Sunday, December 31, 2006

The Year 2006 in Energy

The year 2006 has been a spectacular year for energy. Hereby Leonardo ENERGY's list of 10 highlights.
  1. Energy Efficiency becomes top priority in Europe (and beyond). See Hans Nilsson's analysis on the energy efficiency action plan.
  2. Many world records broken on renewable energy technologies, among others:
    the largest wind farm
    the largest wind turbine
    the largest solar power station
    the most efficient solar cell
    the largest wave power station
  3. The emergence of the smart grid concept with smart metering
  4. The turnaround of US on energy & climate policy, through the 25 x 25 vision (Renewable Energy World, Dec issue, p 113), 8 states introducing CO2 restrictions, ...
  5. Among others, Al Gore's movie has made climate change a public issue, addressed daily in mass media
  6. A comeback for nuclear appears imminent
  7. A blackout leaves 10 million Europeans in the dark.Regulators need to start regulating beyond price.
  8. The first year of full operation of the European Emission Trading Scheme
  9. Passive Houses emerge as a mainstream technology, offering the potential to almost eliminate low temperature heat demand in buildings.
  10. Reality dawns on the illusion of the hydrogen economy

Comments, suggestions and additions welcome.

Saturday, October 21, 2006

Energy units - counting numbers of zeroes

Energy comes in many different forms - kinetic, thermal, chemical, magnetic, electric. From the humble electron-volt (eV) used to describe nuclear processes, to the tera-watt-hour (TWh) output from nuclear power stations, we count 34 orders of magnitude. Oil experts like to think of energy in terms of tonnes of oil equivalent (toe), coal experts in tonnes of coal equivalent (tce) and power engineers swear by the kilo-Watt-hour (kWh) and its multiples MWh - GWh - TWh. All these units are measures of energy, and can be expressed in the SI unit of energy, the Joule. Many of the units on this page, while commonly used, are not part of the International System of Units (SI).

Hereby an overview of some of the energy units that are frequently used (source):


Unit frequently used in physics. 1 erg = 10E-7 Joule.

eV (electronVolt)

1 eV = 1.6 * 10E-19 Joule. It is the energy that an electron would require when dropping through a potential of 1 volt.


A barrel of oil is 42 gallons, or 159 liters. The chemical energy obtained when burning a barrel of oil is 6,120 megajoule (MJ), or 1,700 kWh. Hence, there is about 10 Kwh (thermal) in a liter of oil.

toe (tonne of oil equivalent)

A tonne of oil equivalent is roughly 7 barrels. Using IEA's unit convertor (see below), one can verify it to be equal to 41,868 MJ or 11,630 kWh (thermal).

tce (tonne of coal equivalent)

Using IEA's unit convertor (see below), a tonne of coal equivalent is 0.7 toe. Hence, a tce = 29,308 MJ or 8,141 kWh. There are about 8 kWh in a kg of coal.

BTU (British Thermal Unit

A unit defined as that amount of energy that will warm one pound of water by one degree Fahrenheit. 1 BTU = 1055 Joule.


The amount of energy required to warm 1 g of water by 1 degree Celsius. 1 cal = 4.186 J. The human body needs about 2000 Kcal per day, i.e. about 3 GJ or 850 kWh of food energy per year.


A quadrillion BTU is a Quad (10E15). Hence, it's 1,055 quadrillion Joule, or 293 billion kWh. This is the annual primary energy input for 12 thermal power stations with 33% conversion efficiency.

kWh (kiloWatt-hour)

A kWh is the amount of energy consumed by a 1 kW device during a period of 1 hour. 1 kWh = 3,600,000 J.


The metric unit for energy. It is the amount of energy consumed in a 1 Watt device (e.g. a torch bulb) during 1 sec. 1J = 1 Ws = 1 Nm (Newton meter). The Newton is the basic metric unit for force, equivalent to the weight of a mass of approximately 102 grams. A Nm is the mechanical energy required to exert a force of 1 N over a distance of 1 m.

unit convertors

There are many more units for expressing energy. See following links:

Sunday, September 17, 2006

What is the function of dams, and what are the reservations against them?

By Juergen Giesecke, Energie-Fakten

Mankind already manages water flows since 4 millennia, to provide for the necessities of life. The practice of storing large water quantities using dams started with ancient Mediterranean cultures, and has been continuously developed  until modern times. The world has about 46,000 dams that are higher than 15 meters (earthfill and masonry). There were 6 billion people on this planet in 2002 - a number  increasing with 80 million each year, and 20% of them suffer from water scarcity. And about a third lacks basic sanitary facilities.

Well over 70% of large dams around the world are used for the irrigation of agricultural land to secure food supply. Further important functions are the supply of drinking water for citizens,  process water for industry and commerce, and cooling water for thermal power stations. A further function is flow control for flood protection and electricity generation from hydropower, the most effective use of this constantly regenerating energy.

By holding water in reservoirs and releasing it as the need arises, dams modify the existing natural conditions of life for animals and plants, as well as the habitat of  local population, primarily through the relocation of people who must leave the area where they settled, live and cultivate land. Roads change, and religious and cultural sites are disturbed for the future reservoir. Accumulation of nutritient-rich sediments not only leads to silting of the reservoir, but it also deprives the river downstream of natural sedimentation and manuring, and it  disturbs its seasonal flow where areas are intermittently flooded and drained. In addition, depending on the characteristics of subsoil and soil layers, groundwater levels may change. Changes in the micro-climate near artificial large reservoirs can be significant in tropical climates, through increased water evaporation, and the slack water near dams facilitates development of life-threatening diseases. Also, we cannot ignore security risks, resulting from the storage of large water quantities, and possible collapse of the barrage construction. 

Dams have, depending on type and provisions, demonstrated lifetimes of well over 100 years. They provide a large contribution to the basic necessities of life for the resident population and they have become an essential part of the human imprint on the cultivated landscape. But they require careful precautions and provisions to minimize ecological damages, impact on landscape aesthetics, influence on the habitat of people, animals and plants, and to keep risks small.

For this purpose, over the last 3 decades and on a global scale,  professional societies have developed  comprehensive instructions, manuals, regulations and training/education programmes.

Interdisciplinary cooperation of specialists from engineering, natural sciences, economics and humanities have now become as self-evident for large dam projects, especially those with considerable use of hydro power, as have public relations and awareness raising with the broad population.

