Technology Review, 2012-11-27).
- Graves, C., Ebbesen, S.e D., Mogensen, M., and Lackner, K. S. (2011). Sustainable hydrocarbon fuels by recycling CO2 and H2O with renewable or nuclear energy, Renewable and Sustainable Energy Reviews, 15(1), 1-23
- Sahara Solar Breeder Foundation. The aim is to turn sand into PV using solar power. See also Saudis to make desert sands into solar polysilicon (Green Prophet, 2012-04-08).
- Abengoa CSP plant in Chile (Renewable Energy Focus, 2011-06-17). The plant will provide heat for the production processes of Minera El Tesoro.
- Sustainable organic fuels for transport (SOFT) – a concept for compatible affordable mobility using carbon-neutral liquid fuels, R.J. Pearson, J.W.G. Turner, M.D.Eisaman, K.A.Littau, G. Taylor (Lotus Cars and PARC, no date).
- Zinc air fuel cell ("ZAFC")
- The synthesis of fuel from sunlight features in James May's Big Ideas: Power to the People (BBC Two, 2008-10-12).
The relevant part is between 50:30 and 58 minutes into the programme.
- Le four solaire de Parkent en Ouzbékistan (Enerzine.com)
- There is a section on solar chemistry in Concentrating solar power: from research to implementation (PDF, 2.8 MB, European Commission, 2007).
- Turning CO2 back into hydrocarbons (New Scientist, 2008-02-28)
- A concrete proposal
- Sandia’s sunshine to petrol project seeks fuel from thin air (press release from Sandia National Laboratories, 2007-12-05). See also Sunshine to petrol project.
- Clean Hydrogen Producers Ltd. (CHP). This company specialises in the production of hydrogen by solar thermal cracking of water.
- Hydrogen Power Inc. Production of hydrogen-on-demand from aluminium and water, with a catalyst.
- See Concentrating solar power: from research to implementation (PDF, 2.8 MB, European Commission, 2007), pages 31-36.
thermo-chemical cycles to split water at solar thermal towers as a key to
solve world energy & ecological problems by artificial fuels.
- Los Alamos Renewable Energy LLC
- Beyond oil and gas: the methanol economy (PDF, 89 KB, George A. Olah, Angew. Chem. Int. Ed. 2005, 44, 2636 –2639)
- Safe hydrogen (magnesium hydride slurry as a pumpable hydrogen fuel)
- Aluminum could add up to a new fuel option (EarthTimes.org, 2007-05-19). Describes how hydrogen can be generated from aluminium and water so that aluminium may serve as an energy vector.
- Purdue pursues hydrogen fuelled dreams (Carbon Free, 2007-08-31). Describes the possible use of an aluminium/gallium alloy as an energy vector that produces hydrogen from water.
- Solar Hydrogen Energy Corporation
- New Scientist:
- Boron: a
better energy carrier than hydrogen?
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Last updated: 2015-01-29