ojdo » Energy

DESERTEC studies: AQUA-CSP

ojdo — Wed, 06 Apr 2011 03:00:36 +0000

AQUA-CSP is one of three conceptual studies which explored different parts of the DESERTEC project, a concept which relies on solar power from the world’s desserts as a major energy source for Europe. In previous posts I already talked about the two other studies MED-CSP andTRANS-CSP, the first focused on generation, the second on transportation of the generated electricity. This article deals with the third, often overlooked, aspect if this undertaking: desalination of huge quantities of sea water.

Water crisis

It might not be apparent yet, but growing world population, incresing per-capita consumption of usable water plus global warming will most probably lead to a severe shortage of fresh water in the aride regions of the world. This so-called water crisis has many unsettling implications. So we better think about ways to alleviate or even prevent the crisis.

Desalination

Desalination is an energy-intensive process to remove salt from sea water. Coupled with filtering it can supply fresh water. This is where the local benefit of having huge CSP (concentrating solar power) plants in desert regions. Continuous, carbon-neutral electricity plus a reliable water source are things I definitely would like to have in my country when facing a water crisis in the foreseeable future.

DESERTEC studies: TRANS-CSP

ojdo — Wed, 03 Mar 2010 03:00:55 +0000

In a previous post I wrote about MED-CSP, a study being part of the DESERTEC project which outlines a scenario for generating huge amounts of electricity by means of Concentrating Solar Power applied in the Mediterranean region. CSP stands for solar thermal power plants which do not operate with the photovoltaic effect used in solar cells, but for using the solar radiation to directly heat a medium—typically a fluid—which then is used to propel an ordinary steam turbine like used in fossil fuel or nuclear power plants.

While the last post focused on the MED-CSP study which explores the technical potential for generating electricity, this article deals with the transmission of a part of this energy to Middle and Northern Europe where it can substitute fossil fuels.

TRANS-CSP

The study begins with a chapter comparing three technologies that could be used to transfer solar Electricity from MENA to the Northern states. Those options are hydrogen, the conventional alternating current (AC) grid and a high voltage direct current (HVDC) infrastructure.

Hydrogen quickly drops out in such an application as two conversion steps, long transport and storage lead to an efficiency of the whole process below 30%. Also the conventional AC grid has not a sufficient efficiency. For 3000 km, only about 55% energy efficiency can be reached.

A HVDC line is significantly better with about 90% efficiency over 3000 km. That is why the study proposes to construct 20 transmission lines all over Europe until 2050, each with a transfer capacity of 5 GW. Such an infrastructure could then deliver 15 % of the projected electricity demand of Europe. Figure 1 summarises this scenario for 30 European countries from Scandinavia to South-Eastern Europe.

Image 1: TRANS-CSP scenario of gross electricity production and import for the analysed European countries until 2050. The import of other than solar electricity to the region is negligible. Diagram reproduced from the TRANS-CSP summary

The projected development includes three main trends:

Until 2020 the declining nuclear power plants and rising electricity demand are compensated mainly through natural gas and coal plants.
Starting in 2020, solar imports begin. Growing shares of wind energy and biomass usage begin to substitute coal and gas.
In 2050, natural gas usage has fallen back to a year 2000 level. Coal use for electricity production is less than half compared to the year 2000.

Concerning replacement of base load: the study projects that renewable energies will primarily reduce fuel consumption until 2020, but hardly substitute power capacities. Another interesting fact concerns the dependency from energy imports, an argument that is often brought against the DESERTEC project. Figure 2 outlines the amount of energy imported from foreign countries to the EU.

Image 2: Import dependency inclusive CSP import in the TRANS-CSP scenario compared to the current trend of import dependency in the EU. Diagram reproduced from the TRANS-CSP summary

By strengthening renewable energies within the European Union, import dependency can be dramatically reduced. The solar import of 15% of our electricity from MENA countries then are peanuts compared to the energy that today is imported in form of coal, oil, gas and uranium.

