Abstract:
A system for utilizing coal energy includes a thermal power generator near a coal field area that converts coal energy of the coal field area located remotely from a demand end to electric energy. It also includes an alternating current load at a demand end side, an alternating current power distribution network, and an electric power transmission mechanism that transmit electric energy from the thermal power generator to the power distribution network. The electric power transmission mechanism is a combination of super conductive power transmitting system that transmit direct current electricity with small transmission loss utilizing super conductive power transmitting cables and a conventional power distribution network operating at ambient temperatures. Electricity is transmitted to the demand end through the alternating current power distribution network by converting alternating current at a feeding point of the power distribution network where the current is fed with an alternating current converting mechanism provided at the connecting end.

Description:
[0001]     This is a continuation of International Application No/PCT/JP2004/004685 having an international filing date of 31 Mar. 2004; this International Application was not published in English, but in Japanese as WO 2004/088815.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention is related to a system for utilizing coal energy including peat energy, particularly to effective utilization of coal energy produced at a remote cold district, more particularly to an effective system for utilizing coal energy, wherein the coal is converted to electric energy at a production region by thermal power generation and the converted electric energy is transmitted to a demand end by combination of super conductive electric cables and a conventional power distribution network.  
         [0004]     2. Description of the Related Art  
         [0005]     Fossil fuels such as petroleum, natural gas, and coal is utilized for thermal power generation. Petroleum is transported by mammoth tankers or pipelines. Natural gas is transported by LNG ships or pipelines as liquid natural gas. Coal is transported by ore ships. However, as for problems of transportation of a fossil fuel to exportation bases from digging bases, of loading and unloading of a fossil fuel to and from ships, and of storage of a fossil fuel at importation bases or power plants, the coal has a big drawback in logistics condition compared with petroleum and natural gas.  
         [0006]     Although petroleum and natural gas is transported by pipelines on land, transportation of coal by cars has problems of heavy weight and wastefulness. However, coal bears 30% energy supply of the world and is more abundant than petroleum. Therefore, energy transformation development of coal has been performed such as transformation to low cost liquid fuel or gaseous fuel. It has been studied that liquid or gaseous fuel, which is obtained by energy transformation at production regions, is used in Japan.  
         [0007]     Many international cooperations are made concerning coal energy technology development. As bilateral cooperations, cooperation between Japan and U.S.A., and cooperation between Japan and Australia have been performed. Although, other than the above cases, coal producing countries such as China, Indonesia, Russia, Mongol, etc., cooperate with each other, they have not been practical.  
         [0008]     Therefore, effective utilization of coal, whose amount of deposits is several times as much as that of petroleum or natural gas, is an issue of 21 century, though it is far more inferior to petroleum or natural gas among fossil fuels with regard to logistics.  
         [0009]     Further, the amount of peat deposits in the world is as big as 500 billion to one trillion. Particularly, peat has low heat energy and is low on sulfur and ash, and is effective as biomass energy.  
         [0010]     Meanwhile, as for demand and supply of electricity, peak load is increased as demand of electricity is abruptly increased based on different economical growth by different districts, so that satisfaction to the demand of electricity is imbalanced with respect to districts.  
         [0011]     Particularly, as for supply and demand, absolute value of electricity demand as well as peak load has been increased so that load factor has been lowered year after year. To cope with the fact, necessity compels electric power companies to build power plants having as large capacities as suffice peak load. To correspond to requirement of increasing capacity of electric power system, installation of power generating plants, power lines, and transformer stations is necessary for supplying the electric power matching with the increasing load. However, plant sites are hard to locate in the vicinity of cities. Besides, it is typical for the hydraulic resources to be far from the cities. Meanwhile, areas capable of using as a power generating plant is getting more difficult to acquire from a viewpoint of environmental problems, which makes it difficult to newly build a power plant.  
         [0012]     There is CIGRE Keyone Address (Paris, Aug. 28, 1994) as an idea of collaboration involving many countries. In the literature, a collaboration system of Mediterranean region and a collaboration system of Africa region are shown. For example, in a collaboration system of Africa region, (1) a collaboration of peak loads in winter and summer, and (2) mitigation of daily peak demands by considering  4  hours time difference between west and east are described.  
         [0013]     In order to dissolve the imbalance of satisfaction for regional power demands, realization of a wide area accommodation system of energy and electricity is strongly desired by considering regional difference. A power loss and difference of voltage among countries are big problems with regard to power transportation and accommodation utilizing a wide area power distribution network.  
