Solar power from the desert
rather than desert in Germany: renewable energy in a trans-European
context
by Rolf Hug
23.02.2007
Should the global temperature
increase by a mere five degrees “the Sahara would end in Berlin”,
chief climate consultant of the Federal government and Director
of the Potsdam Institute for Research on Climatic Consequences,
Joachim Schnellnhuber, warned with regard to the United Nations
report on climate changes on 2 February 2007. In order to avoid
this the Trans-Mediterranean Renewable Energy Cooperation (TREC)
developed a solution with which our electricity may be obtained
in future from the desert. TREC bases its approach on an initiative
of the Club of Rome and does not only give an answer to what
is to happen when the sun sets over the desert oil supplies (“Twilight
in the desert” is the latest book by George W. Bush’s
former energy consultant Matthew R. Simmons). TREC, established
in September 2003, developed a comprehensive concept for energy,
water and climate security in Europe, the Middle East and Northern
Africa, in short: EUMENA (EUrope, Middle-East, Northern Africa).
The
far-reaching recommendations made by TREC are based on scientific
studies conducted by the German Centre for Aviation and Space
Travel (DLR) that prove that the deserts of Northern Africa
and the Middle East could become a permanent source of clean
energy
for the countries of Europe by the middle of the 21. century,
that greenhouse gas emissions could be reduced by 70% and that
nuclear energy can be abandoned.
Solar thermal parabolic trough power plant; planned sites for
the power plants (concentrated solar power; photovoltaics, water
power, biomass and geothermal energy. High-voltage direct-current
power lines (red lines); Source: Solar Millennium, TREC.
TREC considers the feeding of desert electricity into
the European network as a complementary measure and under no circumstances
as an alternative to the utilisation of European renewable energy resources.
Power from the desert is to speed up the reduction of CO2 emissions in
the MENA states as well as in Europe and is to increase energy security
in EU states in which the utilisation of renewable energy is not yet
advanced and – in the long run – it is to lead to a reduction
of electricity rates. Since the implementation of the concept will take
at least two decades, political measures are to be taken immediately
and a favourable economic framework is to be established, TREC emphasises.
Proven technologies are available already
TREC focuses primarily on wind
energy and concentrated solar power (CSP) with which electricity
can be generated in solar thermal power plants that can then be supplied
to consumers in Europe with the help of efficient HVDC transmission.
Technologies required for this are available already and have stood
the test of time. What has been sadly lacking up until now is the political
will to go ahead with such an energy turnaround, a framework in which
this form of power supply can prove its realistic competitiveness
with
regard to conventional production from fossil-nuclear sources and
the necessary courage of potential investors. The international network
of
scientists and politicians now wants to implement the concept that
also includes photovoltaics, hydro power, geothermal heat and biomass
at the
respective most appropriate locations together with representatives
from politics, industry and finance.
Function scheme of a solar thermal parabolic
trough power plant. Source: DLR. [Wording: Field of solar collectors, Hot
tank, Storage, Cold tank, Heat transfer fluid pump, Reheater, Superheater,
Preheater, Network, Turbine, Condenser, Feed-water pump, Generator, Cooling
tower
Greenpeace, the german Green Party, the German Physics
Society (DPG) and the Scientific Advisory Council of the Federal Government
for Global Environmental Changes (WBGU) together with other institutions
and associations support this project. The Solar Report outlines the
so-called DESERTEC concept, focuses on certain technical aspects of power
generation in the desert as well as the transmission of power and shows
the perspectives of this ambitious project that are well worth broad-based
discussions. History and technology of solar thermal power plants were
already discussed in the reports titled "Solarthermische Kraftwerke
als Option für eine klimafreundliche Elektrizitätsversorgung" and "Solarthermische
Kraftwerke: Technologie-Transfer in den "Sonnengürtel" (links
and further information at the end of this Solar Report).
Solar heat driving
efficient 100 MW steam turbines
Thus far solar power supply from the
desert was a mere play of ideas, was hardly perceived by the public
and was rightfully criticised. The idea to produce gigantic amounts
of hydrogen
with the help of photovoltaics and to transport these to Europe on
tankers, upon closer scrutiny, proves to be a cul-de-sac: this results
partially
from the enormous and thus costly conversion losses in the production
and distribution of solar hydrogen, for which the oil industry infrastructure
would merely be copied. And, solar thermal power plants in sunny
locations around the Mediterranean Ocean, where electricity is generated
in steam
turbines with heat from concentrated sunlight, have distinct advantages
in comparison to the generation of electricity with photovoltaic
modules.
