Coping with an ever increasing load

ESB Networks staff plan and manage huge growth loads in the greater Dublin area

We are all familiar with the unprecedented level of development that has taken place around the whole country and in particular around the greater Dublin area. In the 10 years from 1996 to 2006 there was a 55% increase in load. Claire Quane, HV Planner Dublin Asset Management, tells the story

ESB Networks
In order to provide electricity to the new housing estates, industrial parks, factories etc, staff in ESB Networks have been working hard to plan and manage the current and future load requirements.

Background
The Greater Dublin Area is supplied from four Bulk Supply Points (BSP), 220kV/110kV stations, Finglas, Inchicore, Ringsend and Carrickmines, as indicated in Figure 1. The BSP's provide HV connections to various 110/38kV and 110kV/MV stations in discrete geographical areas in the Greater Dublin Area; these stations then in turn feed the load.

Prior to connection large customers and developers approach ESB Networks about the availability of capacity to provide a connection to their installation. Such interactions are referred to as load enquiries. The level of load enquiries in Dublin is extremely high with 771MVA of load enquiries currently in the Greater Dublin Area. It is anticipated that the vast majority of these developments will require connection within the next five to seven years.

Figure 2 shows the historical level of load growth in the Dublin area. In the 10 years from 1996 to 2006 there was a 55% increase in load. Based on the load enquiries currently in hand there is potentially a similar level of load growth over the next five to seven years, though it is anticipated that some of these developments will not go ahead and others may develop more slowly than indicated by developers. According to Sheila O'Connor, Manager ESB Network Investments North, these are unprecedented levels of growth which will have a very significant impact on the HV networks in Dublin.

Major developers are seeking connections all across the city, and this will clearly affect the level of load at each of the BSP's. The additional load expected at each BSP is estimated to be as follows:

Finglas: 254MVA
Inchicore: 252MVA
Ringsend: 91MVA
Carrickmines: 174MVA

The existing and expected level of load in Dublin is such that capacity on the HV network will be an issue, hence significant transmission and distribution reinforcement will be required over the coming years.

Specific Areas

There are a number of areas where the level of load growth is particularly large, and consideration of how these areas will be accommodated is needed. By way of example two such areas are given detailed consideration below.

1. North Fringe
A very large section of land stretching from Baldoyle in the east to the M1 is to be developed; this area is referred to as the North Fringe. In addition to the North Fringe development a number of other new customers are seeking connection west the M1 and some existing customers are increasing their load requirements. The load is expected to develop, over the entire area, from Baldoyle to Finglas. It is expected that 140MVA of load will require connection over the coming years.

The existing HV networks do not have sufficient capacity to supply the load that is seeking connection and both transmission and distribution reinforcement is required. Following an extensive study it was established that ESB will be required to reinforce the network as follows:

• Install a new 110kV circuit from Finglas 220kV station to Kilmore 110kV station
• Construct two new 110kV/MV stations in North Fringe
• Extend the 110kV busbar at Kilmore 110kV station
• Construct a new 220kV/110kV station at Balgriffin

2. Ballycoolin
A substantial number of load enquires and applications have been submitted in the Ballycoolin/College Park area, with load enquiries to date totalling 46MVA. Further enquiries of another 30MVA are under consideration in this area. The following reinforcements will be required to be carried out.

• Installation of additional 220kV/110kV transformer capacity at Finglas BSP
• Installation of a third 110kV/MV trafo at College Park
• Development of a new 110kV/MV station in the area

Reinforcements Required

There are other major load developments in the Greater Dublin Area which will require significant network reinforcements in the coming years. Figure 3 identifies the locations for these reinforcements.

Currently there are a number of projects underway and many more planned to begin construction over years to come. The distribution system will be reinforced as follows:

• There are five 110kV/MV stations under construction at present, shown in red. Located at Ashbourne, Balbriggan, Sallynoggin, Leopardstown and North Quays
• In addition construction will begin on six 110kV/MV stations in 2007, shown in orange. These stations are at Ballymun, Pelletstown near Phoenix Park, Adamstown, Cookstown, Cherrywood, and Dardistown at Dublin Airport for terminal 2
• An additional five 110kV/MV stations will begin construction in 2008/2009, shown in blue. These stations are at Kilmainham, Trinity College, ParkWest, North Fringe and Greystones

Conclusion

There has been a significant upsurge in the level of load enquires around Dublin in recent times (770MVA). It is therefore challenging for ESB Networks to deliver these stations within the timescales being indicated. This will involve very significant HV work including the development of HV stations and the installation of HV underground cables in congested urban streets.

Planning Permission is often given for developments without consideration of electrical infrastructure needs. This can result in the developer not engaging with ESB until an advanced stage of the project which provides an additional challenge to ESB in providing connection on time

The relationship between the transmission and distribution systems sometimes necessitates the study of both systems together to ensure that the overall best solution is found. Such studies are complex and significant engagement and cooperation between the ESB Networks and EirGrid is required. The North Fringe project is an example of a successful outcome to such a joint study.

The level of capital work planned in the coming years is challenging in terms of our ability to deliver on such a major and complex programme. However, given the track record of staff in Network Projects who have consistently delivered, ESB Networks is confident of meeting its commitment to provide its customers with an excellent standard of service.

"We are confident in our ability to deliver on this challenging work programme," says Denis O'Leary, Head of Asset Management. "This will allow Dublin to continue to develop as one of the major capital cities of Europe."EM