PLUG in for profit and environment An innovative solution to exchange electric power between LNG carriers and terminals

Transcription

1 PLUG in for profit and environment An innovative solution to exchange electric power between LNG carriers and terminals Damien Féger

2 PLUG in for profit and environment An innovative solution to exchange electric power between LNG carriers and terminals Damien Féger, Snecma, Forêt de Vernon, Vernon, France Ian Harper, Wavespec, Fullbridge Mill, Fullbridge, Maldon, Essex, CM9 4 LE, United Kingdom Michel Leduc, Leduc, 1 rue de Folenrue, Vernon, France Fabien Wimmer, Converteam, 3 avenue des trois chênes, Belfort Patrick Louazel, Staubli, Place Robert Stäubli, Faverges, France Andrei Morch, Sintef, 7465 Trondheim, Norway Abstract Anticipating tighter harbour emissions controls and the development of Renewable Energy Sources (RES), PLUG, acronym for Power Generation during Loading and Unloading, is a joint research and development effort supported by the European Commission to develop an innovative, high capacity (up to 25 MW), ship to shore electric power interface for the new generation of DFDE LNGCs. This interface will allow to connect the vessel to the local electric power grid during harbour operations in order to: - Import power from the grid for hotel and cargo pumps loads ( cold ironing ) to avoid local emissions penalties. - Run the ship s diesel generating plant at full capacity and sell power to the grid, while acting as a low emission shadow power backup for RES projects. The project objective is not only to develop and qualify safe and user friendly operations for power transfer, but, as well, to provide an effective software link to the market to enable an efficient and speedy (real time: less than 15 minutes) decision making between the different stake holders (crew, ship owners, charterers, port and state authorities ) to either export or import (cold ironing *) power between the vessel and the shore. The paper presents the status of this two-year project initiated in 2006, such as proposed connector and power line technologies, proposed on board and harbour implementation strategies and trade offs, as well as the prospects of the first full size demonstration test in PLUG PLUG Figure 1: PLUG Project LOGO Introduction to the PLUG project PLUG is a joint research and development effort supported by the European Commission to develop an innovative, high capacity (up to 25 MW), ship to shore power interface for the new generation of Dual Fuel Diesel Electric (DF/DE) Liquefied Natural Gas carriers (LNGCs). This interface will allow to connect the vessel to the local power grid during harbour operations in order to: - Run the ship s diesel generating plant at full capacity (up to 25 MW) and sell power to the grid, while acting as a low emission shadow power backup for RES projects; - Import power (up to 8 MW) from the grid for hotel and cargo pumps loads to avoid local emissions penalties (cold ironing) and use oversupply of local RES capacities The project objective is not only to develop and qualify safe and user friendly operations for power transfer, but, as well, to provide an effective software link to the market to enable an efficient and speedy (real time: less than 15 minutes) decision making between the different stake holders (crew, ship owners, charterers, port and state authorities ) to either export or import (cold ironing *) power between the vessel and the shore. FEGER 2

3 The different partners main roles within this project are the following: - Snecma (France): as project coordinator and leader, - Converteam (France): electrical architecture, - Stäubli (France): high voltage /high power connector technology, - Wavespec (United Kingdom): crew and terminal operation procedures, - Leduc (France): Harbour engineering, - Sintef (Norway): link to the market software. The upcoming cold ironing requirement The drive to reduce the volume of atmospheric emissions generated by shipping continues to gain momentum and spur new initiatives. One concept that is being promoted by a number of ports is that of cold ironing, whereby the ship s machinery is switched off upon berthing and a connection is made to the shore side electricity supply in order to provide the vessel with a source of power to meet its hotel and cargo-handling requirements during its stay at port. Beyond local emissions aspects, cold ironing may become a way to reduce global emissions as, depending on the country considered, a significant share of on shore power may come from emission free sources, such as nuclear or RES, while becoming, due to the increasing prices of bunker compared to these alternative power sources, more and more cost effective. Cold ironing operations have already been implemented for a number of cruise liners. For LNG carriers, at the moment, the market has a wait and see attitude towards cold ironing as most ship owners considers cold ironing as an expensive extra constraint on their operations. They are, nevertheless, anticipating this upcoming requirements to be made mandatory by port authorities in the near future, as an approach to reduce emissions and: - Several working groups have been set up at OICMF and ISO level to establish cold ironing power interface standards, - Reservations are made for such interfaces on new build LNGCs. The power generation opportunity For the new generation of vessels using electric propulsions such as cruises vessels and DF/DE LNGCs, ship owners could consider, to maximize their vessels profitability, to run, whenever on board generation cost is lower than local on shore power market price, their generators during loading / unloading operations to export and sell power to the local on shore power grid. For the LNG carriers and terminals, this would allow, among others things, to valorise directly the peak boil off gas, which is generated during these operations, instead of flaring or re liquefying it. In most cases, see figure 2, the on board generation cost can be considered as constant and rather inexpensive, as the Capital Expense required to pay the generators, the converters and their auxiliaries has already been paid for, as well as the crew, and the only additional expenses are the ones relevant to the extra fuel and maintenances linked to this extra operating time. In front of that, the local power market price is expected to vary widely, depending on the usual high volatility of power demand and supply, which fluctuates on a seasonal, daily and hourly basis. If a power exchange capability can be established between the local power grid and electric propulsion vessels, these could therefore be in a position to play and beat the market, in any case, by either exporting power when prices are high or importing power when they are low. FEGER 3

