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replacements for fossil fuels—what can be done about it?

briefing document

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Replacements for fossil fuels—what can be done about it? is third of a series of briefing documents on the problems of power consumption, posed by the steady depletion of fossil fuels and most particularly of pumpable oil.
One of a grouping of documents on global concerns at abelard.org.
On energy
1 Replacing fossil fuels—the scale of the problem
2 Nuclear power - is nuclear power really really dangerous?
33 Replacements for fossil fuels—what can be done about it?
3a Biofuels   3b Photovoltaics (solar cells)
3c tar sands and shale oil
5 Energy economics—how long do we have?
6 Ionising radiation and health—risk analysis
7
Transportable fuels   
7a
Fuel cells and battery-powered vehicles
8 Distributed energy systems and micro-generation
9 Fossil fuel disasters
10 books on energy replacements with reviews
On global warming
4 Global warming
4a Anthropogenic global warming, and ocean acidity
4b energy pricing and greenwash
4c How atmospheric chemistry and physics effects global warming
4d Antarctica melting ice, sea levels, water and weather implications

Tectonics: tectonic plates - floating on the surface of a cauldron

sustainable futures briefing documents

Index
Introduction      

The delivery of power

How much will this cost?  


Integrated power  
Options:  Microgeneration and conservation Attempts to clean up coal
  Methane hydrates   In-situ coal gasification
  Wind   Coal to oil
  Tidal and wave More direct solar methods:
  Biofuel   Photovoltaic cells
      Solar thermal collectors


This document assesses the scale of fossil-fuel-replacement options other than nuclear power. Nuclear power is discussed with in Is nuclear power really really dangerous? Nuclear power is the only current technology that can fully meet the issues raised in Replacing fossil fuels—the scale of the problem.

Current reserves of pumpable oil are reckoned to be about one trillion barrels, another trillion barrels is estimated to be in shale and tar sands.
A further 10 trillion tonnes oil equivalent are estimated as available as coal reserves.
[7.2 barrels is approximately one metric tonne, it varies with oil density.] click to return to index on fossil fuel replacements

How much will this cost?

From the table above and the electricity usage and derivation table, the USA will probably need to decide to generate seven times as much electricity as at present (that is eight times the present amount, minus the generating capacity we already have in place). You will see from the electricity usage and derivation table that the in-place capital generating plant of the USA is equivalent to 430 big power stations and, therefore, is worth about $430 billion. Seven times this figure, the price of the new plant required, is approximately $3 trillion.

Now a power station may, at present, be expected to last approximately thirty years. Taking both our $430 billion and our $3 trillion, we are referring to a total of $3.5 trillion of plant, and replacing one-thirtieth of this each year, that is somewhat over $100 billion each and every year.

The American economy runs at about $10 trillion a year, and growing. $100 billion is about one percent of the US GNP year in, year out. As can be seen, this is a very large project, but perfectly do-able.

To emphasise the scale of this, it means, for example, the United States building 100 nuclear power stations each and every year, or Britain building ten each year. It has been recently announced (2003) that Germany intends to build the equivalent of 25 power stations, using wind power, by 2030. This is approximately half their present electricity generating capacity. For Germany to reach the level that I am estimating, would require the Germans to add approximately that capacity each and every year, not just once over 27 years. As you will see, this is no trivial project. You may work out similar figures for your own economy, by reference to the Fuel usage efficiency table.

Remember, this is somewhat of a theoretical calculation. For example, we could make our power stations last for 40 years, and it is doubtful that we will attempt to replace all our transportable oil equivalent through electrical fabrication, but again I remind you that my purpose is to enable you to grasp the scale of the problems.click to return to index on fossil fuel replacements

 

The delivery of power

In a Western economy, about 15% of usable power is delivered in the form of electricity, but that delivered power takes about 40% of the total power used by an economy to generate the electricity. The remaining 60% is shared between transport and various heating requirements.

To supply the 30% required for heating, using electricity, would require twice the current electricity generating capacity presently in place.

To produce a transportable fuel from electricity would probably take three or four times the electric power to produce a given amount of fuel.[1] Thus, assuming that 30% of fuel is in a transportable form such as methane, a generating capacity of something like six to eight times the present level of electricity generation would be required just to produce the transportable fuel.

