About electricity tariffs

Electricity tariffs allow users to take into account the cost of various control strategies when working out the optimum control strategy for a system. The Electricity Tariff object contains one or more tariffs that describe the charging schemes for supply of electricity to a site including: fixed charges, 24 hour charging profiles and changes in charging profiles over the year.

Traditionally, in the UK, electricity tariffs fall into three main categories:

• Demand - This tariff has no restrictions or penalties and electricity is supplied effectively on demand to the consumer.
• Night/Day - This tariff offers incentives for night time use and has always been more attractive financially in the water industry where night time pumping may be possible by using reservoir storage.
• Seasonal Time of Day (SToD) - This relatively recent form of tariff offers higher savings if certain peak periods could be avoided generally at winter peak hourly demands.

InfoWorks WS Pro uses this historical approach which still provides an accurate way of modelling tariffs despite major consumers now being able to negotiate contracts with a variety of electricity suppliers.

Rates can be defined for HIGH (>1000 volts) and LOW voltage electric systems.

The following items are taken into account in the InfoWorks model:

• Standing Charge (fixed charge per month)
• Availability Charge (unit charge per kVA per month)
• Maximum Demand Charge (unit charge per kVA of maximum demand)
• Unit Charges: Day/Night (unit charge per kWh) Other flat rate unit charges, such as Climate Change Levy can be taken into account by adding the charges to the energy consumption unit charge.
• Seasonal Demand Charges (unit charge per kVA) A distinction is made between Working Days (Monday to Friday) and Weekend Days(Saturday and Sunday).

In IWLive Pro, tariff data either comes from electricity tariffs via the default simulation specified in the Default Model page of the Baseline, or from switch objects.

Electricity tariffs can be configured to be updated from Live Data in IWLive Pro prior to a run. This can be implemented in IWLive Pro Administrator, using the Fields page of the Baseline Object window.

Electricity tariffs are visualised and edited in the Profile editor. This editor gets displayed when the button is clicked on for a tariff in the Fields page of the Baseline Object window (IWLive Pro Administrator) or the Electricity Tariff window (IWLive Pro Operator).