electricity based on the principle of meeting prevailing demand in the most cost-efficient way (see also Economic dispatch). AEMO then dispatches these generators into production by sending automatic generation control (AGC) target signals to each generating unit. A dispatch price is determined every five minutes (termed Dispatch Intervals, abbreviated as DI) to determine the spot price for each 5-minute trading interval abbreviated as TI. Before October 2021, six dispatch prices were averaged every half-hour. There are 5 trading regions for each of the regions of the NEM. AEMO uses the spot price as the basis for the settlement of financial transactions for all energy traded in the NEM. There is a maximum price that generators can bid in at. Under the Rules, the AEMC adjusts this maximum spot price MPC (market price cap) by movements in the consumer price index by 28 February each year for the rate to commence on 1 July. For the 2020-2021 financial year the MPC was $15,000/MWh. There is a further limit on the price called the Cumulative Price Threshold, which is the sum of value of all the TI's for the previous 7 days, calculated on a rolling basis. When this exceeds $224,600, AEMO caps the bids to a nominated value, currently $300/MWh. Whilst the price is capped in this manner, it is known as an Administered Price period. The process continues until the rolling average drops to allow normal trading without impinging the threshold too rapidly again. Market Price Cap (MPC) – which was previously called the value of lost load (VoLL) – is the price automatically triggered when AEMO directs network service providers to interrupt customer supply in order to keep supply and demand in the system in balance. From 1 July 2022 to 30 June 2023 the MPC has been set to $15,500/MWh. From 1 October 2021 to 30 June 2022 was $15,100/MWh. The MPC for the 2020-2021 financial year was $15,000/MWh; $14,700/MWh in 2019-2020; and $14,500/MWh in 2018-2019. For the 2017-2018 financial year the MPC was $14,200/MWh and the Cumulative Price Threshold was $212,800. The maximum price was $14,000/MWh in 2016-2017, $13,800/MWh in 2015-2016, $13,500/MWh in 2014-2015, and $13,100/MWh in 2013-2014. The Rules also set a minimum spot price of minus $1,000 per MWh which is the market floor price. This negative market floor price allows generators to pay to stay online when the cost of staying online is lower