Taming the desert: energy out of Africa
If this area in Africa were covered with solar panels it would generate enough electricity to fulfil the world’s requirements
Desert energy could provide power for 90 per cent of the human population living less than 3,000km from a desert
Solar panels could be used to power steam plants in the same way that coal steam plants do
HDVC could become a more effective way to carry solar-generated electricity
Harvesting the vast energy potential from Africa's deserts could provide a much needed boost to Europe's energy supply.
"Within six hours deserts receive more energy from the sun than humankind can use in a year." How could you not, given this staggering claim from Dr Gerhart Knies, want to harvest this energy, even when confronted with the economic, social, financial and technological challenges?
These figures were also the germ of the Desertec Foundation, created four years ago under the auspices of Dr Knies, its founding chairman. The concept was developed by a network of politicians, scientists and economists from around the Mediterranean, from which arose the Desertec Foundation. It demonstrates a way to provide climate protection, energy security and development by generating sustainable power from the sites where renewable sources of energy are at their most abundant.
It is planned that all kinds of renewables will be used, but the sun-rich deserts of the world play a special role. By using heat storage tanks, concentrating solar-thermal power plants in deserts can supply electricity on demand day and night. This makes them an ideal complement to fluctuating energy sources such as wind and photovoltaic power and allows a higher percentage of these variable energy sources to be used in the future electricity mix.
It would require solar panels on less than 0.5 per cent of the desert surface to supply enough power to feed the energy plans of the entire world. The foundation's plans were not as ambitious as that. Its stated aim was to supply enough power to meet the needs of North Africa, and to ship the surplus to Europe, where it is claimed it could meet up to 15 per cent of demand. The foundation believed that by 2050, 125GW of power could be generated in North Africa.
Concentrated solar power
The concept is simple. It has long been realised that deserts are ideal for optimal solar radiation. The power would be generated primarily from concentrated solar power (CSP) using the parabolic trough design, although elements of photovoltaic, wind and hydro were to be accommodated. Most sites would include thermal salt storage allowing 24-hour supply. The surplus energy would be moved to Europe by a network of HVDC cables.
Despite the difficult social-economic conditions, regional policy is working in Desertec's favour. Algeria has a generous feed-in-tariff scheme for CSP and has pledged to invest $20bn by 2030. Morocco has 2GW of solar planned by 2020 and is looking for a 40 per cent renewable energy contribution by 2050.
Back in Europe, Germany has a feed-in-tariff specially designed for desert solar. With its abandonment of nuclear energy it is in need of this energy to meet its 80 per cent renewable target by 2050. Finance is available from World Bank, which has pledged $750m to develop 900MW of renewable energy across the MENA region.
The man now holding the reins is Dr Thiemo Gropp, co-founder of Desertec, who has followed the development of renewable energies for many years. As an entrepreneur he has built and led several nationally, as well as internationally, successful technology companies.
"Desertec is always thought of as a project, but it is actually a concept," he explains. "It is about realising a vision or a concept on a global basis. From that point of view I can say that Desertec is even more necessary than ever.
"We have seen very good progress in different regions in the world, not only in the MENA [Middle East and North Africa] region. There are promising steps in South America, very good progress in Asia and last but not least on the MENA region on the Arabian Peninsula. We think that Desertec is making good progress, however there are always hurdles and some are quite tricky. We have to just cope with them.
"The purpose of Desertec was always to generate for the local community," Dr Gropp continues. "It is not in the first place energy for Europe, however this can be a side effect and that was always the story of Desertec.
"There is such a high energy demand in the MENA region that a lot of energy will be used or needed in the region. However, the export factor to Europe came from the fact that we also have certain demand or will have a certain demand in the future. In Germany, for example, we are building high amounts of wind and PV power which is highly volatile. CSP power from North Africa could compensate some of that."
It appeared that the plans had hit rocky waters last November when two major industrial partners abandoned the scheme ' Bosch and Siemens. Bosch abandoned its solar operations entirely. Having poured vast resources into developing a solar power operation it conceded that it was unprofitable, so stepped away.
Siemens also pointed the finger of blame at the profitability of the solar sector. Due to the changed framework conditions, lower growth and strong price pressure in the solar markets, the company's expectations for its solar energy activities have not been met, the company said in a statement.
"We think Desertec is a civil society movement," Dr Gropp says. "However, we have always said that if you want to take big steps and create big results it will be in collaboration or hand-in- hand with industry otherwise you will have incremental moves forward.
"It is not done or driven by industry, but we need industry as partners and it has to become a business. The motivation behind Desertec is to create a sustainable solution for corresponding nations ' so it is building bridges between Germany or France or the UK, and between countries in North Africa and the MENA region.
"It has to be mutually beneficial, creating jobs, creating benefits, creating education, creating clean air and reducing climate change for everybody," Dr Gropp continues. "This can be achieved only if you have a wide agreement within society rather than just a few companies moving ahead. However, in order to do this you also need the companies, so this is what we clearly say and why we work together with companies."
Despite that setback – and however it is couched it is a setback – there have been positive signs for the foundation. A recent cooperation agreement between Germany and Tunisia focuses on the expansion of electricity grids, energy efficiency, energy research, renewable energies and the political backing of the Desertec project.
Within the framework of the energy cooperation, Tunisia will benefit from the know-how of German technology companies in these areas.
