Replacing fossil fuels:
the scale of the problem

a briefing document

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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. See World oil resources table for details.
There is a similar table for coal resources. As you will see, even with known coal resources, the current situation is not nearly as critical as it is for oil. This is probably an under-estimate of coal reserves, as the pressure to find new reserves has, so far, been considerably less than the pressures posed by oil depletion.

1. Fossil fuels are filthy. See also Global warming.
2. Replacing more than half the current energy use in the United States with solar input is somewhere between extremely problematic and impossible. See Pimentel.
   I am unconvinced that Pimentel is accounting for the energy costs of extraction of fuel oil from bio-mass, or for the problems specified in Note d below. Also in this paper, Pimentel does not pay sufficient attention to the potential contributions from conservation nor to nuclear power.
3. The desire for energy is still increasing in the United States and is vast in the rest of the world.
4. The population of both the United States, and of the planet, are currently increasing .
5. Major inroads on this problem are possible with a whole range of conservation and efficiency measures. For a good primer see, for example, Lovins. Strangely, Lovins does not appear to attend to the scale of the problems.
6. In the current circumstances, there is only one technology that comes even within shouting distance of meeting the problems. In fact, the potential of that technology is vastly surplus to the scale of the problem. That technology is nuclear power generation.
   The rest of the technologies together may make useful contributions, but they are completely incapable of coming anywhere near to tackling the scale of the energy problem.

Notes:

1. For more on nuclear power, see is nuclear power really really dangerous and radiation risk item.
2. For more on conservation, see also improving life in backward areas and items on water and soil problems.
3. There are two ways of controlling population: the Chinese methods or the Western method of education, particularly of females. Education is, by far, the most effective method of birth-control known. For completeness, there are also more grim ways—the Horsemen of the Apocalypse: disease, famine and war.
4. There is much talk around concerning ‘the hydrogen economy’. I am unconvinced that it makes any serious sense for road transport because of inefficiencies involving weight and handling. I note that many manufacturers are putting a lot of work into this, but I am suspicious that this may be some luxury or commercial vehicle market, or just some pork-barrel project.
   
   I am much more optimistic concerning a methanol formation route but, with either hydrogen or methanol, my current guess is that the power input requirements for fuel formation are about four to six times the current power used in vehicle fuels. In other words, a monumentally vast expansion of what amounts to nuclear power generation.
5. There are also many possibilities of lifestyle change: smaller housing units, sharing facilities, less travelling.
6. A sensible change, which would also improve income distribution, would be to apply rationing to petrol consumption, while allowing individuals to sell their ration in an open market.

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,
produces (8760 x 1000) or 8,760,000 megawatt hours (MWh) of electricity in one year.

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 (MWh) electricity.
However, a tonne of oil used in a power station to generate electricity produces about one third of this amount, that is 4 MWh electricity.
[Note: all energy uses involve inefficiencies. In this case, the efficiency would be expressed as 33%.]

Thus, a 1000 MW power station, using oil as its energy source, would consume
8760 x (1000 /4) = (8760 x 250) tonnes of oil in a year,
that is 2,190,000 tonnes of oil, in order to generate its full capability.[1]

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, see The delivery of power.

Here is a brief assessment for the United States of America, by far the most extravagant user on the planet.

	The USA is currently burning 25% of the world’s energy usage, and doing this with about 1/20th of the world’s population. Of course, the USA also produces 20% plus of the world’s measured GDP ( Gross Domestic Product). But, as you will see, the USA is far from optimally energy-efficient.
	US total power consumption is in the region of 3 terawatts. (As usual, be careful of figures that look highly ‘accurate’; we are often guessing within, say, 10%.)
	A terawatt is one million (1,000,000) megawatts of power. In theory, one large coal or nuclear power plant generates 1,000 MW (1 gigawatt) of electricity.
	The present USA energy requirement, of 3 terawatts of power, is equivalent to the energy produced by about 3000 large (1000 megawatt) generating plants (i.e. three thousand ‘big power stations’). Recall that much of the input power to a country is burnt for heat and transport, only some of the power is used to generate electricity. In fact, only about one third of the input power to a country is used in the form of electricity.
	But the process of generating electric power is only approximately 38% efficient. That is, it requires just over two and a half times as much oil energy to produce the electric energy provided. The implications of these calculations are taken forward further at the start of Replacements for fossil fuels—what can be done about it?

A simple outline on the scale of energy consumption can be found here.
For more detail, but less clarity, look at Pimentel.

Variation of supply
Wind energy

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
Consider a region that can be supplied with electricity from a 1000 MW generating plant. Assuming that this is a controllable power generator, it can be regarded as 80% efficient—it can be relied upon to produce about 800MW. Remember that in an advanced country, there will be many such generating plants, and that they will not tend all to be operational at the same time. Homes, factories, power stations in the region are all connected to a ‘national grid’. Thus, if one power plant is having problems, other plants connected to the grid will normally take up the load, thus maintaining a relatively steady supply of electrical power.

