Methodology
Methodology for indicator calculation
Total final energy demand (consumption) is the sum of energy consumption in each final demand sector. In each sub-sector or end-use, at least six types of energy are shown: coal, oil, gas, electricity, heat and renewables. However, this aggregation conceals more detail. For example, the different oil products are modeled separately for the transport sector, and renewables are split into "biomass and waste" and "other renewables". Note that the terms "total final energy demand" and "total final energy consumption" are convertible accordingly to the World Energy Outlook 2004.
The projections are made with the use of the World Energy Model 2004 developed by Internation Energy Agency.
Overview of the World Energy Model 2004 (WEM)
The WEM is a mathematical model made up of five main modules: final energy demand, power generation; refinery and other transformation; fossil fuel supply and CO2 emissions. Figure C1. (World Energy Outlook, 2004, p.532) provides a simplified overview of the structure of the model.
The main exogenous assumptions concern economic growth, demographics, international fossil fuel prices and technological developments. Electricity consumption and electricity prices dynamically link the final energy demand and power generation modules
The IEA's WEM is a principal tool used to generate detailed sector-by-sector and region-by-region projections for the Reference and the Alternative Scenarios. (see definitions of scenarios under section reference scenario). The model has been updated and revised over years and the development process continues.
In the WEM 2004 projections of Total Final Energy Consumption are made within 4 sectors: Industry, Transport, Residential and Services, and non-Energy Use sectors.
Industry sector
The industrial sector in the OECD regions is split into six sub-sectors: iron and steel, chemicals, paper and pulp, food and beverages, non-metallic minerals and other industry. For the non-OECD regions, the breakdown is typically based on four instead of six sub-sectors.
The output level of each sub-sector is modelled separately and is combined with projections of its fuel intensity to derive the consumption of each fuel by sub-sector.
Transport sector
Transport energy demand is split between passenger and freight and is broken down among light duty vehicles, buses, trucks, rail, aviation and navigation. Passenger cars and light trucks are subdivided by fuel used - gasoline, diesel, alternative fuels or hybrids of these. Freight trucks are divided between gasoline- and diesel-driven. The gap between test and on-road fuel efficiency is also projected.
For each region, activity levels for each mode of transport are estimated econometrically as a function of population, GDP and price. Additional assumptions to reflect passenger vehicle ownership saturation are also made. Transport activity is linked to price through elasticity of fuel cost per km, which is estimated for all modes except passenger buses and trains and inland navigation. This elasticity variable accounts for the "rebound" effect of increased car use that follows improved fuel intensity.
Residential and services Sectors
For the certain number of the non-OECD regions, energy consumption in the aforementioned sectors has been calculated econometrically for each fuel as a function of GDP, the related fuel price and the lag of energy consumption. For the OECD regions and major non-OECD regions, the number of households using each fuel for water heating and space heating is projected econometrically, with some saturation limits on shares.
Lighting intensity and appliance intensity per household are then projected separately and combined with total household numbers to yield electricity demand for these end-uses.
The services sector model splits consumption by fuel into three end-uses: heating, hot water and cooking use (HHC); personal computer use (including related equipment); and other electricity end-uses, including ventilation, space cooling and lightning.
The procedures for calculation of the non-Energy Use sector was not identified in the World energy Outlook 2004 methodology description.
Detailed schemes for calculating projections for other sectors mentioned above are presented in pp. 537, 538 of the World Energy Outlook 2004 (Annex. C)
Key model assumptions for the reference case
The central projections derived from a Reference Scenario. They are based on a set of assumptions about governmental policies, microeconomic conditions, population growth, energy prices and technology.
Governmental policies and measures
The reference Scenario takes into account only those governmental policies and measures that were already enacted - though not necessary implemented - as of min-2004. The Reference Scenario does not include possible< potential or even likely future policy initiatives. Major new energy policy initiatives will inevitably be implemented during the projection period, but it is difficult to predict which measures will eventually be adopted and how they will be implemented, especially towards the end of the projection period.
Although the Reference Scenario assumes that there will be no change in energy and environmental policies through the projection period, the pace of implementation those policies and the way they are implemented in practice are nonetheless assumed to vary by the fuel and region. For example electricity and gas market reforms are assumed to move ahead, but at varying speeds among countries and regions. In all cases, the share of taxes in energy process is assumed to remain unchanged, so that retail process are assumed to change directly in proportion to international prices. Similarly, it is assumed that there will be no changes in national policies on nuclear power. As a result, nuclear energy will remain an option for power generation only in those countries that have not officially banned it or decided to phase it out.
Macroeconomic factors
Economic growth is by far the most important driver of energy demand. The link between total energy demand and economic output remains close. Detailed GDP assumptions by region are set out in Table below.
