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Monday 2nd April 2012
Resilient Electricity
Guest Articles, Energy Contributor: Walt Patterson

Three decades ago, in 1982, the American energy visionary Amory Lovins and his wife Hunter published Brittle Power, a study commissioned by the civil defense arm of the Pentagon. It was an alarming analysis of the vulnerability of US systems, in particular US energy systems, to disruption, by mishap or malice. But it also indicated many ways to reduce that vulnerability. Ever since then the US military has played a leading role in transforming traditional energy systems, and especially electricity systems, to make them more robust and resilient. Curiously enough, however, the civilian side of US electricity has lagged well behind. So have electricity systems elsewhere. As the threats continue to mount, so do the opportunities. Three decades later, traditional electricity is long overdue for an upgrade.

Traditional electricity is based on design criteria now more than a century old, out of date and obsolete. It arose because of the economies of scale of steam power and water power, the only prime movers then available. Throughout the most of the twentieth century a better power station was always thought to be a bigger power station, farther away. The common technical model, replicated all over the world, is based on large, remotely-sited, central-station generators, most of which operate either intermittently or at only partial load most of the time. If a single one of such huge units fails, the shock could bring down the whole system. Accordingly the system has to have at least one spare unit of the maximum size, running but not generating, to provide emergency backup, so-called 'spinning reserve'.

The central-station generators that use fuel waste two-thirds of the fuel energy before it even leaves the power plant. The arrangement necessitates long lines of network, in which line losses cost another significant fraction of the energy flowing. The configuration is inherently vulnerable to disruption over a wide area and almost instantaneously. Despite what politicians would have you believe, electricity is not a commodity. It is a process, happening in technology. If the process is interrupted anywhere on the system it may be disrupted everywhere, within seconds. For example, on 14 August 2003, a tree fell in Ohio, bringing down a transmission line. The electricity diverted to a neighbouring line, overloading it. Protective devices broke that circuit too. In a matter of moments a cascading collapse left some 50 million people in the northeastern US and Canada without electricity. Nearly two weeks passed before supply was back to normal. That was spectacular, but far from unique. The blackouts we hear about, in the rich parts of the world, are all too common; but they are far outnumbered by those we do not hear about.

In recent years the constraints on traditional electricity have tightened yet further. In many major cities the underground cables are now fifty, sixty, seventy or more years old, overloaded and deteriorating, yet almost impossible to replace. Permission for wayleaves for new overhead transmission lines is now politically explosive, nearly unobtainable essentially everywhere. Traditional coal-fired and nuclear generating plants anywhere except in centrally-planned countries are both financially and environmentally intensely controversial, and growing steadily more so. Keeping the lights on is getting progressively more difficult.

If we were starting now to electrify society, with what we now know about technology, finance, politics and environment, the resulting electricity systems would look unrecognisably different. Better generators can now be smaller, cleaner, more efficient units closer to users, and indeed even on the same premises. Gas-fired micro cogeneration using gas engines is already long since well-established, providing electricity, heating and sometimes also cooling, from the same amount of fuel, by a unit in the cellar of an office building, hotel, hospital or shopping mall. Such installations do not even require on-site maintenance. Heavily instrumented, they send information about their performance to a control centre that may even be in another town. Any sign of drift alerts a field technician, who will probably rectify the problem before the users of the building even notice it. The units may be purchased or leased, or the customer may pay a service contract or simply buy the electricity, heat and cooling provided.

The concept of on-site and local provision of electricity, heat and cooling has enormous potential. Local systems can now also include wind turbines, photovoltaic arrays, solar thermal arrays, geothermal wells, heat pumps, micro turbines and fuel cells, either already or soon to be similarly economic, clean and convenient. Smaller units pose much less of a threat to the system in case of failures or faults. Moreover, if you are generating your own electricity you are much less likely to waste it. An integrated local system will foster high-performance user-technology and user-infrastructure, by directing investment into the optimal balance of system assets, making sure the user-technology, especially the building, is high quality before even thinking of generation. Sensing and control technology can allow generation and loads both to interact in real time, making such a system self-stabilising.

Local systems need not be completely isolated. Some interconnection through longer lines will still be valuable, for backup and to feed in electricity from more remote installations such as offshore wind. But these longer lines will now be of secondary importance. The main source of faults on a traditional electricity system is the network. Reducing its size, and eliminating many of the long lines, will reduce dramatically the likelihood of large-scale system breakdown. At the same time, converting some of the long lines to high-voltage direct current or HVDC can double or even triple the carrying capacity of the line, with the same conductors and towers. DC operation for some circuits, and back-to-back AC-DC-AC linkages with power electronics, will block the troublesome transient disturbances that can travel thousands of kilometers in a flash on AC lines but are stopped completely by DC.

