Abstract :
Since 1990 the quality of the electricity supply has been managed by NGC, under a portfolio of contracts for ancillary services. The structure and strategy behind these contracts is to facilitate reliable and economic system operation to meet NGC´s licence obligations. NGC have argued that it is becoming more and more difficult to meet these obligations since the introduction of CCGT plant. The response capability of connected generating plant becomes particularly critical under lightly loaded system conditions. This is primarily due to the large percentage of plant that is unable or not providing a response under the current contractual arrangements. In an attempt to address the issue, changes have been proposed to the Grid Code that define a minimum level of frequency response capability NGC have also vigorously pursued CCGT plant to comply with their interpretation of connection conditions that apply to system frequency. The concerns have now been escalated to Government level. The President of the Board of Trade has issued, under the terms of the review of Energy Sources for Power Stations, a remit to consider the technical factors related to provision of system stability, frequency control, flexibility of response to demand or supply variations and ancillary security services provided by the use of gas in generation. The paper provides an indication of the generic capabilities of modern CCGT plant in meeting current grid code conditions and providing economic frequency response services