Assuming that the lower factor of three times can be met, with improving technology and large-scale efficiencies, and all power passing through an electrical stage, it will be seen that a Western society would be looking at eight to ten times present electrical generating capacity in order to meet its present consumption desires.

all figures approximate

present primary power inputs present power delivered at point of use, in terms of total primary power input

electricity inputs required to match present primary power inputs

electric generating capacity required to match present power delivered at point of use [2]
electricity 40% 15% - 1 x present capacity
transport 30%   3 – 4 x present inputs 6 – 8 x present capacity
heating 30%   1 x present inputs 2 x present capacity
all 100%     approx. 10 x present capacity

Naturally, some of this processing need not go through an electrical stage, but my whole intention is to accustom people to the scale of the problem posed by depleting fossil fuels.

Taking an example of ten times present electricity consumption (present comsumption is produced by about 40% of current energy inputs), you will see that the prime energy input required to produced ten times present electricity would amount to about four times the current total prime energy inputs in Western societies.

That is, ten times the 40% (400%) of current energy inputs presently used for electricity generation.


From another angle:

As will be seen by an analysis, such as that done by Pimentel, a modern state could probably meet about half its wishes from non-fossil fuel methods other than nuclear power (or other, as yet undeveloped, alternatives). However, even that 50% would be a vast undertaking, and will not just gush up out of the ground. Pimentel allocates about 17% of the US land area to that purpose. While interesting, this study is not convincing in several ways: it does not deal with EROEIs, oil substitution, or distribution means.

In another study, Pimentel estimates that approximately 33% (one third) of energy could be saved by sound conservation methods implemented over the next ten years.


It is also clear that much can be done in improving energy efficiencies by insulation, and by better buildings and engineering design. Also, much is possible in rearranging our lives and working practices. Meanwhile, material and biotech sciences are racing ahead at such a pace that it is very difficult to guess at the relevant advances and contributions that these sciences will produce.

Further, at least five-sixths of the world population presently comes nowhere near click to return to index on fossil fuel 
replacementsWestern standards of living.


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Integrated power

Now thus far, I have been discussing the power needs for the future and relating that to the concept of a ‘big power station’. However, while we have a mixed power system including pumped oil and other fossil fuels, electricity production involves some inherent weaknesses.

Using the United Kingdom as an example, the electricity produced amounts to the output of around 42 big power stations, but you will recall from Replacing fossil fuels—the scale of the problem there is variation of demand (and there are downtimes). So, to keep people on line requires more than the number of stations allowed for in the supply calculations (in Replacing fossil fuels), quite a lot more stations. In the UK, the peak demand runs at around 60 big power stations.

There is yet more. The installed capacity in the UK is approaching 80 power stations! The difference between peak load plus down time for repairs and the installed capacity is known as overbuild. This overbuild becomes an even bigger problem when attempting to integrate wind power into a electricity grid supply system. In Denmark, peak capacity is about 3.7 big power stations, whereas installed capacity is approaching 7 big power stations. And still the Danish electricity system has to rely on links to the rest of Scandinavia and to Germany. For details.

The situation is likely to change radically once power stations become a source of storable fuel, such as methane or even perhaps hydrogen. At that point, power stations will not tend to lie idle during off-peak times (note that is around one third of potential production), nor will any overbuild need to lie idle. The system will be smoothed by production of transportable fuel. This production has another advantage in that remote sites are no embarrassment, as the transportation of liquid fuel will not require a considerable infrastructure to transport electricity from those remote sites. Much cheaper methods like road transport will be available.

See here for proposed nuclear-hydrolysis technology. Three and a half GoldenYak (tm) award

This technology is based on a hydrogen model, which has yet to convince that it is viable despite optimistic noises from politicians and government grant receiving car manufacturers. The authors claim that producing hydrogen by electrolysis is around 85% efficient. They also claim that more hydrogen can be produced by sensible reactor design, by using otherwise waste heat to force the disassociation of water into hydrogen and oxygen. This second process is expected to yield efficiencies in the range of 40-50% much lower than electrolysis, but still a tremendous potential bonus.

Methods of methane production from water and air using electric power are said to be approximately 38% efficient at the present time (see several papers by Specht et al. for further details).

click to return to index on fossil fuel replacements


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Options

Microgeneration and conservation

The future of energy production will probably involve local community and individual household generation. This is not an either/or situation. Systems will be range from very large and central distribution to the very local systems for personal use and efficiency, including conservation.

