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{{For|the sports term|Resting the starters}}
{{Short description|Process of balancing the supply of electricity on a network}}
[[File:Load diagram.png|thumb|Daily load diagram; Blue shows real load usage and green shows ideal load.]]
'''Load management''', also known as '''demand-side management''' ('''DSM'''), is the process of [[Load balancing (electrical power)|balancing the supply of electricity]] on the network with the electrical load by adjusting or controlling the load rather than the power station output. This can be achieved by direct intervention of the utility in real time, by the use of frequency sensitive relays triggering the circuit breakers (ripple control), by time clocks, or by using special tariffs to influence consumer behavior. Load management allows utilities to reduce demand for electricity during peak usage times ('''peak shaving'''), which can, in turn, reduce costs by eliminating the need for [[peaking power plant]]s. In addition, some peaking power plants can take more than an hour to bring on-line which makes load management even more critical should a plant go off-line unexpectedly for example. Load management can also help reduce harmful emissions, since peaking plants or backup generators are often dirtier and less efficient than [[base load power plant]]s. New load-management technologies are constantly under development — both by private industry<ref>[http://tdworld.com/mag/power_mega_load_management/ Example of largest load management system developed by private industry]</ref> and public entities.<ref>[http://www.oe.energy.gov/ US Dept. Of Energy, Office of Electricity Delivery and Electricity Reliability]</ref><ref>[http://www.electricdistribution.ctc.com/monitoring_load_management_technologies.htm Analysis of current US DOE Projects] {{webarchive |url=https://web.archive.org/web/20081015185316/http://www.electricdistribution.ctc.com/monitoring_load_management_technologies.htm |date=October 15, 2008 }}</ref>
==Brief history==
Modern utility load management began about 1938, using ripple control. By 1948 ripple control was a practical system in wide use.<ref>{{cite journal |last1=Ross |first1=T. W. |last2=Smith |first2=R. M. A. |title=Centralized ripple control on high-voltage networks |journal=Journal of the Institution of Electrical Engineers - Part II: Power Engineering |date=October 1948 |volume=95 |issue=47 |pages=470–480 |doi=10.1049/ji-2.1948.0126 |url=https://ieeexplore.ieee.org/document/5296967 |
The Czechs first used ripple control in the 1950s. Early transmitters were low power, compared to modern systems, only 50 kilovolt-amps. They were rotating generators that fed a 1050 Hz signal into transformers attached to power distribution networks. Early receivers were electromechanical relays. Later, in the 1970s, transmitters with high-power semiconductors were used. These are more reliable because they have no moving parts. Modern Czech systems send a digital "telegram." Each telegram takes about thirty seconds to send. It has pulses about one second long. There are several formats, used in different districts.<ref name = "energo">{{cite web |title=Ripple control |url=https://www.egc-cb.cz/en/products-for-power-industry/ripple-control.html |publisher=EnergoConsult CB S.R.O. |
In 1972, [[Theodore George “Ted” Paraskevakos]], while working for [[Boeing]] in [[Huntsville, Alabama]], developed a sensor monitoring system which used digital transmission for security, fire, and medical alarm systems as well as meter-reading capabilities for all utilities. This technology was a spin-off of his patented automatic telephone line identification system, now known as [[caller ID]]. In, 1974, Paraskevakos was awarded a U.S. patent for this technology.<ref>U.S. Patent No. 3,842,208 (sensor monitoring device)</ref>
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|title = The Remote Control Frequencies
|author = Jean Marie Polard
▲|accessdate = 21 June 2011
}}</ref>) onto the standard 50–60 Hz of the main power signal. When receiver devices attached to non-essential residential or industrial loads receive this signal, they shut down the load until the signal is disabled or another frequency signal is received.
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The main disadvantage compared to ripple control is a less fine-grained control. For example, a grid authority has only a limited ability to select which loads are shed. In controlled war-time economies, this can be a substantial disadvantage.
The system was invented in [[PNNL]] in the early 21st century, and has been shown to stabilize grids.<ref>{{cite web|last1=Kalsi|first1=K.|display-authors=etal|title=Loads as a Resource: Frequency Responsive Demand Control|url=https://www.pnnl.gov/main/publications/external/technical_reports/PNNL-23764.pdf|website=pnnl.gov|publisher=U.S. Government|
==Examples of schemes==
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|title = Mega Load Management System Pays Dividends
|author = Michael Andreolas
|date=February 2004
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}}</ref> is found in Florida and is managed by [[Florida Power and Light]]. It utilizes 800,000 load control transponders (LCTs) and controls 1,000 MW of electrical power (2,000 MW in an emergency). FPL has been able to avoid the construction of numerous new power plants due to their load management programs.<ref>
{{cite web
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|title = FPL Files Proposal to Enhance Energy Conservation Programs
|date = May 2006
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===France===
France has an EJP tariff, which allows it to disconnect certain loads and to encourage consumers to disconnect certain loads.<ref>[https://archive.
===Germany===
The distribution system operator Westnetz and gridX piloted a load management solution. The solution enables the grid operator to communicate with local energy management systems and adjust the available load for EV charging in response to the state of the grid.<ref>{{cite web |url=https://www.gridx.ai/press-releases/following-a-successful-pilot-gridx-agrees-on-cooperation-with-westnetz|title=GridX Press Release: Following successful pilot, gridX agrees on cooperation with Westnetz }}</ref>
===United Kingdom===
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In the UK, night storage heaters are often used with a time-switched off-peak supply option - [[Economy 7]] or [[Economy 10]]. There is also a programme that allows industrial loads to be disconnected using circuit breakers triggered automatically by frequency sensitive relays fitted on site. This operates in conjunction with [[Standing Reserve]], a programme using diesel generators.<ref>[http://www.claverton-energy.com/commercial-opportunities-for-back-up-generation-and-load-reduction-via-national-grid-the-national-electricity-transmission-system-operator-netso-for-england-scotland-wales-and-offshore.html Commercial Opportunities for Back-Up Generation and Load Reduction via National Grid, the National Electricity Transmission System Operator (NETSO) for England, Scotland, Wales and Offshore.]</ref> These can also be remotely switched using BBC Radio 4 Longwave [[Radio teleswitch]].
SP transmission deployed Dynamic Load Management scheme in Dumfries and Galloway area using real time monitoring of embedded generation and disconnecting them, should an overload
==See also==
* [[Energy management system]]
* [[Energy storage as a service]] (ESaaS)
* [[National Grid (Great Britain)#Estimating costs per
* Calculating the cost of back up: See [[spark spread]]
* [[Energy in the United Kingdom]]
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