4 On board generation cost Figure 2: Example of power market price compared to on board generation cost PLUG Objectives Like most environment friendly actions, cold ironing can first be expected to be a source of extra operational constraints, costs and safety hazards, to which the industry, and especially the LNG industry, may be reluctant, while power generation towards the shore may be seen, as well, too troublesome to be worthwhile. This reluctance has build up partly due the proposed technical solutions, which have been based on existing power connector technologies, requiring a significant amount of manual handling by the crew and the terminal operator. To challenge this reluctance, and make power exchange between LNG carriers & terminals not only an environment friendly but a cost effective and user friendly operation, one of the main objective of the PLUG project has been therefore to work out a new concept of power interface and power exchange software to offer, compared to other off the shelf solutions, a significant advantage in terms of operations, safety and decision making. The table 1 summarizes the corresponding PLUG project main objectives. Item To develop a quick connection Emergency release capability Versatility Versatile w.r.t vessel size and types Capability Compatible with CTE Safety Plug in and out operations Real time capability Competitive Objectives Connection in less than 15 minutes Compatible with current emergency requirements Compatible with 50 /60 Hz power grid Frequency Compatible with existing LNG terminal harbour facilities Applicable to LNG, containers carriers, cruise ships Up to 25 MW Capable to exchange power in both directions Power/fuel measurements fully compatible with Custody Transfer Equipment Safe or safer than state of the art power interfaces Compatible with LNG carrier and terminal safety requirement s Fully automated operation without manual handling Direct interface with power trade quotation system enabling a quarter of an hour ahead capability Investment below 0,5 M for the terminal and 0,3 M for the vessel, no extra crew requirement Operations as simple as a for a mooring line FEGER 4

5 Product range Beyond LNGCs, the PLUG concept should be attractive as well for oil tankers (because they have similar safety requirements) and ferries (because they have a strong interest in fast connecting / disconnecting operations with minimum personnel). The project is therefore considering the following product range: - a 2 MW /6600V capability for small size LNGCs and Ferries cold ironing - a 8 MW /6600 V capability for large size LNGCs and oil carriers cold ironing ; - a 25 MW /6600 V capability to allow DF/DE LNGCs to provide power to the shore. Proposed connector and power line technologies: Physically, the power line is split into two main components: - An on board power interface which contains the power socket linked to the vessel main power switch board, as well as the mechanical system handling the power line towards the socket and the on board control command post. Several location of this power port are possible, depending on owners or terminal operators implementation strategies, but the trend is to locate this interface at the aft of the vessel, close to the main switch board and away, or LNG and oil carriers, from the potentially gas hazardous cargo area, see figure 3. - A power line which, on one end, is connected to the on shore power grid, and on the other, is equipped with a single, self mating, connector providing all the power, grounding and control command interfaces. Several possibilities exist for the handling and storage of this power line, depending, on owners or terminal operators implementation strategies. Dolphins Gang ways LNG pipes Power line (storage) (active) Mooring lines Power line must comply with carrier movements and different power port locations m from cargo Manifold Figure 3: Possible PLUG power line implementation in the case of LNG or oil carriers FEGER 5

