Patent Application
20230313397
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2020-031886, filed on Feb. 27, 2020, and International Patent Application No. PCT/JP2021/006456, filed on Feb. 19, 2021, the entire content of each of which is incorporated herein by reference.
The present invention relates to a hydrogen supply system including a hydrogen station.
In recent years, hydrogen has attracted attention as clean energy, and fuel cell vehicles using hydrogen as a fuel have been spreading. In order to further spread fuel cell vehicles, it is necessary to prepare a hydrogen station as a fuel supply infrastructure. In a hydrogen station, hydrogen is compressed and stored in an accumulator, and high-pressure hydrogen is charged into a fuel cell vehicle via a dispenser. Hydrogen to be a fuel is produced by a method of steam-reforming city gas, liquefied petroleum gas, or the like, a method of dehydrogenating an organic hydride such as methylcyclohexane, or the like.
Generally, there are two types of hydrogen stations: an on-site type and an off-site type. The on-site hydrogen station produces hydrogen by its own hydrogen production device and supplies the hydrogen to a fuel cell vehicle. In contrast, the off-site hydrogen station procures hydrogen produced in another site and supplies the hydrogen to a fuel cell vehicle. For transportation of hydrogen, a hydrogen trailer, a hydrogen carrying vessel, or the like is used.
In recent years, the amount of power generated by renewable energy such as sunlight and wind power has been increased. Since a power generation amount by renewable energy has a large time variation, an adjustment capability for adjusting a power supply and demand balance is required. For example, a supply and demand adjustment system has been proposed in which hydrogen is produced and stored using surplus power from renewable energy, and the stored hydrogen is transported to a hydrogen station for use and used for power generation (for example, see JP2014-111984A and JP2019-144897A).
In order to transport hydrogen with high efficiency, it is necessary to compress the hydrogen to a high pressure or to cool the hydrogen to a cryogenic temperature, and it is costly to store and transport a large amount of hydrogen. In addition, when hydrogen produced by the water electrolysis reaction is used for power generation, it is not preferable from the viewpoint of energy efficiency.
The present invention has been made in view of such a situation, and one object of the present invention is to provide a technique for improving energy efficiency of a hydrogen supply system.
A hydrogen supply system according to an aspect of the present invention includes a plurality of hydrogen stations for supplying hydrogen gas to a fuel cell vehicle, and a management apparatus that manages supply and demand of the hydrogen gas of the plurality of hydrogen stations. The plurality of hydrogen stations include a plurality of on-site hydrogen stations. The on-site hydrogen stations each include an electrolysis device that produces hydrogen gas by an electrolytic reaction consuming power supplied from a commercial power network, a compressor that compresses the hydrogen gas produced by the electrolysis device, an accumulator that accumulates the hydrogen gas compressed by the compressor, and a dispenser that fills the fuel cell vehicle with the hydrogen gas accumulated in the accumulator. The management apparatus adjusts a power consumption amount of a plurality of electrolysis devices included in the hydrogen supply system, on the basis of a command for adjusting supply and demand of power of the commercial power network.
Another aspect of the present invention is a hydrogen supply system. This hydrogen supply system includes a plurality of hydrogen stations for supplying hydrogen gas to a fuel cell vehicle, a plurality of hydrogen production sites that produces hydrogen gas to be supplied to at least one of the plurality of hydrogen stations, and a management apparatus that manages supply and demand of hydrogen gas of the plurality of hydrogen stations and the plurality of hydrogen production sites. The hydrogen production sites each include an electrolysis device that produces hydrogen gas by an electrolytic reaction consuming power supplied from a commercial power network, and an accumulator that accumulates the hydrogen gas produced by the electrolysis device. The plurality of hydrogen stations each include a compressor that compresses the hydrogen gas supplied from at least one of the plurality of hydrogen production sites, an accumulator that accumulates the hydrogen gas compressed by the compressor, and a dispenser that fills the fuel cell vehicle with the hydrogen gas accumulated in the accumulator. The management apparatus adjusts a power consumption amount of a plurality of electrolysis devices included in the hydrogen supply system, on the basis of a command for adjusting supply and demand of power of the commercial power network.
Another aspect of the present invention is a hydrogen station. This hydrogen station includes an electrolysis device that produces hydrogen gas by an electrolytic reaction consuming power supplied from a commercial power network, a compressor that compresses the hydrogen gas produced by the electrolysis device, an accumulator that accumulates the hydrogen gas compressed by the compressor, a dispenser that fills a fuel cell vehicle with the hydrogen gas accumulated in the accumulator, and a control device that controls a power consumption amount of the electrolysis device on the basis of a command for adjusting supply and demand of power of the commercial power network.
Still another aspect of the present invention is a method for managing hydrogen supply and demand in a hydrogen supply system. The hydrogen supply system includes a plurality of hydrogen stations for supplying hydrogen gas to a fuel cell vehicle. The plurality of hydrogen stations include a plurality of on-site hydrogen stations. The on-site hydrogen stations each include an electrolysis device that produces hydrogen gas by an electrolytic reaction consuming power supplied from a commercial power network, a compressor that compresses the hydrogen gas produced by the electrolysis device, an accumulator that accumulates the hydrogen gas compressed by the compressor, and a dispenser that fills the fuel cell vehicle with the hydrogen gas accumulated in the accumulator. In this method, a command for adjusting supply and demand of power of the commercial power network is acquired, an adjustment margin of power consumption of the electrolysis device of each on-site hydrogen station is calculated, an adjustment amount of power consumption of each electrolysis device is determined within a range of adjustment margin of each electrolysis device such that a sum of adjustment amounts of power consumption of the plurality of electrolysis devices included in the hydrogen supply system becomes closer to an adjustment target amount of supply and demand of power included in the command, and the power consumption of each electrolysis device is adjusted on the basis of the determined adjustment amount.
