Basic Decimal System Prefixes
Prefix
Symbol
Multiple
Example
Kilo
k
103
1 kJ = 1 000 J
Mega
M
106
1 MJ = 1 000 kJ
Giga
G
109
1 GJ = 1 000 MJ
Tera
T
1012
1 TJ = 1 000 GJ
Examples:


1 GJ = 109 J = 1 000 000 000 J
1 kt = 1 000 t (Reminder: 1 t = 1000 kg , therefore 1 kt = 1 000 000 kg)
Basic Energy Units
Joule (J) – Basic (SI) energy unit for energy.

Multiples are kJ, MJ, GJ, TJ, etc.
Watt-hour (Wh) – Energy unit used mostly for electricity.

1 Wh = 3 600 J  1 GWh = 3.6 TJ

1 TJ = 0.2778 GWh ( = 1/3.6 GWh)
Tonne of Oil Equivalent (toe) – Energy unit used in IEA energy balances.

1 toe = 41.868 GJ
In the following table, you will find all the conversion factors between the most commonly used
energy units:
Calorific Values
A calorific value is a conversion factor used to convert a fuel quantity between natural units (mass
or volume) and energy units (energy content). There are Net Calorific Values (NCV) and Gross
Calorific Values (GCV). Depending on the product, we may want to convert using GCV or NCV. When
we want to convert from or to gross energy content, we use the GCV and when from or to net
energy content, we use the NCV.
Examples:
What is the (net) energy content of 100 kt of Anthracite with an NCV of 25 000 MJ/tonne?

100 kt * 25000 MJ/tonne = 100 kt * 25 000 GJ/kt = 100 kt * 25 TJ/kt = 2 500 TJ
What is the volume of an amount of Natural gas with an energy content of 1 000 TJ (Gross) if its GCV
is 40 000 kJ/m3?

1 000 TJ / (40 000 kJ/m3) = 1 000 TJ / (40 TJ/ (106*m3)) = 25 000 000 m3 = 25 Mm3.
Basic Excel Functions
The SUM function

Adds all the values given and provides their sum

”=SUM(1,2,3)“ will show 7 on the cell

Instead of a fixed number, you can input a formula, e.g. ”=SUM(B1:B10,C1,D1:D2,E1:G1)“
The AVERAGE function

Returns the average of the given values

”=AVERAGE(2,3,7)“ will return 6

Instead of a fixed number, you can input a formula, e.g. ”=AVERAGE(A1:B3,D1/D2,3*E1)“
The ROUND function

Rounds a number to the decimals specified

”=ROUND(4.1586,2)“ will round to 2 decimal points, so the result will be 4.16. Similarly:

”=ROUND(4.1586,0)“  4

”=ROUND(4.1586,1)“  4.2

Instead of a fixed number, you can input a formula, e.g. ”=ROUND((C1+D1)/B1,0)“
Of course, you can combine functions:

“=ROUND(SUM(A1:B10)/3,0)” will return the sum of the cells A1 to B10, divided by 3 and
then rounded to 0 decimal points (therefore rounded to the closest integer).