Decentralising and optimising electricity systems to make them more resilient also has yet more profound implications. We hear a lot about what people call energy problems, about global 'energy security' and climate. But these problems are not about 'energy'. They are quite specifically about fuel. What causes our problems of supply security and disturbance of the climate is the way we use and depend on fuel. The rational response would be to reduce our dependence on fuel. We can do so in two ways, parallel and complementary. One is to stop wasting it, by investing to upgrade user-technology, especially buildings - the most important energy technology of all. The other is to recognise that we use two kinds of electricity. One is based on fuel – coal, oil, natural gas or uranium. The other does not use fuel. Instead you invest to set up a physical asset – a hydroelectric generator, a wind turbine, a photovoltaic array or solar thermal array, a geothermal well, a marine installation – to harvest natural ambient energy flows and turn them into useful electricity.

Most people call this electricity 'renewable'. A better term is 'infrastructure electricity'. As with upgrading user-technology, infrastructure electricity entails an initial investment, after which the infrastructure delivers the service, with minimal subsequent running cost. Such an arrangement, much less dependent on fuel, is also much less vulnerable to disruption – more robust and resilient. The US military is demonstrably following this precept. Delivering fuel to a war zone costs not only money but lives. US military planners have long since endeavoured to minimise what would otherwise be daunting and dangerous dependence on fuel, by making their base buildings and other facilities as high-performance as possible, and by installing local infrastructure electricity generation. The example is there. Sensible energy policy, for civilians as well as the military, ought to function accordingly. A sustainable energy future starts with robust, resilient local systems and infrastructure electricity.

© Walt Patterson 2012

 

Trained as a nuclear physicist, Walt Patterson has spent his life teaching, writing and campaigning. He has published thirteen books and hundreds of papers articles and reviews on nuclear power, coal technology, renewable energy, energy systems, energy policy and electricity. His works include Transforming Electricity and, most recently Keeping The Lights On: Towards Sustainable Electricity. He has been a fellow of what is now the Energy, Environment and Development Programme at Chatham House in London since 1991 and is a visiting fellow of the Science Policy Research Unit, University of Sussex. He is also on the editorial board of European Energy Review.

Brun | Profession | 05.10.2013 | 16:26
It is typically more exepvsine for you to designate "green" power. It is a method to subsidize the building of more wind power, but in reality wind power is not any more "green" than nuclear power. The intermittent nature of wind power makes it necessary to have some sort of "backup" power, usually gas, wind uses much more concrete and steel than nuclear power for the same amount of megawatts. Wind power actually has a larger "footprint" than nuclear power, it takes more land to produce the same amount of power. We need to explore all the methods of producing power while minimizing the effect on the environment, this is one way of donating to that cause and voting with your $$.
Bhowz | Profession | 06.06.2012 | 10:34
This is a very complex issue. At the siplsemt level, wind energy is free because the fuel (wind) is free. In the case of coal, the fuel must be mined, processed, and in many cases, transported great distanced to the point where it is converted to electricity. And with coal, there is a major cost penalty of cleaning the effluent from the coal plant sulfur, mercury, nitrogen oxides, CO and CO2, have to be removed. Also, the efficiency of the conversion of latent energy in coal to electricity is less than the conversion of wind energy to electricity. Wind has some inherent economic penalties. The most significant is that the source of energy (wind) is intermittent, and since there is no way to store electric energy, it is necessary that there be an alternative source to meet demand when the wind isn't blowing. Those alternative sources are usually fossil fuel sources, most often natural gas. And that also means that there necessarily must be greater spare capacity on the system when there is significant reliance on wind. Also, the capital cost of a wind plant is greater per kilowatt of capacity than the capital cost of a coal-fired power plant. And there are some maintenance costs with wind that don't exist with coal-fired plants the fact that individual units are smaller in size means that maintenance tends to be more of a full-time activity with wind plants, whereas it is a periodic activity with coal-fired plants. The fact that workers have to climb several hundred feet into the air to get to those units adds to the cost. And finally, there are some wear-out' phenomena with wind that don't exist with coal and for which technical solutions are slow in coming many wind machines involve gear boxes where there are some significant torque problems, and there are known issues with intermittent torque fatigue failures of wind turbine blades.Finally, there is the issue of getting the energy to the consumer. With wind, electricity must be produced where the wind is blowing, but that's rarely where the load is. So power must be transported, often hundreds of miles. And the reality is that most of the most attractive areas for wind production are nowhere near existing power transmission facilities. Coal also tends to be found at great distances from population (load) centers. But coal has an economy of scale advantage coal plants are typically much larger in capacity than wind plants, so the cost of building, maintaining, and operating the transportation facilities to move either the coal itself or the electricity produced by that coal will be less than the cost of transporting the electricity produced by a wind plant.Today, from the consumer's perspective, electrical energy produced from wind is early equal in cost to electrical energy produced from coal. But the reason for that (in the US) is that the wind energy receives tax credits that offset some of the inherent costs. The theory in offering these tax credits is that they are encouraging development of technology, and as that technology evolves, some of those inherent costs will be addressed in a way that eventually will make wind competitive with fossil fuels. That theory is true I worked on one of the first commercial wind generation systems (in the late 1970 s), and at that time the cost was astronomical. There have been great advances in technology that have reduced costs significantly, and there are developments on the horizon that will result in even further savings.
A | Profession | 05.04.2012 | 13:39
Fascinating stuff!