7 yrs
News in Brief, BB200703

EWIS preliminary findings made public


In 2006, a consortium of European transmissions operators (TSOs), including UCTE, ETSO, NORDEL, ATSOI and UKTSOA, completed the first so-called pre-phase of a European wide grid study on the integration of wind power. The European Wind Integration Study (EWIS) investigated the need for measures to be taken by legislators, regulators, grid operators and users to agree on a harmonised set of rules for the integration of wind power. The first stage of the study focused on the expected situation at the end 2008. A more extensive investigation – EWIS II, which is to be supported by the European Commission, will consider a larger number of aspects, over a longer time frame (up to 2015).

Such a grid study is needed at European level, since the grid-related aspects of wind power integration on a continental scale have not yet been studied in detail. As described in the EWEA Grid Report 2005, the European power system, including its operation, is not yet optimally designed for handling variable output sources, such as wind power. In daily practice TSOs are learning which situations – especially with respect to power flows as a consequence of cross-border exchange - are likely to occur and how they could be handled. Due to the current developments in the European internal electricity market and the expansion of renewable energy, the need for accelerating the improvement of the interconnecting infrastructure has become more urgent. In this respect, it should be mentioned that in 2006 the wind power industry also launched a study, TradeWind, coordinated by EWEA. The objective of this study is to examine the market and interconnected aspects favouring the large-scale integration of wind power with a time horizon set at 2030. EWEA’s objective is to analyse the kind of grid that will be needed when wind power is delivering almost 25% of Europe’s electricity demand.

In the first EWIS report (preliminary phase of the project launched on 15 January 2007), findings concerning grid impacts are summarized qualitatively in relation to load flow, grid congestion, bottlenecks, system operation, balancing, grid losses, reactive power compensation and economics. The TSOs subsequently formulate a number of recommendations, mostly with respect to policy, legislation and regulation. A major undertone in the formulation of the EWIS findings and recommendations is a concern for grid security and developing operational solutions on the short term (up to 2008). The document also contains a brief description of underlying technical details, methods and assumptions.

The main findings of EWIS 1, namely that the integration of wind power in 2008 can be handled by adequate technical and operational measures, do not come through clearly - anyone consulting the report needs to ‘read between the lines’.

A problem with the formulation of the main findings is a lack of regard for the variety in European-specific grid situations. The choice of language means that perceptions in certain European countries (Northern Germany and the Netherlands), with respect to overloads of lines and grid losses, are extended to cover the whole of Europe. However, there is no evidence to support this (in Spain, Scandinavia and the United Kingdom, for example).

Various unfounded statements, concerning the necessary power balancing power and reserve capacity are also put forward, which are not based on analysis carried out in the study. These contradict the findings of many other studies, including the German dena study (2005) and international system studies, which can be found in the IEA Annex 25.

Also surprising is the fact that the report totally disregards the present capability of most wind turbine technology to provide grid support during system disturbances. Instead, the emphasis is on yesterday’s wind power technology (which met with TSO requirements)!

In fact, the analysis overlooks the many benefits of integrating wind in the system and the positive impact of wind energy on the electricity supply (as seen from system operators view). These benefits include:

- a more secure and economic supply due to the indigenous character of wind power;
- fixed price advantages;
- wind power contribution to system adequacy;
- environmental benefits;
- rapidity of capacity deployment; and
- embedded generation benefits.

EWEA is forwarding its comments and questions about the study directly to the EWIS team. The answers will enable a better understanding of the report and the assumptions and to develop a balanced opinion on the study. At the same time, EWEA together with the TradeWind consortium is working on the development of an effective information exchange with EWIS phase II. This should enable an optimal utilisation of expertise, both on specific wind technology and grid related aspects in both studies.

Information on TradeWind can be found on www.trade-wind.eu