       SUMMARY OF THE INVENTION  
       [0014]     The present invention relates to a system for utilizing coal energy, wherein coal including peat energy of coal mines is converted to electric energy through thermal power generation utilizing effectively an electric power storage facility comprising super conductive power transmitting cables or super conductive coils and a conventional power distribution network, and the electric energy can be distributed to remote locations.  
         [0015]     One aspect of the present invention is a system for utilizing coal energy comprises means for thermal power generation near a coal field area that converts coal energy of the coal field area, existing at a remote area different from a demand end, to electric energy by a thermal power generation. It further includes an alternating current load at a demand end side, an alternating current power distribution network, and means for electric power transmission that transmits electric energy from the means for thermal power generation near the coal field area to the power distribution network. The means for electric power transmission can be a combination of super conductive power transmitting system that transmits direct current electricity of small transmission loss utilizing super conductive power transmitting cables and a conventional power distribution network operating at ordinary temperatures. Electric energy is transmitted to the demand end through the alternating current power distribution network by converting alternating current at a feeding point of the power distribution network where the current is fed with an alternating current converting mechanism provided at the connecting end.  
         [0016]     Further according to the present invention, the means for electric power transmission can be a normal power distribution network at normal temperature at the connecting end of which an electric power storage facility comprising a super conductive coil is provided and electric energy is transmitted to the demand end through the power distribution network, thereby power fluctuation at the demand end or the power plant side is absorbed.  
         [0017]     The present system can be applied to a coalfield zone in cold remote districts of bad logistic condition such as Siberia, neighboring countries of Russia or Eastern Europe. The system is thought up instead of a conventional system in which coal produced in a production area is transported to a thermal plant at a demand end to generate electricity. While coal produced in a production area is converted at a thermal plant near the coal field so as to transmit on an existing power distribution network, a super conductive power transmitting cable having a function of storing electricity by itself is interposed therebetween or an electric power storage facility comprising super conductive coils is provided to transmit electricity to a power distribution network at a demand end. Consequently, fluctuation or stoppage of power can be absorbed by compensation since the power transmitting cable has a function of electric power storage even if fluctuation or stoppage of power occurs at the demand end side or the power plant.  
         [0018]     As shown specifically in  FIG. 5 (B), instead of transmitting surplus power to a demand end side at a surplus power period like in spring or autumn or at night of the demand end, power is introduced through a flow divider  91  to super conductive cables  82 ,  83  at the part where a conventional power distribution network is not connected. After taking in the surplus power, a closed circuit is formed by shutting current by-pass circuits  92   s ,  94   s  to store the taken electric power. When a supplying amount of power runs short, dipping from a demand such as in summer or winter or at the day time of a demand end, the stored power is lead to a power cable  81  through a connector  93  by opening the current by-pass circuit  94   s  to transmit to the power distribution network at the demand end.  
         [0019]     Further, as shown in  FIG. 6 , the same is the case of providing a electric power storage facility comprising a super conductive coil at a connecting end between a feeding line of a power plant side (a power generator in case of a delivery-with-pressure station) and a conventional power distribution network.  
         [0020]     When a cross-channel region or a big river and the like lies therebetween, the means for electric power transmission is preferably provided with relay parts, between which a super conductive power transmitting cable is preferably provided or an electric power storage facility comprising a superconductive coil is preferably provided at a connecting end to the conventional power distribution network.  
         [0021]     The means for electric power transmission can be power transmitting cables provided along natural gas pipelines along which delivery-with-pressure stations are provided at predetermined intervals. Waste heat thereof can be recovered by power generation with Rankine cycle. The generated electric power can be fed to the power transmitting cables through means for super conductive transmission of electricity or through electric storage facilities at the connecting ends comprising super conductive coils.  
         [0022]     The means for thermal generation of coal, including peat field production region side, can be constructed between a plurality of systems or nations having thermal power plants. In this case, in view of absorbing load fluctuation between the power plants, power is preferably fed to the power transmitting cable between the power plants through an electric power storage facility comprising a super conductive coil at the connecting end.  
         [0023]     Further, if an electric power storage facility comprising a super conductive coil is provided at receiving side of electricity after voltage is lowered at a transformer station, the cost can be cut down.  
