A measure of the variation of outside temperature where building designers and users are able to determine how the energy consumption of a building is related to the weather. They quantify how far, and for how long, the external temperature has fallen below set base temperatures (normally 15.5ºC for heating applications). The daily data can then be totalled for any required period – a week, month or year and so forth and compared directly with energy data. If, assuming no additional energy is used, a building’s temperature of 15.5ºC drops to 14.5ºC, this is regarded as +1 degree day; 13.5ºC as +2 degree days; 16.5ºC as -1 degree days; 17.5ºC as -2 degree days and so on.
European Union Emissions Trading Scheme [EU-ETS]Created for the purpose of encouraging the 25 member states to meet their environmental obligations as set out under the Kyoto Protocol, the scheme was introduced to reduce the region’s total greenhouse gas emissions. Based on a cap and trade system, the EU-ETS comprises two phases. Phase I (2005-2007) monitors carbon dioxide levels within the energy-intensive industrial sector. Phase II (2008-2012) will look to include all sectors including aviation, maritime transport and forestry as well as all five greenhouse gas emissions.
Liquefied Natural Gas [LNG]Primarily made up of methane, LNG is natural gas that has been cooled to approximately -260°F (-160°C) at atmospheric pressure. It is odourless, colourless, non-toxic, non-corrosive and less dense than water. Taken from wells, the gas is liquefied through refrigeration and transported in specially designed tankers. On reaching its destination, LNG is then regasified (converted back to gas) and via combined cycle gas turbines, used to generate electricity.
Measurement Class (see also Profile Class)Metering Point Administration Number [MPAN]
Also known as the Supply Number, MPAN is a unique identifier for the supply to a particular address and is needed in order to change the supplier. This is divided into two parts: the MPAN Core, (13 digits at the bottom) and the Supplementary Data (8 digits at the top) as depicted in the figure below (Fig. 1).
MPAN Core
A 13-digit number (the bottom line of the Supply Number) made up of the: Distributor Identifier or the company which provides the distribution networks for the supply address (first two digits); the Meter Point ID which is linked to the supply address (an 8 digit number); and the Check number (three digits long).
MPAN Supplementary Data
The 8-digit number on the top line of the Supply Number. It indicates the Profile Class, Meter Time Switch Code (MTC) details and the Line Loss Factor Code.
Figure 1 - MPAN
Power Factor
Power factor is the relationship between working (active) power and total power consumed (apparent power). Essentially, power factor is a measurement of how effectively electrical power is being used. The higher the power factor, the more effectively electrical power is being used and vice versa. A distribution system’s operating power is composed of two parts: Active (working) power and reactive (non-working) magnetising power. The active power performs the useful work; the reactive power does not as its only function is to develop magnetic fields required by inductive devices (as depicted in Fig. 2 below).
Figure 2 - Power Factor
Profile Class
Profile classes are used for non half-hourly metered supplies providing the electricity supplier with an expectation as to how electricity will be consumed throughout the day (see Table 1 below). The profile class is the first 2 digits of the supply number - see ‘MPAN’.
Table 1 - Profile Class
Where half-hourly metering is installed (large consumers) the profile class is 00.
Renewables Obligation [RO]
Introduced in April 2002, the Renewables Obligation commits electricity suppliers to increase the amount of power they generate from sustainable sources each year. The RO target was recently amended from 15.4 per cent (to be achieved by 2015/16), to 20 per cent (to be achieved by 2020). The compliance of utilities is demonstrated through the production of Renewables Obligation Certificates [ROCs], given to Ofgem (depicted in Table 2 below).
Table 2 - Renewables Obligation