1. UK ENERGY SCENARIOS crossing the fossil and nuclear bridge to a safe, sustainable, economically viable energy future Preliminary scenarios for discussion and development only February Mark Barrett
SENCO Sustainable Environment Consultants

2. Scenario development process
Introduction
Models used
Demand drivers
End use sectors
Supply sectors
Discussion
energy
emissions
economics
System dynamics and spatial issues
More international aspects
Energy security
Please note that some of the slides are animated (they have animated in the title). View these slides for a few moments and the animation should start and keep looping back to the beginning.

3. Introduction 1
This outline of UK energy and environment scenarios has been developed with the intention of identifying the main problems the UK will face in meeting future energy needs and environmental objectives, and to describe possible policy options for resolving these problems. The approach here is to assume policy options and estimate the energy, emission and microeconomic impacts of these policy options. It is not claimed that the scenarios are optimum in that more robust and cost-effective solutions may be found. The aim is to illustrate a development path that is incremental, flexible, and secure, with no undue reliance on fuels or technologies having substantial risks.
The aims are to identify energy and environment strategies that:
enhance the security of UK energy services by reducing imported fuel dependence and technology risk
meet energy needs with safe, sustainable energy systems
limit environmental impact, with an emphasis here on:
the greenhouse gas, carbon dioxide,
atmospheric pollutants; sulphur dioxide, nitrogen oxides, particulate matter and carbon monoxide
are technically feasible and economically viable
give a practical development path leading from finite fuels to renewable energy
A broader aim is to consider temporal and spatial aspects of energy demand and supply, within the UK and at the international scale, to ensure technical feasibility and take account of the international context

4. Introduction 2
The scenarios are designed to be practical, feasible, but are not necessarily ‘best.’ It is not possible to objectively define the best scenario because:
although there is some agreement about goals concerning the environment, consumption, technology risk and irreversibility, market cost, subsidies, etc., the weights attached to these goals are subjective and differ between individuals and groups
there are aspects which it will never be possible to accurately quantify, such as: what is the probability of an accident or terrorist attack on current or future nuclear facilities, and what would be its impact on the UK, even if radioactive release were negligible?
the future evolution of technologies in the long term is uncertain; half a century ago, the UK had negligible nuclear power or natural gas supply.
Some observations:
Developments of social structure, attitudes, demand, supply, technology, etc. are all, to some extent, determined by national policies.
Planning UK energy futures can not be done in isolation from Europe and the rest of the world, because of global energy resources, energy trade, and international politics.
As yet there are no supply options which score highest on all criteria and therefore these must balanced according to present knowledge. The further into the future, the greater the uncertainties with respect to demand, technology development, and the international context. As solar electricity (e.g. photovoltaic), electricity storage and long distance transmission become cheaper, then there may be agreement that other options are inferior and the ‘energy problem’ will perhaps be ‘solved.’.
No consideration is made here of how policy options would be implemented with statutory, fiscal or other instruments. A presumption is made that these would be developed and applied as necessary to secure the UK’s future energy services and economy, and to protect the environment.

5. Policy options
The policy aims are to be met using five classes of option:
Behaviour change: demand, and choice and use of technologies
demand substitution, modal shift from truck to rail, lower motorway speeds, smaller cars, less air travel, building temperatures...
Demand management
insulation, ventilation control, recycling, efficient appliances...
Energy efficient conversion
diesel engines, cogeneration...
Fuel switching
low/zero emission renewable and other sources
Emission control technologies
flue gas desulphurisation, catalytic converters, particulate traps...

6. Policy options
In the scenarios, technologies are excluded according to criteria of irreversibility, exposure to risk of large scale hazards, the lack of clear market costs, or if they do not work. Accordingly:
new nuclear capacity is excluded because of irreversibility, lack of market cost because of insurance, and risk of large scale hazard.
carbon sequestration through pumping CO2 underground is not deployed because it an irreversible technique that increases primary CO2 emissions, and the risks of accidental release in the long term are impossible to quantify reliably. It also may be argued that sequestration will diminish efforts towards energy efficiency and renewables.
fusion is excluded because it does not work and would produce radioactive wastes.
Currently, hydrogen is not included in any scenario. This is primarily because of the low overall efficiency of producing hydrogen from electricity or gas and then converting it into motive power or heat: it wastes more primary fossil or renewable energy than using electricity as a vector. In the stationary sectors, it is better to use electricity, renewable and fossil fuels directly. In surface transport vehicles, an increasing fraction of demand can be met with electricity in hybrid electric/fossil fuelled vehicles. Hydrogen as a fuel for aircraft is a distant prospect. If the production and utilisation efficiency of hydrogen improve, or other difficulties such as electric vehicle refuelling are insurmountable, then hydrogen would be reviewed.

