Marine vessel power generation system

A marine vessel power generation system comprising a conventional machinery arrangement, such as an internal combustion engine (2) and a generator (3), a propulsion system, and a main switchboard (6). In order to provide an environmental friendly power generation system, when the marine vessel enters, leaves or is in port, said system is provided with an H2O operated power generation arrangement (8) for generating H2O from seawater in order to produce electrical energy.

This is a national stage application filed under 35 USC 371 based on International Application No. PCT/FI2007/050320 filed Jun. 1, 2007, and claims priority under 35 USC 119 of Finnish Patent Application No. 20065481 filed Jul. 6, 2006.

TECHNICAL FIELD

The present invention relates to a marine vessel power generation system comprising a conventional machinery arrangement, such as an internal combustion engine and a generator, a propulsion system, and a switchboard. The present invention also relates to a method for power generation on a marine vessel.

BACKGROUND ART

Marine vessels are usually provided with means for production of auxiliary energy, i.e. for additional propulsion purposes, as well as for the use of hotel consumers, etc. Conventionally auxiliary energy is produced by means of e.g. smaller diesel engines, i.e. auxiliary generator sets connected to the switchboard of the power generation system. Such engines are usually not of very high efficiency and they also generate considerable emissions.

SUMMARY OF THE INVENTION

An object of the present invention is to avoid the drawbacks of known solutions and to provide an environmental friendly marine vessel power generation system.

The basic idea of the invention is to provide a two mode power generation system suitable for power generation at sea on one hand and for power generation in port, or close to port, on the other hand. For this purpose the power generation system further comprises an H2operated power generation arrangement for generating H2from seawater in order to produce electrical energy.

The H2power generation arrangement advantageously includes an H2electrolysis device, an H2storage and an H2operated power generation apparatus.

At sea (first mode) the conventional machinery arrangement of the marine vessel, in addition to propulsion, is used to provide electrical energy for e.g. hotel consumers and for the H2electrolysis device for producing H2to be supplied to the H2storage for future use. The power generation at sea may thus be carried out by low cost fuels such as heavy fuel oil.

In port, or close to port, (second mode), all power generation for propulsion as well as electrical energy for hotel consumers, is carried out by the H2operated power generation arrangement, whereby the H2stored in the H2storage is supplied to the H2operated power generation apparatus for producing the required electrical energy. Consequently, there are no emissions in port, where the environmental impact is greater than at sea. The energy used in port is thus generated at sea with low cost fuels.

The H2operated power generation apparatus provides electrical energy for an electrical propulsion arrangement or a combined mechanical and electrical propulsion unit of the propulsion system as well as for e.g. hotel consumers by way of the switchboard. The H2operated power generation apparatus may thus independently and separately from the conventional machinery arrangement provide for the electrical energy consumption on the marine vessel when desired, particularly in port or close to port in order to avoid any emissions in an environmentally sensitive area. Furthermore, such an H2operated power generation apparatus generally has better efficiency than small diesel engines conventionally used for auxiliary energy production. This also means that there is no need to use low sulphur high cost fuels in port. Lower emissions also have economical benefits due to reduction of related fees.

DETAILED DESCRIPTION

InFIG. 1andFIG. 2a marine vessel power generation system is generally indicated with reference numeral1. The power generation system comprises a conventional machinery arrangement, such as an internal combustion engine2and a generator3, in this embodiment a shaft generator3connected to the free end of the internal combustion engine2. Further, the arrangement includes a heavy fuel oil (HFO) storage4for supplying fuel to the internal combustion engine2. The internal combustion engine2drives a propulsion system, in this embodiment a mechanical propulsion unit5including a main shaft51and a propeller52directly connected to the internal combustion engine2. The internal combustion engine2also drives the generator3, which delivers electrical energy to a switchboard6.

The switchboard6is shown to be connected to an auxiliary switchboard61for delivering electrical energy for the use of e.g. hotel consumers9. Electrical energy for such hotel consumers may be provided directly from the switchboard6as well. The propulsion system further includes an electrical propulsion arrangement7. The electrical propulsion arrangement7may include two separate electrical propulsion units71, which may be bow thrusters, stern thrusters or electric pods. The electrical propulsion arrangement7is connected to the switchboard6for receiving electrical energy from the switchboard6.

Such a set-up is more or less conventional. Most often one or more auxiliary generator sets (not shown), including internal combustion engines, are connected to the switchboard for providing additional electrical energy thereto.

In the present invention, however, the power generation system further comprises an H2operated power generation arrangement8, including an H2electrolysis device81for production of H2from sea water, an H2storage82comprising special gas storage tanks, and, in this embodiment, two H2operated power generation apparatus. A double apparatus is advantageous e.g. in view of redundance.

The H2operated power generation apparatus may be an internal combustion engine, e.g. a gas driven engine or a gas turbine, or a fuel cell.

The H2electrolysis device81is powered by electrical energy generated by the generator3and delivered from the switchboard6. The H2electrolysis device generates H2from seawater when the marine vessel is out at sea and supplies H2to the H2storage82for subsequent use as described below.

