Replacing fossil fuels:
|Replacing fossil fuels—the
scale of the problem is the first in 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||on global warming|
|sustainable futures briefing documents||
Tectonics: tectonic plates - floating on the surface of a cauldron
There are constant, ill-informed
debates and reports that suggest that we can easily replace
our fossil fuel usage by wind, or solar cell power, or
some such method. Within current technology, this is a
pipe-dream, it is impossible, it simply cannot be done.
This does not mean that we are all dooooooooomed; but
we are faced with a tremendous problem as reserves of
fossil fuel, especially cheap pumpable oil, diminish.
oil resources table for details.
To understand the problems in replacing fossil fuels, it is necessary to look at several variables.
A big power station
There are 8760 hours in one year.
Therefore, a nuclear power station with a 1,000 megawatt (MW) generating capability, working at 100% capacity,
I am taking a 1000MW (1GW) plant as a standard unit. This I am also calling a big power station.
1 tonne oil equivalent equates to 12 megawatt hours
Thus, a 1000 MW power station, using oil as its
energy source, would consume
In the real world, however, controllable power-generating equipment (that uses coal, oil or nuclear fuel) only works at 80 85% capacity, after downtimes and peak demands are taken into account.
Scale of the problem
Buried fossil fuels are like a great bank account from the past, from which currently we are drawing down reserves at a horrendous and unsustainable rate through our profligate burning of fossil products. (To the problems caused by this depletion of fossil fuel reserves must be added the problems of the filthy mess that most fossil fuel usage generates.)
It is important to grasp the vast quantities of energy being used for sustaining modern civilisation. It will probably take the reader some time, and imagination, to adjust to this. A table providing figures for several countries in terms of big power stations is available here. For more numbers and analysis, and potential costs, seeThe delivery of power.
Here is a brief assessment for the United States of America, by far the most extravagant user on the planet.
A simple outline on the scale of energy consumption
can be found here.
Variation of supply
Electricity generation using wind is not controllable, it depends on the vagaries of when the wind blows. On average, this is about 35% of the time.
Wind power is unsuitable as the main energy source for the national grid because it is intermittent. Wind power at 100% load is still uneconomic, not only because three times as many windmills are necessary, but also because considerable storage capacity would be required for when the windmills are unable to generate power, because no wind is blowing in that region.
Average power over a region
Now come to wind and windmills. A windmill is operational for only about 35% of the time, and if the wind does not blow in one part of the region, it is quite probable that the wind will not be blowing in other parts of that region. So, unlike a nuclear power station, the production of energy cannot increased at will. Because of this lack of flexibility in wind power, it has been estimated that only approximately 10 20% of grid power can be supplied economically and efficiently by wind generation.
If the electricity generated by wind systems could be stored, then, if approximately three times the wind generating capacity desired for peak load were installed, theoretically such a system would be satisfactory.>
But another problem still remains. There are probably
not enough suitable sites to establish anything like sufficient windmills.
Variation of demand
Demand for power is not even and steady, nor is it completely predictable. There is greater demand for power in winter, for heating, and there is more requirement for lighting homes, offices and streets when the sun goes down, while a manufacturing plant may be shut down at night. Patterns of demand may be imagined as similar to road systemsthere are rush-hours, while at 4 a.m. the roads are nearly empty.
A generating capacity designed to meet peak loads will be lying idle much of the time, thus wasting resources; or, otherwise, may be described as being economically inefficient. The ideal situation would be to operate expensive plant 24 hours a day and every day of the year, so that the money (capital) invested in the plant was always paying its way.
The storage problem
If energy is not wanted immediately, for instance to switch on a light, some means of storage of energy required for later use has to be achieved. A battery, a dam, a gallon of petrol, a hydrogen fuel cell, a log for the fire, or radioactive sources, are all means of storing power/energy.
Learn to think clearly about the difference between generating and storing power.
|[With some references from Greg Hennessey, Lavigne, the Enlightenment]|
Fuel usage efficiency
The following table attempts to give some impression of the fuel-use efficiency of various countries. The higher the number in the fourth column, the greater the the fuel-use efficiency in that country. What is particularly striking is the low usage efficiency of the United States.
However, there are many possibilities that could make such a table misleading. A country producing low added-value goods or having a large subsistence farming sector, with cheap labour inputs, could appear more energy efficient than a country producing high-technology goods.
There are also issues such as the low monetarisation of many less advanced countries, and the high purchasing premium on reserve currencies, especially the $US . But a major factor must be the low taxes on fuel in the United States, and even subsidies for fuel use; for more see Transportable fuels. With such apparently cheap fuel, market signals are bound to go out that do not encourage conservation. In Europe, there are high taxes on fuel usage, thus there are strong pressures to conserve.
Fuel usage efficiency
|energy usage in big
power station(1 GW) equivalents
electricity in big power station (1 GW) equivalents
|country’s population (in millions)>||average installed
|2001 figures||from CIA factbook||from BP p.37 2001 figuresx conversion factor||(col.1/col.2) *1000||2001 data from 'world total net electricity consumption'/ conversion factor ||from CIA factbook||col5/col6|
There is also an easy to follow and clearly presented report, Key world energy statistics from the IEA. It has recently [December, 2007] been issued by the International Energy Agency. This report has comprehensive data tables and charts for fossil fuels.
Section headings are Supply, Transformation, Consumption, Energy Balances, Prices, Emissions, Outlook, Energy Indicators, Conversion Factors, Glossary.
The problem of finding a long term solution to storing the nuclear waste still hasn't been solved.
The consequence of another major nuclear explosion would be catastrophic.
power - is nuclear power
email email_abelard [at] abelard.org
© abelard, 2003, 1 february
the address for this document is https://www.abelard.org/briefings/replacing_fossil_fuels.php