7. Scenarios
With these classes of options and exceptions, the aim is to show that commonly agreed social, environmental and economic objectives can be achieved with low risk.
Five scenarios combining the five classes of policy option in different ways have been simulated. Proceeding from scenario 1 to 5 results in decreased emissions and use of technologies or fuels that have irreversible impacts.
Base/Kyoto: base scenario
Carbon15: medium levels of technical change
Behaviour: behavioural change only
Tech High: high levels of technical change
Tech Beh: technical and behavioural change
The scenarios presented here are preliminary and for discussion because:
recent historic data were not available at the time of scenario development
many technical and economic aspects of the scenarios need a thorough review

8. The energy system: demand and supply options
Energy demands and sources can be linked in many ways. The appropriate linkage depends on a complex of their distribution in space and time, and the economics of the technologies used.

9. Integrated planning
Energy planning should be integrated across all segments of demand and supply. If this is not done, the system may be technically dysfunctional or economically suboptimal. Energy supply requirements are dependent on the sizes and variations in demands, and this depends on future social patterns and demand management. For example:
In 2040, what will electricity demand be at 4 am? If it is small, how will it affect the economics of supply options with large inflexible units, such as nuclear power?
The output from CHP plants depends on how much heat they provide, so the contribution of micro-CHP in houses to electricity supply depends on the levels of insulation in dwellings.
Solar collection systems produce most energy at noon, and in the summer. The greater the capacity of these systems, the greater the need for flexible back-up supplies and storage for when solar input is low.
The scope for electric vehicles depends on demand details such as average trip length. Electric vehicles will add to electricity demand, but they reduce the need for scarce liquid fuels and add to electricity storage capacity which aids renewable integration.
Electricity supply systems with a large renewable component require flexible demand management, storage, electricity trade and back-up generation; large coal or nuclear stations do not fit well into such systems because their output cannot easily be varied over short time periods.
The amount of liquid biofuels that might available for air transport depends on how much biomass can be supplied, and demands on it for other uses, such as road transport.
Is it better to burn biomass in CHP plants and produce electricity for electric vehicles, or inefficiently convert it to biofuels for use in conventional engines?

10. Models used for constructing scenarios
Some description and sample outputs are presented for the following models:
SEEScen: Society, Energy and Environment Scenario model used for basic national energy scenarios across all sectors
EleServe : Electricity system model used to study detailed operation of electricity system
EST Energy Space Time model used to illustrate issues concerning time varying demands and renewable sources at geographically distant locations
InterEnergy Energy trade model used to study potential for international exchanges of energy to reduce costs and facilitate the integration of renewable energy
More on the models may be found at:

11. Technical basis: SEEScen: Society, Energy, Environment Scenario model
SEEScen is applicable to any large country having IEA energy statistics
SEEScen calculates energy flows in the demand and supply sectors, and the microeconomic costs of demand management and energy conversion technologies and fuels
SEEScen is a national energy model that does not address detailed issues in any demand or supply sector.
Method
Simulates system over years, or hours given assumptions about the four classes of policy option
Optimisation under development

12. Energy services and demand drivers
Demands for energy services are determined by human needs, these include
food
comfort, hygiene, health
culture
Important drivers of demand include:
Population increases
Households increase faster because of smaller households
Wealth, but energy consumption and impacts depend on choices of expenditure on goods and services which are somewhat arbitrary
The drivers are assumed to be the same in all scenarios.
The above drivers are simply accounted for in the model, but others are not, for example:
Population ageing, which will result in increases and decreases of different demands
Changes in employment
Environmental awareness
Economic restructuring
More on consumption at:

13. Energy demand: food
Food consumption increases with population. Therefore:
More biowaste for energy supply
Less land for energy crops, depending on import fraction
Land and energy use for food depends on food trade and factors such as the fraction of meat in the diet

14. Future demand: general considerations
Predicting the activities that drive the demands for energy is fundamentally important, but uncertain, not least because activities are partially subject to policy.
Some demands may stabilise or decrease, for example:
commuting travel as the population ages and telecommunications develop
space heating as maximum comfort temperature levels are achieved
Demands may increase because of the extension of current activities:
heating might extend to conservatories, patios, swimming pools
air conditioning may become more widespread
cars might become heavier and more powerful
as the population enjoys more wealth and a longer retirement, more leisure travel might ensue
Or because new activities are invented, these being difficult to predict:
new ways of using energy might arise; witness home computers, cinemas, mass air travel in the past; the future we may see space tourism
Basic activity levels are assumed to be the same in all scenarios, although in reality they are scenario dependent. For example, many activities are influenced by scenario dependent fuel prices - the purchase and use of cars, air travel, home heating.
Furthermore, energy consumption in the services sector and industrial sectors are themselves dependent on basic energy service demands. For example: energy consumption for administering public transport or aviation is dependent on the demands for those services; the energy consumed in the iron and steel or vehicle manufacturing industry depends on how many cars are made, which is scenario dependent; the energy consumption of manufacturing industry depends on how much loft insulation there is houses. The effects of energy demands on economic structure and its energy consumption are not considered here. (This is rarely analysed in energy scenarios because the effects of these structural changes may be relatively small; and it is difficult to calculate them.)

