Future energy demand and supply
Future energy demand and supply

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Future energy demand and supply

5 Managing energy use in the future

Anyone who believes exponential growth can go on forever in a finite world is either a madman or an economist.

(Kenneth Boulding, c. 1980)

The final years of the 20th century brought increasing concerns over the use of all resources, including energy, and the rise of international initiatives to address the problems. The 1992 Earth Summit at Rio de Janeiro drew up a 'sustainable development plan' showing how resources, transport, trade, biological diversity, agriculture and fisheries could all be managed to maintain the quality of life for future generations. Among other recommendations, the industrialised nations agreed (in principle) to stabilise emission of carbon dioxide (from fossil fuels) at 1990 levels by the year 2000. (This was not achieved.) Discussions at Rio were followed by the 1997 Kyoto Protocol, which aimed for 5% below 1990 CO2 emission levels by 2012.

  • Would achievement of the Kyoto Protocol aims stop the increase in the concentration of atmospheric CO2?

  • No. Stabilisation of CO2 emissions at even 5% below 1990 levels merely means that the atmospheric concentration of CO2 would increase by almost the same amount each year as in 1990 — instead of a net annual addition of some 1010 t of CO2 it would be 9.5×109 t.

Although some nations have been reluctant to commit to environmental initiatives, growing numbers of people in the affluent societies of Western Europe, North America and Australasia have begun to 'think globally, act locally', initiating and supporting programmes of materials recycling, energy conservation and efficiency, waste reduction, and so on. The ultimate aim is for 'sustainable development' (Sheldon, 2005), that is, development within our ecological means, which modern humans abandoned when they began consciously modifying their environment to build our modern civilisation.

To put it more explicitly, sustainable development must eventually involve:

  • phasing out extraction of non-renewable resources
  • increased use of renewable resources
  • recycling all manufactured materials
  • releasing all anthropogenic wastes at rates commensurate with natural cycles.

In the early 21st century world, the main priority is to decrease fossil fuel consumption. Using alternative, renewable energy sources will help, and in some cases, using recycled and biodegradable materials — though a full energy audit may reveal that more energy is required for recycling some products than for manufacturing them anew from raw materials. (More commonly, it is the high relative financial cost of recycling that deters such schemes.) Less equivocal is the benefit of energy conservation. This can take place either on the supply side or the demand side. Demand side measures are very diverse, and may involve approaches that are either technological or social; we do not consider them here. Supply side measures involve increasing the efficiency of power generation and distribution; as an illustration, less than half the energy in the gas fuel for the most efficient UK power stations in the early 2000s is actually available to the electricity customer. Much of this unused energy takes the form of waste heat, which could be used to heat buildings, as in Denmark.

Efficiency has been a theme throughout this unit, but mainly applied to efficiencies of conversion, as in solar PV electricity generation. The theoretical maximum efficiency for this promising technology is limited to around 30% by physics, and is currently about 15%. Yet efficiency applies to all aspects of human energy use, a revealing example being the use of electricity to pump water; the most fundamental need of a modern society. Say the electricity was generated at a coal-fired power station using 100 arbitrary units of primary energy. Energy losses there are around 70%, so only 30 units enter the transmission grid. Transmission is very efficient (91%), pump motors operate at around 88%, and pumps themselves at around 75%. Once water is flowing through all the pipelines and valves to the user, distribution is about 47% efficient in energy terms, partly due to constrictions to the flow of a viscous fluid, and partly due to leaks. The net result of this chain of inefficiency is that the pumped water contains only 9.5 of the original 100 primary energy units. Transportation is very much worse. After more than a century of development, car engines deliver no more than 13% of fuel energy to the wheels, of which more than half heats the tyres, road and air. But the efficiency in terms of useful work, taking people back and forth, is a pathetic 1%, since 95% of the mass transported is the vehicle itself! More or less the same happens with every means of using energy to do useful work.

