than the cost of shutting down and re-starting their plants. For a renewable generator, staying online may also cost less than what generators receive from support mechanisms like the Renewable Energy Target scheme, plus their own costs. Physical equipment Generators For comprehensive information of generators in Australia, see List of power stations in Australia. Transmission network The transmission network service providers (TNSPs) are operators of the high voltage electricity transmission networks. There are five state-based TNSPs servicing each of the regions in the NEM, with crossborder interconnectors linking the state grids at state borders to allow electricity to flow from one state to another. Four of the networks form a wide area synchronous grid except for Tasmania which is linked via HVDC. The TNSPs link generators to the 13 major distribution networks that supply electricity to end-use customers. The TNSPs are: TNSPs participate in the Australian Energy Regulator's (AER) revenue proposal process, where submissions of the TNSPs, the AER and other interested parties are used to set the maximum allowable revenue (MAR) for the TNSPs for a five-year period. The crossborder interconnectors are: NSW-Queensland — Terranora interconnector (Directlink) (HVDC) NSW-Queensland — Queensland – New South Wales Interconnector (HV AC) Victoria to New South Wales Interconnector Victoria-Tasmania — Basslink (HVDC) Victoria-South Australia — Heywood interconnector (HV AC) Victoria-South Australia — Murraylink (HVDC) System reliability NEM reliability standards are established by the Australian Energy Market Commission (AEMC) Reliability Panel. These standards currently require that unserved energy per year for each region must not exceed 0.002 percent of the total energy consumed in that region that year. The NEM is required to operate with defined levels of reserve in order to meet the required standard of supply reliability. Under current standards, AEMO is required to ensure 850 megawatts of reserve is carried across the entire NEM. The reliability safety net provisions of the National Electricity Rules provide that AEMO must procure sufficient reserve to ensure that the reliability of supply meets the reliability standard. When reserves acquired by AEMO are dispatched they are bid in at the MPC thus setting the spot price at the maximum level. Financial markets In addition to physical spot trading through the NEM, there is a separate financial trading market for electricity. Prices in the spot market are highly volatile and the spot price can spike to several hundred times the average price for short periods. Therefore, buyers