Could Solar Thermal Power Run a Hydrogen Economy?

A hydrogen-based economy has been debated for a while now, particularly because hydrogen could prove a safer and more efficient fuel for the standard automobile. The thing is, hydrogen is not easy to produce, transport or store. Hence, the back-and-forth debating. But Derek Abbott, Professor of Electrical Engineering at the University of Adelaide in Australia, thinks that a hydrogen economy is the sustainable fuel of the future.

The image shows why hydrogen is better in terms of punctured and ignited fuel tanks.  Gasoline is heaver and therefore expands and burns beneath the car, engulfing it in flames.  The hydrogen in the same 60-second span simply burns itself out vertically due to its gaseous state.  And hydrogen burns clear – the visible flame comes from salts and other materials in the air being burnt off.

But back to hydrogen’s costliness.  Abbot proposes solar thermal generation as a means of large-scale energy production that is even more cost effective than nuclear power.  Abbot argues that nuclear power has hidden costs, such as decommissioning after their 30-year plus lifespan, a process that requires around $6 billion.  Abbot also says that solar thermal generation is the premier method of harvesting solar energy. Silicon solar cells, such as those used in most of the PV panels you see, need arsenic to be produced and there won’t be enough arsenic to go around – not to mention the fact that it’s dangerous.  Silicon cell PV panels also rely on semiconductors that are affected by the temperature range they operate in.  Solar thermal, on the other hand, needs heat and temperature fluctuations to help its process.

Solar thermal works by using mirrors to focus sunlight on a central point that is filled with a liquid (water or oil generally). Once heated, the liquid produces steam that turns a turbine.  Essentially, solar thermal is the same as all other main forms of generating power, with the exception that the heat source is the sun rather than carbon or fission options.

Interestingly, Abbot points out that wind and hydrogen power are essentially diluted forms of solar energy.  In the case of wind, it is the sun that warms the earth to create convection currents. In the form of hydrogen, it’s the sun that produces rain by evaporating water into the atmosphere (hydrogen is derived from water).

In terms of sustainability, running vehicles on hydrogen rather than electricity is superior. The batteries in electric vehicles consume chemicals and finite resources, such as lithium, and release high levels of toxic waste. On the other hand, vehicles that burn hydrogen simply emit clean water vapor and do not require the unsustainable use of chemicals. Another advantage is the fact that today’s gasoline combustion engines can be retrofitted to run on hydrogen. The car manufacturing industry has infrastructure tailored to combustion technology.

“With solar-hydrogen, questions of safe handling are not the issue,” said Abbott. “Industry already uses 50 million tonnes of hydrogen annually, and so storage and handling are well-trodden areas. The BMW company has demonstrated the hydrogen combustion engine in a family-sized car [the BMW Hydrogen 7]. Also, 20% of buses in Berlin use hydrogen combustion.”

Abbot may be on to something here. Could the ultimate goal of producing regional hydrogen be more cost-effective than our current system?  Abbot estimates that using 8% of the world’s deserts could produce well beyond the world’s current needs for energy and would therefore leave plenty of solar power for hydrogen production.  The cost would be roughly 1.7 billion dollars for solar thermal installations, aka “less than the going rate of a war.”  Rather funny man for such a learned fellow.

The article from PhysOrg.com is much more in-depth and poses some interesting points about sustainability on a global scale.  I suggest the reading, there are some very nifty thoughts on preservation of nonrenewables for things like ink and dyes.  The Treehugger image above shows the breakdown of a solar thermal generator like those used in the Mojave Desert.

There’s a large-scale hydrogen plant that has recently gone online in Rodeo, California, near San Francisco.  Check out the info here.

Image credit to University of Miami via PhysOrg.com

Posted on October 23rd in Solar News by Craig.