6 The figure 4 gives an overview of the power port : On board winch Power-line connector On board connector (in the green box) Conduct tube Operator Power-line Roll: avoid power-line damages Figure 4: On board power port when the power-line is connected Footprint of the power port is optimized, and its weights is less than 3 tons, making easy its accommodation in any location on board the vessel, even in a retrofit case. The power line is equipped with a single watertight, self mating connector which is towed into position (see figure 5) into the on board power socket by a towing line and provides, in one operation, all the required connections. No direct handling of the power line is therefore required, and operations can be performed by a single crew member, typically the on board electrical engineer, without any reliance on any of the crew deck hands, which are usually at this time busy setting up the mooring lines and the cargo loading arms The power connector is a watertight (20 m depth) assembly with self-closing lids covering the power and control command interfaces. The front end of the connector is equipped with a an attachment point for the towing cable and its shape is designed to allow an easy insertion into the hull opening leading to the power port. The single connector, which fits into a special port in the hull of the vessel, can be hooked up within a period of 5 minutes. It is brought on board by a dedicated towing line without any manual handling. A special device under patent enables an automatic alignment of the three phases, control command and grounding. The connector is capable, once the power line has been de energized, of being remotely and safely released in less than 60 seconds in the event of an emergency, by unrolling the towing cable until its complete release. This emergency release action can be initiated from either shore or on board alarm, but, as well, automatically, in case of the detection of extra mechanical loads on the power line (for example if the vessel break its mooring lines and drifts away), providing a built in break away capability. With these features, PLUG meets and exceeds the on going safety requirements under discussions within OICMF and ISO cold ironing working groups. FEGER 6

7 Visual inspection /cleaning Watertight lids opening and self mating Power lids opening Ready for power exchange Figure 5: Power connector concept and operations The corresponding typical operations are described in figure 5 and 6, depending whether an aerial or floating power line is considered. Connecting pulling cable Power line active Towing power line Emergency release Figure 6: Power line operations, aerial power line case Connecting towing cable Floats, or aerial supports Towing power line Aerial line Power line active Emergency release Figure 7: Power line operations, floating power line case FEGER 7

8 EUR/MWh Other key issues which have been success fully solved are the selection of the power contact technology (see figure 8) which is already used for other marine applications such as the Pod electric propulsion systems, as well as the detailed concept of the self mating /de mating connector. Figure 8: PLUG power contact technology Link to the market software The project has studied possibilities for electricity exchange between LNG tankers and harbours. In order to make the study more specific, the study uses Snøhvit project in Northern Norway, which is Europe's first export facility for liquefied natural gas (LNG), as an example and reference point. The Snøhvit project will use natural gas from the Snøhvit, Albatross and Askeladd fields in the Barents Sea for production of LNG at processing facility on Melkøya Island outside Hammerfest in Northern Norway. Accordingly, the Norwegian Electricity Market has been used as a reference point in the project. The electricity system in Norway is deregulated - the liberalisation of the market implied a separation of tasks related to the trade and transport of electric energy. The spot market (Elspot) is operated by the Nordic Power Exchange (NordPool). This is a contractual market where contracts are traded daily for physical delivery during the next 24 hours; hence the market is referred to as a day-ahead market. Trading is based on an auction trade system and the prices are calculated based on the balance between the bids and offers from all the market participants. The spot market is probably the most relevant target product for electricity exchange since it is based on a 24 hours time frame (day-ahead) and the minimum tradable volume (0.1 MWh/h), which are acceptable for electricity exchange between a vessel and harbour. The electricity spot market is characterised by a high volatility of electricity prices, which can differ significantly both on seasonal and even hourly basis. Figure shows variation of the system price for The registered difference between the lowest (8,8 Euro/MWh) and the highest (49,67 Euro/MWh) price during the given period was more than 5 times. System price at Nord Pool Spot ( ) Date Figure 9 Electricity System Price for Source: NordPool ASA FEGER 8

9 Several other market arrangements related to provision of the balancing services have been studied. At present participation in these markets puts several requirements, which are difficult to meet (especially when it comes to min capacity, required for participation in the market). However these markets can be considered in the future. The growing price volatility and scarce generation capacity are probably the most known features of deregulated electricity markets. An efficient operation in the spot market environment requires a frequent decision making and regular developing of generation schedules based on day-ahead electricity spot prices. In the project it has been developed a Link to Market demonstrator software, which is primarily intended to be used as decision-support tool on a local level and can be adapted to technical characteristics of a particular vessel in a particular port of call. A typical user interface provided by this software is given figure 10. Figure 10: Example of PLUG link to the market and decision making software interface To perform the simulations and calculations, some information from the user/carrier is necessary. This input data is divided into five categories: - Generator data - Energy demand data - Contract data - Distribution network tariff data - Emission data In order to study interaction between the spot market and a vessel, several simulations have been made, based on historical electricity prices for The sample simulation example uses electricity spot prices from the 9th of January of 2006, where it was a very high price variation during a day. The simulation is related to an LNG boat with three auxiliary generators with different capacity and generation price. Duration of the call is 19 hours. FEGER 9

