Illuminating the bar room

Few topics generate as much heat and as little light as the integration of wind energy into power systems. What happens when the wind stops blowing? According to bar room wisdom, wind energy can never assume a major role in providing electricity because it is not a firm source of power. Yet in Denmark, Spain and northern Germany, wind contributes significantly to everyday supplies -- and the lights stay on. There is no mystery about this. Power systems are used to coping with fluctuations in demand far greater than those from a series of wind plant. A severe gust of wind is never going to instantly trip all the turbines along Denmark's west coast, yet a major coal fired plant can go suddenly off-line. An integrated power system is designed to cope with that eventuality.

Bar rooms are seldom full of experts who know such things, but as places of great heat and not much light they tend to be frequented by politicians. Herein lies the real problem of integrating wind. It is politicians, who have no real knowledge of how electricity systems work, who devise the frameworks for their operation. Wind cannot meet instant demand or go instantly off-line -- and technically there is no need for it, or any other plant, to do so. But the emerging commercial frameworks for today's liberalised electricity markets expect just that, with ferocious penalties for "uninstructed deviations." This is what has happened in California, where 2000 MW of new wind is caught in the noose, and what will happen to wind in Britain under the country's new electricity trading arrangements.

Politicians should listen to the growing body of hard-nosed utility experts who have looked dispassionately at the issues and concluded that most electricity systems can operate with wind energy penetration levels approaching 30%, subject to some changes to operating procedures, for very modest extra costs. Such costs should be debited to wind plant -- it is not suggested they qualify for a free ride.

The keys to high levels of wind penetration (and to system security) lie in masses of transmission and lots of geographical diversity, all cleverly integrated. Many interconnections make light work for power system operators and the wider the net is drawn, the smoother the output from substantial amounts of wind plant (page 42-46). Denmark copes with its 17% of wind power by shunting excess electricity along high voltage lines to Germany, Norway and Sweden, and buying it back again if need be -- trade which it made a profit on last year (page 45). As the country proceeds towards its goal of 50% wind by 2030, however, transmission will be a bottleneck unless something is done about it. Indeed, from Denmark to Spain (page 24) to the western United States, new wind development is bumping up against the transmission barrier.

Fortunately for wind, the need for more transmission is at the top of the energy political agenda in the developed world, thanks mainly to the electricity crisis in the western United States. The political focus is where it needs to be. Confusing the message, however, is the current enthusiasm for fragmentation of electricity systems. The aim is laudable -- the promotion of more competition. But the market and decentralisation enthusiasts must not be allowed to stop development of the transmission and distribution essential for system security and lots of renewables. When market frameworks are done right, transmission reinforcement will emerge as a cost-effective solution to assimilating high renewables penetration in many regions, though that will not be the case everywhere. Wind lobbyists need to get to grips with these facts before entering the fug of the bar room to shed some true light.

In the cool of a Danish summer

Business is remarkably adept at responding to the call of the market. Solutions to the absorption of high levels of wind in liberalised markets are already emerging (page 46). Chief among them is aggregation, on paper, of both dispersed supply and demand. These trading packages are coming into being in both England and the eastern US. Furthermore, better wind forecasting will give system operators more scheduling flexibility and on the hardware side, companies like ABB are working on high capacity cables, obviating the need for a lot of extra knitting in the sky. Denmark's path to a low-carbon future is the gradual replacement of its coal plant with wind and largely distributed biomass. Ways of keeping the system stable will have to be found and wind, along with smaller biomass plant, will almost certainly have a role to play. Turning off wind turbines is at the bottom of the long list of solutions, however (page 46-47).

This month's European Wind Energy Conference in Copenhagen is happening in the right place at the right time. In the cool of a Danish summer, there should be plenty of opportunity for less heat and more light. July could also see the adoption, at long last, of the much debated EU directive on renewables (page 24). Its provisions for identification of all the green electricity generated in the EU is an essential first step to Europe-wide trading of priority "must take" supplies. Such trade will make the most of the benefits for wind power of a highly integrated transmission system over a huge geographic area. The participation in the market of all countries linked to that centralised system, particularly Germany at its hub, is a vital prerequisite for the realisation of wind's full potential, onshore as well as offshore. Decentralisation makes no economic or technical sense, neither will it promote reduced greenhouse gas emissions.

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