E
urope’s demand for LNG has increased significantly during the past year. Normally, LNG is imported via conventional shore-based regasification plants. This involves transferring the LNG to terminals for storage in tanks before it is regasified and pressurised with vaporising equipment, prior to it being delivered to the distribution networks. Such terminals, however, require a lengthy construction time, and the current instant demand for LNG in Europe clearly requires quicker solutions. During the past 15 years, alternative solutions have been developed that are faster and which, by extension, are also less expensive. Among these are Wärtsilä’s regasification modules designed for use onboard FSRU vessels, as well as shuttle and regasification vessels (SRVs). The increasing global demand for LNG in order to ensure energy security is in turn increasing the pressure for chartering FSRUs and is supporting investments in new units. To cover the new demand in Europe, several FSRUs have been chartered by different countries. These FSRUs have all been available on the market, either built on speculation and not yet under charter, or available following the end of a charter. At present, the surge in demand has resulted in virtually no more FSRUs being available. Thus, in order to cover Europe’s energy gap, the options are either to convert old LNG carriers to FSRUs or build completely new FSRU vessels. For these vessels, having the regasification (regas) equipment onboard allows high-pressure gas to be delivered to land-based networks, either via a floating buoy and a submerged pipeline system from offshore, or via loading arms on a jetty. Both FSRUs and SRVs provide greater flexibility than conventional land-based regas facilities, and the time from investment decision to start-up is relatively short. By offering a fast-track means for opening energy markets, supply diversity is increased, costs are reduced, and environmental benefits are enhanced. A further advantage of utilising an FSRU, rather than a fixed, land-based regas facility, is that it can be moved to a new offshore location should the business environment change.
Kjell Ove Ulstein and Per Helge Madsen, Wärtsilä Gas Solutions Norway AS, examine the development of water glycol heated regasification systems for use on FSRUs and offshore jetties.
A seawater heated regas system During the period from 2006 until mid-2020, Wärtsilä has developed and delivered 23 regas systems for FSRUs and one for an offshore jetty. The first two systems were steam heated using a water-glycol mix as the intermediate medium, but subsequently 11 deliveries were made using seawater as the heating medium with propane utilised as the intermediate medium.
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