Having had a quick look at solar energy already, one of the key issues is the efficient production of energy from solar cells using widely available materials. Scientists at Harvard University have been addressing this.
The Artificial Leaf
This carries out the same processes as in nature but it allows for collection of oxygen and more importantly hydrogen which can be used as a fuel. The leaf is made of a silicon wafer: one side produces oxygen and the other produces hydrogen from photosynthesis. The the important break through with this research is that cheap and widely available metals have been used as catalysts in the reaction, instead of platinum which how it was originally achieved (Reece et al, 2011, Science). As it really highlights in the paper, the most important development is the cheap and widely available materials that are used in the process.
Harvard Professor and one of the main authors on the paper, Daniel, Nocera, explains the process in this Horizon clip.
No external wires or controls are needed, the silicon chip just has to be placed in water. This is what it actually looks like, with some real leaves in the background in case you hadn't seen them before... More information can be found on the MIT News Site
“Meet the frackers” has become a popular name for news
articles, TV documentaries and campaign groups linked to fracking. Over the next few weeks I am focus on fracking for my blog posts. Firstly lets introduce the process of hydraulic fracturing for oil and gas and
address two of the key issues the process has raised.
Hydraulic fracking is a process where fluid is pumped into
rock at high pressure which causes the rock to fracture. This creates more
space within the rock and allows oil and gas to percolate through the formation
therefore it can be pumped to the surface and extracted. It has been used in
the USA, extracting gas from areas such as the Marcellus Shale, for the last
decade and has recently been given the green light by the UK government.
Video: BBC Horizon programme "Fracking: The New Energy Rush"
Issue One: Does fracking cause earthquakes?
The honest answer: yes it can. The more the more important
question is do these earthquakes matter and can they be avoided? Recorded earthquakes
induced by hydraulic fracturing have a magnitude in the range of 1.0 – 3.8. This
causes comparable ground shaking to a large articulated lorry driving past your
house. Much higher magnitude earthquakes have been recorded from the use of controlled
explosions in mining, up to 5.1, and from reservoir impoundment where the
weight of the water causes ground fracturing, up to 7.9. (Davis et at 2013). So
the earthquake damage cause by earthquakes induced by fracking doesn't even
come close to other anthropogenic causes.
Even if the earthquakes are small, it is important that oil
and gas companies do all they can to avoid it in the first place. This can be
achieved by improved research and method in the operations. A review of
fracking in the UK was carried out which addressed the earthquakes causes in
Blackpool (Royal Society and Royal Academy of Engineers 2012). They recommended
that better fault plane analysis could help minimise risk of earthquakes by
avoiding injecting fluid directly into fault planes. Overall they gave fracking
the go ahead in the UK.
Water contamination has been a huge issue for some US
fracking operations. Using geochemical isotropic tracers at a fracking site in Pennsylvania,
it was shown that increased levels of methane, chlorine and potassium in
groundwater are “related to stray gas contamination directly linked to shale
gas operations”. (Darrah et al 2012, Procedia of Earth and Planetary Science). This
maybe a case where improved technology and processes can prevent this occurring
again however for some communities fracking has already had a severe impact on
quality of life.