15. Future demand: activity projections
In these scenarios, the activity growth in all sectors is assumed to follow from population, household and wealth drivers. The activity projections are shown in the chart. The outstanding growth is in international aviation, a service the UK mainly exports.

16. Domestic sector Main options exercised:
Clothing, heating system control and thermostat setting
High levels of insulation and ventilation control
Efficient lights and appliances
Solar water heating, micro gas CHP and electric heat pumps are the main supply options
Zoned heating and clothing to reduce average house temperature
Note that solar electricity production (e.g photovoltaic) is included under central supply, even though much of it would be installed at end users’ premises

17. Comfort temperature, clothing and activity
Appropriate clothing reduces energy demand and emissions. A slight improvement in clothing could reduce building temperatures. A degree reduction in average building temperature could reduce space heating needs by about 10%.

18. Building use
Better control heating systems in terms of time control and zoning of heating can reduce average internal temperature and energy use.

19. Domestic sector: house heat loss factors
Implementation of space heat demand management (insulation, ventilation control) depends on housing needs and stock types, replacement rates, and applicability of technologies. Insulation of the building envelope and ventilation control can reduce house heat losses to minimal levels.

20. House: monthly space heating and cooling loads
Energy conservation technologies have these effects:
Space heating demand is greatly reduced by insulation and other measures
The potential growth in air conditioning depends on detailed house design and temperature control
There is less seasonal variation in total heat demand

21. Domestic sector: useful energy services per household
Space heating reduced, but not comfort
Other demands eventually grow because of basic drivers
Water heating becomes a large fraction of total, demand management requires further analysis

22. Domestic sector: electricity use
Electricity demand is reduced because of more efficient appliances, including heat pumps for space heating.

23. End use sectors: energy delivered to services sector
More commentary to follow.

24. End use sectors: energy delivered to industry sector
More commentary to follow.

25. Transport Options exercised:
Demand management, especially in aviation sector
Reduction in car power and top speed
Increase in vehicle efficiency
light, low drag body
improved motor efficiency
Shift to modes that use less energy per passenger or freight carried:
passengers from car to bus and train
freight from truck to train and ship
Increased load factor in the aviation sector
Some penetration of vehicles using alternative fuels:
electricity for car and vans
biofuels principally for longer haul trucks and aircraft

26. Passenger transport: carbon emission by purpose
Commuting and travel in work account for 40-50% of emissions

27. Passenger transport: carbon emission purpose and by trip length

28. Passenger transport use by mode trip length
Short distance car trips account for bulk of emissions.

29. Passenger transport : potential effect of teleworking

30. Passenger transport: carbon emission by mode of travel

31. Passenger transport: mode of travel by distance

32. Passenger transport: carbon emission by car performance
Car carbon emissions are strongly related to top speed, acceleration and weight. Most cars sold can exceed the maximum legal speed limit by a large margin. Switching to small cars would reduce car carbon emissions by about 40% in ten years. Switching to micro cars and the best liquid fuelled cars would reduce emissions by about 90% in the longer term.

33. Passenger transport: Risk of injury to car drivers involved in accidents between two cars
Cars that are big CO2 emitters are most dangerous because of their weight, and because they are usually driven faster. In a collision between a small and a large car, the occupants of the small car are much more likely to be injured or killed. The most benign road users (small cars, cyclists, pedestrians) are penalised by the least benign.

34. Transport: road speed and CO2 emission
Energy use and carbon emissions increase strongly with speed. Curves for other pollutants generally similar, because emission strongly related to fuel consumption.
These curves are only applicable to current internal combustion vehicles. Characteristics of future vehicles (e.g. urban internal combustion and electric powered) would be different. Minimum emission would probably be at a lower speed, and the fuel consumption and emissions at low speeds would not show the same increase.
Low speed emission
Average conceals start/ stop congestion
And car design dependent

35. Transport: road speed and PM emission

36. Transport: road speed and NOx emission

37. Transport: road speeds
A large fraction (40-50%) of vehicles break the speed limits on all road types. This law-breaking increases carbon and other emissions, and death and injury due to accident. Enforcing the existing limits, and reducing them, would significantly reduce emissions and injury.

