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Transmission system operators under fire

All of Europe's transmission system operators are supposedly behind a report on the integration of the large volumes of wind power needed to meet the EU's targets for renewables. The tenor of the report, however, suggests it was written by recalcitrant power engineers with an eye to the wishes of Germany's electricity behemoths rather than the need for cheap, clean and secure electricity supplies

The first of a series of reports by Europe's transmission system operators (TSOs) on integrating wind power into electricity networks contains "various unfounded statements" about the need for balancing power and reserve capacity, "totally disregards" the grid support provided by wind plant during systems disturbances and "overlooks the benefits" to system operation of increasing volumes of wind power, says the European Wind Energy Association (EWEA).

The aim of the European Wind Integration Study, a supposedly joint effort by the TSOs of western Europe, Scandinavia, Britain and Ireland, is to establish a "harmonised set of rules for a reliable integration of wind power." Its focus is on identifying action required of legislators, regulators, grid operators and users to achieve Europe's targets for renewables energy while maintaining security of supply. The preliminary report deals with the period to 2008 and a subsequent study will cover the years to 2015.

On the positive side, any effort by Europe's TSOs to study wind integration is a step in the right direction, concedes EWEA's Christian Kjaer. Indeed, the TSOs give a cautious all-clear on wind and the networks, at least to 2008. Any risk in raising wind capacity from 41 GW in 2005 to 67 GW in 2008 can be reduced by adequate planning together with incremental strengthening and technical improvements to the network, they say.

But that news is buried in the report, which overlooks the benefits of wind power, such as its stable price, cleanliness, the speed at which it can be deployed and its local generation advantages, says Kjaer. Furthermore, it does not reflect the genuine interest of many TSOs in accommodating large volumes of wind power, he adds.

The report's five main recommendations -- a single EU renewable energy market, separate allocation of balancing costs for wind, a demand for grid support from wind plants, and remits for TSOs to have full control of wind power despatch and more freedom to build transmission -- are strongly criticised by Kjaer: "There are no findings to back-up these conclusions. The conclusions are not supported by the accompanying analysis."

According to the TSOs, economic development of wind power would be aided by introducing a single support mechanism across Europe. It would ensure the most efficient sites are developed and an even spread of wind capacity, instead of its concentration today in just a few countries. Kjaer retorts that one level of support would see investment concentrated in windy areas where most money is to be made.

Next, the TSOs say all wind power needs backing up: "The variable contributions from wind power must be balanced almost completely with other back-up generation capacity located elsewhere." Furthermore, "Wind generation should be made responsible for unbalances they create." Kjaer points out that back-up is needed for all power plant. "We do not need dedicated back up to accommodate the use of wind energy," he says. And only overall system imbalances need to be accounted for economically, not individual imbalances from any plant.

Kjaer also takes issue with the TSOs' claim that most wind turbines "do not actively contribute to grid stability," when the requirement for turbines to trip off the grid during network disturbances came from system operators in the first place. Modern wind plant can and do meet the latest TSO grid codes. "The emphasis in the report is on yesterday's wind power technology," says Kjaer.

The TSOs recommend they get complete control of wind generation. "Volatile generation should better be regulated at European and national level in order to ensure the right for TSOs to reduce or switch off wind generation when security and stability of the transmission grid are endangered," they argue. Either that, or the short term auction capacity available for trading power on congested wires must be reduced. When winds are strong "a large proportion of cost-effective power generation is pushed out of the market," states the report. Rules giving wind priority on the wires should be re-examined. They are "legally questionable," say the TSOs; they discriminate against conventional electricity and cross border trade of green power within the EU.

Kjær says the report is "taking a problem in one particular area in Europe and extrapolating it to all areas." He refers to the long running spat between the four German TSOs and the Netherlands' TSO. The Germans, instead of balancing wind with other generation in their own area, offload excess power onto the Netherlands (Windpower Monthly, July 2005).

Lastly, the TSOs say rules for permitting transmission should be streamlined, but they make no reference to improving their own processes. None of the report's recommendations require action by the TSOs. Nor does the report consider what might happen if, or when, the EU Commission's call for full separation of generation and grid operation is acted upon. When that happens, the TSOs interests would no longer be linked to those of their sister companies -- fossil fuel and nuclear generators.

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