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When can we expect nuclear fusion?

By Joachim Grawe 

In partnership with Energie-Fakten

Nuclear fusion offers a great hope for mankind's future energy supply. It imitates in a technical process the physical phenomena occurring in the sun and all other stars, where hydrogen nuclei are combined ('fused') into helium nuclei, releasing giant quantities of energy according to Einstein's formula E=mc2.

On earth, it is impossible to achieve the enormous pressure of 100 billion bar inside the sun. Therefore, fusion of the lighter nuclei of 2 isotopes (i.e. atoms with a different number of neutrons in the nucleus) of hydrogen is being pursued: i.e. deuterium (with a nucleus of 1 proton, as in 'normal' hydrogen and 1 neutron) and tritium (1 proton + 2 neutrons). Deuterium is abundantly available in oceans at a concentration of 140 g/tonne. Tritium can be produced from the common metal lithium.

To initiate ('ignite') the fusion process, the D-T mixture needs to be converted into a plasma - i.e. a state whereby nuclei are separated from the electrons that normally surround them. The plasma needs to be heated to at least 100 million degrees, under extreme compression, and kept for a prolonged period while containing its heat inside. At all times, contact of the plasma with its container - a round tube called 'torus' - needs to be avoided. This is achieved through very strong magnets.

Containment of the plasma has been achieved already in 1951. The European test facility JET in Culham (UK) could achieve in 1997 to generate 16 MW of heat for a short while, consuming twice as much power to conduct the experiment. A larger reactor will be constructed from 2007 in Cadarache (France), through world-wide cooperation. This reactor will for the first time produce an energy surplus. It will be used for 10 years to build experience. If the results are positive, construction of the first demonstration reactor 'DEMO' will start. The energy return of this reactor should be a factor 4.

From 2060, nuclear fusion could provide a sizeable contribution to energy supply. It represents the next stage of development for nuclear technology, after the 'backup solution' nuclear fission. Fission is expected to contribute from 2020 with so-called Generation-IV reactors, which offer better reactor safety.

This contribution was originally published in the German languageon september 7, 2006 by Energie-Fakten.

Tuesday, June 13, 2006

Big Coal: The Empire of Denial

Big Coal: The Dirty Secret Behind America's Energy FutureReview by Jeff McIntire-Strasburg via Sustainablog.

This morning I said I'd have a review up of Jeff Goodell's Big Coal: The Dirty Secret Behind America's Energy Future up in a few days, but since I started reading the book yesterday, I literally have not been able to put it down. That's a testament to Goodell's skills as a writer, and the incredible stories he tells as he examines the role of coal in American growth over the past century and Chinese growth in the coming one. Along the way, Goodell tells the stories of miners, utility executives and global warming activists, among others, creating a very readable book on an incredibly complex subject.

I picked up the phrase "the empire of denial" from Goodell's epilogue, and that's essentially how "Big Coal" is characterized through the book: in denial of not only the human and environmental costs of their product, but also in denial about the inevitable waning of this energy source even as it's seeing a renewal of interest in the US. A few executives tied in with coal production, primarily in the big utility companies, recognize that regulation of CO2 is coming, and think it's in their best interest to get ahead of the curve by, at the very least, investing in new power plants that incorporate coal gasification and carbon sequestration technologies. By and large, though, the big utilities are building old-school dirty coal-burning plants (such as one going up in Southern Illinois) as quickly as possible to make a quick buck before regulation becomes a fact of life and requires the coal industry to internalize the costs it passes on, at least in terms of pollution. Yes, they're incorporating the latest scrubbers and such into these new plants, but as Goodell notes, even these new "clean" plants will still emit tons of CO2, mercury, and combustion wastes such as fly ash, continuing Big Coal's legacy as one of the biggest contributors to global warming and public health problems.

Goodell divides his book into three sections, each corresponding to a stage in the "lifecycle" of coal production and consumption: the first deals with mining, the second with burning the black rocks in power plants, and the third with the effects of emissions. Goodell's choice to look at the full picture, from mine to power plant to disposing of wastes, as well as the exhaustive research he puts into each section, makes this book a bit overwhelming -- in one sense, it mirrors recent books like James Howard Kunstler's The Long Emergency which examine how oil underlies almost every aspect of life in developed countries. Goodell's take on the future is certainly much less dramatic than Kunstler's, but he makes it clear that we're on the threshold of big changes in how we produce energy in this country. The coal industry's mantra has been "We'll figure out the problems later when we've made technological advances to deal with them," but Goodell makes clear that 1) some of the most promising technological advances are ready for commercial use, but the utility companies aren't willing to spend the necessary money on them, and 2) we're simply no longer in a position to put off facing the music on climate change and other environmental problems.

While looking at the big picture, Goodell never forgets that it's individuals who pay some of the most horrific prices for our dependence on the cheap electricity provided by coal. We read stories about two of the miners rescued from the Quecreek, Pennsylvania mine disaster in 2002, a woman who's family homestead has been devastated by the new floods produced by mountain top removal in the Appalachians, and a man in China's poorest province who's created his own methane digester to produce usable gas from his farm animals' poop. The facts and statistics in this book are fascinating, but it's the stories of individuals dealing with the past and present of Big Coal that really kept me turning pages.

This is an important book, especially as coal is experiencing a renaissance in the US. Goodell's no pie-in-the-sky idealist: he recognizes we will be burning coal for the foreseeable future. At the same time, he makes it amply clear that if we choose to keep burning it as we always have, the costs we'll face shortly down the road will dwarf the economic problems that that conservative politicians and their industrial sugar-daddies love to tout as a reason why we can't regulate CO2 and other greenhouse gases. The book will be available to buy on Thursday, June 8.

Wednesday, May 31, 2006

Accidents in the energy sector

One of the measures for sustainability of energy systems is their (low) level of risk. This can be measured based on the occurrence of severe accidents in the past, or, insofar possible, through model calculations.

The Paul Scherrer Institute (PSI) in Villingen, Switzerland owns the world's most comprehensive database on severe accidents in the energy sector. Accidents are considered as 'severe' if they have one of the following consequences: at least five fatalities or at least ten injured or at least 200 evacuees or an extensive ban on consumption of food or releases of hydrocarbons exceeding 10,000 t or enforced clean-up of land and water over an area of at least 25 km2 or economic loss of at least five million USD(2000).