Plannable electricity supply, even if the sun’s not shining
Contrary
to photovoltaics, where solar radiation is directly transformed
into electricity by solar cells, solar thermal power plants boast high
degrees
of efficiency and low electricity production costs even in great
heat. This is generally unknown to the public, as is the fact that solar
thermal
power plants do not only provide electricity when the sun is
shining. They have heat storage tanks (e.g. liquid salt tanks) that can
be heated
over the hottest hours of midday with surplus solar energy and
can thus enable the production of solar power after sunset. And also
during the
day this stored heat can be used to produce electricity if the
need arises.
Because of solar thermal power plants having the capacity
to provide
power according to demand, they are one of the few technologies
for the utilisation of renewable energy that can not only cover the
ever increasing
electricity demand in EUMENA countries, but can also reduce
or even replace conventional power plant capacities.
The DLR scenario
requires
covering
of peak consumption plus 25 % reserve capacities and this
is what is currently being practised. According to TREC this is only
practically
possible if by 2050 the fossil power plant capacities were
doubled or
if solar thermal power plants are utilised, since other renewable
energy sources either generate too little controllable electricity
(photovoltaics and wind) or are restricted in terms of their energy
potentials (biomass
and hydropower). The DLR scenario thus envisages to maintain
gas-driven peak-load power plants with low capacity utilisation until
2050, whereas
conventional base-load power stations will disappear almost entirely.
Power supply scenario in EUMENA countries until 2050. According
to this EUMENA future model solar thermal power plants will be utilised
to cover 68 % of the local electricity demand in MENA and Europe by 2050,
13 % for desalination of water in MENA and 19 % are allocated to the export
of electricity from MENA to Europe. Source: DLR [Wording of graph: Installed
performance [GW]; Photovoltaics, Wind, Geothermics, Water power, Biomass,
Waves / Tides, Solar th. power plants, Oil and gas, Coal, Nuclear, Secured
performance, Peak load
If solar thermal plants also utilise co-generated heat,
e.g. for air-conditioning, for generating industrial process steam or
for desalination of sea water, ideally up to 25 % of the captured radiation
can be transformed into electricity and an additional 40 % into utilisable
energy. According to TREC, this exceeds the energy utilisation efficiency
of conventional photovoltaic plants by four to six times.
If large-scale
construction of solar thermal power plants is carried out in the coming
years and if all possible benefits of scale are utilised, the DLR has
calculated that production costs, including the transmission to Europe,
will amount to approximately five euro cents per kilowatt-hour. Currently
production costs of solar thermal power plants are approx. 15 to 20
cents per kilowatt-hour according to calculations by TREC and DLR, and
are
thus significantly lower than those of photovoltaics. In hybrid operation
with an improved utilisation of the steam generating power plant with
added combustibles, this price could even be decreased to below 10
ct/kWh. Electricity generation costs of a modern wind energy plant with
an output
of 2 000 kilowatt at an average location are 6.4 ct/kWh; 15 to 20 years
ago they were on a similar level as the costs of solar thermal power
plants. This shows that – as was the case when wind energy was
introduced to the market – public investments are necessary to
fully utilise the potential of solar thermal power plants, TREC emphasises.
Solar thermal power plants can achieve the highest degrees
of efficiency and thus also the lowest electricity costs among renewable
energy forms. Source: Solar Millennium.
Studies prove feasibility and high electricity yields
Two studies conducted
by the German Centre for Aviation and Space Travel (DLR) in 2005 and
2006 prove with satellite-supported data that solar thermal power plants
can generate sufficient electricity to cover the increasing demand
of the MENA states and Europe by utilising less than 0.3 % of the desert
areas of MENA. Furthermore, sea water can be desalinated in the process
and thus drinking water is produced. Complemented with wind energy
plants
that can, for example, transform the strong Passat winds in southern
Marocco into electricity, new perspectives for a secure and climatically
neutral electricity supply with new dimensions are created.
250 gigawatt-hours
of electricity each square kilometre per annum
DLR researchers Franz
Trieb and Hans Müller-Steinhagen calculated that a surface area of one
square kilometre in the desert can produce approx. 250 gigawatt-hours
of electricity per annum.
This is 250 times more than can be harvested from one square kilometre
of biomass and still five times more than from the best wind energy plants
and hydro power plants.
Trieb and Müller-Steinhagen elucidate this
by way of an example: a surface area the size of Lake Nasser in Egypt
(6 000 km2, see picture) receives as much energy from the sun as is currently
extracted in the Middle East in the form of oil (9 billion barrels per
annum – 1 barrel equalling to 159 litres).
Source of photos: CIA
Factbook
The DESERTEC concept does not envision the erection of a few gigantic
power plants but rather for the construction of many decentralised power
plant blocks with capacities of between 50 and 200 MW that are spread
among the MENA states.
