Tier 1 and tier

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The activity data used in a Tier 1 approach for combustion in the energy sector are derived from energy statistics, compiled by the national statistical agency. Comparable statistics are published by the International Energy Agency (IEA), based on national returns. If national data are not directly available to the national inventory compiler, a request could be sent to the IEA at [email protected] to receive the country's data free of charge.

Primary data on fuel consumption are normally collected in mass or in volume units. Because the carbon content of fuels is generally correlated with the energy content, and because the energy content of fuels is generally measured, it is recommended to convert values for fuel consumption into energy units. Default values for the conversion of fuel consumption numbers into conventional energy units are given in section 1.4.1.2.

Information on energy statistics and balances methodology is available in the "Energy Statistics Manual" published by the IEA. This manual can be downloaded free of charge from www.iea.org. Key issues about more important source categories are given below.

ENERGY INDUSTRIES

In energy industries, fossil fuels are both raw materials for the conversion processes, and sources of energy to run these processes. The energy industry comprises three kinds of activities:

1 Primary fuel production (e.g. coal mining and oil and gas extraction);

2 Conversion to secondary or tertiary fossil fuels (e.g. crude oil to petroleum products in refineries, coal to coke and coke oven gas in coke ovens);

3 Conversion to non-fossil energy vectors (e.g. from fossil fuel into electricity and/or heat).

Emissions from combustion during production and conversion processes are counted under energy industries. Emissions from the secondary fuels produced by the energy industries are counted in the sector where they are used. When collecting activity data, it is essential to distinguish between the fuel that is combusted and the fuel that is converted into a secondary or tertiary fuel in Energy Industries.

MAIN ACTIVITY ELECTRICITY AND HEAT PRODUCTION

The main activity electricity and heat production (formerly known as public electricity and heat production) converts the chemical energy stored in the fuels to either electrical power (counted under electricity generation) or heat (counted under heat production) or both (counted under combined heat and power, CHP); see Table 2.1.

Figure 2.2 shows the energy flows. In conventional power plants, the total energy losses to the environment might be as high as 70 percent of the chemical energy in the fuels, depending on the fuel and the specific technology. In a modern high efficiency power plant, losses are down to about half of the chemical energy contained in the fuels. In a combined heat and power plant most of the energy in the fuel is delivered to final users, either as electricity or as heat (for industrial processes or residential heating or similar uses). The width of the arrows roughly represents the relative magnitude of the energy flows involved.

Figure 2.2

Power and heat plants use fuels to produce electric power and/or useful heat.

Heat plant

Fuel In

Figure 2.2

Heat plant

Fuel In

Heat out

Fuel In

Fuel In

Power out

Power & Heat

Fuel In

Power & Heat

Fuel In

Heat out

Power Out

Heat out

Power Out

PETROLEUM REFINING

In a petroleum refinery, crude oil is converted to a broad range of products (Figure 2.3). For this transformation to occur, part of the energy content of the products obtained from crude oil is used in the refinery (See Table 2.1.). This complicates the derivation of activity data from energy statistics.

Figure 2.3 A refinery uses energy to transform crude oil into petroleum products.

Crude Oil In

Figure 2.3 A refinery uses energy to transform crude oil into petroleum products.

Crude Oil In

Petroleum products out

In principle all petroleum products are combustible as fuel to provide the process heat and steam needed for the refining processes. The petroleum products include a broad range from the heavy products like tar, bitumen, heavy fuel oils via the middle distillates like gas oils, naphtha, diesel oils, kerosenes to light products like motor gasoline, LPG and refinery gas.

In many cases, the exact products and fuels used in refineries to produce the heat and steam needed to run the refinery processes are not easily derived from the energy statistics. The fuel combusted within petroleum refineries typically amounts to 6 to 10 percent of the total fuel input to the refinery, depending on the complexity and vintage of the technology. It is good practice to ask the refinery industry for fuel consumption in order to select or verify the appropriate values reported by energy statistics.

MANUFACTURING INDUSTRIES AND CONSTRUCTION

In manufacturing industries, raw materials are converted into products as is schematically presented in Figure 2.4. For construction, the same principle holds: the inputs include the building materials and the outputs are the buildings.

Manufacturing industries are generally classified according to the nature of their products. This is done via the International Standard Industrial Classification of economic activities that is used in Table 2.1 for convenient cross-referencing.

Figure 2.4 Fuels are used as an energy source in manufacturing industries to convert raw materials into products.10

Manufacturing Industry

Raw ma

Fuels in

Figure 2.4 Fuels are used as an energy source in manufacturing industries to convert raw materials into products.10

Raw ma

Fuels in

Products out

10 For some industries raw materials might include fossil fuel. Some fuel might be derived from by-products or waste streams generated in the production process.

Raw materials used in manufacturing industries can also include fossil fuels. Examples include production of petrochemicals (eg methanol), other bulk chemicals (eg ammonia) and primary iron where coke is an input. In some cases, the situation is more complicated, because the energy to drive the process might be directly delivered from the chemical reactions of the manufacturing processes. An example of this is the manufacture of primary iron and steel, where the chemical reaction between the coke and the iron ore produces gas and heat that are sufficient to run the process11. The reporting of emissions from gases obtained from processing feedstock and process fuels obtained directly from the feedstock (e.g. ammonia production) follows the principle stated in Section 1.2 of this Volume and detailed guidance given in the IPPU Volume. In summary, if the emissions occur in the IPPU source category which produced the gases emitted they remain as industrial processes emissions in that source category. If the gases are exported to another source category in the IPPU sector, or to the energy sector, then the fugitive, combustion or other emissions associated with them should be reported in the sector where they occur. Inventory compilers are reminded to discriminate between emissions from processes where the same fossil fuel is used both for energy and for feedstock purposes (e.g. synthesis gas production, carbon black production), and to report these emissions in the correct sectors.

Some countries may face some difficulties in obtaining disaggregated activity data or may have different definitions for industrial source categories. For example, some countries may include residential energy consumption of the workers in industry consumption. In this case, any deviations from the definitions should be documented.

Tier 3 estimates incorporate data at the level of individual facilities, and this type of information is increasingly available, because of the requirements of emissions trading schemes. It is often the case, that coverage of facility level data does not correspond exactly to coverage of classifications within the national energy statistics, and this can give rise to difficulties in combining the various sources of information. Methods for combining data are discussed in Chapter 2 of Volume 1 on General Guidance and Reporting.

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