The database not only includes accidents with the production of energy, but covers the entire energy supply chain, since accidents occur in each stage, during exploration, transport, processing, storage, distribution until waste treatment and disposal.

The PSI database ENSAD (Energy Related Severe Accident Database) contains currently 18,400 entries, mainly from the period 1969 { 2000. Comparisons between fossil energy carriers, hydro and nuclear power can be summarised as follows for this time span. Severe accidents are by far more frequent in emerging and developing nations compared to industrialised OECD countries with their distinct safety culture. Over the past 30 years, the OECD countries experienced for coal, gas (natural gas) and liquified gas (LPG, mineral products) a respective total of 75, 90 and 59 severe accidents with at least 5 fatalities, and with oil even 165. Hydro and nuclear power with no severe accident with direct fatalities are clearly less vulnerable, but the maximum possible hypothetical consequences could be very large.

Compared to the rare severe accidents, we see relatively frequent small accidents, especially with renewable energy. Systematic central data on this subject is collected only on a limited scale, which explains why data is often incomplete.

Through improvements in technology and training, as well as the optimisation of the interaction between man and machine, the number of severe accidents, as well as their impact on mankind and the environment can be significantly reduced.

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Can electricity save energy?

Electricity's share in the final energy mix has been steadily increasing. It is currently around 18% of final energy, and close to 40% of primary energy consumption. In the light of this growth, views of an 'all electrical' society have
been occasionally expressed.

The high growth of electricity can also be seen as a problem. Is electricity the 'bad student', hindering primary energy demand to go down in absolute terms? Is electricity a high quality but polluting energy form, that should be only used when there is no alternative?

But electricity is just an energy carrier, which due to its high quality, can be converted with high efficiency into practically any energy service. An integrated resource viewpoint should be taken when evaluating the efficiency of electricity to deliver energy services. For example, an electric vehicle can be about twice
as efficient than a combustion vehicle in converting primary energy into transport services.

Based on the integrated resource view, we can speculate that it is actually the growth in electricity consumption that is pushing down primary energy demand below GDP growth, a view which is today as speculative as its alternative mentioned above.

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Friday, April 21, 2006

Reading the Kyoto Protocol - Ethical Aspects of the Convention on Climate Change

Reading the Kyoto Protocol: Ethical Aspects of the Convention on Climatic ChangeBy Etienne Vermeersch (ed) et alii

By the year 2005, one would expect everything possible to have been said on the Kyoto Protocol, but this book offers a new perspective, if you can read beyond its title.

Written by philosophers and sociologists, the book includes 7 essays, each carefully worded - a trait of the discipline. It's virtually impossible to reflect the rich arguments of 7 authors in a short summary, and we don't even try, but here are some of the ideas as an appetiser.

In the introduction, Etienne Vermeersch distinguishes between 2 types of rationality, i.e. k-rationality (where 'k' stands for knowledge) and d-rationality (where 'd' stands for doing). K-rationality represents the search for rational knowledge, and in the case of climate change, an optimal k-rational form has not, and probably never will be achieved, although consensus is growing. But without k-rationality, d-rational action is still perfectly possible. D-rational action has well-defined aims, and uses the most efficient means to realise these aims. In conclusion, d-rational action could help us avoid living a lasting contradiction between lofty principles and our questionnable practices.

Raoul Weiler argues that climate policy calls for a new time scale for effective policy making and implementation, hitherto unknown. Building consensus on policy and making it sustainable over a prolonged period of time is made complicated through teh absence in the Western World vision of any intrinsic value system for the ecosystem. This is an untenable situation, since the soon-to-be outnumber the living: at least twce as many people will be having lives in the 21st century than are alive today. Ever hastier decisions and actions, without long-term understanding will not be the solution.

Riccardo Petrella concludes that Kyoto and Johannesburg have failed to ensure minimal conditions for a sustainable world. He calls for a Humankind Protocol to replace the Kyoto Protocol. Such protocol would be based on the recognition of a number of public goods (air, sun, ...), citizen participation and a world political entity representing humankind (not member states, such as the UN).

This book leaves the straightjacket of what is politically achievable within the time horizon of a regulatory mandate, and refreshingly thinks out of the box, but it is not a theoretical book. And you don't have to agree with it - as the authors happily don't with each other.

Thursday, April 20, 2006

Power to the People

Power to the People: How the Coming Energy Revolution Will Transform an Industry, Change Our Lives, and Maybe Even Save the PlanetBy Vijay Vaitheeswaran

A very readible book, based on interviews rather than desk research, this book offers quotes from energy gurus rather than graphs and tables. Because of this approach, it gives a good reflection on what is currently at stake in the energy world. Reading its index, it is as much about people and organisations as it is about keywords.

The central theme of the book is that the combined forces of market liberalisation and growing environmental concerns, in combination with new technology (fuel cells and micropower), will revolutionize the power system, leading to an energy internet. This is based on intelligent homes and buildings, micropower generated close to the point of use, and a distribution system allowing multi-directional energy flows.

With new technology becoming available, and ageing power infrastructure (requiring 10 Tdollar investment over the next 30 years), we have a window of opportunity to replace end-of-life power with something new. But 3 camps polarise the energy debate 'don't worry', 'keep pumping' and 'ride your bicycle'. None of these get it right, and consensus needs to be built around the 4th micropower way.

Overall, the book provides a good fresco of today's energy debate. The picture drawn for us is attractive, though it's not the only one possible. It leans more towards ngo's and institutes such as Worldwatch and Rocky Mountains, and it is a bit biased against big power, big oil and big coal. If you want to read a book in the 'small is beautiful' camp, with a focus on politics rather than science, this book would not be a bad choice at all.

Factor Four - Doubling Wealth, Halving Resource Use

Factor Four: Doubling Wealth - Halving Resource Use: The New Report to the Club of RomeBy Ernst Von Weizsaecker, Amory B and L Hunter Lovins

A book written around a simple but appealing idea: we can double our wealth while halving our resource use. It has inspired a 'factor X' school of though (e.g. factor 10).

Its first part offers 50 examples to increase resource productivity, giving a wealth of information, but some examples are a bit extreme, and backup evidence is not easy to find (e.g. super refrigerators). Others are impractical (e.g. hypercars, not exactly the vehicle to bring the kids to school with). Claims in Factour Four are not traceable to a verifiable source.

