Intelligent grids renewable energy and smart appliances: keeping the lights on

On 4 November 2006, a major European blackout left more than 15 million customers with no electricity for several hours. The initial cause of the blackout was a planned disconnection of an overhead power line across a river in north-west Germany to allow a ship to pass, which resulted in minor changes in load flows. However, reconnecting the circuit line proved problematic: N-1 criterion (the ability of the transmission system to lose a linkage without causing an overload failure elsewhere) could not be met, leading to a huge pan-European blackout.

As Transmission System Operators (TSOs) struggled to reintegrate the system, insufficient network communications exacerbated the original problem. While the TSOs were bringing the frequency back to 50Hz, a lot of small-scale generation, distributed systems such as wind farms connected automatically and in an uncontrolled manner.

Within half an hour, the situation changed rapidly with unexpected load flows threatening the N-1 safety limit. An uncoordinated attempt to re-route the load flow tripped a 380kV interconnector and an electrical blackout cascaded across Europe extending from Poland in the north-east, to the Benelux countries and France in the west, through to Portugal, Spain and Morocco in the south-west, and across to Greece and the Balkans in the south-east.

Keep the world's lights on

In light of these Pan-European-scale blackouts, political decisions taken to combat climate change are now beginning to shape the landscape of electricity generation and supply.

In many countries interruptions to the electricity supply is commonplace as demand outstrips supply. China, Brazil and Italy have all had significant power failures in the past decade but these, according to an academic paper published in January 2014, are just "dress rehearsals for the future" in which the lights will go out with increasing frequency and severity.

Hugh Byrd of Lincoln University, UK, and Steve Matthewman of Auckland University argue that we should abandon the idea of uninterrupted electricity supply as peak oil, political instability, infrastructural neglect, global warming and the shift to renewable energy resources converge.

However, this gloomy view is not supported by the industry, which believes that the application of innovation, investment and new technology can be harnessed to ensure continuity of supply with an increasing component of low-carbon electricity. However, while security may be assured, the cost of energy appears to be set on an inexorable upward trajectory.

Our current networks are complex, fragile systems made up of a mix of large-scale generators, transmission system operators, distribution system operators, smaller-scale generators and consumers. They are subject to regulatory control and political input, and as a result lots of changes are in the pipeline.

The imperative to 'decarbonise' electricity is leading to a switch away from large fossil fuel plants and towards renewable and distributed generation. This is driving large-scale changes in the transmission infrastructure to accommodate the new geographically diverse sources of power. New technology is enabling the development of a more interactive 'smart grid' where networks will be able to communicate with appliances and consumers, leading to more efficient use of energy.

At a national level, the political aim is to develop secure, affordable sources of low-carbon generation. Unfortunately this energy 'trilemma' has a resemblance to the 'project management triangle', which is represented in two forms: fast, good and cheap versus cost, scope and timescale. Currently, getting all three together is not an option.

New European network codes

Within the EU there are 28 TSOs, over 2,000 distribution system operators and millions of consumers. Ensuring the system is fit for the 21st century means that changes to network management are required, and new European regulations are in the pipeline.

The Third Energy Package will progressively introduce new European Network Codes intended to make the EU energy market, already physically linked by interconnectors, operate better across the whole of Europe.

Mike Kay, networks strategy and technical support director at Electricity North West explains: "Nine priority network codes are being progressively introduced from end 2014 over a couple of years."

Some of the codes concern trading and operation of the market, but Kay points out: "At the other end of the spectrum, the new law catches electricity customers in it and makes all of us who have solar PV on our roofs significant users and places new obligations on us in relation to how our equipment must perform."

The draft codes have been prepared by the TSOs who want to ensure the integrity of the EU grid is not undermined by growth of small-scale renewables. Kay says: "Germany now has over 20GW of solar PV and there are some issues about the upper frequency limit of that generation. Potentially it could all trip off at the same time and because there is so much of it, that could give the German grid quite a headache."

There are similar concerns in the UK as increasing amounts of wind and solar generation change the way the grid behaves. The trend to replace large-scale fossil fuel generation with renewable energy sources actually makes systems more fragile. The large generators found in thermal power stations are physically enormous rotating masses with a huge inherent dampening effect. By contrast, a system made up of lots of smaller wind turbines without the huge damping mass attached is inherently more volatile.

New demand connection codes are another change. These are likely to require smart appliances to provide information to the network companies. Appliances such as smart fridges, white goods and electric vehicle chargers will be asked to work to patterns that minimise the overall stress on the distribution and transmission networks.

The exchange of information between customers and electricity companies is likely to be contentious. Headlines such as 'Spy in the fridge' and 'The CIA wants to spy on you through your TV' have raised awareness of the potential for smart appliances to communicate with outside agencies.