This follows on from the announcement late last year about an agreement between themselves and the Moroccan Agency for the Development of Renewable Energy and Energy Efficiency (ADEREE). This focuses on the exchange of expertise and know-how in developing energy policy and regulation.
"Even North Africa is not a single project," Dr Gropp says. "The MENA region is a huge area and by the end of the day I don't know how many projects we will have. Hopefully it will be hundreds – projects of all sizes, different countries, and different types.
"Basically, Desertec is promoting a concept," Dr Gropp adds. "They use the energy coming from the desert and combine it with other energy to create a complete solution out of it. It could be CSP, wind, or photovoltaic. In some regions it could even be hydro. Altogether this will create a final solution."
Moroccon solar power
Plans by Morocco to generate an additional 500MW from two new concentrating solar power plants moved forwards late last year. A $1bn deal was signed for construction of one of the plants by the end of the year.
The plants, to be sited near Quarzazate on a 2,500 hectare area of land, are among five planned by the North Africa desert nation by 2020 at an estimated cost of $9bn. They will have a combined capacity of 2,000MW.
"If you look at Morocco, this is a success and it has been supported by World Bank," Dr Gropp says. "We are very happy that Morocco has moved forward and created a solar plan that is now being realised. This solar plan has, of course, been inspired by the Desertec concept.
"It will not have connection to Europe in the first place, though future projects might have this connection and might export power to Europe, but not initially."
Dr Gropp continues: "It will most probably include storage and, of course, will have a high local content. It's important to mention that it's a Moroccan project. It's controlled by the MASEN, the Moroccan Solar Energy Agency. National governments have to pick up the concept of the idea and realise it locally."
So how is the project faring? Robert Pitz-Paal, co-director of the DLR Solar Research Institute, feels that it is performing well. "In contrast to widespread public perception, Desertec is not simply an investment programme where a start is made today on a project that will reach completion in 40 years. It is far more about initiating sustainable development."
Over the last four years, the main players have already succeeded in convincing numerous countries in North Africa to invest in renewable energy sources for the long term. "The first solar power plants have already been built in Morocco, Algeria and Egypt; the total investment is many billions."
Pitz-Paal expects that in the next 10 to 15 years, the countries of North Africa will consume the vast majority of the electricity they generate. Imports to Europe will not take place on a large scale until after 2030. "By that time, in Europe we will have a very high proportion of variable wind and solar power in our national grids," he adds. "Large-scale networking and solar power plants as controllable sources of electricity should then be helping to cost-effectively stabilise the power grid."
Pitz-Paal is keen to dispel the myth that Desertec is all about power supply to Europe. "We expect that it is the countries in North Africa that will be the principal beneficiaries of this initiative," he says. "We are already observing an increase in local added value from project to project."
Given the vast potential of desert energy, the rather torpid take-up is surprising.
"We run around giving 300 talks a year because it seems to be obvious, but you have to explain it again and again," Dr Gropp says. "There are a lot of interest and pressure groups behind the fossil fuel industry. Lobby groups will try to find arguments against what we propose and so you have to convince with simple and clear statements.
"Finally, if you look at the gross economic situation, it is also profitable... well, let us say the most economical solution, because the calculations that are made are comparing apples with pears."
Concentrating solar power
It works just like a coal steam power plant, with the difference that concentrated solar power is used for steam production, instead of coal. Large mirrors are positioned in such a way that they reflect and concentrate the sunlight onto a certain point much like capturing sunlight through a magnifying lens.
A major advantage of this technology is that a part of the Sun's heat can be collected in heat storage tanks during the day and then run through steam circuits at night or specifically during peak hours, depending on the demand. With this technology, renewable and controlled energy can be provided according to the demand of the electricity grid.
Facts and figures
Research by the German Aerospace Centre shows that CSP plants in North Africa and the Middle East will be capable of producing up to 470,000MW by the year 2050.
Investment in the construction of a CSP plant with air-cooling, which is capable of producing 250MW, currently amounts to approximately '1bn.
In good locations, the solar plants can be operated at full capacity day and night on solar power alone thanks to heat storage tanks; the life-time of such a plant would be more than 40 years.
If saltwater from nearby coasts is used instead of drinking water for the cooling units, a 250MW collector field may be used to operate a 200MW turbine and 100,000m3 of drinking water may be produced a day (over four million litres per hour) through the process of water desalination.
By using level Fresnel reflecting mirrors, there is even the possibility of using the shade underneath collector fields for agricultural purposes.
High-Voltage Direct Current transmission
HVDC transmission is a way of carrying clean electricity over long distances to the places in the world which consume large amounts of energy.
Around 90 per cent of the human population live fewer than 3,000km from deserts and could be efficiently supplied with clean desert electricity.
The line losses are very low – only around 3 per cent per 1,000km – and the extra cost is only one or two cents per kilowatt hour. This is more than compensated because solar power plants located in deserts are much more efficient due to the longer and more intensive solar irradiation and fewer winter months.
There are dozens of lines up to 1,700km long (Inga-Shaba, Democratic Republic of Congo) with capacities of up to 5GW (Yunnan-Guangdong, China) already in operation around the world. HVDC lines are also used in Europe: Sardinia is connected to the mainland by undersea HVDC cable and there is a whole network of HVDC connections between central Europe and Scandinavia.
HVDC lines take up less space than conventional AC power lines and can be laid over long distances underground. This increases public acceptance and means the network can be extended faster.
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