Researchers at the University of Illinois have modelled what would happen if very large scale wind and solar power stations were installed in the Sahara. If these covered 9 million square kilometres, it would mean lower temperatures, higher rainfall and more vegetation for the desert.
Such a large installation is unlikely in the immediate future, if only because the power output would be four times the current world demand. The idea is also not new, in 2009 the Desertec organisation proposed a similar idea, integrating output from renewably resourced electricity production in a system that would power the Middle East, North Africa and Europe. The importance of this study is the impact on vegetation it has shown possible.
"Our model results show that large-scale solar and wind farms in the Sahara would more than double the precipitation, especially in the Sahel, where the magnitude of rainfall increase is between 20mm and 500mm per year," said Dr Yan Li, the lead author of the paper from the University of Illinois, US. "As a result, vegetation cover fraction increases by about 20%."
It is important to note that the effect is caused by a combination of wind turbine and solar production as they have different effects on their immediate environment.
With wind turbines, it's all about the mixing of air caused by the rotation of the blades. Wind farms mix warmer air from above, which creates a feedback loop whereby more evaporation, precipitation and plant growth occurs.
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Solar panels actually reduce the reflection of sunlight from the surface known as the albedo effect. This triggers a positive albedo-precipitation-vegetation feedback that leads to precipitation increases of about 50%, the authors report.
There are very early moves towards the idea. Interconnectors are planned between Tunisia and Europe to export power from proposed Concentrated Solar Power stations. CSPs work by heating a liquid, usually a concentrated salt, in either tubes at the focus of trough-shaped parabolic mirrors or in “solar boilers” at the top of tower in a field of mirrors. The latter has an advantage that the individual mirrors can be flat and moveable so the whole field is a parabolic mirror. The lack of inclusion of CSP’s effects might undermine or re-inforce the effect the Illinois team describe (note: why do Americans appear to ignore CSP and slavish believe in photovoltaics as the only option?)
NOVEL DESIGN FOR WIND GENERATORS IN CITIES
One major problem with wind farms appears to have been addressed so that small personal generators could be hung on the wall in urban areas.
Wind power currently produces 4% of the world's electricity. But wind farms can only capture "horizontal" wind and tend to be located in rural areas because of this. In cities, where wind is more multi-directional because of large buildings and other obstructions, such systems are complex to use.
The inventors, Nicolas Orellana and Yaseen Noorani from Lancaster University, set out to solve the problem.
"If we could find a solution that caters for the half of the world's population who live in cities, we could give these people an opportunity to generate their own energy and contribute to the environment," explained Mr Noorani.
The two have come up with a portable, low cost design that will generate power using wind coming from any direction. They have won the UK 2018 James Dyson Award of £2000 to kick-start production development. They are also eligible for the international prize of £30,000.
BBC BAN CLIMATE CHANGE DENIERS’“BALANCE”
The Charter and Agreement under which the BBC operates requires that they are politically impartial. In the past there have been complaints about their inclusion of climate change deniers in the name of “balance”.
The Guardian revealed in October that the BBC had apologised for an interview with Lawson on the Radio 4 Today programme after admitting it had breached its own editorial guidelines for allowing him to claim that global temperatures have not risen in the past decade. The regulator Ofcom subsequently ruled the BBC had breached broadcasting rules.
The Today programme was also censured by the BBC complaints unit for an interview with Lawson in February 2014 and has been criticised for failing to implement fully the findings of the BBC Trust’s 2011 review into the “accuracy of the BBC’s coverage of science”
Now new “Editorial Guidelines” have been issued and BBC staff invited to training in how to report climate change. These have been obtained by Carbonbrief.org who have published them today. Of particular note:
- Be aware of ‘false balance’: As climate change is accepted as happening, you do not need a ‘denier’ to balance the debate. Although there are those who disagree with the IPCC’s position, very few of them now go so far as to deny that climate change is happening. To achieve impartiality, you do not need to include outright deniers of climate change in BBC coverage, in the same way you would not have someone denying that Manchester United won 2-0 last Saturday. The referee has spoken. However, the BBC does not exclude any shade of opinion from its output, and with appropriate challenge from a knowledgeable interviewer, there may be occasions to hear from a denier.
- There are occasions where contrarians and sceptics should be included within climate change and sustainability debates. These may include, for instance, debating the speed and intensity of what will happen in the future, or what policies government should adopt. Again, journalists need to be aware of the guest’s viewpoint and how to challenge it effectively. As with all topics, we must make clear to the audience which organisation the speaker represents, potentially how that group is funded and whether they are speaking with authority from a scientific perspective– in short, making their affiliations and previously expressed opinions clear.