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In February, the Energy Networks Strategy Group published a paper called ‘Our Electricity Transmission Network: A Vision for 2020’. At 148 pages it sets out in detail the potential generation and demand background which meets the UK targets of 15% of energy demand being provided by renewable sources and a 34% reduction in Green House Gas emissions by 2020. It also takes into consideration what would be required to meet the Scottish and Welsh Governments’ 2020 renewable energy targets i.e. the equivalent of 100% of Scotland's electricity demand should be met from renewables and 7TWh pa of Welsh electricity production by 2020. With customer demand assumed to be static (at ~ 60GW), Global Energy Advisory has long made the point that it is policy which is driving investment, not demand, with end customers picking up the costs.
The purpose of the report was to determine what was required to accommodate (that is connect and transmit) a further 38.5GW of new generation (a little under half of current generation), of which 23GW could be a combination of onshore and offshore wind generation on to the system. The investment is £8.8bn, which is an increase of previous estimates by £4.1bn which is largely due to including the costs of possible provision of new subsea links from Scottish Islands (Western Isles, Orkney Islands and Shetland Islands) to the mainland.
The power market in the UK is currently under reform with the introduction of a new capacity market planned. So if existing and new plant both receive capacity payments (there are none now); and with an additional 38GW of new plant and ~100GW on the system, then, even paying for capacity could be very expensive or literally un-affordable for customers.

Part of the reason there could be so much plant on the system is that the nuclear fleet in the UK has received between 5-7yr life extensions. There is also the assumption that the first new nuclear plant connects to the grid in 2019/20. Coal plant closes due to environmental directives, but 12GW of new conventional CCGT capacity could be built. However, there could be a staggering 26GW of wind capacity in 2020 with 17GW being offshore. It is also possible that interconnections could be supplying the UK at some point; these could amount to another 6.7GW of capacity[1].
The report notes.
“The predominant power flow on the GB transmission system is from North towards the South. In the North of Scotland, generation is assumed to significantly increase with onshore, offshore wind and marine renewables. The level of demand is not anticipated to increase… Accordingly, there is a predominant net export of energy from the region to the Central Belt of Scotland. Additional power flows in the Central Belt of Scotland, within the Scottish Power Transmission network, would place a severe strain on the 275 kV elements of the network and, in particular, the north to south and east to west power corridors. The Upper North network of the England and Wales transmission system also experiences increased power flows which require reinforcements on the system. The increased power transfers across the North to Midlands boundary and/or the increased generation off the East Coast and/or Thames Estuary could result in severe overloading of the northern transmission circuits securing London especially when interconnectors around the South East area are assumed exporting to mainland Europe, hence the need for reinforcing London networks”.
Capacity is about potential to generate which is different from ‘energy generation’ because power-stations do not produce at their name-plate capacity (MW) all of the time. However, having so much generation potential/capacity on the system will mean there will be times when there is not the space to allow all of the power plants to generate at the same time. When this happens they get paid for what is called “being constrained off”. It would be an inefficient power grid that has too much power generation and in the wrong place. So without the £8.8bn of investment then there could be strain on the grid and maybe not all the power will be able to flow all of the time. The problem is that constrained off payments can be very high, which is not in the interests of the end customers who ultimately pick up the costs.
Constrained Off Payments
National Grid, who operates the UK high voltage power transmission system has to abide by rules and regulations. When the power grid is constrained, National Grid has to compensate the stations that would have been generating for the lost sales as if the power plant had been operating. For example when say a coal power station is constrained off the power grid, the National Grid actually pays the system operator a sum less the fuel saved by that generator. The average price per MWh constrained amounted to £215 MWh, with the range being £150MWh to £800MWh. The problem is, that when some renewable generators are constrained off then they are not just paid for the energy profit but also Renewables Obligation Certificate (ROC) foregone, worth approximately £50 per MWh, plus the Climate Change Levy Exemption Certificate (LEC), which is worth approximately £4.85MWh. Therefore constraining off renewable generators can be costly.
Importantly, on the 23rd of May 2011 between 14:40 and 17:10 National Grid was simultaneously transferring English electricity to Scotland and also paying two Scottish wind farms to reduce generation. It was thought because the wind was unpredictable that day that either the generators could not forecast their production for the system properly, at a time when National Grid obviously had difficulty balancing the system. An investigation was made, but the payments were considered not ‘unusual’ but as an indication of an ongoing structural problem in the network. Can we therefore deduce that with so much plant on the system, in places where it’s hard to transmit the power from; that the number and amount of constraint generation will increase? There must be a better way.
Power Source
If there is too much generation available on the grid, then customers with flexible energy use could consume more. Similarly, if the grid is under stress when there is potentially little wind out-put or a problem on the system then customers with flexible energy use could consume less. It will not just be the National Grid who will be looking for consumption flexibility but the energy traders and even the companies that operate the lower voltage networks as they too need to push demand around their systems to keep the local power gird safe. Also it has to be the smaller customers in the local area, at what we call the embedded level, to respond. Therefore if you are a customer who can be flexible in how and when you consume, we thought it fair that you should be compensated for helping to keep the lights on.
Currently National Grid uses STOR[3] to keep the system stable, but this is mainly in the form of back up generation, rather than flexible consumption. However, Mr Ed Davey, the Energy Minister, told the Scottish Lib Dem conference in Inverness on the 3rd of March: “(This is) the first government to seek to make reducing energy demand at least as important as how we increase supply”. Energy efficiency and the demand side response as it is known has been a elusive objective in past decades, but now it will be in timely demand. The problem is that National Grid has never needed such a wide-scale response as they will need in the future and customers don’t know how to go about making them-selves known for balancing services.
Prisim[4] is a commercial framework, structured by Global Energy Advisory, which unlocks the flexible load response at scale. To us it seemed fairer for customers, who ultimately pick up the costs of future network connection and investment, get a chance to earn a market return for helping the grid to keep in balance. Prisim customers also provide balancing services at competitive cost compared to generating units whose prices we have seen vary from £150MWh to £800MWh. National Grid is a company of engineering excellence, but in the future, as the constrained payments are showing, he will need more flexibility from all customers to keep the power system in balance and asking customers to take a bit more power could be very helpful indeed.
If you would like to earn revenue for being flexible with your energy use then for more information contact:
[1] IFA (France-England) 1.9GW, Britned (Netherlands-England) 1.2GW, Moyle (Northern Ireland-Scotland) 0.5GW, East-West (Ireland-Wales) 0.5GW expected 2012, NEMO (Belgium-England) 1GW expected 2019, Norwegian (Norway-England) 1.4GW expected 2018.
[3] Short Term Operational Reserve
[4] Prisim = Purchasing, Risk management , Investment, Sales and Intermittency Management
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