Technical difficulties

If the scenario becomes reality, Europe would have a share of 80% renewable energies for electricity production in 2050. This requires a efficient backup structure to compensate fluctuating feed-ins from renewable energies in form of natural gas peaking plants. The local electricity grid will have to be consolidated to redistribute electricity from the centres of production (offshore wind, rural biomass) to locations of demand (cities).

Subsidies and external costs

One argument against the further financial support of renewable energies with premium feed-in tariffs as realised in Germany is that this money could be spend wiser to improve the efficiency of traditional (i.e. fossil and nuclear) technologies. This arguments forgets that those technologies itself are heavily subsidised already. These subsidies are direct or indirect and include:

Grants or low-interest loans to energy producers
Quota, technical restrictions and trade embargoes
Direct investment in energy infrastructure
Public research and development
Demand guarantees and mandated deployment rates
Price controls and market-access restrictions

and last, but especially not least:

Environmental external costs

External costs were and are a current research topic. In Europe, the ExternE project group investigates external costs caused from energy production. They have a short definition of external costs:

An external cost [...] arises when the social or economic activities of one group of persons have an impact on another group and when that impact is not fully accounted, or compensated for, by the first group. Thus, a power station that generates emissions of SO2, causing damage to building materials or human health, imposes an external cost.

When those costs are assessed, they can be re-internalised. Ways to do this are either taxes on technologies that cause the costs or by financially supporting alternative technologies which avoid those costs. External costs which have not yet been fully assessed are nuclear costs caused by nuclear waste disposal and transport. Other unquantified costs are political costs for wars on finite resources or military presence in general to secure access to them.

So support for renewable energies is not only fair but rather necessary to neutralise an otherwise unbalanced situation.

What’s next

In the next and final DESERTEC studies article I will cover AQUA-CSP, a study estimating the potential for providing water by desalination of sea water, powered by abundant energy from CSP plants in desert countries in Northern Africa.

DESERTEC studies: MED-CSP

ojdo — Wed, 30 Dec 2009 02:00:44 +0000

This article originates from a presentation given by Hani El Nokraschy, one of the leading persons of the DESERTEC foundation. He presented the foundation’s vision towards a sustainable generation of electrical energy and drinking water around the Mediterranean Sea for Europe, Africa and the Middle East. His presentation covered the three main studies called MED-CSP, TRANS-CSP and AQUA-CSP. CSP stands for Concentrating Solar Power and is the key technology for exploiting the huge potential of solar energy that shines on Africa’s deserts.

I split the presentation to three articles, each presenting one of the studies. So this article deals with the idea from which DESERTEC originated and the first study MED-CSP.

The idea

According to an interview with Jörn Aldag, one of DESERTEC’s founding fathers, the idea originate at the physician Gerhard Knies who worked at the research centre Desy in Hamburg. After the Chernobyl disaster in 1986 he realised that nuclear energy could not be a solution to mankind’s energy problems. His second thought was the simple fact that world’s deserts together receive energy equivalent to the annual global energy consumption — in 6 hours.

So even when just the technically and ecologically exploitable potential is used, it should be easy to cover our energy demand without having to burn fossil fuels. To estimate this potential and to show a possible strategy for its exploitation until 2050 in the Mediterranean area was the task of the study MED-CSP.

MED-CSP

The study’s name is an abbreviation for Concentrating Solar Power for the Mediterranean Region. It investigated the potential for electricity supply from renewable sources in countries around and near the Mediterranean Sea. The region is described as EU-MENA which stands for Middle East and Northern Africa. This includes — amongst others — Spain, Italy in Europe; Algeria, Morocco and Egypt in Africa and Turkey, Iran and Saudi Arabia in Middle East. From this potential it then develops a scenario which demonstrates that it is possible not only to meet the energy demand of future growth in developing countries, but also export excess energy to central Europe for mutual benefit.