38. Transport: aviation Aviation is a special sector because:
There is no near physical limit to growth as for land transport
It has the most rapid growth in demand of any major sector
Its emissions have particular impacts because of altitude
Aircraft are already relatively energy efficient
For these reasons, aviation is projected to become a dominant cause of global warming over the next few decades. The UK is a large exporter of aviation services, and fuelling this export will become perhaps the major problem in UK energy policy. Currently there is no proven alternative to liquid fuels for aircraft.
Most aviation is international with special legal provisions, and so aviation (and shipping) can not be analysed in isolation from other countries.
Aviation is discussed in detail in reports that may be downloaded at: 6

39. Aviation: control measures
Aviation emission control measures can be classed under demand management, technology and operations.
Engine
Freight
Airframe
CONTROL
MEASURES
Technology
Demand
management
Business
Aircraft size
Passenger
Leisure
Speed
Operation
Traffic control
Altitude
Load factor
Route length 6

40. Aviation: effects of technical and operational measures
Behavioural measures (other than reducing basic demand) such as increasing aircraft load factor and reducing cruising speed are as important as technological improvement. These measures can be implemented faster than technological change, as the average aircraft operating life is about 30 years. 7

41. Aviation scenarios
Aviation emissions can only be stabilised if all technical and operational measures are driven to the maximum, and the demand growth rate is cut by half. To reduce aviation emissions by 60% would require further demand reduction. 9

42. Transport: passenger demand by mode and vehicle type
Demand depends on complex of factors: demographics, wealth, land use patterns, employment, leisure travel. National surface demand is limited by time and space, but aviation is not so limited by these factors.

43. Transport: freight demand by mode and vehicle type
The scope for load distance reduction through logistics and local production is not assessed. International freight is estimated.

44. Transport, national: passenger mode
Shift from car to fuel efficient bus and train for commuting and longer journeys. The scope for modal shift from air to surface transport is very limited without the development of alternative long distance transport technologies.

45. Transport: national : freight mode
Shift from truck to rail. Currently, no assumed shift to inland and coastal shipping.

46. Transport: passenger vehicle load factor
Load factors of vehicles, especially aircraft, assumed to increase through logistical change.
Vehicle load capacities (passengers/vehicle; tonnes/truck) assumed unchanged.

47. Further analysis: electric vehicles
Electric (EV) or hybrid electric/liquid fuelled (HELV) vehicles are a key option for the future because liquid (and gaseous) fossil fuels emit carbon, will become more scarce and expensive and are technically difficult to replace in transport, especially in aircraft.
Electric vehicles such as trams or trolley-buses draw energy whenever required but they are restricted to routes with power provided by rails or overhead wires. Presently there are no economic and practical means for providing power in a more flexible way to cars, consequently electric cars have to store energy in batteries. The performance in terms of the range and speed of EVs and HELVs is improving steadily such that EVs can meet large fraction of typical car duties; the range of many current electric cars is miles. A major difficulty with EVs is recharging them. At present, car mounted photovoltaic collectors are too expensive and would provide inadequate energy, particularly in winter, although they may eventually provide some of the energy required.
Because of these problems it may be envisaged that HELVs will first supplant liquid fuelled vehicles, with an increasing fraction of electric fuelling as technologies improve.
Hydrogen is much discussed as a transport fuel, but the overall efficiency from renewable electricity to motive power via hydrogen is perhaps 50%, whereas via a battery it might be 70%. For this reason, it is not currently included as an option. If the efficiency difference were narrowed, and the refuelling and range problems of EVs are too constraining, then hydrogen should be considered further.

48. Transport: passenger vehicle distance
A large reduction in road traffic reduces congestion which gives benefits of less energy, pollution and travel time.

49. Transport: freight vehicle distance
Some growth in freight vehicle distance. Vehicle capacities and load factors important assumptions

50. Transport: passenger: fuel per passenger km
Reductions in fuel use because of technical improvement, better load factors, lower speeds, and less congestion.

51. Transport: passenger: delivered energy
Future passenger energy use dominated by international air travel.

52. Transport: freight delivered energy
Freight energy use dominated by trucks. Potential for further shift to rail needs investigation.

53. End use sectors: useful energy services
Useful energy supply and services increase
Growth in all end uses except space heating

54. Energy conversion: efficiencies
Preliminary graph showing efficiencies of energy conversion. Efficiencies greater than one signify heat pumps. Declining efficiencies are where the cogeneration heat fraction falls, and the electricity fraction increases

55. End use sectors: energy delivered by sector
Delivered energy decreases because of demand management and energy conversion efficiency gains.