Kay says: "There is a lot of debate about the demand connection code for appliances – clearly we want a world where customers are in total control of what their appliances do, but there could be opportunities for effective co-operation between customers and networks."

He continues: "There are also legitimate concerns about data security. Work is underway to make smart-metering data secure – network operators might get smart-metering data aggregated at street level so that individual customer's data is not distinguisable."

"Demand is no longer as predictable as it used to be when it followed a predictable daily occurance. Now there is so much generation down to the domestic scale it makes it much more difficult to see how demand will present itself over a day or week or year."

Security of supply

National Grid, the UK 'system operator' for the high-voltage electricity transmission network, announced new system-balancing tools in 2013 to improve security of supply as the decline in available power leads to tighter margins, increasing the challenge of matching generation with demand.

Businesses will be encouraged to cut their'power use between 4pm and 8pm on weekday evenings during the winter months in return for cash discounts. The level of discount will be determined by a tender to be run by National Grid with a view to delivering the scheme from winter 2014-15.

"Britain has one of the most reliable power systems in the world, but with margins tightening there can be no room for industry complacency on security of supply," Ofgem's chief executive Andrew Wright said in a statement. "Therefore we have approved these new tools to act as an extra insurance policy that is available for National Grid to protect consumers' power supplies."

The Demand Side Balancing Reserve (DSBR) mechanism will also be used to reward owners of small embedded generation during peak times. National Grid already runs similar demand-management schemes, paying big energy users such as hotels, hospitals and commercial buildings to temporarily reduce their energy demand during peak times.

National Grid's UK peak weather electricity demand forecast for winter 2013/14 was 54.8GW. This figure has been decreasing since 2005, attributable to energy-saving measures, a move away from heavy industry to less energy-intensive industrial activity, increasing volumes of small embedded generation and increased customer demand management.

European supergrid

The EU is working towards a single European electricity market with diverse sources of supply and integrating offshore wind generation. Network operators face the issue of balancing the intermittent output from growing fleets of wind farms with patterns of peak industrial and consumer demand.

The development of high-voltage direct current (HVDC) technology is making much longer interconnectors feasible. This technology is being deployed as wind farms are developed further from the shore, while discussions are underway at a European level about the benefits of developing a North Sea grid for offshore wind.

Britain has 4GW of interconnector capacity: 2GW to France (IFA), 1GW to the Netherlands (BritNed), 500MW to Northern Ireland (Moyle) and 500MW to the Republic of Ireland (East West). Interconnector flows are largely driven by price, so the market dictates the direction of flow.

Looking forward, the 1GW Nemo Link connecting the UK and Belgium is planned for 2018. By 2020 additional links with Ireland, a 750km 1.4GW interconnector linking the east of England with Norway and a second interconnector with France could be in place.

National Grid is investigating other interconnector projects including potential links to Denmark and Iceland. The supergrid would mean that geothermal energy from Iceland, hydro power from Norway, and wind energy from the UK and Ireland could be harnessed in mainland Europe.

Bridging the capacity gap

The European Union's Large Combustion Plant Directive (LCPD) requires plants to reduce SOx, NOx and dust emissions. The 2001 LCPD update set out the options for existing plants to either retrofit flue gas treatment equipment to meet new emission limits, close by the end of 2007 or restrict themselves to 20,000 hours of operation from 2008 to the end of 2015.

In the UK around 10GW of coal and oil plants have opted-out of the LCPD and are scheduled to close by the end of 2015. The UK fleet of aging nuclear reactors built in the 1970s and 1980s are coming offline over the next decade. The fossil fuel and nuclear capacity going out of service represent a lot of a generation that needs to be replaced, much of it in the short term. Where will this come from?

There are a number of technically feasible ways of generating low-carbon energy. However, none are currently commercially viable and developing them on an industrial scale requires political and regulatory support in order to attract investment.

A range of mechanisms are used including Feed-in Tariffs (FiTs), Renewable Obligations and, most recently, the UK's new Electricity Market Reform 'Contract for Difference' (CfD) mechanism.

The UK government is committed to new nuclear power and has signed contracts with EDF to support new reactors at Hinckley Point in Somerset. The deal is currently undergoing critical scrutiny by the EU Commissioner for Competition with a detailed review of the deal against State Aid criteria expected to be completed by the summer. The utility is delaying its investment decision until then. Two other potential consortia are also closely watching events. New UK nuclear power is unlikely to be generating to the grid before 2020.

Renewable energy generation

Subsidies and support have led to the rapid growth of renewable energy generation. The UK has excellent wind, tidal and wave resources, but developing the technologies to turn these into electricity requires political will and financial investment.