Technological measures involve improving the efficiency of energy use and effectiveness of conservation in a variety of ways:

  • reducing heat loss from buildings, by improving insulation, window glazing, etc.
  • making more efficient appliances such as boilers, fridges, lightbulbs, computers, photocopiers, pumps, and other industrial, commercial or domestic machines
  • improving the efficiency of transport vehicles, and developing vehicles that run on alternative fuels, for example hydrogen in fuel cells (Figure 21) or biofuels
  • improving control systems so power is consumed only when needed, and at the lowest efficient output levels
  • recycling waste heat produced by some industrial processes (e.g. kilns) for lower temperature applications (e.g. drying raw materials or products)
  • using less materials (e.g. thinner metals in car shells), or materials that are less energy-intensive (e.g. plastic, rather than steel, car bumpers).
Figure 21 This bus is powered by a fuel cell running on hydrogen gas.

The last point is part of a wider range of both technological and social measures grouped under the term de-materialisation, which means using less material (and thus less energy) — either in production or consumption. One example would be product packaging; this can in many cases be reduced drastically at source without affecting the quality of the product, but in addition, consumers buying the product could re-use elements of the packaging rather than simply disposing of it. Such small social adjustments may seem trivial, but they can effect powerful changes in society. One illustration is the comparison between the consumerist, 'throw-away' attitudes of the late 20th century, and the ingenious practicality of people during World War II, when nothing was wasted unnecessarily. It could be argued that the only difference between that time of crisis and now is that the threat of war was perceived as being closer to home, because modern society cushions individuals in the developed world from the impacts of their consumerism.

In addition to de-materialisation, social approaches to energy conservation would also involve rearranging our lifestyles, both individually and collectively, to reduce the energy required for a particular service. The author is fortunate enough to live within walking distance of a town centre, schools, and other amenities, but many newer towns (such as Milton Keynes) are designed with lower population densities, so that most journeys are impractical without using a car or bus. As Figure 22 shows, car and van use in the UK soared from 1952 to 1990, and is still increasing, partly reflecting a trend of fewer people per vehicle.

Figure 22 Annual passenger-kilometres travelled in the UK, 1952-2000, by transport mode. Note: Air travel data refers to internal flights only.

In 2005, there were few signs that this trend was reversing, even with the introduction of such measures as bus lanes, congestion charging (e.g. Inner London) and multiple-occupancy vehicle lanes (e.g. Leeds). The implication is that people in developed countries such as the UK are finding it difficult to shake off our addiction, as a society, to fossil fuels, and the lifestyle that cheap, plentiful energy has so far brought us. More worryingly, rapidly developing countries such as China and India are experiencing the same, dramatic rise in vehicle use and accompanying urban pollution. International air travel, not included in Figure 22, is a burgeoning problem, with air traffic, airports and even the size of airliners all increasing, while prices on many routes actually fall, encouraging demand. In effect, any savings in energy due to conservation measures are presently more than offset by increases in vehicle numbers and usage, and politicians are loth to upset potential voters by curbing consumer demand (for instance, by more draconian fuel taxes).

A further complication is known as the rebound effect. This is the tendency for individuals or organisations, once they have saved money by implementing energy saving measures, to spend that 'extra' money on additional energy-consuming activities, such as providing higher quality services. For instance, a householder who installs better loft insulation could save on heating bills. However, they may simply heat the house to a warmer temperature, or for longer periods, and use the same amount of energy as before. Alternatively, they may splash out on an overseas holiday with the money saved from the lower bills, using energy-intensive air travel that offsets any energy savings in the home. One way governments can counter the rebound effect is to give incentives for citizens to spend such financial savings in ways that are energy-frugal rather than energy intensive. However, ultimately the responsibility lies with the individual concerned, and how much they share prevailing environmental concerns — in fact, how much they really desire '… to maintain the quality of life for future generations'.

Activity 4

The UK is fortunate in having access to a wide range of energy sources, and the numerous options for future energy supply has fostered considerable debate on what the best 'energy mix' should be. Printed below are brief, edited extracts from various sources that highlight different aspects of the energy debate.

Since 1990, the demand for electricity in the UK has grown by 25%. Gas power stations now generate the largest proportion of electricity in the UK, and the share of gas generation is expected to increase further to 50% in 2012, following the closure of older nuclear stations and coal stations. At the current time, NGT [National Grid Transco] is not anticipating any new nuclear plants. The UK will soon become a net importer of gas, and in 2013/14, 66% of gas requirements will be imported. Of the current 22 GW gas-fired generation, only 6 GW has a back-up fuel option should the supply of gas be halted. It seems to me that an interruption to the gas supply could lead to significant shortfall of generation.