Any combinations of the above constituents, and modifications of the expressions of the present disclosure among methods, apparatuses, systems, and the like are also effective as aspects of the present disclosure.
Embodiments will now be described, by way of example only, with reference to the accompanying drawings which are meant to be exemplary, not limiting, and wherein like elements are numbered alike in several Figures, in which:
Before describing the invention in detail, first, an outline thereof will be described.
The present embodiment relates to a hydrogen station for supplying hydrogen to a fuel cell vehicle using hydrogen as a fuel, and particularly to a hydrogen station including a water electrolysis device for producing hydrogen.
The water electrolysis device can produce hydrogen on site by electrolyzing water by consuming power supplied from a commercial power network.
In a commercial power network, it is necessary to balance supply and demand of power in order to stably supply power, and a power company that operates the commercial power network responds to fluctuations in power demand by combining various power generation methods. In recent years, the amount of power generation by renewable energy such as wind power generation and solar power generation tends to increase, but since the amount of power generation depends on weather such as wind power and sunlight, it is difficult to artificially control the amount of power generation. Therefore, a demand response mechanism for balancing supply and demand of power by adjusting the power demand amount instead of adjusting only the power supply amount is being used.
In the demand response, a consumer consuming power adjusts power consumption amount in response to a gap between supply and demand of power. The consumer who has adjusted the power consumption amount is paid a reward according to the adjustment amount. For example, when power demand is insufficient due to an increase in the amount of power supply by solar power generation in good weather, the supply and demand of power are adjusted by increasing power consumption amount. Conversely, when the power demand is excessive due to a decrease in the amount of power supply by solar power generation in bad weather, the supply and demand of power are adjusted by reducing the power consumption amount. Adjustment of supply and demand of power may be managed via an intermediary called an aggregator. The aggregator divides the adjustment target amount requested from the power supply side and distributes the divided adjustment target amount to a large number of consumers so that the large number of consumers can adjust the power consumption amount in a cooperative manner. In addition, there is also a demand response bidding system, and by bidding for an adjustment amount instructed by the power supply side or the aggregator, it is possible to acquire a right to adjust the power consumption amount and receive a reward according to the adjustment result.
A real-time property is required for adjustment of supply and demand of a commercial power network, and for example, it is necessary to provide an instructed adjustment capability in a short time such as within 5 minutes or within 30 minutes. In addition, in the case of providing the power supply and demand adjustment capability, it is necessary to continuously adjust the power consumption amount over a specified time such as 30 minutes or 1 hour. In the present embodiment, by adjusting the power consumption amount of the water electrolysis device installed in the hydrogen station, an adjustment capability for alleviating the power supply and demand gap in the commercial power network is provided. At this time, by calculating the adjustment margin of the power consumption of the water electrolysis device on the basis of the supply and demand plan of hydrogen in the hydrogen station, it is possible to quickly provide the adjustment capability within a range not affecting the supply of hydrogen. Furthermore, by controlling power consumption amounts of a plurality of water electrolysis devices installed in a plurality of hydrogen stations in a cooperative manner, it is possible to secure adjustment capability required at the minimum for bidding.
Hereinafter, the present invention will be described on the basis of preferred embodiments with reference to the drawings. The embodiments are mere examples and not intended to limit the invention, and all features described in the embodiment and combinations thereof are not necessarily essential to the invention. The same or equivalent constituent elements, members, and processes illustrated in the drawings are denoted by the same reference numerals, and redundant description will be omitted as appropriate. In addition, the scale and shape of each part illustrated in each drawing are set for convenience in order to facilitate the description, and should not be limitedly interpreted unless otherwise specified. In addition, when terms such as “first” and “second” are used in the present specification or claims, the terms do not represent any order or degree of importance, but are used to distinguish one element from another. In addition, in each drawing, some of members that are not important for describing the embodiments are omitted.
The water electrolysis device 12 produces hydrogen gas by an electrolytic reaction that consumes power supplied from a commercial power network 90. Examples of the type of the water electrolysis device 12 include a solid polymer type, an alkali type, and a solid oxide type. The water electrolysis device 12 is desirably in a solid polymer type from the viewpoint of being installed and operated in the hydrogen station 10. In the case of the solid polymer type, space saving can be achieved as compared with other types, and treatment of alkali waste liquid is not necessary. In addition, the solid polymer type is advantageous in that it is resistant to vibration when the water electrolysis device 12 is transported to and installed in the hydrogen station 10.
Rated output is determined for the water electrolysis device 12, and it is recommended to operate the water electrolysis device 12 while maintaining the rated output. An example of the rated output of the water electrolysis device 12 is 1,600 kW, and the hydrogen production capacity at this time is 320 Nm3/h. The water electrolysis device 12 can be operated even with an output different from the rated output, and the output can be adjusted within a range from the minimum rated power to the maximum rated power. When the output of the water electrolysis device 12 is adjusted, the power consumption amount changes according to the output, and the production amount of hydrogen gas also changes according to the output. The minimum rated power of the water electrolysis device 12 is 10% to 50% of the rated output, and is, for example, 20% (for example, 320 kW) of the rated output. The maximum rated power of the water electrolysis device 12 is 120% to 200% of the rated output, and is, for example, 150% (for example, 2,400 kW) of the rated output.
The compressor 14 compresses the hydrogen gas produced by the water electrolysis device 12 to generate hydrogen gas (also referred to as pressurized hydrogen gas) having a higher pressure than the hydrogen gas that is not compressed. Examples of the compressor 14 include a reciprocating compressor (reciprocating type) using a general metal piston, an ionic compressor that substitutes a piston with a nonvolatile ionic liquid, and a diaphragm compressor that increases the pressure by pressing a stainless steel film against a metal head. The compressor 14 is preferably a reciprocating compressor having excellent followability and durability in order to cope with load fluctuation that may frequently occur in accordance with adjustment of supply and demand of power. The pressurized hydrogen gas generated by the compressor 14 is accumulated in the accumulator 16. The compressor 14 may receive hydrogen gas produced in another site, and for example, may generate pressurized hydrogen gas by compressing hydrogen gas carried into the hydrogen station 10 through the hydrogen trailer 94.