56. End use sectors: energy delivered by fuel
Reduction in fossil fuel use through efficiency and shift to alternatives.

57. Energy supply: electricity
Options exercised:
Phase out of nuclear and coal generation
some fossil (coal, oil, gas) capacity may be retained for security
Extensive installation of CHP, mainly gas, in all sectors
Utilisation of biomass waste and biomass crops
Large scale introduction of renewable electricity
wind, solar, tidal, wave
Electricity supply in the scenarios requires more analysis of demand and supply technicalities and economics, particularly:
future technology costs, particularly of solar-electric systems such as photovoltaic
demand characteristics including load management and storage
renewable supply mix and integration

58. Energy supply: electricity : generating capacity
Capacity increases because renewables (especially solar) and CHP have low capacity factors. Some fossil capacity would perhaps be retained for back-up and security.

59. Electricity: generation
Finite fuelled electricity-only generation replaced by renewables and CHP. Proportion of fossil back-up generation depends on complex of factors not analysed with SEEScen.

60. Electricity: generation costs (excluding distribution)
Because of increased CHP and renewables, the fraction of capital and operation and maintenance costs increases and the fraction of fuel costs decreases

61. Electricity: scenario generation costs (excluding distribution)
Relative generation costs depend critically on future fuel prices, but in these scenarios the larger demand scenarios have higher electricity costs.

62. Energy: primary supply
Total primary energy consumption falls, and then increases
Fraction of renewable energy increases, then falls

63. Fuel extraction
Extraction of oil and gas tails off as reserves are depleted
Biomass extraction increases

64. Fuel reserves Oil and gas reserves effectively consumed
Large coal reserves available for strategic security

65. Energy trade
Nuclear fuel imports decline; gas and oil imports increase and stabilise; some electricity export.

66. Energy flow charts
The flow charts show basic flows in 1990 and 2050, and an animation of The central part of the charts illustrate the relative magnitude of the energy flows through the UK energy system. The top section shows carbon dioxide emissions at each stage. The bottom section shows energy wasted and discharged to the environment.
Please note that the scale of these charts varies.
Observations:
Energy services:
space heating decreases
other demands increase, especially motive power and transport
Fuel supply
increase in efficiency (CHP)
increase in renewable heating, biomass and electricity
imports of gas and oil are required
electricity is exported

67. UK Energy flow chart: 1990

68. UK Energy flow chart: Animation 1990 to 2050

69. UK Energy flow chart: 2050

70. Environment
Often, the energy and environment debate concerns itself simply with routine, easily quantified emissions such as CO2, and ignores the many other impacts of energy demand and supply, even though they may as important in economic or social terms.
There are particular problems concerning the environmental impacts of energy.
The definition and precision of calculation of many impacts are poor for technical reasons.
Future impacts depend on developments in technology, legislation and other controls.
Some impacts are routine, such as CO2 emission; others, such as a nuclear accident, are not routine and have probabilities of occurrence and consequences that are impossible to calculate with any certainty.
Some impacts are physical; others, such as the threat of attack on a nuclear facility, are not physical but can still have impacts.
Some impacts are not directly associated with technical energy processes. For example, in the low emission scenarios, road traffic injuries and deaths would be reduced through measures such as less car travel and enforced speed limits. There would be further social benefits such as more equal access to transport, and disbenefits such as less car driving.
The impacts are different in kind: gaseous, liquid, solid, radioactive, biological, visual, land take, etc. There is no objective method to weigh these against each other except through political processes.
SEEScen presently calculates
Atmospheric emissions of CO2, and of SO2, NOx, PM and CO although these are imprecise
Some other impacts such as the number of aerogenerators and the fraction of land area used for biomass production

71. Environment: carbon dioxide
Note the historical emission inaccuracy because of data. The TechBeh scenario has a decline in CO2 emission of about 80%, and then an increase, primarily because of aviation.

72. Environment: CO2 emission by scenario
There is an eventual upturn in emissions as assumed demand growth overtakes technology and behavioural options.