A reader who expects after reading through 50 examples, a practical and economic case will be presented on Factor Four will be disappointed. The examples are left to speak for themselves. In the second part, the authors move into a call for action. A range of solutions is eloquently proposed, mainly to create new markets, or reshape existing ones (e.g. through tax reform) to obtain the desired results. Part 2 supports the book's role as manifesto.

In its final part, Factor Four touches on some of the wider boundaries of resource productivity, in particular the idea that GDP and welfare are becoming weakly correlated (for example, car accidents trigger a number of services that are accounted for in GDP, but welfare is destroyed). Also, there is the issue of trade - we may be falsely under the impression to be greening our society, while all we do is just exporting pollution.

Overall, Factor Four is a good discussion document and excellent manifesto for action. We should be pleased it has been written, but need to be critical while readin

The Skeptical Environmentalist

The Skeptical Environmentalist: Measuring the Real State of the WorldBy Bjorn Lomborg

This book aims to measure the 'real state' of the world from an environmental viewpoint, and placing humans at the center stage. Its scope is broader than energy, but a large portion is devoted to energy resources and climate change. Its approach is to look at long-term trends, with the conclusion, not without controversy, that the world has never been in better shape, though there remain problems with global warming, the ozone layer, loss of rainforests, ...

Sunday, April 16, 2006

With high prices for oil and gas, does solar energy not become cheaper?

By Joachim Grawe

In partnership with Energie-Fakten

As always, there is no simple answer:

  1. As an alternative for the preparation of hot water using oil or gas, solar collectors will become competitive in the short run, if the price for heating oil remains at the current level (or even increases) and when the gas price follows, based on the price fixing clause in customer contracts. This has already been announced.
  2. In Germany, solar collectors, in any case flat-plate collectors, do not suffice for heating in winter. Installing them in addition to an oil or gas heating facility means double investment. Despite higher oil prices, payback is long. Oil prices must rise significantly before the combined heating with oil and solar becomes economical.
  3. As for electricity production with solar energy (photovoltaics), the increase in oil price has no influence, and the likely increase in gas prices has probably little influence. This is because (light) heating oil is hardly used in power generation (share in 2004 electricity production: 0.2%). Natural gas, with 9.1%, has a higher share in electricity production. But the use of natural gas can be reduced, in favour of coal. Conversely, the share of gas can increase only to a limited extent, if (due to high prices) few new gas-fired power plants are constructed, and when the operating life of nuclear power plants is extended. The debate is open whether large-scale electricity generation from photovoltaics will ever become competitive, due to more attractive alternatives (also among renewable energy sources).

Related articles (in German):

This contribution was originally published on September 8, 2005 by Energie-Fakten.

Saturday, April 15, 2006

Why Carbon Fuels Will Dominate The 21st Century's Global Energy Economy

Why Carbon Fuels Will Dominate the 21st Century Energy EconomyIf provocation stimulates lateral thought (de Bono), you will find it hard to think straight while reading Peter Odell's book. Its opening sentence sets the tone: 'Realism over the critical issues of energy supply and use in the 21st century's economies and societies has become a very scarce commodity'. Peter Odell's goes on and explains that it will be very difficult to move away rapidly from carbon fuels. He presents a 100-year scenario for the 21st century during which the world will consume 3 times more carbon energy (1660 Gtoe) than in the 20th (500 Gtoe). He finds that carbon energy is not as scarce a commodity as above mentioned realism, and is confident we have the resources to support such demand.

Carbon fuels take the center stage in the book, with 3 of the 6 chapters devoted to coal, oil and gas. Alternative energy, defined as renewable & nuclear energy, but excluding non-commercial biomass, is occasionally mentioned. Alternative energy will start its rise in the 2nd half of the 21st century, supplying 30% of the cumulative energy needs during the century, and ending it with a 43% market share. Gas will be the fuel of the 21st century, coal will decline in relative terms, and oil is expected to peak before the middle of the century.

The book deliberately and consistently mentions carbon fuels rather than fossil fuels, The hypothesis of the fossil origin of oil and gas dates back from the 18th century, and the book devotes a chapter to an alternative theory suggesting an inorganic origin of oil and gas. We know relatively little of the deep earth crust, and this theory may be as valid as its alternative. In any case, the 'Russian-Ukranian theory of the abyssal, abiotic origin of petroleum' merits more than an instant dismissal because of its origin.

This compact book will delight anybody open to challenge conventional wisdom on our energy system.

Friday, April 07, 2006

Double or Quits? The Global Future of Civil Nuclear Energy

Double or Quits: The Future of Civil Nuclear EnergyBy Malcolm C Grimston & Peter Beck

This book argues for the nuclear industry and governments to take action to ensure that nuclear power remains available as a practical option. Such action needs to take place on 5 fronts: public perception, economics, waste (including reprocessing and proliferation), safety and R&D.

Nuclear has already received its first chance in the 70's and 80's, during which time several governments have provided substantial resources to a nuclear programme. This has resulted in an industry which generates about one sixth of the world's electricity, with an impressive safety records and without the emission of greenhouse gasses. However, nuclear electricity has not delivered on economics. And views are divided between supporters and opponents on the outcomes of nuclear's first chance.

A second chance for nuclear electricity will depend on a number of factors, some within the industry's control, but many beyond its control: will fossil fuels remain available? at what price? will renewables fulfil the predictions of its supporters? how severe will be the impact of climate change? ... Moreover, a healthy nuclear industry will be needed to develop new generation reactor types, novel waste management techniques and attract the young and brightest engineers and scientists. But all these needs are at the same time preconditions for a healthy nuclear industry.

But other energy technologies are equally not without challenges. In summary, the authors identify 2 key issues: to enable decision making to assess whether R&D concepts can be successful in commercialisation and decision-making structures that can manage the complex issues surrounding nuclear power. 'Double or Quits' is essential reading for all who wish to explore under what circumstances nuclear energy might make a positive contribution.

Wednesday, April 05, 2006

What's the importance of cogeneration?

By Eckhard Schulz 

In partnership with Energie-Fakten

Mature technologies are now available for the combined production of electricity and heat (cogeneration). They can use fossil or nuclear energy carriers, as well as biomass.