The accumulator 16 includes a high-pressure accumulator 22 and an intermediate accumulator 24. The high-pressure accumulator 22 stores high-pressure hydrogen for filling a fuel cell vehicle 92 through a dispenser 18. The pressure of the hydrogen gas accumulated in the high-pressure accumulator 22 is, for example, 82 MPa. The intermediate accumulator 24 stores hydrogen gas to be secured as a stock by the hydrogen station 10. The pressure of the hydrogen gas accumulated in the intermediate accumulator 24 is, for example, 45 MPa. An example of the capacity of the intermediate accumulator 24 is 1,500 Nm3.
The hydrogen gas accumulated in the intermediate accumulator 24 can be accumulated in the high-pressure accumulator 22 by being compressed by the compressor 14. In addition, the hydrogen gas accumulated in the intermediate accumulator 24 can be compressed by the compressor 14 and then charged into the fuel cell vehicle 92 without passing through the high-pressure accumulator 22. For example, when the hydrogen demand exceeding the production capacity of the water electrolysis device 12 occurs, the hydrogen demand can be covered by using the hydrogen gas stored in the intermediate accumulator 24. The intermediate accumulator 24 can also store hydrogen gas for supply to other hydrogen stations. For example, the hydrogen gas stored in the intermediate accumulator 24 may be supplied to other hydrogen stations by filling the hydrogen trailer 96 or the like with the hydrogen gas. To be noted, the intermediate accumulator 24 is not an essential component, and the intermediate accumulator 24 does not have to be provided in the hydrogen station 10.
The pre-cooler 17 cools the high-pressure hydrogen supplied to the fuel cell vehicle 92 via the dispenser 18 to a predetermined temperature (for example, −40° C.). The pre-cooler 17 includes, for example, a refrigerator (not illustrated) for cooling the high-pressure hydrogen. By filling a hydrogen tank of the fuel cell vehicle 92 with the cooled high-pressure hydrogen, it is possible to reduce the temperature rise of the hydrogen tank of the fuel cell vehicle 92 at the time of filling with the high-pressure hydrogen.
The dispenser 18 supplies high-pressure hydrogen to the fuel cell vehicle 92 that has come to the hydrogen station 10. The pressure of the hydrogen gas charged into the fuel cell vehicle 92 is determined by regulations and laws of each country, and is, for example, 70 MPa in Japan. The amount of hydrogen gas supplied to the fuel cell vehicle 92 in one filling is, for example, 30 Nm3.
A control device 20 controls operations of various devices installed in the hydrogen station 10. The control device 20 is realized by an element or a circuit such as a processor (e.g., CPU) and a memory (e.g., ROM and/or
RAM) of a computer as a hardware configuration, and is realized by a computer program or the like as a software configuration. It should be understood by those skilled in the art that various functions of the control device 20 can be realized in various forms by a combination of hardware and software.
The control device 20 operates on the basis of the supply and demand plan of hydrogen in the hydrogen station 10. In the hydrogen supply and demand plan, a demand amount, a supply amount, and an inventory amount of hydrogen gas in the hydrogen station 10 are planned for each time.
The demand amount of hydrogen gas corresponds to a predicted value of a filling amount of hydrogen gas charged into the fuel cell vehicle 92 from the dispenser 18. The predicted value of the filling amount for each time can be calculated, for example, by integrating the filling amount per one time (for example, 30 Nm3) with the predicted number of fuel cell vehicles 92 that will come to the hydrogen station 10 per unit time. The demand amount of hydrogen gas may be predicted on a daily basis, or the demand amount of hydrogen gas for each time may be calculated from the demand for hydrogen gas per day. The demand amount of hydrogen gas may include a shipping amount of hydrogen gas supplied to another site through the hydrogen trailer 96 or the like.
The supply amount of hydrogen gas corresponds to the production amount of hydrogen gas produced by the water electrolysis device 12. The production amount of hydrogen gas can be calculated on the basis of the operation output of the water electrolysis device 12 of each time. The supply amount of hydrogen gas may include the amount of incoming hydrogen gas supplied from another site through the hydrogen trailer 94 or the like.
The inventory amount of hydrogen gas is a residual accumulation amount of hydrogen gas stored in the accumulator 16. The inventory amount of hydrogen gas may include only the residual accumulation amount of the high-pressure accumulator 22 or may be a total value of the accumulation amounts of the high-pressure accumulator 22 and the intermediate accumulator 24. The inventory amount of hydrogen gas may include an accumulation amount of a hydrogen tank different from the high-pressure accumulator 22 and the intermediate accumulator 24. For example, an accumulation amount of a hydrogen tank permanently installed in the hydrogen station 10 separately from the high-pressure accumulator 22 and the intermediate accumulator 24 may be included, or an accumulation amount of a hydrogen cylinder bundle or a hydrogen cylinder temporarily stored in the hydrogen station 10 may be included.