73. Environment: nitrogen oxides

74. Environment: particulate matter

75. Economics
In SEEScen, the direct annual costs of fuel, and the annuitised costs of conversion technologies and demand management are calculated. The model does not account for anything unrelated to fuels or technologies, including:
indirect costs and benefits, such as the economic savings following a shift away from cars leading to reduced health damage because of accidents, toxic air pollution, and the value of reduced travel time
macroeconomic issues relating to the energy trade imbalance or exposure to fluctuating international fuel prices
Such economic impacts of energy scenarios can be of greater importance than direct costs. For example, the value of traffic related health injury and time lost in congestion is generally much greater than the costs of controlling noxious emissions from vehicles.
International fuel prices are critical to the relative cost effectiveness of measures. It is probable that the UK would follow a ‘low energy emission’ path in parallel with other countries, at least in Europe. In such an international scenario, finite fossil and nuclear fuel prices will be lower than in a higher demand scenario. Thus the implementation of options affects the cost-effectiveness of those options - a circularity:
the more renewable energy deployed, the cheaper the fossil fuels leading to an increase in the relative cost of renewables
the more the consumption of fossil and nuclear fuels, the higher the prices for those, leading to an increase in the relative cost of fossil and nuclear energy

76. International context
Fuel availability and price will depend on global and regional demand levels.
SEEScen was used to model the five scenarios for the five largest energy consumers near the UK: France, Germany, Spain and Italy.
Because the measures exercised are the same, the primary energy consumption of these countries varies in similar ways in the scenarios, although there are differences in detail.
This illustrates how regional energy demand might vary according to policies, and it has consequences for energy prices.

77. Economics: fuel prices
International fuel prices are critical inputs to the economic analysis of scenarios.
Fundamentally, costs in the long term are determined by the remaining amounts and marginal extraction costs of the reserves of finite fossil and nuclear fuels. Prices depend on costs and future demand-supply markets.
It may be argued that if the UK pursues a ‘low finite energy’ path then it is likely that other countries will be doing the same, at least within Europe.
The top chart shows a ‘high demand’ price projection, the bottom a ‘low demand’ projection.
These merely illustrate possible differences in trends. It may that the relative prices of gas, oil and coal will change.
This requires further analysis.

78. Economics: TechBeh scenario annual costs of fuel, conversion and demand management
The annuitised costs of each fuel, technology and demand management option are calculated for each of the end use and supply sectors. In the low demand scenario, the fraction of total cost due to converters (boilers, power stations, etc.) and demand management increases as compared to fuels.

79. Economics: Base scenario annual costs of fuel, conversion and demand management
In higher energy supply scenarios, the fraction of costs due to fuel increases because renewable energy and CHP constitute smaller fractions. One implication of this, in comparison with a lower demand scenario, is that economic security is degraded because of the sensitivity to prices and availability of imported, globally traded fuels.

80. Economics: total cost by scenario
The more secure, lower impact systems for providing energy services may not have higher costs than high demand and emission scenarios because more cost effective demand management is taken up. Also, fossil fuel prices will be lower because European/global demand will be lower (the UK will not, or cannot act alone).

81. Economics: energy trade costs
The cost of increased imports of fossil fuels is partially balanced by electricity exports.
Note that the costs of imports are positive and exports, negative.

82. Economics: scenarios: energy trade total cost balance
The energy trade cost deficit increases in higher energy consumption scenarios because imports are greater and fuel prices are higher

83. Observations on scenarios: national energy
The scenarios are preliminary and could be improved with more recent data and sectoral analysis. However, the relative magnitudes of energy flows, emissions and costs are illustrative of the main problems, and possible solutions.
The scenarios show that:
Large reductions in carbon dioxide and other emissions are possible without utilising irreversible technologies with potential large scale risks - nuclear power and carbon sequestration.
Transport fuel supply is a more difficult problem than fuelling electricity supply or the stationary sectors which have many potential fuel sources. Transport is the most difficult sector to manage, because:
demand management options are limited as compared to the stationary sector
of growth, especially in aviation
limited efficiency improvement potential as efficiency is already a strong driver in freight transport and aviation
lack of alternatives to liquid fuels, especially for aviation
The potential for the direct use of electricity as a transport fuel rather than the inefficient production and use of secondary fuels such as biofuels or hydrogen needs more exploration
In all scenarios, under the assumption of continued growth in energy service demand, emissions increase in the longer term as the effects of known technologies are absorbed. Behavioural options are important, especially if nascent technologies do not become technically and economically feasible. Therefore analysis and speculation on the following might be useful:
possible future socioeconomic changes and impact on energy service demands
long term technology development

84. Observations on scenarios: economics and environment
The total cost of energy services may be less in low emission scenarios because of the cost effectiveness of demand management and efficiency as compared to supply. This assumes that in the future, as now, the UK energy system is not optimal in economic terms because of market imperfections which lead to inadequate investment in demand management and energy efficiency.
The UK is less exposed to international fuel price fluctuations
Demand management and renewables reduce the UK balance of payments deficit for energy trade
Energy use and emissions increase when presumed growth overtakes implementation of current technology options. In the long term, therefore demand management, service and renewable energy technologies will require further implementation. A particular need is to find substitutes for liquid fuelled aircraft for long distance transport.