Figures from the Global Wind Energy Council (GWEC) show global wind power capacity increased to more than 318GW in 2013, an increase of 35GW over the previous year. Europe's installed wind capacity is over 117GW.

Winds blow stronger and more consistently out at sea and the last two decades has seen development of offshore wind farms (OWFs). North-west Europe is the epicentre for this new industry, with the UK the leading generator with over 3.6GW capacity followed by Denmark, Germany and Belgium, but lots of work is needed to bring down the unit cost of installing and operating in the harsh offshore environment.

Another 21st century challenge for the power industry is to harness the natural power of the sea on a sufficient scale to provide a stream of predictable and affordable low-carbon electricity. Marine energy is a vast resource of great potential, but the technology for converting it into a usable format is in its infancy and much investment and development work is needed to bring it to market.

The European Ocean Energy Roadmap published by the European Ocean Energy Association set out generation targets of 1'per cent of EU electricity generation (3.6GW of installed capacity) by 2020, and 15 per cent (c.188GW) by 2050.

Excellent wave and tidal resources mean that the UK is well placed to be a world leader in marine energy. Substantial development work lies ahead and investment in the technology and the transmission network will be required, however, before tidal and wave farms can be relied on to generate to the national grid.

The nascent industry has now reached the stage where a number of full-size prototypes have been installed on sea berths where they have successfully generated to the grid. The next stage is to install the devices in arrays. Various tidal and wave devices are competing for backers and looking for investment from utilities and power companies.

Carbon capture and storage

The International Energy Association says that carbon capture and storage is an essential part of any lowest-cost mitigation scenario limiting long-term global average temperature increases to significantly less than 4°C. Its analysis finds that 3,400 projects will be needed by 2050, of which around 100 projects need to be operational by 2020. The technology to capture and store CO2 from fossil fuel plants exists and yet investment in developing CCS has been at a virtual standstill since 2008.

The European Commission planned to use income from Europe's Emissions Trading Scheme (ETS), which placed a price on carbon emissions to finance development of CCS demonstrators. However, the financial crisis has led to drop in energy demand, a collapse of price of carbon and generally diverted attention away from climate change towards economic recovery, effectively mothballing plans for CCS.

The UK government has recently awarded funding for front-end engineering and design (FEED) studies on two demonstrator projects: the Peterhead CCS Project and the White Rose CCS Project. However, commercial scale CCS remains a long way down the line.

The need for innovation and development work is a recurring theme across all the technology strands needed to meet climate change targets and keep the lights on.

DECC's TINA project – Technology Innovation Needs Assessment – was launched in August 2010 to create a robust knowledge base to guide government investment decisions. The project highlights the innovation needs of the diverse technologies – from nuclear R&D, buildings retrofit, hydrogen for transport to offshore wind – likely to be most important in delivering energy and climate change targets.

Funding streams are in place for the different Technology Readiness Levels (TRLs): research (TRL 1-2), applied research and development (TRL 3-5), demonstration (TRL 6-7) and pre-commercial deployment (TRL 8-9).

Moving to an intelligent grid system

An efficient, low-carbon electricity supply needs intelligent transmission and distribution networks. A 2012 Ernst &Young Report for SmartGrid GB estimates the cost of deploying a UK smart grid by 2050 as £27bn. It concludes that smart grid solutions will be cheaper in the long run than conventional network upgrades and that we stand to gain much and risk comparatively little from their timely deployment.

In February 2014 EPRI (the Electric Power Research Institute) launched a study on the transformation of the electric power grid brought about by the rapid rise of Distributed Energy Resources (DER) such as rooftop solar panels and high-tech microgrids. The study supports EPRI research and lessons learned from the circumstances surrounding Germany's extensive deployment of distributed solar PV and wind about the technical and economic value of planning for integration of DER.

"The grid is expected to change in different, perhaps fundamental ways, requiring careful assessment of the costs and opportunities of different technological and policy pathways to fully integrate DER into the electric power system," Dr Michael Howard, president and CEO of EPRI says.

"If we are going to realise the full value of these resources, while at the same time continue to provide affordable and reliable electricity, we need to integrate them into every aspect of grid planning, operations and policy."

Smart Grids actively integrate information into the power system in order to make more efficient use of resources. The essence of the smart grid is information and control. The architecture of the existing high-voltage transmission grid includes sensors and sophisticated control systems, but incorporating communications throughout the distribution system and into the home of every consumer is going to take time and investment.

Developments of a range of energy storage systems, including batteries, will offer a spectrum of opportunities to make smarter use of future electricity. Electricity is an essential part of the critical infrastructure we all take for granted. However, as the industry endeavours to implement a tranche of far-reaching infrastructure changes, the spectre of blackouts still lurks in the background.