See distributed energy systems and micro-generation.

 

Methane hydrates

I have seen it quoted that there are 10 trillion tonnes of natural methane hydrates in the shallow seas around the world. That is, approximately 70 trillion barrels. Clearly, this is a major potential resource.

Hydrate:
a compound containing water in the form of HO molecules. The best known hydrates are crystalline solids that lose their fundamental structures upon removal of the bound water.

Examples of hydrates are: washing soda (sodium carbonate decahydrate; Na CO 10HO), borax (sodium tetraborate decahydrate; Na BO 10H O), and also blue vitriol (copper sulphate pentahydrate; CuSO 5HO).

A number of gases, notably the noble gases and simple hydrocarbon gases, form crystalline hydrates, called clathrate compounds, at relatively low temperatures and pressures. A clathrate is a solid in which one component is enclosed in the structure of another.
Clathrate crystals have a structure in which the water molecules form a loosely held framework surrounding the gas molecule.

“Hydrate research entered a second phase in the 1930s, when E.G. Hammerschmidt determined that hydrate was responsible for plugging natural gas pipelines, particularly those located in cold environments. For the next 40 years, a small body of researchers investigated the physics of various clathrates, including the construction of the first predictive models of their formation. A prime focus of this work was (and continues to be) the development of chemical additives and other methods to inhibit hydrate formation.”

Methane hydrate is the most abundant natural form of clathrate, a unique class of chemical substance in which molecules of one material (in this case, water) form an open solid lattice that encloses, without chemical bonding, appropriately-sized molecules of another material (in this case, methane).

Also ...

“... the U.S. Geological Survey estimates that methane hydrate may, in fact, contain more organic carbon than all the world's coal, oil, and non-hydrate natural gas combined. The magnitude of this previously unknown global storehouse of methane is truly staggering and has raised serious inquiry into the possibility of using methane hydrate as a source of energy.”

lake bottom methane
Lake Kivu, on Rwanda’s north-western border:

“the methane comes from lake bed bacteria.”

“The gas reserve should be enough to supply the country's electricity needs for 400 years.”

attempts to clean up coal

reasonable summary of present coal generation problems
The claimed proven reserves figures look highly over optimistic to me [see also Energy economics—how long do we have?]

This document is also recommended:

“Despite the improving efficiency of coal-fired power stations, carbon dioxide emissions remain a problem. A range of approaches of carbon capture and storage (CCS) have been developed and have proved to be technically feasible.

“They have yet to be made available on a large-scale commercial basis because of the costs involved.”

marker at abelard.org

us futuregen clean coal project agreed
The report cited below looks rather optimistic, and maybe even muddled at present, but it is useful research. The project is, in fact, very small in terms of US future energy requirements, and will be very costly relative to current generating plant. As you may realise, I am also very unconvinced by ‘the hydrogen economy’ regularly being touted by the Bush advertising machine. Therefore, treat this section with caution.

Coal is a considerable potential resource, but is presently inherently filthy. This proposed project is a step towards attempting to alter that situation.

“The Integrated Sequestration and Hydrogen Research Initiative is a $1 billion government/industry partnership to design, build and operate a nearly emission-free, coal-fired electric and hydrogen production plant. The 275-megawatt prototype plant will serve as a large scale engineering laboratory for testing new clean power, carbon capture, and coal-to-hydrogen technologies. It will be the cleanest fossil fuel-fired power plant in the world." [Quoted from fossil.energy.gov - .pdf format]

marker at abelard.org

“The FutureGen Industrial Alliance, including big utilities like American Electric Power Co. and Southern Co. and coal producers like Peabody Energy, have signed a deal with the Energy Department to build the 275-megawatt plant, worth $950 million.”

“ Other US partners are Consol Energy Inc., Foundation Coal Holdings and
Kennecott Energy.

“International partners are China Huaneng Group, China's biggest coal producer, and mining and energy group BHP Billiton Ltd./Plc., the world's biggest mining company headquartered in Melbourne, Australia.” [Quoted from planetark.org]

Note the growing co-operation that is being built by the USA with the obvious intent on spreading leading edge technology to developing countries. A rational approach to Kyoto-type objectives.

marker at abelard.org

This next article has a typically foolish heading and spin that could only be written by people who do not understand the United States and the American approach to government.