         [0024]     Means for supplying cooling energy for maintaining super conductive state can be installed together with means for transmitting electric power at the electric power storage facility comprising means for super conductive transmission of electricity or a super conductive coil utilizing a super conductive power transmission cable.  
         [0025]     The connecting end of the super conductive power transmission cable and the demand side power distribution network can be provided with a power relay part comprising means for converting currents for converting direct current to alternating current and a power load adjusting means for regulating an appropriate power transmitting amount to the power distribution network by checking a state of power load from the demand side power distribution network disposed at the upstream of the means for converting currents. The means for converting currents and the means for adjusting power load can be super conductive apparatuses using means for supplying cooling energy.  
         [0026]     The means for supplying cooling energy can be provided along the means for super conductive transmission of electricity, and that cooling energy can be supplied for maintaining super conductive state of superconductive apparatuses including the super conductive cable.  
         [0027]     The means for supplying cooling energy can be provided in the district where the means for converting currents of the super conductive transmission cable which forms the means for transmitting electric power and the means for adjusting power load. The means for supplying cooling energy cools the super conductive cable and the super conductive apparatus. In case there is a relay part of the means for transmitting electric power, a electric power storage facility is preferably provided at the relay part.  
         [0028]     The coal field zones of the remote district or cold district can include Siberia including Far East of Russian, CIS, Eastern Europe and further a deep district of China. Demand ends can include Japan, Korea, China coast area, or Russia city districts and developed countries in Europe.  
         [0029]     The coal fields of neighboring countries of Russia (CIS), inland countries of China, Siberia district including Far East are scattered in undeveloped remote districts and have abundant amount of deposits. In order to transmit the electricity obtained thermal generation systems near the coalfields comprising thermal plants groups formed in these areas to alternating current power load systems in metropolitan regions of demand ends of electric power distribution networks such as urban areas in Russia, in developed countries in Europe, further urban areas along coast districts in China, urban areas in Korea or urban areas in neighboring countries of Russia, or to alternating current power load systems in metropolitan regions of demand ends of Japanese electric power distribution networks through Hokkaido, power needs to be transmitted for an extremely long distance. Therefore, in order to feed power to a district that does not have an existing power distribution network or to a power distribution network between power plants or natural gas pipe lines, power load fluctuation of power plant side (including a generator of a delivery station of natural gas), of a demand end side or a conventional electric power distribution network between nations or over a channel can be appropriately corresponded by feeding power with means for super conductive transmission of electricity having an electric power storage function and little power loss or through a electric power storage facility comprising super conductive coils to a connecting end of a conventional electric power distribution grid.  
         [0030]     Further, as for a system for supplying cooling energy provided at a power feeding line or at a connecting end or a relay point of a conventional power distribution network, a cooling energy base can be formed in the installed sites of the means for converting currents, in the installed site of power load adjusting means, and at a plurality of relay parts, the cooling energy base being provided with a low temperature refrigerator producing cooling agent that cools a super conductive cable for transmitting direct current and a super conductive apparatus, a cooling agent storage tank that store the produced cooling agent, and a supplying pump disposed at the storage tank.  
         [0031]     The system for supplying cooling energy cools means for converting currents provided at connecting ends of inlet and outlet of each power transmission system, which is a combination of means for superconductive transmission of electricity and a conventional power distribution network, and which reaches demand ends from a thermal plant, means for adjusting power load provided at the upstream of means for converting currents of a connecting end of a demand end power distribution network, and super conductive cables, to maintain a superconductive function.  
         [0032]     The system for supplying cooling energy is provided with a storage tank for storing a generated cooling agent, and a pump for delivering the cooling agent to a super conductive cable and means for converting currents, and means for adjusting power load, along the system for electric power transmission.  
         [0033]     The low temperature refrigerator in the system for supplying cooling energy can be constructed in such a manner that a refrigerating cycle by a refrigerator operated with carbon dioxide as a refrigerant, which is taken out as exhaust gas of a thermal plant, is connected with a refrigerating cycle of liquid nitrogen or extreme low temperature brine as a cascade structure so as to deliver extremely cooled cooling agent to a super conductive cable, means for converting currents, or means for adjusting power load.  
         [0034]     Thus, since carbon dioxide and nitrogen are natural refrigerants, environment is not polluted, and, in addition, cooling for maintaining super conductive condition is possible.  