The operation plan of the water electrolysis device 12 is determined on the basis of the demand amount and the inventory amount of hydrogen. The operation plan of the water electrolysis device 12 is determined such that the inventory amount of hydrogen falls within a range from a predetermined lower limit value (for example, 100 Nm3) to an upper limit value (for example, 1,500 Nm3) under a situation where the inventory amount of hydrogen fluctuates with the lapse of time according to supply and demand of hydrogen. For example, the inventory amount of hydrogen can be kept within the predetermined range by determining the operation plan of the water electrolysis device 12 so that the hydrogen demand amount and the hydrogen supply amount in one day correspond to each other. For example, by dividing the hydrogen demand amount (for example, 6,300 Nm3) per day by 24 hours, the hydrogen production amount (for example, 263 Nm3/h) per hour can be determined, and the operation output (for example, 82% of the rated output) corresponding to the hydrogen production amount can be determined. At this time, the hydrogen production amount for each time is adjusted so that the residual accumulation amount in the accumulator 16 does not fall below the lower limit value or exceed the upper limit value. In the example of
When it is necessary to provide the power supply and demand adjustment capability to the commercial power network 90, the control device 20 calculates the adjustment margin of the power consumption amount of the water electrolysis device 12. Here, the adjustment margin of the water electrolysis device 12 is an increase/decrease range of the power consumption amount of the water electrolysis device 12 in which increase and decrease can be performed within a range in which the operation of the hydrogen station 10 is not hindered. The control device 20 calculates the adjustment margin of the water electrolysis device 12 on the basis of the hydrogen supply and demand plan, the current value of the operation output of the water electrolysis device 12, the current value of the residual accumulation amount of the accumulator 16, and the like.
First, a case of increasing the power consumption amount of the water electrolysis device 12 will be described. The operation output of the water electrolysis device 12 can be increased to the maximum rated power of the water electrolysis device 12. In this case, the adjustment margin is restricted by the difference between the current value of the operation output and the maximum rated power of the water electrolysis device 12. For example, when the water electrolysis device 12 is operated at the rated output and the maximum rated power is 150% of the rated output, the adjustment margin is 50% of the rated output. To be noted, the difference between the current value of the operation output and the maximum rated power of the water electrolysis device 12 is also referred to as “operation margin”.
When the power consumption amount of the water electrolysis device 12 is increased, the production amount of hydrogen is increased as compared with the original supply and demand plan, so that the residual accumulation amount of the accumulator 16 may reach the upper limit. Since hydrogen cannot be stored beyond the maximum accumulation amount of the accumulator 16, the adjustment margin of the water electrolysis device 12 is also restricted by the accumulation margin of the accumulator 16. The accumulation margin of the accumulator 16 is a difference between the current value of the residual accumulation amount of the accumulator 16 and the maximum accumulation amount. For example, when the current value of the residual accumulation amount is 1,300 Nm3 and the maximum accumulation amount is 1,500 Nm3, the accumulation margin is 200 Nm3.
In order to adjust the supply and demand of power, it is necessary to maintain a state in which the power consumption amount is increased over a designated time (for example, 30 minutes or 1 hour), and it is necessary to prevent the hydrogen production amount during this time from exceeding the accumulation margin (for example, 200 Nm3). Therefore, a value (for example, 400 Nm3/h) obtained by dividing the accumulation margin (for example, 200 Nm3) by the power supply and demand adjustment time (for example, 0.5 hours) is the upper limit of the production amount per hour. At this time, the upper limit value of the output of the water electrolysis device 12 is the operation output (for example, 125% of the rated output) corresponding to the upper limit value of the production amount (for example, 400 Nm3/h). At this time, the adjustment margin is a difference between the current value of the driving output and the output upper limit value. For example, when the water electrolysis device 12 is operated at the rated output and the output upper limit value is 125% of the rated output, the adjustment margin is 25% of the rated output.
To be noted, the accumulation margin of the accumulator 16 may be calculated in consideration of the demand amount of hydrogen. For example, if the fuel cell vehicle 92 is filled with hydrogen from the dispenser 18 in the power supply and demand adjustment time period, the accumulation margin of the accumulator 16 increases accordingly. Therefore, the hydrogen demand amount in the power supply and demand adjustment time period may be added as the accumulation margin of the accumulator 16. For example, when the current value of the residual accumulation amount is 1,300 Nm3, the maximum accumulation amount is 1,500 Nm3, and the hydrogen demand amount in the power supply and demand adjustment time period is 300 Nm3, the residual accumulation amount may be 1,500−1,300+300=500 Nm3. In addition, a value (for example, 150 Nm3) obtained by multiplying the hydrogen demand amount in the power supply and demand adjustment time period by a predetermined safety coefficient (for example, 0.5) may be added to the accumulation margin. By setting the safety coefficient, it is possible to reduce the possibility that the accumulation margin is eliminated when the actual result of the hydrogen demand is smaller than the prediction.
The control device 20 calculates the adjustment margin of the water electrolysis device 12 on the basis of both the operation margin of the water electrolysis device 12 and the accumulation margin of the accumulator 16. Specifically, a relatively smaller value among the adjustment margin based on the operation margin of the water electrolysis device 12 and the adjustment margin based on the accumulation margin of the accumulator 16 is set as the adjustment margin of the water electrolysis device 12. For example, when the adjustment margin based on the operation margin of the water electrolysis device 12 is 50% of the rated output and the adjustment margin based on the accumulation margin of the accumulator 16 is 25% of the rated output, the adjustment margin of the water electrolysis device 12 is set to 25%. The control device 20 may determine the adjustment margin of the water electrolysis device 12 on the basis of either the operation margin of the water electrolysis device 12 or the accumulation margin of the accumulator 16.
Next, a case where the power consumption of the water electrolysis device 12 is reduced will be described. The operation output of the water electrolysis device 12 can be reduced to the minimum rated power of the water electrolysis device 12. In this case, the adjustment margin is restricted by the difference between the current value of the operation output and the minimum rated power of the water electrolysis device 12. For example, when the water electrolysis device 12 is operated at the rated output and the minimum rated power is 20% of the rated output, the adjustment margin is 80% of the rated output. To be noted, the difference between the current value of the operation output and the minimum rated power of the water electrolysis device 12 is also referred to as “operation margin”.
