(1) Introduction(4.4) Generators & Loads
Network users can be classified under three headings:
- Generators - whose express purpose is to provide energy to the network.
- Suppliers - who will be responsible for supplying energy to end users.
- Self-generators - who have an ability to generate some of their own energy but require the network to support their demand when their own generation is inadequate or shut down.
Generators deliver energy at their point of connection to the conveyance network i.e. station gate, where metering will be installed normally (3). Consequently generators will not be using the conveyance system when generating and therefore will not be liable for usage charges. Generators who also require a supply of energy from the network will be charged for energy on an appropriate supply tariff which contains an element for conveyance UoS. For generators of sufficient size to require conveyance network connection, examples of appropriate tariffs would be the high voltage maximum demand or industrial economy tariffs. Generator import/export plant and metering will be arranged to record net energy exported to the network and, separately, energy imported.
Suppliers will be purchasing energy from the network and reselling it to end-users. Clearly UoS charges will be applied to suppliers, including GE's own supply business.
Self generators who connect to the conveyance network, but balance their own generation against their load, will normally not transfer any energy through the network, and will, therefore, not make any payment to the network operator through energy transfer UoS charges.
To compensate the network operator for the need to maintain network availability, on standby, for the self-generator's use when his generator is unavailable, GE believes it is equitable to levy an availability charge. This would be levied on a monthly basis according to the capacity held available for the self-generator. This charge could be considered to be analogous to an insurance premium covering failure of the user's own generator.
Where a self-generator requires a supply of energy through the network then he will be charged for energy on an appropriate supply tariff, incorporating UoS charges. Examples of such tariffs would be the Industrial HV maximum demand tariff or the Industrial Economy tariff.
3 The point of connection to the conveyance system is usually defined as the position of the metering equipment. This position also usually forms the boundary of ownership of network assets, such that plant and cables between the generator and the meter belong to the generator operator and plant and cables between the meter and the body of the network belong to the network operator. This position will also be considered to be the "commercial; boundary" through which energy will pass between generator and network operator.