The Electricity Supply Board (ESB; ) is a state owned (95%; the rest are owned by employees) electricity company based in Ireland with operations worldwide. While historically a monopoly, the ESB now operates as a commercial semi-state concern in a "liberalised" and competitive market. It is a statutory corporation whose members are appointed by the Government of Ireland.
Business areas The ESB is composed of several distinct, separate and legally demarcated companies. By business area, the principal companies are:
ESB Networks Limited manages construction and maintenance of the electricity transmission system. (The transmission system operator is an independent state company, EirGrid).
ESB Generation and Wholesale Markets (ESB GWM) operates a portfolio of power stations across the country, along with holdings in wind and other renewables.
Electric Ireland is a regulated supply company, one of fourteen companies (as of 10 October 2021) operating in the domestic market. Since 4 April 2011 the Commission for Energy Regulation no longer sets the company's prices; the trade-off for this was that the division was required to change its name from ESB to Electric Ireland, to "remove confusion" between the ESB's role as operator of the electricity network and a supplier in that market. The previous name, ESB Independent Energy, was dropped in January 2012.
ESB International Limited is responsible for the company's unregulated activities, principally providing electrical engineering consultancy services around the world. It has holdings in many areas, such as power-generation joint ventures, renewables development, and computing consultancy.
Northern Ireland Electricity (NIE) is responsible for the operation and maintenance of the electricity network in Northern Ireland, and has been part of the ESB since they purchased it from Viridian in December 2010. However, the ESB does not own the former supply business of NIE, which was retained by Viridian.
History
The ESB was established by the fledgling Irish Free State government under the Electricity (Supply) Act, 1927 to manage Ireland's electricity supply after the successful Shannon Scheme at Ardnacrusha. The scheme was Ireland's first large-scale electricity plant – and at the time, it provided 80% of the total energy demands of Ireland. To give an idea of the growth in demand, the output of Ardnacrusha is now approximately two per cent of national peak demand for power.
By 1937, plans were being finalised for the construction of several more hydro-electric plants. The plans called for stations at Poulaphouca, Golden Falls, Leixlip (all in Leinster), Clady, Cliff and Cathaleen's Fall (between Belleek and Ballyshannon in County Donegal), Carrigadrohid and Inniscarra (in County Cork). All these new plants were completed by 1949, and together harnessed approximately 75% of Ireland's inland water power potential. Many of these plants are still in operation; however, as could be expected with continuing growth in demand, their combined capacity falls far short of Ireland's modern needs.
With Ireland's towns and cities benefiting from electricity, the new government pushed the idea of Rural Electrification. Between 1946 and 1979, the ESB connected in excess of 420,000 customers in rural Ireland. The Rural Electrification Scheme has been described as "the Quiet Revolution" because of the major socio-economic change it brought about. The process was greatly helped in 1955 by the Electricity Supply Amendment Act, 1955.
In 1947, the ESB, needing ever more generation capacity, built the North Wall station on a 7.5-acre (30,000 m2) site in Dublin's industrial port area on the north side of the River Liffey on the site of an old oil refinery. The original station consisted of one 12.5 MW steam turbine that was originally purchased for a power station at Portarlington but instead used at North Wall. Other power stations built around this time included the peat fired stations at Portarlington, County Laois, and Allenwood in County Kildare.
Because of the risks of becoming dependent on imported fuel sources and the potential for harvesting and utilising indigenous peat, the ESB – in partnership with Bord na Móna – established those stations and ESB also built Lanesboro power station in 1958. Located in County Longford, the plant burns peat, cut by Bord na Móna in the bogs of the Irish midlands. In 1965 the Shannonbridge station was commissioned. It is located in County Offaly. The two stations have been replaced by new peat-fired stations near the same locations, and peat is also used to power the independent Edenderry Power plant, in County Offaly.
As in most countries, energy consumption is low at night and high during the day. Aware of the substantial waste of night-time capacity, the ESB commissioned the Turlough Hill pumped storage hydro-electric station in 1968. This station, located in County Wicklow, pumps water uphill at night with the excess energy created by other stations, and releases it downhill during the day to turn turbines. The plant can generate up to 292 MW of power – but output is limited in terms of hours because of the storage capacity of the reservoir.
The 1970s brought about a continued increase in Ireland's industrialisation and with it, a greater demand for energy. This new demand was to be met by the construction of the country's two largest power stations – Poolbeg in 1971 and Moneypoint in 1979. The latter, in County Clare, remains Ireland's only coal-burning plant and can produce 915 MW – just shy of the 1015 MW capacity of Poolbeg. In 2002 and 2003, new independent stations were constructed – Huntstown Power (north Dublin) and Dublin Bay Power (Ringsend, Dublin).
In 1991, the ESB established the ESB Archive to store historical documents relating to the company and its impact on Irish life.
On 8 September 2003, two of the last remaining places in Ireland unconnected to the national grid – Inishturbot and Inishturk islands (off the coast of Galway)- were finally connected to the mains supply. Some islands are still powered by small diesel-run power stations.