When the marine vessel enters, leaves or lies in port, the stored H2is supplied to the H2operated power generation apparatus83for providing electrical energy to the switchboard6and further to the electrical propulsion arrangement7and, in this embodiment, to the auxiliary switchboard61for the use of e.g. hotel consumers9. Electrical energy for hotel consumers may be provided directly from the switchboard6as well.

The basic idea of the present invention will shortly be described in the following.

FIG. 1represents a first mode of operation of the power generation system1when the marine vessel is at sea.

In this first mode, out at sea, the marine vessel is operated by the conventional machinery arrangement, whereby the internal combustion engine2drives the mechanical propulsion unit5. The internal combustion engine2is fuelled by heavy HFO from the HFO storage4. In addition the internal combustion engine2drives the generator3for producing electrical energy, which is delivered to the switchboard6, on the one hand for use on the marine vessel for auxiliary purposes as described above, and on the other hand for powering the H2electrolysis device81which produces H2by electrolysis of sea water. The H2thus produced is then stored in the H2storage for subsequent use.

This means that the extra emissions from burning of HFO are generated at sea, far away from any shorelines, whereby e.g. sulphur oxides only have their local impact far from more sensitive areas.

The block arrows indicate the flow of energy in this first mode.

FIG. 2represents a second mode of operation of the power generation system1when the marine vessel enters, leaves or is in port.

In this second mode, when the marine vessel has been out at sea and enters port, the conventional machinery arrangement may be shut down. The marine vessel may then idle into port, whereby the propulsion power is provided by the electrical propulsion arrangement7. For this purpose, H2from the H2storage82is supplied to the H2operated power generation apparatus83, which generate electrical energy and deliver it to the electrical propulsion arrangement7by way of the switchboard6. The H2operated power generation apparatus83may also be used to provide any other auxiliary energy needed e.g. by hotel consumers9by way of the switchboard6, or as indicated in this embodiment, by way of the auxiliary switchboard61.

This means that there are no emissions in port, where the environmental impact is greater than at sea. The energy for the marine vessel power generation in port has thus been produced out at sea.

The block arrows indicate the flow of energy in this second mode.

FIG. 3shows another embodiment of a power generation system according to the invention in the first mode of operation, when the marine vessel is out at sea. This embodiment corresponds to the embodiment ofFIG. 1, except that instead of a mechanical propulsion unit a combined mechanical and electrical propulsion unit50is deployed. The combined mechanical and electrical propulsion unit50has the generator3on the main shaft51, between the internal combustion engine2and the propeller52.

In this first mode, out at sea, the marine vessel is operated by the conventional machinery arrangement, whereby the internal combustion engine2drives the combined mechanical and electrical propulsion unit50. The internal combustion engine2is fuelled by heavy HFO from the HFO storage4. In addition the internal combustion engine2drives the generator3for producing electrical energy, which is delivered to the switchboard6, on the one hand for use on the marine vessel for auxiliary purposes as described above, and on the other hand for powering the H2electrolysis device81which produces H2by electrolysis of sea water. The H2thus produced is then stored in the H2storage for subsequent use.

This means that the extra emissions from burning of HFO are generated at sea, far away from any shorelines, whereby e.g. sulphur oxides only have their local impact far from more sensitive areas.

The block arrows indicate the flow of energy in this first mode.

FIG. 4shows the embodiment ofFIG. 3in the second mode of operation, when the marine vessel enters, leaves or is in port. In this context, the electrical energy generated by the H2operated power generation apparatus83, is supplied back to the generator3, which then drives the combined mechanical and electrical propulsion unit50. This arrangement as well provides for emission free power generation.

In this second mode, when the marine vessel has been out at sea and enters port, the conventional machinery arrangement may be shut down. The marine vessel may then idle into port, whereby the propulsion power is provided by the combined mechanical and electrical propulsion unit50, i.e. by using the electrical drive. The marine vessel may of course also be provided with an electrical propulsion arrangement7(as illustrated inFIG. 4), whereby the propulsion power may be provided by the electrical propulsion arrangement7. For this purpose, H2from the H2storage82is supplied to the H2operated power generation apparatus83, which generate electrical energy and deliver it to the combined mechanical and electrical propulsion unit50and/or the electrical propulsion arrangement7by way of the switchboard6. The H2operated power generation apparatus83may also be used to provide any other auxiliary energy needed e.g. by hotel consumers9by way of the switchboard6, or as indicated in this embodiment, by way of the auxiliary switchboard61.

This means that there are no emissions in port, where the environmental impact is greater than at sea. The energy for the marine vessel power generation in port has thus been produced out at sea.

The block arrows indicate the flow of energy in this second mode.

The present invention thus provides for two separate modes of power generation, the first mode for use out at sea and the second mode for use in port.

Although not shown inFIGS. 1 to 4, nor discussed above, the marine vessel may in addition be provided with auxiliary generator sets deployed in parallel with the H2operated power generation arrangement.

The drawings and the description related thereto are only intended for clarification of the basic idea of the invention. The invention may vary in detail, e.g. the number and type of different components, such as the propulsion units, generators, H2storage, etc., may be varied according to need within the scope of the ensuing claims.