“While US President George W. Bush refuses to accept the Kyoto Protocol to cut greenhouse gas emissions, at least 40 million Americans will find themselves bound to the international treaty to curb global warming.

“Since the protocol took effect last February, Seattle Mayor Greg Nickels has convinced 192 cities to agree to cut emissions 7 percent from 1990 levels by 2012 - the recommended target for the United States, which emits 25 percent of the world's heat-trapping gases.”

“California's Republican Gov. Arnold Schwarzenegger has won environmentalists' praise at the conference with progress on his ambitious plan to reduce greenhouse gases in the nation's most populous state 80 percent from 1990 levels by 2050.” [Quoted from planetark.org]

California, if treated as independent of the USA, would be one of the world’s leading economies all on its lonesome! The silly sideswipes at George Bush primarily indicate ignorance on the part of the writer.

marker at abelard.org

carbon sequestration, an infant technology - will it work?

“With more than 3.5 million oil wells drilled in the U.S. since petroleum exploration began in earnest 150 years ago, there is no shortage of potential leaks.

“Experts also worry how so much carbon dioxide will alter the chemistry of the storage formations themselves. Bubbles composed of millions of tons of sequestered CO2 could form an acid that could etch away the confining rocks or erode the concrete caps on well heads.”

“This is the only way for the fossil fuel industries to survive - to become part of the solution," said Fjaeran of Statoil.

“Statoil and Royal Dutch Shell announced a proposal in March for a $1.4-billion, 860-megawatt power plant that involves one of the world's largest carbon-capture and storage operations. Almost half of the project's cost stems from its carbon storage plan, but the companies will use the excess CO2 to boost production of even more oil and natural gas from their depleted fields.”

The numbers being discussed here are absolutely trivial compared with the size of the potential problems.

marker at abelard.org

A useful general survey of current projects (2004) [.pdf format - 19 pages] Three GoldenYak (tm) award
Note the small scale compared with the billions of tonnes surplus currently being produced.


related material
energy economics

in-situ coal gasification

The world’s gas system was originally designed for gas from coal.

This technology appears to have considerable potential as a means of using coal with lessened pollution problems.

Thus far, it seems to concentrate on exhausted pits and be of modest scale. Coal gasification is useful, though, for coal occurring at below profitably mineable depths. A helpful addition to the armoury during transition to the post-fossil fuel economy.

Current worldwide explorative projects.

A short, reasonably clear, summary of the state of play.

[Site reference from Mel Rowing.]click to return to index on fossil fuel replacements

coal to oil

“It is further possible to make watergas in the Karrick retort. The LTC char is especially well suited for the purpose. In other LTC processes, the feedstock must be brought to an incandescent state in a separate operation. The charge in a Karrick retort is in an incandescent state at the end of a run, and means of removing the water-gas are an integral part of the design.

“In 1947, after completing commercial-scale runs on Appalachian coal, Karrick presented the Keynote address to the Convention of the Ohio Society of Professional Engineers. He said, "Great coal-oil and shale-oil industries have existed and do now exist in foreign countries, and many successful plants have existed in the state of Ohio and other states. Recent studies have shown that oil from coals of Ohio can be manufactured by distillation, not hydrogenation, at less than the average price of petroleum."

“Ohio bituminous coal then was selling for $3.50/ton, and natural crude was selling at the Persian Gulf for 34 cents per barrel, and domestic crude for around $2.53. The economics of the Karrick process were such that he was able to claim:

"If the solid smokeless fuel residue from the LTC process was assumed to sell at the same price as the average price of prepared sizes of raw coal, then the cost of the crude oil would be zero dollars per barrel. This condition now exists in Ohio, and there can be made available plenty of low-cost fuel, excellently suited for domestic uses and industrial plants as a by-product of the manufacture of oil from coal. Also, the gas made from coal by these distillation methods is of about the same heating value as average natural gas."
—"LTC is a pyrolysis process that involves heating coal, shale, lignite, or any other carbonaceous material, including garbage) to about 800° F. in the absence of oxygen. Oil is thus distilled from the material, rather than burning as it would if oxygen were present."