Before I get into the details, first some numbers from the EU for comparison: As of 2006, EU27 consumed about 3400 TWh of electric energy. About 55% of this energy is delivered by thermal power (mainly from coal, gas and oil), another 30% by nuclear power and 14% by renewable sources. The missing 1% comes from pumped storage power plants. (Source: Eurostat)

Now to the EU-MENA area: in 2002 the 25 countries had an energy production of 1400 TWh/a, almost completely provided by oil, gas and coal. This isn’t very surprising as states like Iran, Iraq, Saudi Arabia have huge reserves of them.

The scenario

The following image shows the development of electrical energy production in the EU-MENA states for the years 2000, 2010, 2020, 2030, 2040 and 2050.

Image 1: Scenario for electric energy production in EU-MENA countries from 2000 to 2050 in TWh per year, separated by energy source. Diagram reproduced from the original numerical data.

The two remarkable points are obvious: First, the reign of fossil fuels ends. The role of coal and gas rises its peak probably somewhere between 2020 and 2030 and then their importance begins to diminish. Second: At the same time concentrated solar power plants begin to rise in importance. Their enormous potential becomes obvious when realising that they might generate 2000 TWh/a in 2050. That is more than 50% of today’s electrical consumption of EU27. While a lot of the produced energy will be used to power their own economies, a huge share will also be left in order to be exported to the “colder” parts of Europe where it can help replacing fossil fuels burnt there.

Energy production by country

The following diagram gives an idea of the contributions to the proposed future energy production in the Mediterranean area.

Image 2: Projected energy production in 2050 divided by country. Data is from the same source as image 1. 100% are equal to 4020 TWh/a.

I have no striking interpretation for this image. Slice size largely depends on the population and expected state of development in 2050. It just gives an idea of the roles of single countries. Italy and Spain will have exploited nearly all their CSP potential while other countries would still have huge reserves left to grow their energy output.

What’s next

The next article on this topic will be about TRANS-CSP dealing with the infrastructure needed for energy transports from MENA to Europe. It will also focus on the economics (read: price) of production and transport of electricity. The third article will present the study AQUA-CSP which investigated the potential for production of drinking water based on desalination powered by renewable energies.

From finite to renewable energy

ojdo — Wed, 15 Jul 2009 02:00:36 +0000

Fossil resources, i.e. coal, oil and gas, are finite. This fact is not surprising, but is worth to be mentioned. Its direct consequence is that in near future we will have to be able to generate (more precisely: convert) all energy we consume from renewable sources. This need is independent from any consequences that arise from the combustion of fossil fuels (i.e. greenhouse effect). The climate change just adds another “incentive” to realise that necessary shift more quickly. This article tries to give a non-exhaustive overview over the current dependency on fossil fuels and scenarios of possible replacements.

Current state

In 2006, about 86% of the world’s primary energy usage was covered by fossil fuels. This is indeed a strong dependence on resources which won’t be available indefinitely. Furthermore the annual consumption of fossil fuels is increasing. This increasing demand soon might be confronted with Peak Oil, an event which probably marks the end of the era of cheap fossil energy. Peak oil is defined as the instant when the global oil production no longer increases. It is predicted to occur somewhere in the near future, perhaps in the next decade. With high confidence it can be said that we’d better look for replacements now:

Nuclear alternatives?

Some experts and politicians see nuclear power as a feasible source to replace fossil fuels. Nuclear power can mean two options: the first one is nuclear fission as present in all existing nuclear power plants in which uranium is fissioned in a controlled chain reaction to heat water that propels an electric generator. In my opinion their use is irresponsible due to the difficulty—if not impossibility—of safely storing the nuclear waste for thousands of years. Another counter-argument is that uranium is a finite resource, too. The second option still takes at least 50 years of research: nuclear fusion. It is to be like fission, but without the risks of a reactor meltdown and no long-term radioactive waste. I would embrace this source of energy, but it will basically come too late. We need to reduce the use of fossil fuels now, not starting in 2060 or even later.