In a proper comparison (serving the same energy needs through both alternatives), cogeneration uses 15-20% less energy, and contributes an equivalent amount of emission reductions, compared to the production of electricity and heat in separate facilities, i.e. a thermal power plant and a modern boiler. In this case, the comparison needs to be based on the same fuel. When cogeneration is combined with a fuel switch -- from coal to gas, the impact of switching fuel is more important than the impact of cogeneration, due to the favourable characteristics of gas compared to coal. The advantage of cogeneration also decreases with higher efficiency of future power plants.

Cogeneration is above all meaningful for applications where there is a large and continuous (not just seasonal) demand for heat close to the cogeneration facility. If there is no demand for heat from a cogeneration facility, its efficiency for the production of electricity will be lower than for optimised thermal power stations. Larger cogeneration facilities have in general lower production costs than smaller units. But on the other hand, transport of heat to users takes longer and is more expensive.

Cogeneration provides 6% of heat in Germany. Each year, about 55 TWh (1 TWh = 1 billion kWH) is produced. German cogeneration facilities operate less frequently in condensation regimefootnote{i.e. without simultaneous use of heat}, in comparison to other European countries. With a market share of 10% electricity produced from cogeneration facilities, Germany's performance is about average. Denmark is leading. But in Denmark, cogeneration facilities operate a considerable amount of time in the condensation regime. Moreover, the development of individual heat supply on the basis of gas has been inhibited in Denmark by regulation for a long time.

Government supports the further development of cogeneration. In case of district heating, this will not be possible, due to the reducing heat demand for dwellings, based on more stringent regulations for isolation and energy performance. For local heat production, there are growing possibilities if technology further develops (e.g. fuel cells). The already significant portion of cogeneration in industrial energy supply (electricity and steam) can increase further. Above all, the power to heat ratio (more electricity and less heat produced by cogeneration) increases significantly, compared to older facilities.

This contribution was originally published on July 21, 2005 by Energie-Fakten.

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Tuesday, April 04, 2006

Nuclear Renaissance

Nuclear Renaissance: Technologies and Policies for the Future of Nuclear PowerBy W J Nuttall

'Nuclear Renaissance' is not a plea for or against a nuclear revival, but explores technological evolutions that would facilitate a nuclear revival. With its focus on future technology, the book complements 'Megawatts and Megatons', since it continues in a way where the other ends (though there is no link between the 2 books).

'Nuclear Renaissance' covers the waste issue based on the UK, US and Finnish experience. It does not offer a complete and satisfactory solution, but the Finnish approach, based on participation and trust seems to provide a model for the future, as opposed to the approach of a 'nuclear priesthood' from the past.

Technological developments such as high temperature gas-cooled reactors, waste burners, Generation IV reactors and nuclear fusion are covered in depth. But possibly the main merit of the book lies in its careful consideration whether a nuclear renaissance will, needs to or should happen.

In an afterwords, the author offers a thought experiment of a world where nuclear fission as a physical phenomenon would not exist, speculation how such a world would have evolved over the past 70 years. Such a world would have seen quite a different end game to the 2nd World War. The Cold War would surely have occurred, we would not see magnetic confinement fusion and threats to climate would be even worse than we actually face today.

On balance, the author concludes that 'it would seem prudent for the developed world to maintain a civil nuclear power industry on at least its current scale.'

Tuesday, March 21, 2006

Megawatts and Megatons

Megawatts and Megatons: The Future of Nuclear Power andIn this highly accessible book, Garwin and Charpak give a comprehensive overview of nuclear technology, covering both its civilian and military use. The opening sentence "If it is to benefit humanity, concern for our planet and the future of our civilization needs to be matched with an understanding of the facts." sets the tone. Megawatts & Megatons aims for a balanced overview, though it leans towards an essential role for nuclear power.

A sense for the numbers is essential in the energy debate, and the chapter on energy units comes as a real bonus. There are 37 orders of magnitude between the smallest energy unit at atomic scale, the electron volt (eV) or 1.6E-19J and the largest unit in use, the Exajoule (EJ) or 10E18J. One cannot help but wonder whether some statements in the energy debate would be made with a proper understanding of the underlying math.

The book gives an excellent overview of the science and engineering behind current nuclear technology. If it has one weakness, it's on its coverage on potential future developments for reactors and waste management.

An excellent chapter describes radiation and its effect on living things. It talks about natural radiation, and the various sources of man-made radiation (medical & dental X-rays, radon), illustrating the difficulty to assess the effect of low-dose radiation on health.

This book is a must for anybody interested to make up her mind on nuclear technology. Whether you're strongly in favour or against nuclear, your opinion is likely to be more balanced after reading 'Megawatts and Megatons'.

Sunday, February 26, 2006

Energy at the Crossroads

In his 18th book, Vaclav Smil summarizes a lifetime of energy studies in 'Energy at the Crossroads - Global Perspectives and Uncertainties'. The result is a highly accessible book, yet rich in argument.

A chapter on 'energy linkages' looks at the broader energy context (environment, development, war, quality of life, ...). It lies a foundation for a later definition of a necessary energy consumption for essential quality of life requirements.

'Against forecasting' looks back to a century of attempts and often spectacular failures, sometimes by up to an order of magnitude, concluding that the human mind has difficulty assessing the full impact of new technology.

In fossil fuel futures, Smil dares to refer to the Russian-Ukrainian theory of the abyssal abiotic origin of hydrobarbons, calling it 'intriguing' and commenting that it merits more attention that it has received so far in the West.

Before starting the concluding chapter 'possible futures', Smil argues that nuclear energy is likely to have a role, but this role most probably will be limited. Energy efficiency will help as well, but decades of efficiency improvements have seen efficiency gains evaporate for higher demands of energy services. He dares to ask the question of a minimum energy requirements for a decent quality of life, which he estimates at 50-70 GJ/capita, and leaving it to the reader to construct his own scenario's.

In the future energy system, not a single solution will work by itself, and the 'a priori' exclusion of certain options is counterproductive. The path to carbon-free energy is going to take most of the 21st century. The author calls for action of 'complexifying minimalists' rather than 'simplifying maximalists'. We will need a multitude of approaches, flexibility, tolerance and openness.

Finally a personal observation. Sustainable energy may not be an economic or technical problem. The arsenal of solutions is there. At the end of the day, it may be a moral issue.