Renewable energy from the desert: tried and tested
in the USA and also possible in Europe
Solar thermal power plants at
suitable locations are currently already capable of producing economically
feasible
electricity. This is proven by nine solar power plants in the Mojave
Desert (southern California) with an output of 254 megawatt (MW).
For about two decades they have been producing approx. 800 mWh of solar
power per annum. The parabolic trough systems used are currently the
most cost-effective
method of generating electricity from solar energy. In the province
of Granada in southern Spain the German company Solar Millennium AG
is
currently
driving ahead three projects with this technology that was developed
in Germany.
Solar power station at Kramer Junction (USA): over 2 million
km2 of parabolic trough collectors with an electricity generating capacity
of 354 MW produced almost 10 billion kWh of solar power and yields of approx.
1.5 billion US$ by the end of 2001.
Sources: Forschungsverbund Sonnenenergie;
DLR.
High-voltage direct current from the desert to Europe
In
order to transmit the electricity produced in Northern Africa and the
Middle East to, for example, Germany, TREC is counting on high-voltage
direct-current transmission since the conventional AC net is not capable
to transport electricity over distances of a few thousand kilometres.
In the case of underwater lines, a few hundred kilometres are the limit.
The solution is a combination of conventional AC nets for the local
distribution of electricity and HVDC transmission technology for long-distance
transmission.
This is characterised by low transmission losses and is already used
between Norway and Germany and many other locations worldwide.
High
solar power production and low transmission losses
Northern Africa is
already
connected to Europe via electricity cables that would merely have
to be expanded, states Dr Gerhard Knies of TREC. "These cables run
through the sea and we use the high-voltage trick,” the doctor
of physics says. “If we transport energy through a power line and
increase the voltage tenfold, the losses decrease to one percent.” The
losses in HVDC transmission amount to about 3 % per 1 000 kilometres.
The transport to Europe would thus amount to losses of between 10 and
15 %, depending on the exact distance. In Northern Africa two to three
times as much solar thermal electricity can be generated than could be
with the same plants in Europe. HVDC lines with capacities of up to 1.5
gigawatt have been utilised by ABB and Siemens for many years over long
distances. The connection with Northern Africa and the Middle East is
no problem, both companies confirmed at the World Energy Dialogue at
the Hannover Fair 2006.
Left: Control room of one of the two frequency converting
stations of the HVDC transmission line (1 800 MW) covering 960 km between
Tianshengqiao and Guangzhou in China. Right: Thyristor ventilators of an
HVDC line in China. Source: Siemens AG.
More supply security without oil, gas and nuclear energy
Since
the first oil crisis in 1973 Europeans are well aware of the riskiness
of oil supplies; that the gas tap is not always open either was shown
by Russia recently. And most also agree on the risk that nuclear power
poses at home and in politically unstable countries. The TREC concept
provides an alternative to oil and gas monopolies with its solar thermal
power plants and wind energy plants that are to be operated by numerous
private and public owners. The creation of jobs in MENA states, trade
with desert electricity and the resulting economic and social upliftment
can further enhance security, TREC argues. Many “small” solar
power plants with a joint output of between 50 and 200 megawatt and numerous
power lines to Europe create a decentralised production structure and
offer alternative means of transport.
White paper with concrete projects
and solutions for the energy crisis, water supply and climate protection
Currently
TREC is developing a white paper for the Club of Rome that summarises
the DLR studies on “Clean Power from Deserts” as well
as interesting opportunities for co-operation between the EU and
MENA countries.
Particularly in the wake of the alarming climate report of the
United Nations and the shocking results of the report by the chief
economist
of the British Government, Sir Nicholas Stern (Stern-Review), on
the economic consequences of climate changes, these are topics
that should
be at the top of the agenda in Brussels and the various governments
of the member states, because German and European research institutes
and
companies are among the global leaders in the development of solar
thermal power plants and their components. It is also the opinion
of the Federal
Ministry of Environment in Berlin that such systems for environmentally
friendly electricity generation should be exported to and realised
in the sun-belt countries in the south. This would not only further
the
protection of our climate but would also create jobs – even
in Germany. "If the European industrial policy is serious
about its Lissabon Strategy, it must smooth the way for solar thermal
power plant
technology. Now,” the technology group SCHOTT, manufacturer
of receivers for STK, states in a memorandum.
Left: A solar receiver collects concentrated solar energy. Right: SCHOTT
employees in Mitterteich manufacturing and testing parabolic trough receivers.