         [0035]     Because the system for supplying cooling energy can be provided along power transmission systems by way of cold areas of Siberia, Sakhalin, and Hokkaido, it is appropriate that condensing temperature is not elevated even with a refrigerating cycle of carbon dioxide refrigerant. It is also preferable that gas recovered from combustion exhaust gas of power plants is used for environment protection.  
         [0036]     Further, according to the above invention, hot heat source of high temperature water can be formed by sensible heat of condensation in case carbon dioxide is used as a refrigerant.  
         [0037]     On account of recent development of high temperature super conductive material, super conductive state can be kept at a temperature region of liquid nitrogen. Hence, a brine of liquid nitrogen region can be used in the case of high temperature super conductive material.  
         [0038]     Further, using slush nitrogen, which is a mixture of fine particles of solid nitrogen and liquid nitrogen, as a cooling agent results in more efficient utilization of cooling energy.  
         [0039]     As a result of using slush nitrogen, which is a mixture of fine particles of solid nitrogen and liquid nitrogen, the cooling agent is superior in heat load absorption capacity so that it cools effectively super conductive power transmission cables or super conductive apparatuses.  
         [0040]     Above-mentioned slush nitrogen can be produced by sucking and blowing liquid nitrogen together with low temperature cooling gas such as helium and mixing fine particles of nitrogen formed by blowing with liquid nitrogen.  
         [0041]     As formerly stated, the power transmission system and natural gas pipelines are placed side by side; and electric power that is obtained by driving a steam turbine connected to an electric generator utilizing waste heat of gas turbine can be fed to the power transmission system. Since natural gas is also produced in a remote inland of Siberia, a pipeline of natural gas is extended to each port of a demand end. Therefore, power loss in an intervening path of the conventional power distribution network or the long distance between Siberia inland and Sakhalin or Hokkaido can be replenished if power, which is generated at every delivery station of the pipeline, is fed to a conventional power distribution network by means for super conductive transmission of electricity having small power loss for feeding over the power distribution network of the natural gas pipelines, or if power, which is generated at every delivery station of the pipeline, is fed to a connecting end of a conventional power distribution network through a power storage facility comprising a super conductive coil. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0042]      FIG. 1  is a pattern diagram showing a schematic construction of a system for supplying coal energy by super conductive transmission of electricity according to the present invention.  
         [0043]      FIG. 2 (A) is a schematic illustration of a system for supplying cooling energy provided along a power transmission system shown in  FIG. 1 .  
         [0044]      FIG. 2 (B) is a schematic illustration of a system for supplying heat.  
         [0045]      FIG. 3  is a schematic illustration of a base for supplying cooling energy shown in  FIG. 2 .  
         [0046]     FIGS.  4 (A)- 4 (B) are schematic illustrations of delivery station of a supply line of natural gas when a power transmission system is run along a natural gas pipeline, where  FIG. 4 (A) is a drawing showing a case wherein a power line from the delivery station is connected to a conventional power distribution network with a super conductive cable, and  FIG. 4 (B) is a drawing showing a case wherein means for converting currents and an electric power storage facility are provided at the connecting end of the above case.  
         [0047]      FIG. 5 (A) is a drawing showing structures of a superconductive cable applied for the present invention and of a power cable capable of storing electric power.  
         [0048]      FIG. 5 (B) is a drawing showing a case wherein power is stored with the cable shown in  FIG. 5 (A).  
         [0049]     FIGS.  6 (A)- 6 (B) illustrate a case where a super conductive power storage facility comprising means for converting currents and a super conductive coil in case a power transmission line from a power plant or a delivery station is connected to a conventional power distribution network, where  FIG. 6 (A) shows a state of charging or discharging period and  FIG. 6 (B) shows a state of power storing period. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0050]     The invention will now be described in detail by way of example with reference to the accompanying drawings. It should be understood, however, that the description herein of specific embodiments such as to the dimensions, the kinds of material, the configurations and the relative disposals of the elemental parts and the like, and the geographic locations, are not intended to limit the invention to the particular forms disclosed but the intention is to disclose for the sake of example unless otherwise specifically described.  
         [0051]     First, referring to  FIG. 5 , a schematic drawing of a super conductive power transmitting system used in the present invention is explained.  
         [0052]     For example, concerning a super conductive power transmitting system, a super conductive power transmitting technique capable of maintaining a power system stable by storing excess electric power and buffing an abrupt movement of power load wherein a construction cost as well as an operating cost are tried to be diminished is proposed on Japanese laid-open patent publication No. P1993-308726.  