Solar power

The only reliable source of energy that won’t deplete as long as earth exists is the sun. Already with today’s technology it would be possible to supply the vast majority of our energy consumption by solar plants. Here I am not primarily referring to the prominent photovoltaic cells. I rather think of much simpler solar-thermal power plants, which concentrate the sun’s rays in order to directly heat water that is used for the generation of electricity. This type of power plant only makes sense in constantly hot, sunny regions like deserts.

And indeed this idea is not new: the Solar Grand Plan in the USA and the initiative DESERTEC for around the Mediterranean Sea are concepts to construct a huge amount of solar power plants that could provide the better part of the needed electric energy.

What else

Now I talked about a possible substitute for fossil fuels, but only for the generation of electric energy. However, mobility and heating are dependent on fossil fuels, too. So other things have to happen, too:

Modernise buildings to save energy otherwise wasted for heating or cooling. Passive and zero-energy houses exist.
Develop and—especially—apply new concepts for individual mobility. Perhaps the future belongs to electric vehicles, perhaps other ideas will emerge.
Increase research for small and large scale energy storage technologies. This could enable the construction of electric vehicles with higher range.

So all in all there will be a life “beyond petroleum”…

Home (film by Yann Arthus-Bertrand, 2009)

ojdo — Sat, 06 Jun 2009 04:11:38 +0000

Al Gore’s film “An Inconvenient Truth” (2006) was the first big documentary film that received international attention. It covered the current scientific knowledge global warming caused by the artificial greenhouse effect.

Now the film “Home” by the French director Yann Arthus-Bertrand is published. It tries not only to focus on the climate issue but to show the whole picture: exhaustion of natural resources, energy consumption, biologic diversity, pollution and the rising gap between industrialised nations and the rest of the world.

In beautifully filmed footage entirely shot from helicopters the dimension of nature’s beauty is shown. And there is something very special about this film: It is free. That means: on 5th June the film was released on YouTube and broadcasted on French television. Public emissions were organised, too.

Having won the company PPR as sponsors and Luc Besson as producer, the year-long production phase with three film teams operating all over the world could be realised. Over 400 hours of footage were created.

The film start with the earth slowly appearing in sunlight. In the first ten minutes then the history from the appearance of life to us is told. It shows how we converted from hunters to farmers about 10,000 years ago. This change made it first possible to support settlings bigger than small villages: cities were born. But growth still was limited by the work needed to cultivate the land.

This changed dramatically after the industrial revolution and especially when oil began to be exploited. The film visualises this with a hard cut from a small settling to a modern skyline. Oil gets the hitting name “pocket of sunlight” that it is. Using the solar energy harvested million years ago, mankind began to develop incredibly fast.

Using fossil energies for transport, industry and agriculture allowed us to expand our cities and population. Also our use of water increased by magnitudes. Species are extinct at a rate 1000x higher than it used to be thanks to possessive activities all over the globe.

The film succeeds in transporting its message: we must change our lifestyle, or we risk to destroy the foundation of our existence on earth. We must abandon our dependence on non-renewable resources like fossil fuels. We have to economise the waste of goods. We must reduce our consumption of energy.

The film ends with examples of change towards a sustainable future like the use of renewable sources for energy supply and the creation of natural preservation parks. The film states: “It is too late to be a pessimist.” We have still time to act. We as a global community. I think it is our duty to act responsibly: How can we dare to call us homo sapiens and fail in a discipline every bacteria succeed in: to preserve Earth, our home.

ojdo » Energy

DESERTEC studies: AQUA-CSP

Water crisis

Desalination

Further reading

DESERTEC studies: TRANS-CSP

TRANS-CSP

Technical difficulties

Subsidies and external costs

What’s next

Further reading

DESERTEC studies: MED-CSP

The idea

MED-CSP

The scenario

Energy production by country

What’s next

From finite to renewable energy

Current state

Nuclear alternatives?

Solar power

What else

Home (film by Yann Arthus-Bertrand, 2009)

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