Ageing power lines need makeover

The advent of large-scale renew­able ener­gy capac­i­ty in the UK has come just as the country’s trans­mis­sion and dis­tri­b­u­tion net­work needs a com­plete over­haul. It is also pro­vid­ing the oppor­tu­ni­ty to revi­talise oth­er parts of the country’s infra­struc­ture.

This is just part of the infra­struc­ture upgrade that wind and marine ener­gy is help­ing to kick­start around the coun­try. As well as the grid, the UK’s port facil­i­ties are mak­ing them­selves ready to deal with the mas­sive tur­bines that are set to be sit­ed in the waters off the coast.

Much of this work is focused on the east coast – Hull is hop­ing for a £60-mil­lion invest­ment at its Alexan­dra Dock from Siemens, which has plans to build off­shore tur­bines there, although the com­pa­ny has yet to con­firm its final deci­sion.

In Belfast, Denmark’s Dong Ener­gy has plans to build an off­shore wind con­struc­tion facil­i­ty in Belfast Har­bour to help it devel­op projects in the Irish Sea.

On and off­shore, there are also a num­ber of major cabling projects under way. The West­ern HVDC Link will run between cen­tral Scot­land and North Wales via an under­sea cable run­ning along the north-west coast. It will pro­vide an addi­tion­al 2,000 megawatts (MW) of capac­i­ty on the trans­mis­sion sys­tem and will oper­a­tional by late-2015.

This is part of works, totalling more than £7 bil­lion of invest­ment ear­marked for Scotland’s high volt­age net­work, will be spent on replac­ing age­ing infra­struc­ture and con­nect­ing to renew­able gen­er­a­tors, includ­ing new sub-sea links from Scotland’s islands to the main­land.

Con­nec­tions between the UK and Bel­gium, France, Den­mark and Ice­land are under con­sid­er­a­tion

Fur­ther south, the East Anglia Off­shore Wind­farm project is a joint ven­ture between Scot­tish Pow­er Renew­ables and Vat­ten­fall. It has a con­tract with Nation­al Grid to con­nect 7,200MW of wind gen­er­a­tion off the coast of East Anglia to the exist­ing nation­al trans­mis­sion net­work. This would include three poten­tial con­nec­tion points at Nor­wich, Low­est­oft and Bram­ford.

In Cum­bria and Lan­cashire, Nation­al Grid will con­nect a num­ber of new ener­gy projects to the nation­al elec­tric­i­ty net­work. As well as a num­ber of off­shore wind farm projects in the Irish Sea, these include Moor­side, the pro­posed new 3.2‑gigawatt (GW) nuclear pow­er sta­tion near Sel­l­afield. There is no trans­mis­sion sys­tem serv­ing west Cum­bria, so Nation­al Grid is cur­rent­ly iden­ti­fy­ing the best way to con­nect new ener­gy gen­er­a­tion sources with cus­tomers.

Moves are also under way to con­nect to oth­er coun­tries’ grids. The Ener­gy Bridge project will cap­ture wind pow­er gen­er­at­ed onshore and off­shore in Ire­land, and con­nect to the UK main­land via cables laid under the Irish Sea. In June, Stat­nett and Nation­al Grid signed an agree­ment to devel­op an elec­tric­i­ty inter­con­nec­tor between Nor­way and the UK, the world’s longest, with a plan to com­plete it by 2020.

Con­nec­tions between the UK and Bel­gium, France, Den­mark and Ice­land are also under con­sid­er­a­tion.

The main rea­sons for such a dra­mat­ic upheaval are the country’s switch to a low car­bon econ­o­my, renew­able ener­gy gen­er­a­tion and car­bon emis­sion reduc­tion tar­gets, and the need to improve secu­ri­ty of sup­ply.

Why does it need doing? The grid is in need of an over­haul as much of it was installed in the 1950s and 1960s, and now needs replac­ing and upgrad­ing. New gen­er­a­tion capac­i­ty is need­ed and much of that capac­i­ty will be renew­able ener­gy gen­er­a­tion; about 60 per cent of all new grid con­nec­tions are to renew­able projects. This requires con­nect­ing to gen­er­a­tors that are often locat­ed in remote places, such as off the far coast of Scot­land.  And ener­gy sup­ply will become decen­tralised, mean­ing small-scale gen­er­a­tors will need to be able to sell ener­gy back to the grid.

In 2010, the gas and elec­tric­i­ty reg­u­la­tor Ofgem esti­mat­ed this would cost about £200 bil­lion over the next decade, £32 bil­lion of which needs to be invest­ed in pipes and wires. That’s a dou­bling of the rate of invest­ment com­pared to the pre­vi­ous 20 years.

To fund these infra­struc­ture changes, Ofgem has devel­oped RIIO (Rev­enue = Incen­tives + Inno­va­tion + Out­puts), a new per­for­mance-based mod­el for set­ting the net­work com­pa­nies’ price con­trols, which will run over an eight-year peri­od. “Britain faces an unprece­dent­ed need to invest to replace age­ing infra­struc­ture, meet envi­ron­men­tal tar­gets and deliv­er secure sup­plies, “ says Ian Mar­lee, senior part­ner, trans­mis­sion, at Ofgem. “Ofgem’s RIIO price con­trols ensure this work is car­ried out in a way that secures net­work invest­ment at the low­est cost for con­sumers by incen­tivis­ing effi­cien­cy and penal­is­ing poor per­for­mance.”

All these infra­struc­ture changes should negate one of the crit­i­cisms lev­elled unfair­ly against wind and marine ener­gy — that its inter­mit­tent nature means it can­not reli­ably fill the ener­gy gen­er­a­tion gap left by old fos­sil-fuel-hun­gry pow­er sta­tions.

“The new ener­gy infra­struc­ture will mean it’s not a prob­lem if the wind sub­sides. With an expand­ed net­work, we can trans­fer ener­gy from one part of the coun­try to the oth­er and import it from Europe,” says Zoltan Zavody, RenewableUK’s grid pol­i­cy man­ag­er. “Also, wind tends to sub­side grad­u­al­ly, which means there is time to bring reserve pow­er sta­tions up to full speed to keep pace with demand. It’s not a sud­den shut off.”

How­ev­er, the nec­es­sary invest­ment will only hap­pen if the gov­ern­ment makes an ongo­ing com­mit­ment to renew­ables. “The grid com­pa­nies and Ofgem are invest­ing in the net­work, but if there were to be any sug­ges­tion that renew­able ener­gy might not be part of future gen­er­a­tion plans, the grid com­pa­nies would hold back invest­ment in nec­es­sary grid capac­i­ty,” Mr Zavody warns. “Ongo­ing com­mit­ment will give the indus­try and Ofgem the con­fi­dence to invest in the grid capac­i­ty required by renew­ables.”

The advent of large-scale renewable energy capacity in the UK has come just as the country’s transmission and distribution network needs a complete overhaul. It is also providing the opportunity to revitalise other parts of the country’s infrastructure.