When the power consumption amount of the water electrolysis device 12 is reduced, the production amount of hydrogen is reduced as compared with the original supply and demand plan, so that the residual accumulation amount of the accumulator 16 may reach the lower limit. For example, if the accumulator 16 becomes empty, hydrogen cannot be supplied to the fuel cell vehicle 92 that has come to the hydrogen station 10, which hinders the operation of the hydrogen station 10. Therefore, the adjustment margin of the water electrolysis device 12 is also restricted by the hydrogen demand amount in the power supply and demand adjustment time period. In order to meet the hydrogen demand, it is necessary to produce the hydrogen shortage amount obtained by subtracting the current value of the residual accumulation amount from the hydrogen demand amount in the power supply and demand adjustment time period. For example, when the hydrogen demand amount in the power supply and demand adjustment time period is 240 Nm3 and the current value of the residual accumulation amount is 144 Nm3, the hydrogen shortage amount is 96 Nm3. At this time, a value (for example, 96 Nm3/h) obtained by dividing the hydrogen shortage amount (for example, 96 Nm3) by the power supply and demand adjustment time (for example, 1 hour) is the lower limit value of the production amount per hour. The lower limit value of the output of the water electrolysis device 12 is an operation output (for example, 30% of the rated output) corresponding to the lower limit value of the production amount (for example, 96 Nm3/h). At this time, the adjustment margin is a difference between the current value of the operation output and the lower limit value of the output. For example, when the water electrolysis device 12 is operated at the rated output and the lower limit value of the output is 30% of the rated output, the adjustment margin is 70% of the rated output.
To be noted, the hydrogen shortage amount in the power supply and demand adjustment time period may be calculated in consideration of a lower limit value (for example, 100 Nm3) of the residual accumulation amount serving as a buffer. The lower limit value of the residual accumulation amount may match the capacity of the high-pressure accumulator 22, or may be a value obtained by further adding a buffer to the capacity of the high-pressure accumulator 22. By setting the lower limit value of the residual accumulation amount to a value equal to or larger than the capacity of the high-pressure accumulator 22, a state in which the high-pressure accumulator 22 is fully filled with the high-pressure hydrogen can be maintained, and hydrogen gas can be always and immediately supplied to the fuel cell vehicle 92 visiting the hydrogen station 10. In addition, the hydrogen shortage amount may be calculated by using a value (for example, 192 Nm3) obtained by multiplying the hydrogen demand amount in the power supply and demand adjustment time period by a predetermined safety coefficient (for example, 2). By setting the safety coefficient, it is possible to reduce the possibility that the stock of hydrogen runs out when the actual hydrogen demand exceeds the prediction.
The control device 20 calculates the adjustment margin of the water electrolysis device 12 on the basis of both the operation margin of the water electrolysis device 12 and the hydrogen shortage amount in the power supply and demand adjustment time period. Specifically, a relatively smaller value among the adjustment margin based on the operation margin of the water electrolysis device 12 and the adjustment margin based on the hydrogen shortage amount in the power supply and demand adjustment time period is set as the adjustment margin of the water electrolysis device 12.
For example, when the adjustment margin based on the operation margin of the water electrolysis device 12 is 80% of the rated output and the adjustment margin based on the hydrogen shortage amount in the power supply and demand adjustment time period is 70% of the rated output, the adjustment margin of the water electrolysis device 12 is set to 70%. The control device 20 may determine the adjustment margin of the water electrolysis device 12 on the basis of either the operation margin of the water electrolysis device 12 or the hydrogen shortage amount in the power supply and demand adjustment time period.
When providing the commercial power network 90 with a power supply and demand adjustment capability, the control device 20 adjusts the power consumption amount of the water electrolysis device 12 within the range of the calculated adjustment margin. The control device 20 adjusts the power consumption amount of the water electrolysis device 12 within the range of the adjustment margin to be closer to an adjustment target amount instructed from the power supply side or the aggregator, for example. When the power consumption amount of the water electrolysis device 12 is adjusted, the control device 20 may calculate an actual value of the adjustment amount of the power consumption amount. For example, the actual value of the adjustment amount may be obtained by measuring the power consumption amount of the water electrolysis device 12 in the power supply and demand adjustment time period and calculating a difference from the power consumption amount based on the initial operation plan or the power consumption amount immediately before the adjustment.
When providing the commercial power network 90 with the power supply and demand adjustment capability, the control device 20 may update the operation plan of the water electrolysis device 12 so that excess or deficiency of the hydrogen production amount caused by the adjustment of the power consumption amount is eliminated or alleviated. For example, when the power consumption is increased in the power supply and demand adjustment time period, the operation output in a time period different from the power supply and demand adjustment time period may be reduced as compared with the original plan. Conversely, when the power consumption is reduced in the power supply and demand adjustment time period, the operation output in a time period different from the power supply and demand adjustment time period may be increased as compared with the original plan. When the operation plan is updated, similarly to when the operation plan is created, the inventory amount for each time is determined to fall within a range from a predetermined lower limit value to an upper limit value.
In the example shown in
In the examples illustrated in
Specifically, a scheduled value of the hydrogen production amount in the immediate period is calculated on the basis of the predicted value of the hydrogen demand amount in the immediate period and the current value of the hydrogen inventory amount. The operation output may be determined on the basis of the calculated scheduled value of the hydrogen production amount. In addition, the adjustment margin of the water electrolysis device 12 may also be calculated each time. For example, the adjustment margin of the water electrolysis device 12 may be calculated on the basis of the current value of the operation output of the water electrolysis device 12, the scheduled value of the hydrogen production amount in the immediate period, the predicted value of the hydrogen demand amount in the immediate period, and the current value of the hydrogen inventory amount. The power consumption amount in the immediate period of water electrolysis device 12 may be adjusted on the basis of the adjustment margin calculated in this way. In addition, the operation plan of the water electrolysis device 12 may be determined and the adjustment margin may be calculated without using the predicted value of the hydrogen demand amount. For example, the operation plan of the water electrolysis device 12 may be determined and the adjustment margin may be calculated on the basis of only the current value of the hydrogen inventory amount.
