Electrosolar : Photovoltaic Energy
Electrically synthesized fuels sourced from atmospheric CO2-part 1
It is now a substantiated fact that the steadily increasing atmospheric CO2 level from man's fossil fuel based energy production is causing global warming, and that this will cause catastrophic damage to the 'biosphere' within a century unless addressed by a solution that replaces our energy sources by non-fossil fuel alternatives.
Analysts have shown that we have less than fifty years in which to act. We need a reduction in our fossil fuel burning that will be worldwide, viable in the short term, and deep in its impact. For this to occur in a market driven world economy, it needs to be a system that is economic, and technically viable right now.
The only way this will happen is if the worldwide energy companies have a positive choice for a new way forward, retaining their businesses and infrastructure. It is indeed only the energy companies that have the financial resources and necessary focus to address the problem. I believe the concept in this short paper does offer a solution, which has the required incentive.
Hydrocarbons are excellent energy carriers. Liquid hydrogen is impractical for many vehicles because it cannot be kept from evaporating. The transport infrastructure of the planet has been built around hydrocarbon energy carriers. We now appreciate the real cost in terms of global warming, of pumping all that carbon out of the ground and releasing its combustion product into the atmosphere. Approximately 60% of all the carbon extracted has remained in the atmosphere to date, raising the CO2 content from 280ppm by volume to 380ppm by volume. The change to the weather and climate is already becoming apparent.
Oil extraction is responsible for over 50% of the atmospheric CO2 build up. The overwhelming need for renewable fuel for transport has not been addressed. Massive production of bio-fuels would use too much of the Earths arable land.
This document seeks an answer to these problems by proposing that in the future, our hydrocarbon energy carrier medium will be synthesised from carbon dioxide extracted from the atmosphere, rather than from carbon pumped from the ground, and hence the whole petrochemical industry could become carbon neutral.
Non-fossil fuel sources of electric power such as concentrated solar power (CSP) or photovoltaic (PV), together with raw materials of air and water, will be used to extract the CO2 from the air, and recombine it with hydrogen (produced by the electrolysis of water) to make recycled hydrocarbons.
For this to be feasible, four main requirements must be met: 1) The most economic solar power generation feasable. 2). An energy efficient process for atmospheric CO2 extraction. 3). An energy efficient method of water electrolysis for the production of hydrogen. 4). An energy efficient process for catalytic hydrogenation of the CO2, to generate the final plant output of high-grade kerosene and other hydrocarbons.
Large-scale solar energy capture is possible in desert regions such as the African Sahara or the Western Australian desert. In these regions land is cheap, and the number of clear 'blue sky' days is high, leading to the viability of electricity generation using CSP (concentrated solar power) technology. Focussed solar parabolic collectors with 'Stirling' engines running generators, or solar trough collectors using more conventional turbines are already manufactured, and are being deployed in the Mojave desert near Las Vegas USA on a medium scale trial. These have demonstrable solar conversion efficiencies of up to 40%, which lead to a generating cost of about $0.10 to $0.12 per KWhr. A pilot with a ten-kilometre-wide square of this form of PV could produce an average of 5,000 Megawatts using existing technology at an estimated capital cost of £5Bn-£10Bn. It is important to appreciate that the best places for capturing solar energy are remote and not necessarily suitable for transmitting the electrical power generated to urban areas where it can be used directly.