In the energy prospective studies, where the competition possibilities among energy sources are analyzed, the end use, the equipment efficiency and captive uses are the variables used and therefore, for electricity, the theoretical criterion is valid. Therefore, from the technical point of view, there is no restriction on using one or the criterion for representing the figures of hydraulic power and electricity in Energy Balances.

Advantages of maintaining the 0.29 toe/MWh factor:

1. as a habit, we are used to considering the IEO of Brazil as being composed by the famous tripod – petroleum, hydraulic power and biomass. The use of the theoretical criterion would uncharacterize this affirmation.
2. the electric sector, in some way, has used the relative importance of electricity in the final energy consumption in order to enhance the need of investments for expansion.
3. more equitable comparison of the Brazilian per capita IEO with those of other countries that presented significant thermal generation.

Disadvantages of maintaining the 0.29 toe/MWh factor:

1. difficulty in comparing energy data from Brazil with data from other countries. It is usual to compare data from BEN with data from other countries without mentioning the conversion factor criteria.
2. the smaller participation of the other energy sources in the IEO and final consumption.
3. application of two criteria on BEN since the theoretical criterion must be used in the electrical power plants tables (Tables 5.3 and 5.4), price tables (Tables 7.10 and 7.11) and tables with data from other countries (tables B1 and B2).
4. In Annexes F01 to F28 of BEN – Consolidated Energy Balances – the data from Public Electrical Power Plants and Self-producers do not show the real efficiency of thermal generation.

Gradual introduction of the theoretical criterion in BEN, initially with simultaneous presentation of both criteria in some tables of chapter 1 (including that of useful energy) and extensive distribution of this Technical Note in BEN itself and via Internet.

Measurement Units (Commercial) – units that usually express the commercialized quantities of energy sources, for example: for solids, ton (t) or pound (lb), for liquids, cubic meter (m³) or barrel (bbl), for gases, cubic meter (m³) or cubic foot (ft³) and for electricity, watt(W) for power and watt-hour (Wh), for energy.

Common Unit – unit to which the measurement units used for different forms of energy are converted. This unit allows for adding different energy quantities in the Energy Balances. According to the International Unit System – IS, joule or kilowatt-hour are the regulated units used as Common Unit but other units are currently used by different countries and international organizations such as equivalent ton-oil-equivalent (toe), ton-coal-equivalent (tce), calorie and its multiples, British thermal unit (Btu), etc.

Conversion Factors (coefficient of equivalence) – coefficients that permit transforming quantities expressed in measuring quantities to quantities expressed in a common unit. For example, in the case of Brazil, in order to convert tons of wood into toe, the 0.306 coefficient is used, which is the ration between the calorific power of wood and that of petroleum (3,300 kcal/kg/ 10,800 kcal/kg), that is 1t of wood = 0.306 toe.

Calorie (cal) – quantity of heat in kcal necessary to raise the temperature of one gram of water from 14.5^o C to 15.5 ^o C at normal atmospheric pressure (760 mm Hg).

Calorific Power – heat quantity in kcal produced by 1kg or 1m³ N of fuel after complete combustion.

Note: the fuels that produce H2O in the combustion products (derived from combustion or from impregnated water) have a superior calorific power and a lower calorific power. Since most of the time H2O escapes through the chimney as vapor, the inferior caloric power is the one that is practically significant.

watt (W) – Power unit – watt is the power of an energy system in which the energy of 1 joule is uniformly transferred during 1 second.

watt-hour – (Wh) – energy uniformly transferred during 1 hour.

1 Wh = 1 ´ 3,600 s ´ J/s= 3,600 J = 3,600 ´ (0.239 cal) = 860 cal

Therefore, in the theoretical concept 1kWh = 860 kcal

Note: watt, watt-hour and their multiples are measurement units used for hydraulic power and electricity, for power generation and distribution.

joule (J) – Work unit for energy and quantity of heat. Joule is the work produced by a force of 1 newton whose application point moves 1 meter in the force’s direction.

newton (N) – Force unit. Newton is the force that, when applied to a body with 1 kilogram of mass, transmits the acceleration of 1 meter per second squared. Considering the acceleration of gravity as 9.806 m/s2, one has

Internal Energy Offer is the quantity of energy available for transformation and/or final consumption. Therefore it gives the energy before the transmission and distribution processes.

Final Energy Consumption is the energy consumed by the different sectors of the economy to satisfy the needs of different uses such as heat, motive power, illumination, etc. It does not include quantity of energy used as raw material for the production of any other form of energy.

Note: except for statistical adjustments, the difference between Internal Energy Offer and Final Energy Consumption correspond to adding the losses in distribution and storage to losses in the transformation processes (refineries, distilleries, electrical power plants, coking, etc.).