A rolling blackout, also referred to as load shedding, is an intentionally engineered electrical power shutdown where electricity delivery is stopped for non-overlapping periods of time over different parts of the distribution region. Rolling blackouts are a last-resort measure used by an electric utility company to avoid a total blackout of the power system. They are a type of demand response for a situation where the demand for electricity exceeds the power supply capability of the network. Rolling blackouts may be localised to a specific part of the electricity network or may be more widespread and affect entire countries and continents. Rolling blackouts generally result from two causes: insufficient generation capacity or inadequate transmission infrastructure to deliver sufficient power to the area where it is needed. Rolling blackouts are a common or even a normal daily event in many developing countries where electricity generation capacity is underfunded or infrastructure is poorly managed. Rolling blackouts in developed countries are rare because demand is accurately forecasted, adequate infrastructure investment is scheduled and networks are well managed; such events are considered an unacceptable failure of planning and can cause significant political damage to responsible governments. In well managed under-capacity systems blackouts are scheduled in advance and advertised to allow people to work around them but in most cases they happen without warning, typically whenever the transmission frequency falls below the 'safe' limit. Contents * 1 Canada * 2 India * 3 Japan * 4 Pakistan * 5 Ireland * 6 South Africa * 6.1 Blackouts in Western and Northern Cape 2005–2006 * 6.2 Country-wide blackouts 2007–2008 * 7 Tajikistan * 8 United Kingdom * 9 United States * 9.1 Texas * 9.2 California * 9.3 Elsewhere * 10 Footnotes
On 9 July 2012, the Alberta Electric System Operator ordered power companies in the province of Alberta to institute rolling blackouts during a heat wave as six generating plants failed during peak demand in the heat of the afternoon. India
In 2004–05, electricity demand outstripped supply by 7–11%. Due to a chronic shortage of electricity, power-cuts are common throughout India, adversely affecting the country's potential for economic growth. Even in the nation's capital of New Delhi, rolling blackouts are common, especially during the hot summer season when demand far outstrips supply. Rural areas are the most severely affected; it is common for the 44% of rural households having access to electricity to lose power for more than 12 hours each day. The states periodically and chronically affected by load-shedding are Delhi, Uttar Pradesh, Tamil Nadu, Bihar, West Bengal, Orissa, Assam, Maharashtra, Madhya Pradesh, Rajasthan and Andhra Pradesh. The states of Punjab, Goa, Gujarat and Kerala are largely free of any load-shedding due to surplus power. Karnataka still occasionally experiences power cuts. Japan
Rolling blackout in Japan after the 2011 Tohoku Earthquake.
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| Japan instituted rolling blackouts starting on 14 March 2011 due to power shortages caused by the 2011 Tōhoku earthquake and tsunami. The Tokyo Electric Power Company, which normally provides approximately 40,000 MW of electricity, announced that it could only provide about 30,000 MW, a shortfall of 25 percent. This is because about 40 percent of the electricity used in the greater Tokyo area is supplied by nuclear power plants in the Niigata and Fukushima prefectures. Two of those plants, the Fukushima Dai-ichi and Fukushima Dai-ni, were automatically taken offline when the first earthquake occurred and have sustained major damage related to the earthquake and...
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