Next, coordination control of power consumption amounts in a plurality of hydrogen stations will be described. In order to popularize fuel cell vehicles using hydrogen as a fuel, it is necessary to prepare hydrogen stations at various places to improve convenience. Similar to a fuel station for gasoline, diesel fuel, or the like, a form in which a large hydrogen station is provided along a highway and a small hydrogen station is provided in an urban area can be considered. In the case of gasoline, diesel fuel, and the like, it is necessary to transport fuel produced in a large-scale petroleum refining plant to each fuel station by using a carrier ship, a railway, a tank truck, or the like. In contrast, in the case of hydrogen, since hydrogen can be locally produced using a small water electrolysis device, transportation cost can be suppressed. In addition, even in the case of a small hydrogen station in which a water electrolysis device cannot be installed due to factors such as location, demand, and cost, transportation cost can be reduced by transporting hydrogen produced in a nearby hydrogen station or hydrogen production site. Furthermore, by adjusting the power consumption amount of each water electrolysis device installed in the plurality of hydrogen stations in a cooperative manner, it is possible to provide a great adjustment capability to the supply and demand of power of the commercial power network. As a result, it is possible to efficiently use the renewable energy having a large output fluctuation and to suppress the transportation cost of hydrogen, so that it is possible to enhance the energy efficiency in the whole society.
The plurality of hydrogen stations 10a to 10h include a plurality of on-site hydrogen stations (also referred to as on-site STs) 10a and 10b and a plurality of off-site hydrogen stations (also referred to as off-site STs) 10c to 10h. In the example of
The on-site STs 10a and 10b have facilities for producing hydrogen. For example, the on-site ST 10a includes a water electrolysis device 12a, a compressor 14a, an accumulator 16a, a pre-cooler 17a, a dispenser 18a, and a control device 20a, and is configured similarly to the hydrogen station 10 according to the above-described embodiment. In addition, the on-site ST 10b includes a water electrolysis device 12b, a compressor 14b, an accumulator 16b, a pre-cooler 17b, a dispenser 18b, and a control device 20b, and is configured similarly to the hydrogen station 10 according to the above-described embodiment.
The off-site STs 10c to 10h do not have facilities for producing hydrogen. For example, the off-site ST 10c includes a compressor 14c, an accumulator 16c, a pre-cooler 17c, a dispenser 18c, and a control device 20c, but does not include a water electrolysis device. Therefore, the off-site STs 10c to 10h are configured similarly to those obtained by removing the water electrolysis device 12 from the hydrogen station 10 according to the above-described embodiment. The off-site STs 10c to 10h procure hydrogen produced at other sites and supply hydrogen. In the example of
The hydrogen production site 30 has a facility for producing hydrogen, but does not have a facility for supplying hydrogen to the fuel cell vehicle 92. The hydrogen production site 30 includes a water electrolysis device 32, a compressor 34, an accumulator 36, and a control device 38, but does not include a pre-cooler and a dispenser. The hydrogen production site 30 may include a water electrolysis device 32 larger than the water electrolysis devices 12a and 12b of the on-site STs 10a and 10b, and may have a higher hydrogen production capacity than the on-site STs 10a and 10b.
The control device 38 of the hydrogen production site 30 creates a production plan of the water electrolysis device 32 on the basis of the supply and demand hydrogen at the off-site STs 10e to 10h to which hydrogen is to be supplied. When it is necessary to adjust the supply and demand of power of the commercial power network 90, the control device 38 of the hydrogen production site 30 calculates the adjustment margin of the power consumption of the water electrolysis device 32 on the basis of the supply and demand of hydrogen and the hydrogen inventory amount of the off-site STs 10e to 10h serving as supply destinations, the production plan of the water electrolysis device 32, the residual accumulation amount of the accumulator 36, and the like. The adjustment margin of the water electrolysis device 32 can be calculated in a similar manner to the adjustment margin of the hydrogen station 10 according to the above-described embodiment.
The plurality of on-site STs 10a and 10b and the hydrogen production site 30 included in the hydrogen supply system 50 consume power supplied from the same commercial power network 90 to produce hydrogen. Therefore, the plurality of on-site STs 10a and 10b and the hydrogen production site 30 included in the hydrogen supply system 50 have adjustment capability for supply and demand of power on the same commercial power network 90.
The management center 40 includes a management apparatus 42 for managing overall supply and demand of hydrogen in the hydrogen supply system 50. The management apparatus 42 is realized by an element or a circuit such as a processor (e.g., CPU) and a memory (e.g., ROM and/or RAM) of a computer as a hardware configuration, and is realized by a computer program or the like as a software configuration. It should be understood by those skilled in the art that various functions of the management apparatus 42 can be realized in various forms by a combination of hardware and software.
The management apparatus 42 is connected to each control device of the plurality of hydrogen stations 10a to 10h and the hydrogen production site 30, and supports creation of a supply and demand plan of hydrogen in each site. For example, the on-site ST 10a needs to supply part of the hydrogen gas produced by the water electrolysis device 12a to the two off-site STs 10c and 10d. The management apparatus 42 notifies the on-site ST 10a of the demand amount and the inventory amount of hydrogen gas at the off-site STs 10c and 10d serving as supply destinations, and supports the on-site ST 10a to create a supply and demand plan in consideration of the hydrogen demand at the supply destinations. Similarly, the hydrogen production site 30 needs to supply hydrogen gas produced by the water electrolysis device 32 to the four off-site STs 10e to 10h.
The management apparatus 42 notifies the hydrogen production site 30 of the demand amount and the inventory amount of hydrogen gas of the off-site STs 10e to 10h serving as supply destinations, and supports the hydrogen production site 30 to create a production plan according to the hydrogen demand at the supply destinations. The management apparatus 42 may create a transportation plan of hydrogen gas from the on-site ST 10a or the hydrogen production site 30 to the off-site STs 10c to 10h. The management apparatus 42 may collectively create a supply and demand plan of hydrogen at each site.