(Simon Griew, National Grid Transco, 2004)

A serious situation faces this country if we do not address the looming energy crisis. By 2020, this country will be 90% dependent on gas for its energy needs and 70% of that will have to be imported from politically unstable regions of the world such as Russia, Ukraine, Iran and Algeria, through pipelines wide open to terrorist attack. We will be a net importer of energy and all the time sat on millions of tonnes of the coal reserves with which this nation is blessed. Our balance of payments will suffer directly as a consequence. Clean coal technologies are now available and are being further developed and used not only in the US, but in Australia, India, China and many other coal producing countries. In the UK we pioneered the research into clean-coal technology, which was abandoned by the last Tory government in its haste to butcher the mining industry that served, and still could serve, this nation well.

(Steve Kemp, National Secretary, National Union of Mineworkers, 2005)

AMEC is working closely with long-term customers like BP to develop new sources of supply or extend the productive lives of existing fields around the world — often in hostile environments. These oil and gas recovery projects are increasingly vital as the world's stocks begin to dwindle or become unreliable — just look at the recent global petrol price panic sparked by terrorism in Saudi Arabia.

No matter what your view about global warming and the burning of fossil fuels, recent events have shown how vital it is that we extract as much oil and gas as is technologically possible and so keep our carbon-based economy viable until new sources of energy are developed.

(Chris Bond, Oil and Gas Technology Director, AMEC, 2004)

The only renewable source currently capable of supplying a significant amount of electricity is hydropower, and there are few remaining opportunities for large hydropower schemes. The UK is aiming for 10% renewable generation by 2010. If this were to be fulfilled by wind power, then turbines would have to be installed at a rate of 40 per week between now and then; the current rate is 2 per week.

If carbon emissions are to be controlled, nuclear power will have to play an ever increasing role in electricity generation. New reactors produce just 10% of the nuclear waste the old ones account for. If we unlocked our coal it would transform the prospects for using fossil fuel, so carbon sequestration is the key to the future, together with those new nuclear plants. I can't believe the UK will ever get far beyond generating 10% or so of its energy renewably — and that would be a heroic effort.

(Professor Ian Fells, New and Renewable Energy Centre (NAREC), 2004)

Let's all go nuclear, it's the only way. Already nuclear is becoming the grownup solution. And climate change is the nuclear lobby's best weapon: only global warming is more dangerous than massive proliferation of nuclear power across the world.

Malcolm Wicks, the new energy minister, rebuts the myths and factoids now so successfully spread by the anti-wind-power lobby. No, turbines are not taking over the country: only some 800 hectares are needed to reach the 10% target. No, they are not unpopular: 80% support them and 66% would like some in their area. No, the intermittent wind dropping is no problem, since the farms are spread far across the county and existing back-up is quite sufficient. (Eyesores? The UK had 90,000 windmills in the 17th century.) But these myths are gaining ground, alongside the bigger myth that nothing but nuclear will do. However, new nuclear stations would take a decade to build at £2bn each. So it's hard to see this parliament commissioning more nuclear power.

Everywhere there are green shoots of what might be done, if serious money and political attention were devoted to it now. Take micro-generation. You can buy a small windmill to stick in the garden or on the side of your house for just £900: it plugs into an ordinary 13 amp domestic plug, cuts electricity bills by a third and can feed into the grid. Imagine if each adult were given a carbon quota. Those who want to fly a lot or overheat a big house would have to buy extra quotas from low energy users. It would have the interesting side effect of redistributing funds towards those too poor to use their energy ration.

(Polly Toynbee, 2005)

By mixing between sites and mixing technologies, you can markedly reduce the variability of electricity supplied by renewables. And if you plan the right mix, renewable and intermittent technologies can even be made to match realtime electricity demand patterns. This reduces the need for backup, and makes renewables a serious alternative to conventional power sources.

