We've heard a lot recently about the problem of "dependence on foreign oil." For some, "Drill! Drill! Drill!" has become their mantra in the American Presidential election, as hard-pressed consumers desperately hope for some relief from high fuel prices. The problem could be much better categorized though, as simply a "dependence on oil." This toxic liquid, which formed from rotting corpses and dead plant life over millions of years, is hard to find, even harder to get at, expensive to refine and transport and worst of all, it's contributing enormously to Global Warming.
What if there was an alternative though? What if the Earth was covered in lakes of an energy rich liquid that, with a bit of work, could solve our energy problems for good? Well, it might seem fanciful, but such a thing does exist. This liquid was formed billions of years ago. It's completely harmless to the environment and available everywhere. No, it's not some unheard-of rare mineral I'm talking about, but simple water. Actually, the hydrogen in the water.
Ever since I started writing about possible solutions to Global Warming, friends have been sending me articles about new hydrogen cars or hydrogen fuel cells. The problem is that most of the hydrogen available today is produced using fossil fuels. So simply using hydrogen is not a solution to Global Warming. What's required is a means of producing hydrogen from water using renewable energy.
Hydrogen is the most abundant element in the Universe, but as elements go it's pretty promiscuous. It doesn't just sit around. It likes to interact with other elements, in particular oxygen to form water. Hydrogen is like a bad guest at a party. Once it gets into a water molecule it doesn't like to leave! It takes a lot of energy to get it out. Now a team of Greek researchers have found a way to extract hydrogen from water efficiently using sunlight.
The HydroSol project was started in 2002 with €1.33 million in funding provided by the European Union and a further €1.33 million contributed by a consortium of partners from Britain, Denmark, Greece and Germany. Headed by Athanassios Constantopoulos, Director of the Chemical Process Engineering Research Institute based in Thessaloniki, the Greek research team have constructed a reactor that is capable of splitting the molecular bonds that tie oxygen and hydrogen together to form water.
The solar reactor is comprised of a ceramic honeycomb of hundreds of channels coated with what the team calls a nano-material. The material is comprised of oxygen-deficient ferrite structures containing zinc and nickel. The reactor uses a two stage process. In the first stage the temperature of the honeycomb is increased as parabolic reflectors concentrate solar radiation onto its surface. At temperatures between 800 and 1,200 degrees Celsius the nano-material removes oxygen from water, producing hydrogen gas. In the second stage the temperature is increased further to between 1,000 and 1,200 degrees Celsius. As these temperatures are reached the oxidized nano-material is stripped of oxygen, producing oxygen gas. The nano-material is then ready to be used again.
Constantopoulos, who is, ironically, a specialist in catalytic converters for car engines, points out that the system has no moving parts. Water vapour flows in one side and hydrogen flows out the other. The channels provide a large surface area with which the water vapour can interact. Initial laboratory investigations showed that his solar reactor can convert water vapour to hydrogen and oxygen with nearly 70% efficiency using just sunlight. The laboratory based portion of the project was known as HydroSol I.
"The hydrogen produced can be channelled into a fuel cell to produce energy or to a combustion point. The hydrogen can also be stored, solving the problem of storing and transporting solar energy. Secondly, the reactor can be used to recycle carbon dioxide. The hydrogen, together with carbon dioxide, can produce new fuel (such as methane). So a reactor like this can be set up alongside units producing CO2. Thirdly, it can be used to desalinate water. It could be an integrated solution for the Greek islands, providing energy and drinking water just by using the sun and water".
On March 31 2008 the team held their first official demonstration of the solar reactor at Spain's Almeria Solar Platform. The successful demonstration marked the inauguration of HydroSol II. The next phase of the project, HydroSol III, will be a one megawatt power plant based on the technology. "Our dream is for HydroSol III to be made in Greece. The cost is not prohibitive, about €3 million," said Constantopoulos.
In 2006 the team was awarded the European Union's Descartes Prize for scientific research. For those who think that the movement from an oil based society to a hydrogen based society is in the distant future. Think again. Two hydrogen filling stations are already open to the public in Berlin. These stations produce hydrogen on site using electrolysis. However, soon we will be seeing many more of these stations around Europe, especially if good old Greek ingenuity has anything to say about it.
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Sounds promising. Hydrogen is a pretty poor energy carrier and due to the high amounts of energy needed to produce it, transport it and manufacture vessels to contain it, the energy return has been dubious. The filling stations that manufacture it on site solve one of the problems, transport, by avoiding custom pipelines. This Greek technology could be really positive if it can generate enough to offset it's embodied energy. Any idea what it takes to make manufacture this technology?
Written in October 2008