“[...] a ton of coal will yield up to a barrel of oil, 3000 cu. ft. of rich fuel gas, and 1500 lb. of solid smokeless char (semi-coke)[...].” [Quoted from rexresearch.com]

The waste product is carbon dioxide and, consequently, some means of sequestering this will be necessary.

See also transportable fuels.

[Link from ’regn pickford’.]click to return to index on fossil fuel replacements

Tidal and wave power

There are essentially two ways off extracting power from the movement of the seas:

  1. using wave action (primarily caused by winds) and, therefore, not fully reliable;
  2. using the movement of the tides which, although it varies, is regular and reliable.

Both methods are described in this FAQ.
Using ocean currents has also been discussed, but looks highly dubious to me. Such currents tend to be seasonal and their position unreliable.

This is a description of the La Rance Tidal Barrage in France.

A new offshore system is under way off the Devon coast in southern England.

“Martin Wright, of Marine Current Turbines Ltd, said: "We estimate that there is at least 10 gigawatts of power available from tidal power in the UK.

“"That's the same as about half of the existing nuclear industry." ”

That is to say, only around 1/10th of the present electricity usage of the United Kingdom, or about 10 large power stations. This looks like a low estimation to me, but I am no engineer. These sea-oriented methods are not discussed in the much quoted Pimentel assessment.

As the article on the English offshore system states

“Its backers believe the concept can become a rival to wind power because ocean currents are more reliable than wind and also because they are less obtrusive; the structure is built on the seabed and projects just a few metres above the surface.”

Another wave generator design

The item headline is “the world's first commercial wave power station is going into action in Scotland”, but no actual start date is given.

The generator is quoted as designed for 1/2 megawatt, but again details are not given. Windmills are now moving towards 3 megawatts and higher, this design also relies on air pressure.

Non-rigid tidal generator method


well-planned conurbation with sea-water lake

It is further possible to build tidal lakes on the coast which may be very usefully integrated with town planning. As you may see here, people and traffic are more separated than in most town planning. There is a pleasant lake for various activities and views, which includes a circular walk. The lake, if managed properly, is constantly renewed by the sea-tides. Constructing wide tidal ‘rivers’ is also a possibility.


links from Alan G and James Hammerton

click to return to index on 'fossil fuel replacements' page

Wind

Near Artajona, Northern Spain: a  mere row of windmills. Image credit: abelard.org
Near Artajona, Northern Spain: a small row of windmills.

Pimentel reckons that wind power could be expanded in the United States to produce the equivalent of 230 big power stations, which would take up approximately 8 million hectares. My untutored guess is this may well be a considerable under-estimate, as windmills are developed, enlarged in capacity, and may be mounted ever higher in order to reach more powerful winds, or ganged more than one to a pillar, or built out to sea. Whether such development would affect weather conditions, I do not yet know enough to guess.

the increasing return of the age of the windmill

“Last year, enough wind energy came online in the United States to power roughly a half million homes. Next year, that number is expected to climb by another 100,000.”

“For the past five years, it's grown by about 30 percent a year worldwide. In Denmark, it now accounts for some 15 percent of all energy use.

The figure quoted for Denmark is an error, one commonly made. The figure should read, “15% of electricity production”, which is about 5% of Denmark’s energy inputs.

marker at abelard.org

the wind in spain

“Spain, one of the windiest countries in Europe, currently gains around 3 percent of its electricity from wind power and is the second largest European producer of this form of energy and the third largest in the world.

“It expects its current installed generation capacity of 4,100 megawatts from wind power to increase to 8,900 megawatts by 2010.”

marker at abelard.org

the advance and advance of wind power in spain

“[...] momentarily wind power contributed 8,375 mega watts to the nation's power consumption of 31,033.

“Nuclear power, the second largest contributor, added 6,797 mega watts, while coal-fired electric generation came third with 5,081, the statement said.

Over the course of last year wind power contributed nine per cent of the nation's requirement while coal-fired power stations put in 24 per cent and nuclear power 22 per cent.”

Here is more on Spanish wind power and photovoltaics. There is also a short film.

marker at abelard.org

Wind power FAQs Three and a half  GoldenYak (tm) award

marker at abelard.org

This link is to a general but rather disorganised site, which discusses some of the problems with wind power. Despite being negative to wind power, the site remains useful. In contrast to the general negativity of that site, I must declare an interest - I think the windmills are utterly beautiful!

