Electricity market

In economic terms, electricity (both power and energy) is a commodity capable of being bought, sold, and traded. An electricity market is a system enabling purchases, through bids to buy; sales, through offers to sell; and short-term trades, generally in the form of financial or obligation swaps. Bids and offers use supply and demand principles to set the price. Long-term trades are contracts similar to power purchase agreements and generally considered private bi-lateral transactions between counterparties. In economic terms, electricity (both power and energy) is a commodity capable of being bought, sold, and traded. An electricity market is a system enabling purchases, through bids to buy; sales, through offers to sell; and short-term trades, generally in the form of financial or obligation swaps. Bids and offers use supply and demand principles to set the price. Long-term trades are contracts similar to power purchase agreements and generally considered private bi-lateral transactions between counterparties. Wholesale transactions (bids and offers) in electricity are typically cleared and settled by the market operator or a special-purpose independent entity charged exclusively with that function. Market operators do not clear trades but often require knowledge of the trade in order to maintain generation and load balance.The commodities within an electric market generally consist of two types: power and energy. Power is the metered net electrical transfer rate at any given moment and is measured in megawatts (MW). Energy is electricity that flows through a metered point for a given period and is measured in megawatt-hours (MWh). Markets for energy-related commodities trade net generation output for a number of intervals usually in increments of 5, 15 and 60 minutes. Markets for power-related commodities required and managed by (and paid for by) market operators to ensure reliability, are considered ancillary services and include such names as spinning reserve, non-spinning reserve, operating reserves, responsive reserve, regulation up, regulation down, and installed capacity. In addition, for most major operators, there are markets for transmission congestion and electricity derivatives such as electricity futures and options, which are actively traded. These markets developed as a result of the restructuring of electric power systems around the world. This process has often gone on in parallel with the restructuring of natural gas markets. One early introduction of energy market concepts and privatization to electric power systems took place in Chile in the early 1980s, in parallel with other market-oriented reforms associated with the Chicago Boys. The Chilean model was generally perceived as successful in bringing rationality and transparency to power pricing. Argentina improved on the Chilean model by imposing strict limits on market concentration and by improving the structure of payments to units held in reserve to assure system reliability. One of the principal purposes of the introduction of market concepts in Argentina was to privatize existing generation assets (which had fallen into disrepair under the government-owned monopoly, resulting in frequent service interruptions) and to attract capital needed for rehabilitation of those assets and for system expansion. The World Bank was active in introducing a variety of hybrid markets in other Latin American nations, including Peru, Brazil, and Colombia, during the 1990s, with limited success. A quantum leap in electricity pricing theory occurred in 1988 when four professors at MIT and Boston University (Fred C. Schweppe, Michael C. Caramanis, Richard D. Tabors, and Roger E. Bohn) published a book entitled, 'Spot Pricing of Electricity.' It presented the concept that prices at each location on a transmission system should reflect the marginal cost of serving one additional unit of demand at that location. It then proposed quantifying these prices by solving a systemwide cost minimization problem while complying with all of the system's operational constraints, such as generator capacity limits, locational loads, line flow limits, etc. using linear programming software. The locational marginal prices then emerged as the shadow prices for relaxing the load limit at each location. A key event for electricity markets occurred in 1990 when the UK government under Margaret Thatcher privatised the UK electricity supply industry. The process followed by the British was then used as a model (or at least a catalyst) for the restructuring of several other Commonwealth countries, notably the National Electricity Markets of Australia and New Zealand and the Alberta Electricity Market in Canada.