Flexible operation in the UK and Middle East-
Abstract
Technical issues surrounding the selection of new power plant for flexible operation in the UK and Middle East
This presentation will focus specifically on Combined Cycle Gas Turbine (CCGT) plant, since in the 1990s, of the nearly 30 GW of new power plant that was constructed and commissioned in the UK, some 85 per cent used CCGT technology1. Since 2000, the location of new power plant projects has moved to Southern Europe and the Middle East. CCGT technology has remained the preferred technology for new power plant, although sometime used in cogeneration mode particularly in the Middle East. More recently, we have started to see activity in Eastern Europe, which like the Middle East often utilised CCGT plant in cogeneration mode. CCGT plant appears to have remained popular as gas is increasingly geographically more widely available and requires considerably less infrastructure at site than coal fired plant. In addition, the rapid construction time for new CCGT plant, with some manufacturers quoting less than two years, provides additional flexibility for system planners
and reduced interest cost during construction and a faster payback for developers.
In the UK, as a later generation of newer more efficient plant were constructed the early CCGT units moved down the merit order into mid merit operation. In addition, the introduction of the New Electricity Trading Arrangements (NETA) changed the operation of the electricity market, leading to increased use of plant in mid merit operation. These two factors have led to the requirement for the early CCGT plants to change their operating mode from base-load to two-shifting, with the consequential increase in starts and stops as well as
part loaded operation. This change in operation led to the discovery of a series of maintenance issues with the plants, mainly related to the Heat Recovery Steam Generators (HRSG). In many cases, these were exacerbated by this change in operation not having been considered in the initial design of the plant.
Over the last five years, whilst the development of new power plants in the UK has stalled, there has been a steady stream of projects in the Arabian Gulf Region of the Middle East. These projects appear to be driven both by a steady increase in demand and the restructuring of the electricity supply industry in a number of countries. The increase in demand is a result
of population growth, increased affluence and increased tourism. The model for restructuring adopted most widely within the region is for the existing transmission and distribution utility to act as a single buyer with competition amongst developers for the design, financing, ownership and operation of an efficient, low cost Independent Power Plant (IPP).
In this paper the lessons learnt in the 1990s in the development of power plant for the UK will be briefing reviewed. Then this paper looks at how projects in the Gulf Region can be developed to provide flexibility. Finally, the different requirements for the operation of plants in the Gulf are discussed and how the design of a new power station requiring cogeneration can be optimised to meet these operational requirements in a competitive environment.