The management apparatus 42 acquires a command for adjusting the supply and demand of power of the commercial power network 90. The management apparatus 42 receives, for example, an adjustment command issued by a power company or an aggregator of the commercial power network 90 via the Internet. In addition, an adjustment command may be received by telephone, FAX, e-mail, or the like, and the person in charge who has received the command may input the content of the adjustment command to the management apparatus 42. The adjustment command includes a time period in which the supply and demand of power should be adjusted and an adjustment target amount of the supply and demand of power.
When acquiring a command for adjusting supply and demand of power from the commercial power network 90, the management apparatus 42 acquires adjustment margin of power consumption of the plurality of on-site STs 10a and 10b and the water electrolysis devices 12a, 12b, and 32 at the hydrogen production site 30. The management apparatus 42 requests the plurality of on-site STs 10a and 10b and the control devices 20a, 20b, and 38 of the hydrogen production site 30 to calculate the adjustment margin of the water electrolysis devices 12a, 12b, and 32. When requesting the calculation of the adjustment margin, the management apparatus 42 may designate a time in which the supply and demand of power should be adjusted. The control devices 20a, 20b, and 38 in respective sites calculate the adjustment margin of the water electrolysis devices 12a, 12b, and 32 on the basis of the request from the management apparatus 42, and transmit the calculated adjustment margin to the management apparatus 42. The control devices 20a, 20b, and 38 in respective sites may transmit the latest information of the supply and demand plan of hydrogen in each site to the management apparatus 42. For example, the current value of the production amount of hydrogen gas and the residual accumulation amount in each site may be transmitted to the management apparatus 42. To be noted, the management apparatus 42 may calculate the adjustment margin of the power consumption of the water electrolysis devices 12a, 12b, and 32 in respective sites on the basis of the supply and demand plan of hydrogen in the respective sites.
The management apparatus 42 determines the adjustment amount of the power consumption of the entire hydrogen supply system 50 within the range of the adjustment margin of each site on the basis of the adjustment margin of the power consumption of the water electrolysis devices 12a, 12b, and 32 of respective sites. For example, the management apparatus 42 sets the total value of the adjustment margin of respective sites as the adjustment amount of the entire system. The management apparatus 42 may set the adjustment amount in the entire system to be smaller than the total value of the adjustment margin of respective sites. For example, when the adjustment target amount of the supply and demand of power is set stepwise in units of 1,000 kW, 5,000 kW, or the like, the adjustment amount of the entire system may be determined so as to match the stepwise adjustment target amount. The management apparatus 42 may participate in bidding for acquiring the right of adjustment of supply and demand of power within the range of the total value of the adjustment margin of respective sites, and determine the adjustment amount of the entire system on the basis of the adjustment amount that has been successfully bid.
The management apparatus 42 distributes the adjustment amount of the entire system to respective sites and determines the adjustment amount of the power consumption of each site. The management apparatus 42 may equally distribute the adjustment amount of the power consumption to respective sites, and may set a value obtained by multiplying the adjustment margin of each site by a common distribution rate as the adjustment amount of each site. The common distribution rate corresponds to the ratio of the adjustment amount in the entire system to the total value of the adjustment margin of the power consumption of respective sites. For example, when the total value of the adjustment margin of the power consumption of respective sites is 5,800 kW and the adjustment amount of the entire system is 5,000 kW, the distribution rate is 86.2%.
The management apparatus 42 may distribute the adjustment amount of the power consumption to respective sites with a gradient. The management apparatus 42 may determine the adjustment amount of each site according to the magnitude of the adjustment margin of each site. For example, the adjustment amount may be made relatively small for a site having a relatively small adjustment margin, and the adjustment amount may be made relatively large for a site having a relatively large adjustment margin. The management apparatus 42 may individually determine the distribution rate of each site according to the magnitude of the adjustment margin of each site. The adjustment amount distributed to a site having a relatively small adjustment margin may be a value obtained by multiplying the adjustment margin of the site by a distribution rate (for example, 80%) smaller than the common distribution rate (for example, 86.2%). The adjustment amount distributed to the site having a relatively large adjustment margin may be a value obtained by multiplying the adjustment margin of the site by a distribution rate (for example, 90%) larger than the common distribution rate (for example, 86.2%). The management apparatus 42 may distribute the adjustment amount of the power consumption to respective sites with a gradient on the basis of the production amount of hydrogen gas and the current value of the residual accumulation amount in each site. In addition, when the production capacity of the water electrolysis device in each site is different for each site (for example, in the case of 600 Nm3/h, 300 Nm3/h and 100 Nm3/h), the adjustment amount of the power consumption may be distributed with a gradient according to the production capacity of each site. Adjustment according to the current value of the production capacity of the water electrolysis device in each site may be performed, and for example, adjustment may be performed in consideration of a decrease in the output of the water electrolysis device derived from deterioration or the like caused by use for a long period. In addition, the power consumption may be adjusted only in the remaining sites (for example, the on-site ST 10b and the hydrogen production site 30) without adjusting the power consumption in some site (for example, the on-site ST 10a).
The management apparatus 42 sends a command for designating a time period for adjusting the supply and demand of power and an adjustment amount of the power consumption to the site where the power consumption should be adjusted. The management apparatus 42 may send a command for designating the operation output of the water electrolysis device in each site instead of sending the command for designating the adjustment amount of the power consumption. The control device in the site that acquires the command adjusts the operation output of the water electrolysis device in the designated time period to realize the designated adjustment amount of the power consumption. By the respective sites adjusting the power consumption in cooperation with each other, the adjustment target amount of the supply and demand of power instructed from the power company or the aggregator can be realized in the entire hydrogen supply system 50.