There follow some abstracts from one of the many items at that site, with commentary (in green).

I am surprised this technology is not more oriented to producing transportable fuel, for instance ethanol or methanol. I speculate of a time when these wind farms end as transportable fossil fuel producers, akin to the historic great derrick fields of Texas. It is suggested 20MW wind turbines as high as the Eiffel Tower may be a reality by 2015.

“The situation would become much worse [pah!] if/when wind power is exploited to produce hydrogen as fuel. [I regard the idea of a hydrogen-fuelled future as nonsense in the present state of knowledge, much more likely is a liquid fuel] Assuming a very optimistic LF [load factor] of 50% for 3MW wind turbines, a recent study (Oswald and Oswald, 2004) estimated that about 96,000 units would be required to run all British transport vehicles on hydrogen. These would occupy a dedicated area greater than that of Wales or, alternatively, a 10 km strip encircling the entire coastline of the British Isles.”

Bring it on!!

Denmark is the most advanced nation in wind power development and manufacture:

“It is true that Denmark has placed itself in a leading position with regard to the utilisation of wind energy, but until now this has certainly occurred at great cost to nature and with considerable public subsidy" (Jyllands Posten, 2004)

“Despite windy conditions, only 20-24% (LF, ie load factor) of the potential annual output of West Danish wind turbines has actually been achieved over the last five years but this is higher than the 15% calculated for Germany over the same period.” In fact, most of the Danish output is being exported. Therefore, the reality is that Denmark is subsidising electricity that it then exports.

“In contrast, its attempts to assimilate large amounts of wind power into the domestic system have so far proved disappointing, with little reduction in carbon emissions because of the need for backup to protect the integrity of its grid (Sandøe, 2003a). The reality is that despite West Denmark's massive carpet of wind turbines, the region's carbon emissions have recently been rising (Bruun, 2005). Most of its large exports of wind power simply displace 'green' hydro electricity produced in Norway and/or Sweden, helping to replenish reservoirs only in dry periods or when power is cheap. This led a former Chairman of Eltra to ask: ["Is it environmentally friendly to produce electricity with wind turbines if there is no-one who can use it? And is it environmentally friendly to burn natural gas in decentralised heat and power plants while dumping the over-production of Danish wind electricity in Norway, where it possibly leads to water being diverted away from the water turbines?"] (Kongstad, 2001). Processes involved in the manufacture, excavation and/or installation of access roads, massive concrete foundations, turbine components, pylons, and associated equipment also militate against the emission-saving benefits claimed for mega wind power.”

marker at abelard.org

Windmills do not provide reliable background power. They may contribute in due course, but there are several concerns and problems. The bigger they get - they being windmills or problms?, the greater the servicing problems. There are potential weather problems with really large scale projects. It requires building thousands of large windmills to replace just one conventional power station. Doing that takes considerable resources.Ttransporting electricity from distant and dispersed sites is not simple.

There is even considerable concern that wind patterns are shifting with growing global warming.

click to return to index on fossil fuel replacements

Hydroelectric

This is one of the most efficient power sources available. Naturally, much of the available source is, therefore, already exploited.

There are ecological problems such as silting and free river flow.


Geothermal

using volcanic activity to generate hydrogen from water

“Engineers on the project have calculated that increasing the temperature by 200 degrees and the pressure by 200 Bar will mean that, for the same flow rate, the energy extracted from such a borehole will go up from 5MW to 50MW.

“Power station manager Albert Albertsson predicts that, by the end of the century, "Iceland could become the Kuwait of the North". The vision is to use this cheap and carbon-free energy to split water, to yield hydrogen that could be despatched around the world in tankers.”

“Some 90% of all homes in Iceland are heated by geothermal energy; and a number of power stations are also producing electricity from steam at around 240C, extracted from boreholes between 600 and 1,000m deep.”

Remember that the centre of the Earth is hot, due to nuclear activity.

See also using nuclear power to generate hydrogen from water.click to return to index on fossil fuel replacements


More direct solar methods

solar thermal collectors

A miniaturised rooftop device appears to be nearing production [2005].

Note that this is a hybrid system that combines both photo-voltaic with solar concentration.