Energy at the Crossroads: Global Perspectives and Uncertainties

Thursday, February 23, 2006

What can we expect from wood pellets?

Globale Umweltprobleme.By Eike Roth

In partnership with Energie-Fakten

Wood pellets are booming. They have the potential (allegedly):
  • to provide low-cost energy
  • to save exhaustible resources
  • to reduce our dependence from politically instable countries
and above all, they have potential
  • deliver a significant contribution to the reduction of CO2 emissions
And because of this last benefit, they become
  • an important tool to comply with our commitments to mitigate climate change based on the Kyoto Protocol.
Since wood pellets represent another use of solar energy, we should welcome and value their contribution to society.

A reader requested Energie-Fakten for an assessment of the above statements.

We've already taken a position on this subject in a previous answer Can biomass power stations mitigate climate change? Hereby a few additional remarks.

Preliminary note

First of all, we must alert readers to a major distinction: wood pellets can be produced from waste resulting from other wood processing activities - e.g. the furniture industry -or they can be harvested from natural or planted and cultivated trees and bushes (so-called energy plantations). The use of wood residues is basically beneficial, since the raw material for the pellets can be obtained for free (except for the cost of transport, to the extent that the material is not processed on-site) and without a need for further processing. But the volume is relatively small and this type of wood pellets will not make a big difference. In principle, we could produce larger volumes in energy plantations. In this case, we must take into account all expenditures of these plantations (planting, where applicable irrigation, manuring, maintenance, as well as wood chopping and transport) including the machinery, installations and operating supply items required, and also all effects of these energy plantations and their cultivation allocated to the final product - wood pellets. In the latter case, a much more detailed assessment is required.

Technically, equipment for the production and combustion of wood pellets is mature. They operate reliably, without major impact on environment and the equipment for private users (stoves) are sufficiently user-friendly and adequately failure prone. And social acceptance will not be a market barrier.

Low-cost energy

Wood pellets from waste wood are cheap. From energy plantations, despite rising energy prices, wood pellets can still not compete with natural gas, heating oil or coal. When energy prices further increase, economic efficiency will be within reach eventually. We should observe that part of the cost of wood pellets depends on energy costs. With rising energy prices, the cost of wood pellets will increase. Wood pellets will close the cost gap slower than is generally expected. Note as well that transport costs are relatively important, because of the low energy density of wood pellets. Transport from low density areas over long distance to large cities should only be considered on a limited scale.

Clean energy

Waste wood contributes to cleaning energy supply, but its volume does not suffice to make a difference. Energy plantations can make a substantial contribution, but a number of constraints needs to be observed:

First of all, land use for energy competes with land use for food. As long as many hunderds of millions on earth suffer from food shortages, this ethical question cannot be factored out. But even considering sufficient land available for energy use, it still remains to be seen whether wood is the most appropriate application. There are faster growing plants, and a conclusive decision is only possible under consideration of all aspects, for example need for manuring (including environmental impact and impact on total energy demand) and impact on biodiversity. In these areas, we have substantial knowledge gaps.

Land competition is also a factor with technical systems using solar energy: with plants (and trees), the bottleneck is the efficiency of photosynthesis. This is typically 1% (maximum around 5%) and hence substantially lower than the efficiency of technical systems (at present around 10% for solar photovoltaics and around 30% for solar thermal electricity generation, in the latter case only referring to direct solar radiation, since scattered radiation is not usable for these systems; for Germany, scattered radiation represents about 50% of solar radiation, while in tropical areas, its share is substantially lower). Plants grow however by themselves (leaving out manuring and irrigation for a moment), while the technical exploitation of solar energy requires technical facilities (power plants). In the long run, we will see probably a parallel use of plants and technical systems, with technical systems probably taking the larger share.

Finally, we need to point to the need that in the long run, the share of solar energy (in whatever form) and nuclear energy to cover our energy supply needs to be decided on economic grounds, taking into account related requirements, such as security of supply etc. But here as well, the choice is probably and/and rather than either/or.

Fuel dependency from politically instable countries

Since wood pellets inherently represent a domestic energy source, they could very well contribute to the nicreasing our energy independency. A sizeable contribution however depends on the use of energy plantations, whose large-scale application depends on the answer of other questions.

Reduction of CO2 emissions

Combustion of wood pellets releases CO2, exactly in the same amount previously captured. But this does not allow us to conclude that wood pellets are a CO2 neutral energy source. All energy use for the setup and exploitation of energy plantations, the chopping of trees, transport and processing into pellets, as well as all energy consumption for the production and operation of these equipment and installations, produces CO2 emissions. For pellets from waste wood, to the extent facilities are allocated to the main application, these are limited to the pellet production, and transport to the end user. Certified figures are not available, but I estimate that the corresponding CO2 emissions are less than a tenth of what they would be when using fossil energy carriers rather than wood pellets. Wood pellets from waste wood are therefore an appropriate measure for CO2 reduction, to the extent waste wood is available.

For energy plantations, this ratio is clearly less favourable. Also in this case, I do not know of any reliable figures, but when long-distance transports are to be taken into account, the benefit compared to using fossil energy carriers will shrink really fast, and in certain cases can be completely consumed. Wood pellets from energy plantations are probably only practical on a limited scale to adequately reduce CO2 emissions.

Considering CO2 emissions, one should consider whether it wouldn't be better to directly burn wood, rather than converting it into pellets first. This conversion uses energy and releases CO2. In any case, a significant part of the comfort offered by wood pellets would disappear. To a certain extent, we must value CO2 emission reduction against comfort.

Another remark concerning CO2: when considering climate change, the first priority should be to keep CO2 from entering the atmosphere. Wood bonds carbon, and as long as it remains there, it does not enter the atmosphere. We must consider using wood for carbon storage, and cover our energy needs through other (CO2-free) means. This means in principle other forms of solar and nuclear energy. With proper storage, wood can store carbon for a few centuries. By then, we will certainly have much better possibilities than today to protect us against climate change. Wood as medium for carbon storage is likely to be the better strategy compared to wood as fuel, whether we use the intermediate step of wood pellets or not.