85. Observations on scenarios: national and international
The TechBeh scenario has a surplus of electricity; should
less be generated?
the surplus be used to substitute for fossil resources, e.g.
to make transport fuels even if the process is wasteful?
for heating and other uses not requiring electricity?
the surplus be exported as trade for other fuels?
It is not possible to develop a robust and economic UK energy strategy for the long term without consideration of international developments, for a number of reasons:
the UK has transmission linkage with other countries; this is especially important for electricity if renewable sources in the UK meet a large fraction of total demand
the availability of fuels for import depends on global demand
there are international arrangements that constrain UK policy in terms of demand management and supply, for example, treaties concerning international aviation and shipping
This leads to system dynamics and the international aspects of energy scenarios.

86. Energy systems aspects: space and time
SEEScen has a main focus on annual flows, although it can simulate seasonal and hourly flows. Other models are required to analyse issues arising with short term variations in demand and supply, and with the spatial location of demands and supplies.
Questions arising:
Can the demands be met hour by hour using the range of supplies?
What spatial issues might arise?
Some aspects of this are explored and illustrated with these models:
EleServe : Electricity system model for temporal analysis
EST Energy Space Time model
InterEnergy Energy trade model

87. Electricity system: detailed considerations
Electricity demand and supply have to be continuously balanced as there is no storage in the transmission network, unlike gas. This balancing can be achieved by controlling demand and supply, and by introducing storage on the system (pumped storage) or near the point of use: heat and electricity storage (hot water tanks, storage heaters, vehicle batteries) can be used to store surplus renewable energy when it is available, so that the energy can later be used when needed.
The EleServe Electricity Services model has these components:
Electricity demand
disaggregated into segments across sectors and end uses
each segment with
a temporal profile
load management characteristic
Electricity supply
each renewable source with own temporal profile
heat related generation with its own temporal profile
optional thermal generators characterised by energy costs at full and part load, and for starting up
Operational control
load management by moving demands if cost reduced
optional units brought on line to minimise diurnal costs
The following graphs demonstrates the role that load management can play in matching variable demands to electricity supplied by variable renewable and CHP or cogeneration sources.

88. Electricity : diurnal operation without load management

89. Electricity : animated diurnal operation with load management

90. Electricity : diurnal operation with load management

91. Electricity : commentary
The electricity demand-supply simulation :
shows how load management can alter the pattern of demand to better match CHP and renewable electricity generation. The residual demand to be met by generators utilising fuels such as biomass or fossil fuels, that can alter their output, is less variable and the peak is smaller.
demonstrates the importance of demand patterns and technologies in strategies for integrating variable electricity sources
indicates that large fractions of variable sources can be accommodated without substantial back-up capacity
end use or other local storage could play a significant role, especially if electric vehicles are widely used as in some of the scenarios
Further work is required on:
data defining current and future demand technologies
detailed electricity demand forecasts
the feasibility of integrated control of demand and supply technologies, including the accuracy of prediction of hourly demands and renewable supplies over time periods of a several hours or days
more refined optimisation

92. Energy systems in space and time
For temporally variable demand and energy sources, what is the best balance between :
local supply and long distance transmission?
demand management, variable supply, optional or back up generation and system or local storage?
These questions can be asked over different time scales (hour by hour, by day of week, seasonal) and spatial scales (community, national, international).
The EST and InterTrade models have been developed to illustrate the issues and indicate possible solutions for integrating spatially separate energy demands and sources, each with different temporal characteristics.

93. UK energy, space and time illustrated with EST

94. UK energy, space and time illustrated with EST : animated

95. A wider view of the longer term future
Wealthy countries like the UK can reduce their energy demands and emissions with cost-effective measures implemented in isolation from other counties, and in so doing improve their security. However, at some point it is more practical and cost-effective to consider how the UK can best solve energy and environment problems in concert with other countries.
As global fossil consumption declines because of availability, cost and the need to control climate change, then energy systems will need to be reinforced, extended and integrated over larger spatial scales.
This would be a continuation of the historical development of energy supply that has seen the geographical extension and integration of systems from local through to national and international systems.
The development and operation of these extended systems will have to be more sophisticated than currently. Presently, the bulk of variable demands in rich countries is met with reserves of fossil and nuclear fuels, the output of which can be changed by ‘turning a tap.’ When renewable energy constitutes a large fraction of supply, the matching of demands and supplies is a more complex problem both for planning and constructing a larger scale system, and in operating it.

96. International electricity : demand
Further connecting the UK system to other countries increases the benefits of diversity, at the cost of transmission.
The first chart shows the pattern of monthly demands for different European countries.
The second chart shows the normalised diurnal demand patterns for some countries. Note that these are all for ‘local’ time; time zone differences would shift the curves and make the differences larger.