According to the present embodiment, it is possible to provide the commercial power network 90 with a great adjustment capability that cannot be achieved by a single electrolysis device. For example, when the power generation amount from the renewable energy is large, the operation output of each electrolysis device can be increased to increase the ratio of the hydrogen production amount using the renewable energy. In addition, by lowering the operation output of each electrolysis device when power generation using the renewable energy is not expected, the ratio of the hydrogen production amount using power not derived from renewable energy can be decreased. As a result, renewable energy having a large output fluctuation can be efficiently used. In addition, since hydrogen can be produced on site using the water electrolysis device and consumed on site, the transport cost of hydrogen can also be suppressed. Therefore, according to the present embodiment, it is possible to contribute to improvement of energy efficiency in the whole society.
In the above-described embodiment, at least one of the plurality of off-site STs 10c to 10h may receive supply of hydrogen gas from a plurality of sites. For example, the off-site ST 10c may receive supply of hydrogen gas from the plurality of on-site STs 10a and 10b, or may receive supply of hydrogen gas from both the on-site ST 10a and the hydrogen production site 30. In addition, at least one of the plurality of on-site STs 10a and 10b may receive supply of hydrogen gas from the hydrogen production site 30. That is, the hydrogen production site 30 may supply hydrogen gas not only to the plurality of off-site STs 10e to 10h but also to at least one of the plurality of on-site STs 10a and 10b. The hydrogen supply system 50 may include a hub-type hydrogen station. The hub-type hydrogen station is configured to receive supply of hydrogen gas from another site (hydrogen production site or on-site hydrogen station) and supply hydrogen gas to another site (off-site or on-site hydrogen station). The hub-type hydrogen station may be an on-site type having a water electrolysis device or an off-site type having no water electrolysis device.
In the above-described embodiment, the hydrogen supply system 50 does not have to include the hydrogen production site 30. The hydrogen supply system 50 may include a site having an electrolysis device different from the water electrolysis device. For example, an organic hydride production site having an electrolysis device for producing an organic hydride by an electrolytic reaction consuming power supplied from the commercial power network 90 may be provided. The organic hydride is a liquid that easily generates hydrogen gas by a dehydrogenation reaction, and examples thereof include methylcyclohexane, cyclohexane, decalin and derivatives thereof, and 2-propanol. For example, methylcyclohexane can be produced by an electrolytic reaction in which hydrogen derived from water is added to toluene, and hydrogen gas can be produced by a dehydrogenation reaction of methylcyclohexane. Since the organic hydride is a liquid, the transport cost thereof is lower than that of hydrogen gas. Therefore, in the hydrogen supply system 50, an organic hydride may be produced, the produced organic hydride may be transported to another site, and hydrogen gas may be produced from the organic hydride in another site.
The hydrogen supply system 50 may include an organic hydride production site and an on-site hydrogen station that produces hydrogen by a dehydrogenation reaction of the organic hydride. The hydrogen supply system 50 may provide an adjustment capability for the supply and demand of power to the commercial power network 90 by adjusting the power consumption of the electrolysis device in the organic hydride production site. The adjustment margin of the power consumption in the organic hydride production site may be determined on the basis of the supply and demand plan of the organic hydride in the organic hydride production site. The supply and demand plan for the organic hydride may include hourly plans for the demand amount, production amount, and inventory amount of the organic hydride. The demand amount of the organic hydride may be determined on the basis of the supply and demand plan of hydrogen in the on-site hydrogen station serving as a supply destination.
The supply destination of the organic hydride does not have to be an on-site hydrogen station, and may be a hydrogen production site having no facility for filling a fuel cell vehicle. This hydrogen production site has a hydrogen production device for producing hydrogen by a dehydrogenation reaction of an organic hydride. This hydrogen production site may supply hydrogen gas to an off-site hydrogen station. The supply and demand plan of this hydrogen production site is determined on the basis of the supply and demand plan of hydrogen in the off-site hydrogen station serving as a supply destination. In this way, a hydrogen supply network may be constructed by a combination of an organic hydride production site, a hydrogen production site, and an off-site hydrogen station. In this case, the adjustment margin of the power consumption in the organic hydride production site may be determined on the basis of the supply and demand plan of hydrogen in the off-site hydrogen station serving as the final supply destination of hydrogen.
In the above-described embodiment, the hydrogen supply system may be configured not to include the on-site hydrogen station. In this case, the hydrogen supply system may include a plurality of hydrogen production sites and a plurality of off-site hydrogen stations. Similarly to the hydrogen production site 30 described above, each hydrogen production site may have a water electrolysis device, a compressor, an accumulator, and a control device. Similarly to the off-site STs 10c to 10h, each off-site hydrogen station may have a compressor, an accumulator, a pre-cooler, a dispenser, and a control device. Each off-site hydrogen station may receive supply of hydrogen gas from at least one of the plurality of hydrogen production sites. The supply and demand plan of each hydrogen production site may be determined on the basis of the supply and demand plan of hydrogen in the off-site hydrogen station serving as a supply destination. At this time, by adjusting the power consumption of the plurality of water electrolysis devices installed in the plurality of hydrogen production sites, the commercial power network may be provided with an adjustment capability for the supply and demand of power.
The embodiments of the present invention have been described in detail above. The above-described embodiments are merely specific examples for carrying out the present invention. The contents of the embodiments do not limit the technical scope of the present invention, and many design changes such as changes, additions, and deletions of constituents can be made without departing from the spirit of the invention defined in the claims. The new embodiment to which the design change has been made has the effect of each of combined embodiments and modifications. In the above-described embodiments, contents that can be changed in design as described above are emphasized with notations such as “of the present embodiment” and “in the present embodiment”, but the design change is allowed even for contents without such notations. Any combination of the above-described constituents is also effective as an aspect of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-031886 | Feb 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/006456 | 2/19/2021 | WO |