Mitigating climate change

Our climate is not only affected by CO2. Also other gasses contribute to the greenhouse effect. Especially N2O (laughing gas). This is a 150 times more potent greenhouse gas than CO2. It originates, among others, from the use of manure containing nitrogen. Our knowledge is still far insufficient about the nitrogen cycle in soil, water, plants and atmosphere caused by manure, but there are those who fear that intensive manuring (as often required for fast growing crop) has a large climate impact than would be mitigated through the energy use of plants. Until we have a satisfactory answer to this question, it is better to proceed with caution. For complying with our Kyoto commitments, pellets from waste wood are a meaningful (though limited) measure, wood pellets from energy plantations rather not.


The properties attributed to wood pellets apply in theory, but in practice there are always constraints that limit their potential. Wood pellets will be part of our future energy system, but will probably play a smaller role than expected by many today.

Eike Roth, Sonnenenergie - Was sie bringt - was sie kostet, Friedman Verlag Muenchen 1999, ISBN 3-933431-05-0

This contribution was originally published on November 17, 2005.

Monday, February 20, 2006

Sustainable Fossil Fuels

Sustainable Fossil Fuels: The Unusual Suspect in the Quest for Clean and Enduring EnergyIn this book, Mark Jaccard doubts our prospects for moving away quickly from carbon fuels to renewable energy sources, and expects an energy system largely dominated by fossil fuels for the 21st century. This however does not need to be incompatible with a sustainable energy system, which the book defines in practical terms according to 2 criteria:
  1. The prospect for enduring indefinitely an adequate level of energy services
  2. Extraction, transformation, transport and consumption of energy must be benign to people and eco-systems.
One of the central themes is a strong move to clean secondary energy - e.g. electricity and hydrogen, with no harmful emissions at the point of use. On the primary energy side, we see a wider use of new emission-free transformation technologies converting fossil fuel into these carriers, or cleaner burning fuels.

In such a scenario, the prospects of energy efficiency would be reduced. Additional transformation steps would reduce the overall efficiency of the energy system. At the same time, world population & economic development will still result in a 3 times larger demand for energy services than today.

As for the nuclear option, as it is disliked by many, a more widespread use of nuclear power is unlikely unless the technology can produce a significant cost advantage.

Sustainable Fossil Fuels would add 25% to the cost of electricity, and the use of hydrogen in cars would increase personal transport by the same. Overall, household spending on energy would increase from 6% to 8% of income.

Thursday, February 09, 2006

Renewable energy and food supply: will there be enough land?

Today, land is used for living, working, recreation and most importantly, food production. A relatively new use is growing biomass for energy use, which requires vast areas of land because of the diffuse nature of sunlight, and the low efficiency of plants capturing it. There is a direct competition for agricultural land between energy and food. Land requirements for both uses depend on consumption and production per square meter, 2 parameters which vary widely. In this paper, S Nonhebel estimates land requirements based on today's consumption patterns and production efficiency, providing a basis for the construction of scenario's.

How much land?

Total land available is 13 Gha (13 billion ha or 130 million square km). Arable land (1.5 Gha), pastures (3.5 Gha) and forests/woodlands (4 Gha) provide total 9 Gha for growing biomass, which in a world of 6 billion people means 1.5 ha (15,000 sq.meter) per person (under the untenable assumption that humans are entitled to 100% of available land).

How much energy?

In 2003, the world consumed 435 EJ of primary energy, or 70 GJ/pp/year. Developing countries use about 35 GJ/pp/year, whereas developed countries consume 200 GJ. Within developed countries, consumption varies significantly between Japan (100 GJ), Europe (150 GJ) and North America (350 GJ).

How much food?

Just like we express energy use in primary energy equivalents expressed in Joules or tonnes of oil equivalent (toe), food consumption can be expressed in kg grain equivalent. A basic menu requires 200 kg/pp/yr, while rich countries consume more like 800 kg (including fooder required for secondary foods such as beef, porc, ...).

Food and energy production

The paper below mentions following conversion factors:
'rich' 'poor'
Grain yield (kg/m2) 1.0 0.2
Energy yield - photovoltaics (MJ/m2) 780 780
Energy yield - biomass (MJ/m2) 27 1.8

Using these ratio's in combination with today's energy & food diets yields following land requirement per person:
  • developing countries, biomass energy: > 20,000 m2
  • developed countres, biomass energy: 8,200 m2
  • developed countries, photovoltaics: 1,000 m2 (of which 256 m2 PV)


The author concludes that for developing countries, the use of biomass points to a critical situation. For developed countries, PV-systems are the only long-term option, though biomass may function as a transition fuel.

S Nonhebel, Renewable energy and food supply: will there be enough land?, Renewable & Sustainable Energy Reviews, 9(2005) 191-201

Saturday, February 04, 2006

Energy yield factors for the generation of electrical energy

By Joachim Grawe

In partnership with Energie-Fakten

The yield factor of a power plant is – in simplified terms – how many times energy generated during plant operation covers the energy used for constructing the plant. The exact definition is: 'The yield factor is the ratio of net energy production during plant life and the cumulative energy used for construction, operation and operating supply items'. The concept is only meaningful in the context of using regenerative energy sources.

The yield factor has been investigated mainly for electricity generation plants in several studies. Sporadic data is also available for solar collectors, heat pumps, district heating systems and insulation measures. The most solid dataset on this subject is available from the 'Institut fuer Energiewirtschaft und Rationelle Energieanwendung' of the University of Stuttgart, that has developed a series of detailed studies on the subject. It is also worthwhile to mention the 'Forschungsstelle fuer Energiewirtschaft Muenchen' and the Chair of Prof Franz-Jozef Wagner, Gesamthochschule Essen.

The literature on this subject is not fully consistent in its treatment of energy uses for operating power plants (for example maintenance works, or fuel consumption) as well as for demolition and disposal of the plant, or in its treatment of energy conversions (for example from final energy to primary energy). Except for strictly scientific papers, many publications unfortunately make only very superficial statements on these issues. In addition, various assumptions relating to lifetime, loading, technology etc have a significant impact on the outcome. As a result, declarations about the yield factor for selected energy generation technologies will fluctuate a lot. There is however some consistency in the declarations of leading institutes.

As a benchmark for current technology, the values in the following table can be used, which give the net energy yield factor, not including energy required for operating the plant, or demolition. Electricity is converted to its primary energy equivalent. For lifetime, typical values of the respective facilities are used. These are based on the constraints defined in the most solid publications on the subject.

