Renewables cannot guarantee security of supply

Scientific Alliance

For most of us, it’s back to work, with summer receding fast. With autumn and winter just round the corner, our thoughts will turn from keeping cool to keeping warm. Energy prices and security will be priorities once again.

The UK is one of a number of countries apparently set firmly on a path to rely increasingly on renewable energy sources. In practice, this means the focus is firmly on the electricity generating sector, where such a transition can in principle be made with least difficulty. Transport is rather more problematic, although the powers that be retain a touching faith in consumers beginning to buy electric cars in significant numbers. The other major sector – heating – is presently dominated by gas and looks set to continue so for many years to come. In the longer run, electricity again seems to be the energy of choice for this application.

The generating sector thus faces a two-stage problem. In the medium term, the current demand (maybe reduced to some extent by energy efficiency measures) has to be met securely while emissions are considerably reduced (for this is the aim of the entire exercise). If this can be done successfully, then the longer-term challenge is to increase generating capacity very significantly to power road transport and heat domestic and commercial property.

Meeting this bigger challenge would be infeasible if the carbon dioxide emissions associated with the present system cannot be successfully reduced without compromising security of supply, so the stakes are high. Before significant wind and solar energy generating capacity had been installed, the grid was balanced relatively easily by ensuring enough power stations were ready to increase or decrease their contribution at the right time. Since conventional and nuclear sources are dependable – despatchable, in industry jargon – problems would tend to arise only in exceptional circumstances, when demand was very high and a number of breakdowns had occurred.

Most renewable energy is not despatchable, however. Solar farms produce quite predictably, but only during daylight hours and with an output that varies during the day. The output of wind farms is forecastable to a degree, but varies in a wide range over both short and long timescales. So, whatever we hear reported about the contribution of renewables on a given day or over a whole year, this is meaningless when it comes to meeting the essential aim of supplying electricity across the whole country 24 hours a day, seven days a week, 52 weeks a year.

Somewhat surprisingly, National Grid’s new executive director, Nicola Shaw, does not seem to regard this as a problem. According to a BBC report, smart energy revolution ‘could help to avoid UK blackouts’. Ms Shaw, despite her undoubted experience in management (her previous role was as chief executive of HS1) is not an engineer (she has a BA in Modern History and Economics and a Masters in Transport) and will have to rely on advice from experts on such matters, so the optimism apparently runs deep in the organisation.

To be fair, demand management is not seen as the complete answer: “Ms Shaw agreed that more investment in gas-fired power was needed, but argued that between 30% and 50% of fluctuations on the electricity grid could be smoothed by households and businesses adjusting their demand at peak times.” Nevertheless, it has a major role in NG thinking, and yet the efficacy of automatic switching off of domestic appliances is still something of an unknown factor.

In the meantime, we know that peak demand will always come in the early evening period during winter. Even if fridges, washing machines and water heaters are switched off, many people will put the kettle on and cook their evening meal. There is no output from solar panels, and when high pressure areas bring cold, calm conditions, wind output is also minimal. This could result in extended power cuts most winters unless sufficient conventional capacity was available on standby.

Others have also concluded that there may be a degree of complacency to the NG view. For example, the GMB union (which represents power workers), pulls no punches: DSR is ‘fanciful nonsense’ says union. It calls the National Grid ‘naively complacent’ for placing its faith in demand side management. It also slams the use of consumers’ money to compensate companies for interruption of their supply a ‘bonkers policy that only a natural monopoly would dare to implement.’

A more measured but equally damning opinion comes from a new report published by the Scientific Alliance: An examination of National Grid’s Future Energy Scenarios. This study was written by two highly experienced industry professionals – Capell Aris and Colin Gibson – and concludes that current plans will almost certainly lead to severe blackouts. The established supply security criterion, pre-privatization, was for there to be a grid supply failure in no more than four years in a hundred. To meet this standard up to 2025, between six and 16 new gas-fired power stations would have to be built.

Despite this, National Grid and the government seem to be satisfied that there will be no serious problems in the short to medium term. Maybe they have been encouraged by recent winters where, despite warnings of historically low margins of generating capacity, only localised, weather-related blackouts have occurred. But we have enjoyed a series of mild winters and there is no guarantee that we will be so lucky in coming years. Even a single stationary high pressure system could bring a very cold few days and lead to supply failures in an otherwise warm season.

The energy security situation could quickly become the country’s number one priority in such circumstances and cast real doubt on the wisdom of current strategy for the sector. Crisis focusses minds wonderfully, but how much better if the reality of the situation was grasped before the lights go out.


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