10 Electricity: the challenges ahead


In the last decade the electricity sector has witnessed the beginnings of a revolution. Professor Roger Kemp looks at what lies in store for power systems.


For 100 years, the principles behind Britain’s electricity sector have remained largely unchanged. The steam turbine was demonstrated by Sir Charles Parsons in 1884 and, before the First World War, Charles Merz had established the world’s first ac distribution grid in Newcastle upon Tyne. However, the last decade has seen the beginnings of a revolution: an international trend that will change the way established power systems operate.


In Britain the Climate Change Act 2008 and other regulations have triggered a paradigm shift in the way electricity will be produced. So far, we have seen relatively small changes but phasing-out coal-fired power stations and the widespread adoption of renewable energy will change the electricity power system radically. The first challenge facing the electricity supply industry is outside its control; how the load on the grid evolves as other parts of the energy infrastructure decarbonise. Two of the UK’s largest energy uses are for low-grade heat (principally space heating and hot water) and transport (dominated by cars, vans and HGVs). Both these sectors burn fossil fuels and there is no possibility of meeting the UK’s emission targets without drastic reduction in this use.


Although large users of oil and gas, such as power stations or chemical plants, could consider carbon capture and storage (CCS), applying CCS technologies to an individual domestic gas boiler or a private car is beyond imagination, let alone practicability. The timescale for the planning, design and construction of the national electricity infrastructure is measured in decades; the timescale for a major switch from petrol and diesel to electric or plug-in hybrid vehicles (PHEVs) could be less than 10 years. How should the electricity industry prepare for this possibility?


Electricity and beyond


A similar situation can be found in the heat sector. The 2013 DECC report The Future of Heating: Meeting the challenge shows the dramatic difference between the “peakiness” of the demands for heat and electricity. In the graph (taken from the report) the purple line, peaking at about 60 GW, shows the demand for electricity and the blue line, peaking in December at 300 GW, shows the demand for heat. While the demand for electricity varies by a ratio of about 3:1, the demand for heat varies by a ratio of 60:1. One option for decarbonising heating in homes and small businesses would be to replace gas boilers by heat pumps fed from low-carbon electricity. But, even making heroic assumptions about the performance of heat pumps and the adoption of energy saving measures, it is highly likely that the peak load on the grid will increase. What’s more, this will be mainly at times when solar panels contribute very little to electricity supply.


Meeting this seasonal variability without investing billions in plant that stand idle for much of the summer is challenging and will get more so as other sectors decarbonise. The second major challenge of the sector is an inability to decline or “price off” excess load. In most businesses, once the plant is running at capacity, managers can decline to accept new orders. Also, if they know in advance that demand will be particularly high over a particular period, price can be modulated to encourage people to use products or services at off-peak times. However, the electricity industry does not have this freedom; imagine the uproar if consumers switched on their TVs to watch the Cup Final and were presented with the message “Sorry, all our generators are fully loaded at present, please try later.” There are also limitations on the extent to which the industry can modify prices to manage demand. Economists define a free market as one in which economic agents interact freely and price emerges as the


Comparison of heat and electricity demand variability across a year GW


350 300


Heat Electricity


250 200 150 100 50 0 January Month (for the year 2010) December


outcome to the interaction between supply and demand. But given the high fixed costs and low operating costs of low-carbon electricity generating plant and the long timescales for its delivery, a genuinely free market could result in almost free electricity for many days in summer but expensive prices on cold, windless winter evenings. Although economically rational, pricing- off demand would be politically fraught. The political response to a newspaper headline “Pensioner charged £20 to make cup of tea” would not be a throw-away line about it being a free market and that’s how markets work. Storage could solve the problem of the seasonal imbalance between supply and demand for energy. However, storing electricity is difficult with pumped storage being the only widely used technology. Water is pumped to an upper reservoir when energy is plentiful so it can flow down through turbines at times of shortage.


While this technology provides a short term back up to cover generator failure and reduce sudden peaks, the capacity is not adequate to equalise seasonal imbalances. Many different schemes have been proposed, including super-capacitors and flow batteries, but none approach the capacity needed for effective inter-seasonal storage. This is a “whole system” challenge where the solution could be to move storage from electricity to another sector, such as heating, where energy can be stored more cost- effectively. To meet the challenge of decarbonisation, all sectors of the economy will move from fossil fuels to renewable energy. By its nature, renewable energy is a diffuse resource that is harvested over a large area and concentrated to provide useful power where it is needed. For some applications, the concentration and transport of energy may involve liquid fuels but for most applications, electricity is the vector of choice. The challenge for the industry is to evolve from a network where power flows from central generators to millions of users, into a network with millions of distributed generators and users, over which there is very little central control. The concept of a multi-user electricity system being like a road network, where anyone with a driving licence can travel where and when they decide, is politically attractive. However, unlike a road system, an ac electricity network has specific technical limitations.


For example, generators have to be locked- in to the same frequency and an integrated load management and protection system is required. Voltage, waveform and reactive power must be managed while a mechanism must be in place to provide the sudden demands of loads as they start up, without causing voltage transients that disrupt other users.


For the past year, the IET has been studying these requirements as part of the Future Power Systems Architecture project. We now know what the network has to do; how to implement these requirements will be the next big challenge.


Roger Kemp is a Professorial Fellow at Lancaster University and Member of the IET Energy Policy Panel.


Heat & Electricity (GW) Heat/Electricity (GW)


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24