Have we found the 'holy grail' in cutting emissions? Power plant claims to produce hydrogen by splitting water with sunlight



The plant would use an array of mirrors to focus sunlight onto a huge tower

The tower heats up to 1,350 ° C - enough to liberate hydrogen from steam

Scientists describe the process as the Holy Grail of a hydrogen economy

Scientists believe they have achieved the ‘holy grail’ of the green economy by designing a hydrogen production plant that can split water with sunlight.

The University of Colorado at Boulder envisages an array of mirrors that would focus sunlight onto a central tower several hundred feet tall.

The tower would heat up to around 1,350 °C - enough to liberate hydrogen from steam with the help of a metal oxide compound.

A concept design of a hydrogen production plant that could fuel a sustainable green economy with sunlight and water. The tower would heat up to around 1,350 degrees Celsius- enough to liberate hydrogen from steam with the help of a metal oxide compound

'THE HOLY GRAIL'- HOW IT WORKS

An array of mirrors focuses sunlight onto a central tower several hundred feet tall. Metal oxide compound in the tower heat up to around 1,350C and release oxygen atoms.

This changes its material composition causing the newly formed compound to seek out new oxygen atoms.

The addition of steam to the system- which could be produced by boiling water in the reactor with the concentrated sunlight beamed to the tower - cause oxygen from the water molecules to adhere to the surface of the metal oxide.

This frees up hydrogen molecules for collection as hydrogen gas.

‘We have designed something here that is very different from other methods and frankly something that nobody thought was possible before,’ said lead scientist Professor Alan Weimer, from the University of Colorado at Boulder.

‘Splitting water with sunlight is the Holy Grail of a sustainable hydrogen economy.’

Hydrogen could be used as a fuel for road

transport, distributed heat and power generation, and for energy storage.

Writing in the journal Science, the researchers explain how their plant would adopt the same principle as using a magnifying glass to start a fire.

‘We can concentrate sunlight until it is really hot and use it to drive these chemical reactions,’ said Dr Christopher Muhich, a member of the University of Colorado team.

‘While we can easily heat it up to more than 1,350°C, we want to heat it to the lowest temperature possible for these chemical reactions to still occur.

‘Hotter temperatures can cause rapid thermal expansion and contraction, potentially causing damage to both the chemical materials and to the reactors themselves.’

Splitting water with sunlight is described by the U.S. scientists as the Holy Grail of a sustainable hydrogen economy. Hydrogen could be used as a greener alternative to fuel road transport, in distributed heat and power generation, and for energy storage

The quantity of hydrogen produced is entirely dependent on the amount of metal oxide, a combination of iron, cobalt, aluminium and oxygen, and steam.

A working system would require a number of towers each surrounded by several acres of mirrors.

Commercialisation of such a solar-thermal reactor is only likely to happen when the economic conditions are right, claims Professor Weimer.

‘There would have to be a substantial monetary penalty for putting carbon into the atmosphere, or the price of fossil fuels would have to go way up,’ he added.

Last year, British researchers claimed that they had also found the ‘holy grail’ of the green economy by producing petrol from air for the first time.

Air Fuel Synthesis in Stockton-on-Tees, Teesside, made petrol using a small refinery that synthesises the fuel from carbon dioxide and water vapour.

While the company said it used carbon dioxide extracted directly from the air in their reaction, it is mainly using industrial sources of the gas until it is able to improve the performance of 'carbon capture.'

Last year, British researchers claimed that they had also found the 'holy grail' of the green economy by producing petrol from air for the first time. Air Fuel Synthesis in Stockton-on-Tees, Teesside, made petrol using a small refinery that synthesises the fuel from carbon dioxide and water vapour