97. International electricity: supply; monthly hydro output
Hydro will remain the dominant renewable in Europe for some time. It has a marked seasonality in output as shown in the chart; note that hydro output can vary significantly from year to year. Hydro embodies some energy storage and can be used to balance demand and supply; to a degree determined by system design and other factors such as environment.

98. Electricity trade An extensive continental grid already exists
The diversity of demand and supply variations increases across geographical regions
What is the best balance between local and remote supply?
InterEnergy model
Trade of energy over links of finite capacity
Time varying demands and supply
Minimise avoidable marginal cost
Marginal cost curves for supply generated by model such as EleServe

99. InterEnergy – animated trade
Animation shows programme seeking minimum cost for one period (hour)

100. Europe and western Asia – large point sources
The environmental impact of energy is a global issue: what is the best strategy for reducing emissions within a larger region?

101. World There are global patterns in demands and renewable supplies:
Regular diurnal and seasonal variations in demands, some climate dependent
Regular diurnal and seasonal incomes of solar energy
Predictable tidal energy income

102. World: a global electricity transmission grid?
Should transmission be global to achieve an optimum balance between supply, transmission and storage?
Which investments are most cost efficient in reducing GHG emission? Should the UK invest in photovoltaic systems in Africa, rather than the UK? This could be done through the Clean Development Mechanism

103. Security: preliminary generalities 1
Energy security can be defined as the maintenance of safe, economic energy services for social wellbeing and economic development, without excessive environmental degradation.
A hierarchy of importance for energy services can be constructed:
Core services which it is immediately dangerous to interrupt
food supply
domestic space heating, lighting
emergency services; health, fire, police
Intermediate importance. Provision of social services and short-lived essential commodities
Lower importance. Long-lived and inessential commodities
Part of security planning is for these energy services to degrade gracefully to the core.
The various energy supply sources and technologies pose different kinds of insecurity:
renewable sources are, to a degree, variable and/or unpredictable, except for biomass
finite fossil and nuclear fuels suffer volatile increases in prices and ultimate unavailability
some technologies present potentially large risks or irreversibility

104. Security : preliminary generalities 2
Supply security over different time scales
Gross availability of supply over future years. The main security is to reduce dependence on the imports of gas, oil and nuclear fuels and electricity through demand management and the development of renewable energy.
Meeting seasonal and diurnal variations. This mainly causes difficulty with electricity, gas, and renewables except for biomass. Demand management reduces the seasonal variation in demand and thence the supply capacity problem for finite fuels and electricity. Storage and geographical extension of the system alleviates the problem.
Security of economic supply.
Demand management reduces the costs of supply.
The gross quantities of fuel imports are less, and therefore the marginal and average prices
The reduced variations in demand bring reduced peak demands needs and therefore lower capacity costs and utilisation of the marginal high cost supplies
The greater the fraction of renewable supply, the less the impact of imported fossil or nuclear fuel price rise
A diverse mix of safe supplies each with small unit size will reduce the risks of a generic technology failure
Security from technology failure or attack. In the UK, the main risk is nuclear power.
Security from irreversible technology risk. In the UK, nuclear power and carbon sequestration
Environment impacts. All energy sources and technologies have impacts, but the main concern here are long term, effectively irreversible, regional and global impacts. The greater the use of demand management and renewable energy, the less fossil and nuclear, the less such large impacts.

105. Electricity security
Demand management will reduce generation and peak capacity requirements as it :
reduces total demand
reduces the seasonal variation in demand, and thence maximum capacity requirements
It has been illustrated how load management might contribute to the matching of demand with variable supply. This can be further extended with storage, control and interruptible demand.
During the transition to CHP and renewable electricity, supply security measures could be exercised:
Retain some fossil fuel stations as reserves. Currently in the UK, there are these capacities:
Coal 19 GW large domestic coal reserve
Oil 4.5 GW oil held in strategic reserves
Dual fired 5.6 GW
Gas 25 GW gas availability depends on other gas demands
Utilisation, if necessary of some end use sector generation. Currently in excess of 7 GW, but these plants are less flexible because they are tied to end use production, services and emergency back-up
The building of new flexible plant such as gas turbines if large stations are not suitable
Electricity trade with other countries can be used for balancing. There are geographical differences in the hourly variations of demands and renewable supply because of time zones, weather, etc. The strengthening of the link between France and the UK, and creation of links with other countries would enhance this option.

106. Gas and oil security
The measures to improve oil and gas security are basically the same, diversify fuel sources and store fuels:
Diversify supply sources
Extension of the gas transmission system
Develop LNG imports
Increase storage
Enlarge long term gas storage in depleted gas fields
Increase strategic 90 day oil reserve as required by IEA