This gives following yield factors:

Nuclear power station: 100 – 200
Coal-fired power station: 100 – 150
Large hydro station: 100 – 200
Small hydro station: 40 – 100
Wind power plant: 10 – 50
Solar photovoltaics: 2 – 8

When including the energy required for operating the plant, these values become:

Nuclear power station: significantly below 100
Coal-fired power station: significantly below 80

Another characteristic is the energy amortisation factor (energy payback), i.e the period needed by the power station to generate the energy consumed for its construction. In case of photovoltaics, this period can be as long as 8 years – depending on cell-material used. For small hydro power stations, it is in the range of 2-3 years. For other power plants, the factor is similar between 1-2 years.


This question has prompted me to revisit the subject 'energy yield for fossil, nuclear and regenerative energy generation systems'. This has highlighted an error in my thinking on this subject. The latest comparative reviews at the University of Stuttgart and the Technical University of Munich include for nuclear and coal-fired power plants already the energy required for fuel (coal) respectively fissile material (Uranium), or more accurately: their extraction, transport and disposal is included. Hence, for these 2 electricity generation technologies, the yield factor is more than 100.

We can easily crosscheck with the energy amortisation time. The yield factor corresponds to the lifetime divided by the energy amortisation time. This is the time period until the corresponding system has generated the energy consumed for all stages of its lifetime from 'craddle' (material extraction for construction) to 'grave' (demolition and disposal). Expressed in months, it is on average:
  • hard coal just below 4 months
  • brown coal just below 3 months
  • natural gas (combined cycle) just below 1 month
  • nuclear energy *) just below 3 months
  • hydro power below 14 months
  • wind power **) 7-16 months
  • solar energy ***) 70 – 100 months
*) Pressurised Water Reactor, 1300 MW, direct disposal used fuelrods
**) 1 MW, average wind velocity 4.5-5.5 m/sec
***) 5 kW (roof-mounted installation), polycrystalline and amorphous silicon
We can then derive following yield factors:
  • coal-fired power stations (lifetime 30 years = 360 months): 90
  • nuclear power station (lifetime for old facilities 40 years = 480 months, for new facilities 60 years = 720 months): 160 – 240
If we normalise the expected useful life (as for photovoltaic and wind power plants) to 20 years (240 months), we obtain a yield factor of 60 for coal and 80 for nuclear power plants.

This contribution was originally published on October 6, 2005 by Energie-Fakten. The addendum was added November 24, 2005

Tuesday, January 31, 2006

Can Nuclear Power Deliver?

At the beginning of the new year, SEAL is pleased to introduce its new paper 'Can Nuclear Power Deliver?'. Based on literature review and expert interviews, SEAL's 13th briefing paper provides an overview of arguments in the nuclear debate.

Nuclear peril
  • Waste: technical solutions exist, but lack of a political
  • Proliferation: can and needs to be managed
  • Nuclear safety: an issue for older nuclear plants, but
    promising 'passive safety' designs for new reactors

The nuclear promise
  • The power of the atom: a fistful of matter holding enough
    energy to power a city of a million for a year
  • Climate change mitigation: each major nuclear power station
    saves 6 million tonne of greenhouse gasses per year compared to fossil-based electricity
  • Energy security: abundant energy supply when using advanced
    reprocessing and fast neutron reactors

From peril to promise
  • Public opinion - taken hostage by extremes
  • Technology: extremely complex scientific & technical
    challenges need global cooperation and a 'man on the moon' momentum


Nuclear technology needs to address its problems, and holds tremendous promise if it does. The 'nuclear option' does not represent a single option, but offers many choices on building additional reactors, a moratorium ( no new reactors), phaseout (reduce existing reactors), reactor types, waste processing and R&D expenditure.

When excluding all nuclear options, a plan is needed how to build an energy system without it. The fact that we yet have to see such a (transparent) plan may relate to the fact that the numbers simply do not add up without the use of nuclear energy.

Full article

Friday, January 27, 2006

Can biomass power stations mitigate climate change?

By Eike Roth

In partnership with Energie-Fakten

With the combustion of biomass, CO2 is always released into the atmosphere. The rationale of the policy maker to promote biomass is based on the observation that combustion of biomass releases exactly the amount of CO2 that was captured earlier from the atmosphere for growing the biomass. This is correct, but to conclude
therefore that the use of biomass for energy is climate neutral is incorrect,
and serves no purpose.

The proposition is incorrect

The combustion of biomass is only CO2-neutral if it takes place at the place of its origin, without any manipulation, and without the use of technical facilities. However, biomass energy is not practically usable in this way. Any effective energy use
  • uses technical facilities for combustion and, where applicable, for the conversion of the resulting heat energy into electricity or other energy carriers,
  • requires in general manipulation of biomass (harvesting, processing, transport) which use tools or technical facilities and
  • requires often also measures for improving crop yield (planting, possibly irrigation and manuring, care) which use again tools and technical facilities

To produce all these tools and technical facilities requires energy (among others) and using them consumes energy as well. These energy uses in general release CO2, and therefore the total CO2 balance is no longer in equilibrium. For example, there are several estimates that for biodiesel, these additional CO2 emissions are as large as the CO2 release from combusting diesel fuel from mineral oil. If this would apply, then biodiesel would be exactly as harmful for the climate as normal diesel, while more expensive (from an economic viewpoint, i.e including subsidies and several tax reliefs).

Furthermore, a good crop yield requires most of the time manuring leading to N2O releases. N2O is a potent greenhouse gas. Its effect on climate comes on top of the CO2 impact. Although there are still considerable knowledge gaps in this field, in a correct overall assessment, it could very well be that biodiesel – to stay with this example – is more harmful for the climate than normal diesel.

The proposition serves no purpose

The rationale of the policy to use biomass is the mitigation of climate change threat caused by anthropogenic greenhouse gas emissions. Even for the cases where biomass combustion would actually release less CO2 emissions (and other greenhouse gasses) in the atmosphere compared to fossil energy, it would still be more beneficial not to burn the biomass, but use it for carbon storage. We can then produce the necessary energy in other ways with significantly less CO2 emissions (particularly through nuclear energy). Biomass is best kept in its form to store carbon, and keep it a few centuries out of the atmosphere.

Originally published March 2004 by Energie-Fakten in German. Translation by SEAL.