Source: SCHOTT AG
But this will not be sufficient: in order to build up export capacities
of 100 gigawatt – which corresponds to the output of about 100
nuclear power plants – by 2050 in addition to covering the demand
of MENA countries, state subsidies would be required for the construction
of power plants and transmission lines. A single-digit billion figure
would suffice. Experts calculated that the implementation of a single
large solar thermal power plant project as suggested by TREC would reduce
the costs of solar thermal energy production to below the costs of most
fossil fuels. Currently the price for heat from concentrated collectors
that correspond to one barrel of oil is already approx. 50 dollars. According
to TREC this would render the production and transport of electricity
competitive and thus attractive to state and private investors. In terms
of the DLR scenario the total investment would amount to just below 400
billion euro, spread over approx. 30 years.
The beginning: solar thermal
power plants for the Gaza Strip and in Yemen
In order to realise their
concept, TREC suggests endeavours comparable to those of the Apollo
space travel programme with which humanity discovered space. Besides
the required
feed-in regulations or purchase contracts for clean power from the
deserts, an “Apollo DESERTEC” programme could be driven ahead with
three projects that would enable EUMENA to accomplish significant progress.
First investigations have shown that these are technically feasible,
but urgently require financial and political support:
Gaza Solar
Power and Water Project
Solar thermal power plants for the simultaneous
production of drinking water and electricity – as a part
of an international reconstruction programme in the autonomous
Palestinian
territories – could be located on Egyptian territory and
could supply two to three million people in the Gaza strip through
power and
water lines. This project is to become a turning point to the
current catastrophical developments in the Gaza region, regarding
economic
and social problems, the conflict around drinking water and the
stagnating
peace process between Israel and Palestine. The total investment,
according to TREC, would amount to approx. five billion euro.
Sana’a
Solar Water Project
A sea water desalination plant at the Red
Sea and the construction of pipelines to the capital of Yemen
(Sana’a),
the drinking water reserves of which will dry up in about 15
years, could prevent a humanitarian disaster and social unrest
in Yemen
and would
contribute to saving a cultural world heritage site. Since the
alternative of relocating 2 million people would cost about 27
billion euro, an investment
of 5 billion euro into the drinking water pipeline and the related
solar thermal power plants for operation of the pumps would be
a solution that
is economically far more feasible, TREC emphasises.
A
new South-North Power network
Starting the construction of
a power network from South
to North to transport electricity from the deserts to Europe
would lead to an investment boom in the field of renewable
energy in
MENA countries
from 2020 onward and would allow Europe access to cost-effective,
clean electricity. According to the DLR study, the costs of
the required HVDC
lines for the first 10 gigawatt are also estimated to amount
to five billion euro.
Hands-on approach in support of power from the desert. Assembly
of reflectors for a demo-version of a parabolic trough system, assembly
of absorber pipes. Source: Solar Millennium AG
Europe and the Mediterranean countries can only benefit
from such a co-operation
TREC demands that the European Union, as a first
step, supports a campaign that is to convince the governments in the
Middle East and Northern Africa that solar thermal power plants will
be more cost-effective in the long run than plants running on fossil
fuels. MENA countries would benefit from this, even without exporting
electricity.
Clean power from the sun-belt of our earth:
California and Northern Africa are ideal locations for solar thermal
power plants. Large industrial centres in the North can be reached with
HVDC lines.
Source: SCHOTT AG
[Wording: Suitability for solar thermal
power plants: excellent, good, suitable, unsuitable
Furthermore, the EU is to give MENA countries a guarantee
that it will import clean electricity that could be produced from 2020
onward. This is why TREC is of the opinion that the option of solar power
from the South should immediately become part of the EU Energy Portfolio
and should also be followed by the policies of member states. The EU
could accelerate the construction of solar thermal power plants in MENA
countries by consulting and assisting their governments in introducing
feed-in regulations and compensation according to the example of the
German Renewable Energy Law (EEG). Further steps could be international
purchasing obligations on the basis of local feed-in regulations as well
as pre-discussions for planning HVDC lines and the inclusion of the EUMENA
project into the so-called Barcelona Process. This provides an institutional
framework for the Mediterranean policy of the EU and is based on the
concept of intensive co-operation of countries on either side of the
Mediterranean Sea on an equal rights basis. The purpose of this "Euro-Mediterranean
partnership" is peace, stability and prosperity. A secure and climatically
neutral energy supply forms the basis of these.
"Energy is an indispensable
fundament for socio-economic development and is a basic ingredient in
the recipe for peace. It is a basic right that all societies and human
beings should have fair access to energy markets, bearing in mind that
energy production and consumption must be sustainable for future generations,” President
of the Club of Rome, His Royal Highness Prince El Hassan bin Talal from
Jordan, emphasised in his address at the World Energy Dialogue 2006 in
Hannover.