10 8,00 Electricity flow and spot price 160,00 El. flow [MW] 6,00 4,00 2,00 0,00-2,00-4, Hour 140,00 120,00 100,00 80,00 60,00 40,00 20,00 Spot price [Euro/MWh] -6,00 0,00 Electricity flow Spot price Figure 11 Electricity exchange between the spot market and vessel, during high spot price volatility period Connection between the vessel and the local electricity network is established at 03:00. From 03:00 until 05:00 the electricity spot prices ashore are lower then the generation costs, so the vessel imports electricity from the net. After hour 6 the spot prices start to raise and access the own generation costs. The vessel starts Generator 1 with the lowest generation costs in order to cover the own consumption. The further raising of the electricity price leads to activation of all three generators. The generators start to supply electricity to the vessel and simultaneously export the residual capacity to the local net. This lasts until hour 20, when the spot prices start to fall again. The vessel accordingly deactivates Generator 3 with the highest production costs at hour 20 and stops export of electricity at hour 21. The simulation shows that an efficient operation in the spot market environment requires a frequent decision making and regular developing of generation schedules based on day-ahead electricity spot prices. Combination with RES The PLUG consortium is as well investigating the potential combination of the PLUG concept with RES, as from environmental point of view, by providing a power exchange capability between LNG carriers and terminals, the PLUG concept could be fully integrated in a global emissions reduction effort (see figure 12), as it can be used both ways: The LNGCs can be used as a low (typically 10 times lower than a combined cycle gas turbine) cost 25 MW shadow power generation capability for RES when they are not available (for example for wind farms, when the wind is not blowing). The LNGCs can import power from the shore produced by RES for its own consumption, which can be as high as 8 MW when the vessel is activating its electrical cargo pumps to unload the cargo. This concept is not limited to LNGCs, other type of vessel may benefit from this power exchange capability. In most cases (container and bulk carriers, oil carriers, etc ) they will import power to cover their energy needs, instead of using high emission oil burning on board generators, with the corresponding global and local emissions reductions. In some case, for the type of vessels which, like the LNGCs are switching to electric propulsion system (Cruise vessels, ferries ) they could used PLUG in either direction, to either support the local network or reduce their harbour emissions. FEGER 10

11 One could end up with a global emission optimisation at the level of the whole harbour, where, for example, when there is wind, wind power will feed all the vessels calling to port and, where, in case of lack or excess of wind, the lowest emissions vessels (typically the LNGC using natural gas as fuel) could feed the other vessels. The ultimate goal is to develop a global solution that provides the optimum overall reduction in atmospheric emissions for the port community and its vessel traffic. This is expected to be highly cost and emission efficient, enabling, among other things, the harbour to have an arbitrage capability to cope with the fluctuations of wind power and power consumption at a very low cost. If one considers that the typical required shadow power capability required for wind farms projects as their contribution to grid stability in case of lack or excess of wind, is, typically, around 4 % of the installed power, a single LNG carrier, with its 25 MW power generation capability could provide shadow power capability to a 125 MW wind farm. In the case of application of new LNG receiving terminals, such type of contribution of the LNG industry to RES project could be a further benefit to win public and local authorities acceptance Figure 12: PLUG Power and emission global optimisation concept in combination with RES Way forward Presently the consortium is focusing on the development and qualification of a 8 MW /6600 V PLUG which would meet the most immediate capability for LNGCs to allow cold ironing from the shore during cargo unloading without local harbour emissions. This capability has become the target specification for the PLUG prototype and full size tests are considered on a Channel ferry by end of Another activity is the identification of potential candidates to perform detailed cases studies, allowing ship owners and port authorities to assess the environmental and economical benefits they could gain from this innovative concept. Conclusion The technologies selected for the PLUG project, in particular the selected technologies and concept of the PLUG connector, allow to meets or even exceed all the LNG industry operational and safety requirements. Compared to existing solutions, which require significant manual handling, the PLUG concept is a breakthrough with regard to ergonomics and safety. (*) Cold ironing is a US navy term for the use of shore power supply to meet power loads on vessels when they are at harbour. In this case the on board generator sets are switched off, and the engine room becomes cold, hence the term cold ironing. FEGER 11