Wind (onshore and offshore) could realistically provide some 35% of the UK's electricity, marine and dCHP [domestic combined heat and power] each 10-15%, and solar cells 5-10%. In other words, more than half the UK's electricity could ultimately derive from intermittent renewables. The high proportion of wind is because the wind blows hardest in the winter, and in the evening — when demand is highest. The dCHP also produces more at peak times, when demand for hot water and heating is also strongest. Solar makes a smaller contribution, and produces nothing at night. But it is still important to have it in the mix as it kicks in when wind and dCHP production is lowest. A marine-based renewable system works best when it includes both tide and wave. The combination has lower variability, is better at meeting demand patterns, and makes better use of expensive transmission infrastructure.

(Oliver Tickell, quoting Graham Sinden, 2005)

Imagine you control the UK's energy policy for the next 50 years. Considering the extracts above, which of the following measures would you consider to be essential. Bear in mind that different groups may have different outlooks. One may focus on 'green' idealism, another on economic incentives. Equally, the issues might be addressed pragmatically or in the context of which is technologically possible.

  • Government's carbon dioxide reduction targets
  • keeping the nuclear option open while developing technologies for clean coal and maximising oil/gas recovery, and placing more emphasis on carbon sequestration
  • substantial investment in research and development of new and renewable fuel sources on a large scale, such as wind, wave, tidal, geothermal, and nuclear fusion
  • focusing investment on integrating alternative energy sources and improving energy storage and supply, including the use of hydrogen
  • stimulating more local community and micro-generation schemes, while modifying electricity transmission systems to incorporate these diverse, widely distributed generators on a commercial to domestic scale
  • deploying legislation, supported by financial incentives and levies, to encourage energy efficiency and conservation at all levels and reduce consumption of primary energy.


There is no 'right' answer to this, and as the extracts demonstrate, opinions vary widely on such a broad range of issues. The following remarks are included to show the sort of considerations that might arise in a debate of this kind.

An idealistic approach might be to invest heavily in development of alternative energy sources, including methods of storing and supplying such energy (perhaps even devising a practical 'hydrogen economy'). This investment could operate in tandem with draconian taxes and other disincentives (personal carbon quotas?) on fossil fuel consumption (especially by the transport sector), to drive the switch from fossil fuels to renewables. But just how much energy could renewables reasonably provide? How 'green' are massed ranks of wind turbines anyway? And what might this approach do for your political or economic future?

A more subtle way to induce a shift from fossil fuels to renewables might be to employ a range of incentives, investment and education measures to encourage development not only of renewable technologies, but also energy efficiency — at all levels — including conservation, home improvements, and perhaps local community schemes for energy generation and supply. Gradual integration of renewable energy into the existing distribution system would be implemented. You might have to accept a gradual transition over several decades, or even longer, for society to adapt to using different modes of energy. In the meantime, global warming becomes a stark, undeniable reality — but will the comfortable society of an industrialised nation feel threatened enough to change its lifestyle?

A more pragmatic view would be to accept that fossil fuel consumption will only start to abate when prices are forced higher by depletion of reserves, or political pressures, or both in tandem. The emphasis could be more on developing the cleanest possible technologies for burning fossil fuels, and exploiting marginal resources such as tar sands in a more environmentally sound way than at present. After all, necessity is the mother of invention: when the time comes, technologies for renewable energy or nuclear fusion will arise to meet any energy crisis. But can you really rely on such ingenuity? Who, initially, will pay the price if this strategy fails?

A different technological strategy might be to follow a nuclear route: revitalise the nuclear fission generation industry to ameliorate the damaging effects of CO2 emissions, while at the same time pouring money into research and development of nuclear fusion. Fossil fuels will tide us over the long lead times on nuclear power station construction, and by then surely the problems of nuclear waste disposal will have been solved. This approach would give society breathing space to encourage the development of renewable technologies on a more realistic timescale. But what would be the consequences of a major nuclear accident?

Having studied this course, you will now realise that although a great deal is known about how the variety of available energy resources form, how they can be found and exploited, a great deal less is known about the implications of using them. It would be no exaggeration to state that, at the outset of the 21st century and little more than two centuries since the start of the Industrial Revolution, humanity is at a decisive point in its history. Decisions and actions, centred especially on changing how we get the energy that we need, will need to be put into practice — sooner rather than later.


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