NEW CHALLENGES FOR UK NATURAL GAS

摘要

The United Kingdom's self-sufficiency in natural gas has rapidly declined and for the first time the UK has become a net importer of natural gas. Dependence on imported natural gas is set to increase significantly. Some forecasts show the UK may need to import up to 40% of supplies by 2010 and up to 90% by 2020. Winter gas prices are now a factor of 10 higher than 4 years ago and this is seriously impacting big industrial consumers such as ammonia producers and power generators. At present, the main projected increase in imported gas is from Norway, mainly via the Langeled pipeline which landfalls in north-east England (carrying gas from the giant Ormen-Lange development by 2007/8) and from Europe via the existing Zeebrugge-Bacton Interconnector and the Balgzand-Bacton pipeline (operational by 2007). The latter two lines will link the UK with the European gas grid and may open up potential supply sources from the Former Soviet Union (FSU). Several LNG import terminal projects have been undertaken. The first to be completed is on the Isle of Grain near London, which commenced LNG imports during 2005. Two further LNG import terminals, Dragon and South Hook, are under construction at Milford Haven in Wales but will not be fully operational form some years. A further potential development is the upgrade of the former LNG import terminal at Canvey Island, near London. It is estimated that the LNG from these terminals could supply around 25% of the UK's overall gas demand by 2020.Imported natural gas and LNG will both be of varying quality. A recent report (1) commissioned by the DTI, OFGEM (Office of Gas & Electricity Markets) and the Health & Safety Executive (HSE) highlighted that imported gas or LNG is likely to have a higher Wobbe Index (WI) range than currently acceptable in the UK National Transmission System (NTS). The allowable WI range for the UK, as set out in the Gas Safety Management Regulations (GSMR), is between 47.20 and 51.41 MJ/Sm~3.In addition to gas quality issues from imports, depletion of existing offshore UK gas fields and a drop in the number of new UK gas field developments has led to evaluation of more marginal (lower quality) gas fields that would need-special treatment and processing facilities to meet NTS specifications.