Economic Growth Assumptions (average annual growth rates, in %)
| 1971-2020 | 2002-2010 | 2010-2020 | 2020-2030 | 2002-2030 |
| OECD-Europe | 2.4 | 2.4 | 2.2 | 1.7 | 2.1 |
Transition Economies total | 0.7 | 4.6 | 3.7 | 2.9 | 3.7 |
- Russia | -1.1 | 4.4 | 3.4 | 2.8 | 3.5 |
- Other transition economies | -0.5 | 4.8 | 3.9 | 3.0 | 3.8 |
European Union | 2.4 | 2.3 | 2.1 | 1.7 | 2.0 |
| World | 3.3 | 3.7 | 3.2 | 2.7 | 3.2 |
Population Population growth affects the size and composition of energy demand, directly and through its impact on economic growth and development. The WEO population growth rate assumptions are drawn from the most recent UN populations' projections contained in World population Prospects: the 2002 Revision. Detailed populations assumptions by region are set out in Table below.
Population growth assumptions (average annual growth rates, in %)
| 1971-2020 | 2002-2010 | 2010-2020 | 2020-2030 | 2002-2030 |
| OECD-Europe | 0.5 | 0.3 | 0.1 | 0.0 | 0.1 |
Transition Economies total | 0.5 | -0.2 | -0.2 | -0.4 | -0.3 |
- Russia | -0.3 | -0.6 | -0.6 | -0.7 | -0.7 |
- Other transition economies | 0.0 | 0.0 | 0.1 | -0.1 | 0.0 |
European Union | 0.3 | 0.1 | 0.0 | -0.1 | 0.0 |
| World | 1.6 | 1.2 | 1.0 | 0.8 | 1.0 |
Energy Prices As in previous additions of the WEO, average and-user process for oil, gas and coal are derived from assumed price trends on wholesale or bulk markets. Tax rates are assumed to remain unchangeable over the projection period. Final electricity prices are based on marginal power generation costs. The assumed price paths assumed in the table presented below should not be interpreted as forecasts. Rater, they reflect IEA judgment of the prices that will be needed to encourage sufficient investment in supply to meet projected demand over the Outlook period.
Fossil-Fuel Price Assumptions (in year-2000 dollars)
| 2003 | 2010 | 2020 | 2030 |
IEA crude oil imports ($/barrel) | 27 | 22 | 26 | 29 |
Natural gas ($/Btu): | | | | |
- US imports | 5.3 | 3.8 | 4.2 | 4.7 |
| - European imports | 3.4 | 3.3 | 3.8 | 4.3 |
OECD steam coal imports ($/tonne) | 38 | 40 | 42 | 44 |
Technological development Technological innovation and the rate of development of new technologies for supplying or using energy are important considerations. In general, it is assumed that available end-use technologies become steadily in use and the overall intensity of energy consumption will depend heavily on the rate of retirement and replacement of the stock of capital. Since the energy-using capital stock in use today will be replaced only gradually, most of the impact of technological developments that improve energy efficiency will not be felt until near the end of the projection period.
The rate of capital-stock turnover varies considerably according to the type of equipment. Most cars and trucks, heating and cooling systems and industrial boilers will be replaced by 2030. on the other hand, most existing buildings, roads, railways and airports, as well as many power stations and refineries will still be in use then. The very long life of this type of energy-capital stock will limit the extent to which technological progress can alter the amount of energy needed to provide a particular energy service. Retiring these assets before the end of their normal lives is usually costly and would, in most cases, require major new governmental initiatives - beyond those assumed in the Reference Scenario. Refurbishment can, however, achieve worthwhile improvements in energy efficiency in some cases.
Technological developments will also affect the costs of energy supply and the availability of new ways of producing and delivering energy services. Power generation efficiencies are assumed to improve over the projection period, but at different rates for different technologies. Towards the end of the projection period, fuel cells based on hydrogen are expected o become economically attractive in some power generation applications ad, to a much smaller extent, also expected to improve, lowering the unit production costs and opening up new opportunities for developing resources. But the Reference Scenario assumes that no new breakthrough technologies beyond those known today will be used before 2030.
The World Alternative Scenario
WEO also considers Alternative policy Scenario to analyze how the global energy market could evolve were countries around the world to adopt a set of policies and measures that they are either currently considering or might reasonably be expected to implement over the projection period. The purpose of this scenario is to provide insights into how effective those policies might be in addressing environmental and energy-security concerns.
Methodology for gap filling
The development and running of the WEM requires access to huge quantities of historical data on economic and energy variables. Most of the data are obtained from the IEA's own databases of energy and economics statistics. A significant amount of additional data from a wide range of external sources is also used.
The parameters of the demand-side modules' equations are estimated econometrically, usually using data fro the period 19971-2002. Shorter periods are sometimes used where data are unavailable or significant structural breaks are identified. To tae into account expected changes in structure, policy or technology, adjustments to these parameters are sometimes made over the Outlook period, using econometric and other modeling techniques. In regions such as transition economies, where most data are available only from 1992, it has not been possible to use econometric estimations. In such cases, IEA results have been prepared using assumptions based on cross-country analyses or expert judgment.
Simulations are carried out on annual basis. Demand modules can e isolated and simulations run separately. This is particularly useful in the adjustment process and in sensitivity analyses of specific factors.
The WEM makes use of wide range of software, including specific database management tools, econometric software and simulation programmes.
Methodology references
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World energy outlook 2004
IEA (2004) International Atomic Agency (2004) . World energy outlook 2004, OECD/IEA, Paris. Online not available
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