60 wind farms are currently connected to the power system (July 2006) and have the capacity to generate 590 MW of power, depending on wind conditions. These wind farms are mainly owned by independent companies and landowners.
On 16 March 2005, the ESB announced that it was to sell its ShopElectric (ESB Retail) chain of shops, with the exception of the Dublin Fleet Street and Cork Academy Street outlets, to Bank of Scotland (Ireland), converting them into main street banks. Existing staff were offered positions as bank tellers.
On 27 March 2008, the ESB announced a €22bn capital investment programme in renewable energy technology, with the aim to halve its carbon emissions within 12 years and achieve carbon net-zero by 2035.
EirGrid
On 1 July 2006, a new state owned company, EirGrid plc, separate from all parties in the Irish electricity sector, took over responsibility for the operation of the Irish national grid. It has its own separate board and it reports to the CER and its main shareholder, the Irish government. It was established as the operator of the Irish transmission system with ownership remaining with ESB Networks. On 12 March 2007, the Irish Government Policy on Energy stated that ownership of the transmission system would be vested in EirGrid from end 2008. EirGrid is responsible for balancing electricity consumption and generation and for the development of the power transmission system. Eirgrid, in conjunction with System Operator Northern Ireland, operates the all-island wholesale electricity market.
Facilities
GenerationCapacity MWPlantLocationFuelYear First Commissioned963AghadaCounty CorkNatural gas and distillate1980915MoneypointCounty ClareCoal or Oil1985470PoolbegCounty DublinNatural gas with distillate as an emergency back-up1971292Turlough HillCounty WicklowPumped-storage hydroelectricity1968262North WallCounty DublinNatural gas or distillate194796MarinaCounty CorkNatural gas and distillate195486ArdnacrushaCounty ClareHydroelectricity192965Erne (Cathaleen's Fall and Cliff)County DonegalHydroelectricity195030PoulaphoucaCounty WicklowHydroelectricity193819Inniscarra DamCounty CorkHydroelectricity19578CarrigadrohidCounty CorkHydroelectricity19574Golden FallsCounty KildareHydroelectricity19434LeixlipCounty KildareHydroelectricity19384CladyCounty DonegalHydroelectricity1959
Tarbert and Great Island were sold to Endesa in 2008 under the asset-divestment strategy agreed with the CER. This aims to lessen ESB GWM's market dominant position.
The ESB also has significant holdings in wind generation, principally through its wholly owned subsidiary, Hibernian Wind Power.
Former facilities GenerationCapacity MWPlantLocationFuelYear First CommissionedYear Decommissioned90 Ferbane power station County OffalyPeat1957200380 Rhode Power Station County OffalyPeat19602003150West Offaly Power StationCounty OffalyPeat20042020100Lough Ree Power StationCounty LongfordPeat20042020
Proposed facilities GenerationCapacity MWPlantLocationFuelYear Proposed1100–1300 Port Talbot Power Station Port TalbotNatural gas
Technical standards for electrical equipment
The Shannon Scheme was the start of the ESB's heavy reliance on German and Swedish electro-technology. Siemens, AEG and ASEA (Now ABB) equipment was used throughout the Irish generation and distribution system. The Irish system standardised on the 220 volt 50 Hz (now 230 volt) single phase and 380 volt (now 400 volt) three-phase supply systems which had been developed by Siemens and AEG in Germany. Residential installations followed a mixture of British (BS) and German (VDE) & (DIN) standards.
Siemens standard Diazed and the more modern Neozed fuses remain the standard type of fuse used in domestic and industrial installations and modern circuit breakers comply with German DIN standards.
British core colours red (live), black (neutral) and green (earth/ground) were used. These were later updated to brown (live), blue (neutral) and green-and-yellow (earth/ground) as per CENELEC and European standards.
Three-phase core colours also comply with EU standards: brown (L1), black (L2), grey (L3), blue (neutral), green & yellow (earth/ground)
British wiring accessories have generally been used in residential and light commercial installations e.g. junction boxes, light switches, wires and cables etc. However, in recent years European standard wiring accessories are beginning to replace some of these.
In industrial installations, Irish standards have always tended to follow German (DIN) and (VDE) norms.
Earthing/grounding system
TN-C-S is preferred. This is referred to in Ireland as a "neutralised" supply. Most homes and businesses are connected to such a system. Where this system is used, all the metal pipework must be bonded i.e. connected to the system's earth/ground creating an equipotential zone. In such an installation earth straps and yellow and green earth wires can be seen connected to pipework under sinks, in heating systems etc. TT system is used where TN-C-S earthing is not possible due to the design of the local distribution network, or the geology. This system is referred to as 'unneutralised' or 'not neutralised'.
Where a TT network connection is used, the entire supply must be protected by an RCD
Converting a TT supply to a TN-C supply "neutralisation" may only be carried out by an ESB engineer with the approval of ESB Networks. Under no circumstances should a homeowner, or an electrical contractor make any connection between the Earth/Ground and Neutral. To do so inappropriately could expose people to a risk of serious shock or electrocution.
Plugs and socket outlets