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.
For more see Renewable energy: current and potential issues by David Pimentel et al., BioScience,Vol.52 No.12, pp. 1111 – 1120, December 2002 (paper also available for purchase here – $10 US).

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 systems—there 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.

	A power station, or a growing tree, are means of generating usable power.
	A log is a store of energy, but a power station is not. The power station uses means such as oil or uranium to store energy prior to using it in the generating process.
	For completeness, an engine is a device that converts energy from one form to another. Thus, a car engine converts petrol into moving along the road, while a tree converts sunlight into logs.

Energy accounting—
energy return on energy investment (EROEI)

If you want a power source, it is important to analyse the amount of input power (needed to build the source) and running costs (needed to produce that power), and match that amount against the power output that can be expected over the lifetime of the plant.

For example, if it took more energy to build and to run a windmill than the energy that can be extracted during its lifetime, then clearly the windmill is not worth making in energy terms.[2] (This is not the case with windmills.) However, it is the case with some projects, such as producing oil additives from corn. The energy required to produce the oil is approximately 1.4 times the energy that can be extracted from the resulting oil.

Putting a straw down and sucking up oil in the Middle East, and then refining and transporting that oil to market, can give ratios of power output/input of up to 50:1. This makes oil an exceedingly cheap source of energy.

No power sourcing project can sensibly be undertaken without Energy Return on Energy Investment (EROEI) assessments. Purely financial analysis is wholly inadequate, especially where signals are distorted by government subsidies.

Currently, we have the bank of fossil fuels bequeathed to us from the history of the earth. It is important that this windfall be used to build a sustainable power-generation infrastructure, while the bank still holds ‘funds’ (oil, gas, coal, etc.). The job would be vastly more difficult if we were to wait until the bank account was nearly exausted and then attempt to bootstrap ourselves, at a time when we were no longer in possession of this bounty from the past.

An assessment of our position, based on purely market economics, is wholly inadequate.

For more on energy return on energy investment (EROEI), look at this document from the World Nuclear Association.

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

GDP (PPP)
[$ trillion]

energy efficiency

GDP/GWeq
[$ billion/GWeq]

0.054

149.8

1. Average electricity usage per person in terms of required installed capacity, operating notionally at 100% capacity; but this not as simple as it sounds. To understand why, see the integrated power section in fossil fuel replacements.
   
   
2. Conversion factor of 1.37.
   Values in BP table are in million tonnes of oil equivalent (mtoe).
   One tonne of oil equivalent equals approximately 12 megawatt-hours of electricity.
   For instance, USA 2,237.3 mtoe x 12 = 26,847.6 x 1,000,000 MWhr.
   26,847,600,000 / 8,760 (hours in 1 year) = 3,064,700 MWyears.
   3,064,700 / 1,000 = 3,064.7 GWyears. A GWyear is equivalent to a big power station.
   Or (1,000 x 12) / 8,760 = 1.37.
   
   1.37 is what is known in the trade as a fudge factor. In this case, it is obtained as follows:
   The figure from the BP table was 2,237.3 (mtoe).
   After all the sums, the figure we arrived at, in big power stations, was 3,064.7.
   Therefore, 3,064.7 / 2,237.3 = 1.37. So, to save doing all the calculations each time, you just take the figure in the BP column and multiply it by 1.37, saving a lot of work and potential for errors.
   
   
3. Conversion factor of 8.76.
   Values in world electricity consumption table are in billion kilowatthours, or Terawatthour (TWhr).
   For instance, Canada 504.4 TWhr / 8,760 = 0.5757 TWyr.
   0.575 * 1,000 = 57.57 GWyr. A GWyear is equivalent to a big power station.
   Or 8,760 / 1,000 = 8.76.
   
   8.76 is what is known in the trade as a fudge factor. In this case, it is obtained as follows:
   The figure from the world electricity consumption table was 504.4 billion kilowatthours, or TWhr.
   After all the sums, the figure we arrived at, in big power stations, was 57.57.
   Therefore, 504.4 / 57.57 = 8.76. So, to save doing all the calculations each time, you just take the figure from the column for 2001 consumption and multiply it by 1.369, saving a lot of work and potential for errors.

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End notes

1. Sometimes, you will come across references quoted in joules. The relevant scale for the sizes we are talking about are exajoules, that is one quintillion joules, or 10¹⁸ joules, that is one followed by eighteen zeros, that is 1,000,000,000,000,000,000.
   One exojoule is approximately 23.5 million tonnes of oil, that is equivalent to about 10.73 big power stations, I tend to think of it as 10 big power stations. I hope thart you will be pleased to know that beyond this note, I will not be talking about joules or exojoules.
   
   
2. This does not mean that we would not manufacture an energy-producing device, such as a battery, which would cost far more in energy to produce than the energy that is extracted from it. It is often decided to produce such devices for their convenience utility, but it is not a means for producing energy in the first place.

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