“[...] a powerful ally. One that never sends a fuel bill and self-stores waste. That's 93 million miles from anyone's backyard, and now in its sixth billennium of trouble-free operation.”

marker at abelard.org

“Then, in a weekend flash of inspiration, a young Caltech physics grad named Kevin Hickerson figured out how to reduce the number of motors needed to move 25 mirrors independently, a major cost factor. Instead of two motors for each mirror - the traditional approach - Hickerson's solution requires only two motors for any number of mirrors. The key is a mathematical curve known as the conchoid of Nicomedes (named for the ancient Greek mathematician, who discovered it). A grid of ball bearings arrayed to match the conchoid is attached to a frame inside the Sunflower. As the motors move the frame, the bearings control each mirror's position individually.”

Solar concentrator and receiver. Image credit: Energy Innovations, Inc.
Solar concentrator and receiver. Image credit: Energy Innovations, Inc.

“Gross hopes to push the price down another 20 percent within two years as manufacturing scale and more efficient silicon kick in. His focus is the metric nearest the hearts of penny-counting CFOs and facilities managers who rule all those endless miles of sprawling rooftops: payback period. "Right now, PV solar has a 20-year payback, but people are still buying it," he says. "Our target for California is five. In Phoenix we could do 3.3."

Of course, those alluring numbers hide a little secret: Take away rebates and other incentives, and payback periods pretty much double. The hard reality is that, even on the rooftop, even with concentrated sunlight, even with low-cost Chinese manufacturing, unrebated solar kilowatt-hours cost too much for the mainstream energy market. Gross is bold enough to think the Sunflower has a shot at competing straight up with the utility companies, and certainly sooner than the 20-year forecast for PV panels. But for now, he'd rather not have to find out. "Losing rebates would be devastating to all of us," he says. "This is still a very young industry." [Quoted from wired.com]

Energy Innovation Inc. website.

See also Distributed energy systems and micro-generationclick to return to index on fossil fuel replacements


end notes

  1. Allowing for some mass production and increased efficiency (also see here).

  2. Present electricity generating capacity delivers the equivalent of 15% of the total primary power inputs at the point of use. We need to use the delivered electricity as inputs to replace the transport and heating primary inputs that currently come from fossil fuels.

    In other words, that 15% delivered can be used to calculate the required primary inputs if supplied by electricity. Thus to make the 30% of current primary inputs used for transport, you would need 2 times the present electricity generating capacity. To make the 30% of currently primary inputs used for heating, you would need another 2 times the present electricity generating capacity.

    However, producing a transportable fuel (for instance, methane) from electricity is 3 – 4 times less efficient than using the fossil fuels, so to go that route you would need 3 – 4 times as much electricity input as you would need in the idealised situation above. That is, 3 – 4 lots of that 2 times given above, which calculates to 6 – 8 times the present electricity generating capacity.

    Heating using electricity is, in fact, just as efficient as heating using fossil fuels. This means you need the same electricity input as in the idealised situation above. That is, 1 lot of the 2 times above, or just 2 times the present electricity generating capacity!

  3. “US energy conservation and efficiency benefits and costs”, D. Pimentel et al., in Environment, Development and Sustainability 6: pp 279-305, 2004, Kluwer Academic Publishers.

  4. This applies to the northern hemisphere; in the southern hemisphere the arrays would need to be point northwards.click to return to index on fossil fuel replacements

Related further documents
On energy
1 Replacing fossil fuels—the scale of the problem
2 Nuclear power - is nuclear power really really dangerous?
33 Replacements for fossil fuels—what can be done about it?
3a Biofuels   3b Photovoltaics (solar cells)
3c tar sands and shale oil
5 Energy economics—how long do we have?
6 Ionising radiation and health—risk analysis
7
Transportable fuels   
7a
Fuel cells and battery-powered vehicles

8 Distributed energy systems and micro-generation
9 Fossil fuel disasters
10 books on energy replacements with reviews
On global warming
4 Global warming
4a Anthropogenic global warming, and ocean acidity
4b energy pricing and greenwash
4c How atmospheric chemistry and physics effects global warming
4d Antarctica melting ice, sea levels, water and weather implications

Tectonics: tectonic plates - floating on the surface of a cauldron

sustainable futures briefing documents


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© abelard, 2003, 16 april
v.1.5


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the address for this document is http://www.abelard.org/briefings/fossil_fuel_replacements.htm

4185 words
prints as 17 A4 pages (on my printer and set-up)

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