         [0053]     As shown in  FIG. 5 (A), a power transmission cable  16  comprises a first super conductive cable  82  is disposed in parallel with a power cable  81 . A second super conductive cable  83 , wound like a coil in such a manner that the cable  83  contains the power cable  81  and super conductive cable  82 , is provided. A cylinder shaped protective case or jacket  84  is provided outward thereof. An electrical insulating layer  85  is provided at the outer peripheral parts of the power cable  81  and the first super conductive cable  82 . Liquid nitrogen  87  is filled in the protective case  84  so as to cool the power cable  81  and the super conductive cables  82  and  83 .  
         [0054]     As shown in  FIG. 5 (B), a system for electric power transmission  12  comprises a thus configured power transmitting cable  16 . The power transmitting cable  16  stores electric power only by means of combining the power cable  81 , which transmits electricity, with the super conductive cables  82 ,  83 , which store electric power.  
         [0055]     According to the above proposal, the system for electric power transmission  12  is composed of the power transmitting cable  16  wherein the power cable  81 , which transmits electricity, is combined with the super conductive cables  82 ,  83 , which store electric power. In-taken redundant electric power is stored by introducing a redundant electricity to the super conductive cables  82 ,  83  through a flow divider with the action of an electric power converting device  92  and by forming a closed circuit with the closing action of current by-pass circuits  92   s ,  94   s  after redundant electric power is taken in.  
         [0056]     When an amount of power supply dips from that of demand, that is when the power falls short, the stored electric power is introduced to the power cable  81  through a connector  93  by opening the current by-pass circuit  94   s  of an electric power converting device  94 .  
         [0057]     As described above, while an existing power transmission system is maintained as far as possible, a power storage function is added to a power transmission function so that buffing for fluctuation of load and stable operation of power transmission are made possible.  
         [0058]     In other words, a power transmission system  12 , which comprises a power transmitting cable  16 , concerning the present proposal is a system in which a power cable  81 , which transmits electric power, is combined with super conductive cables  82 ,  83 , so that electric power storage is possible by providing a power transmission system  12  comprising the super conductive power transmitting cable  16 .  
         [0059]     More specifically, since a super conductive cable  3  forms an infinite distance solenoid type in the power transmission system  12 , which comprises a power transmitting cable  16 , an self-inductance per unit length L and a stored energy per unit length E can be expressed by following equations: 
 
 L=μ πa   2   n   2   =μ An   2  [H/m]  (1) 
 
 E =(½) LI   2  [J/m]  (2), 
 
 where μ: magnetic permeability, 4π 10 −7  in the case of vacuum, n: a number of turns per unit length of the coil [turns/m], a: a radius of the center of the coil [m], I: electric current [A], and A: an average sectional area of the coil, na 2  [m 2 ] respectively. 
 
         [0060]     Since the stored energy E is proportional to current I squared and average sectional area of the coil A, the larger these values are, the larger electric power can be stored.  
         [0061]     Another super conductive electric power storage facility  70  is shown in  FIG. 6 . In  FIG. 6, 44  is an AC-DC converter which converts AC power from a power system to DC power;  41  is a DC breaker connected to the earth side;  42  is a super conductive coil; and  43  is DC breaker which bypasses between super conductive coils. As shown in  FIG. 6 (A), power can be charged and discharged by introducing electricity stored in the super conductive coil  42  to the power system  30  or by storing redundant electric power to the super conductive coil  42  whose electric resistance becomes zero by means of shutting the circuit with the DC breaker  41  or connecting the DC breaker  43  to the coil  42  side. Thus, it is possible to be prepared for load fluctuation of the power system  30 .  
         [0062]     As shown in  FIG. 6 (B), when the DC breaker  41  is opened, electric energy can be stored in the super conductive coil by continuing to flow electric current in the super conductive coil, whose resistance becomes nearly zero, through the AC-DC converter  44  from the power system side  30 .  
         [0063]     In  FIG. 1 , a system for electric power transmission is constructed in such a manner that a system for electric power transmission comprising the super conductive power transmitting cable  16  (hereinafter referred to as a super conductive power transmitting system  12 ), which has a function for storing electric power, such as from the power generator shown in  FIG. 4 , is combined with a conventional power distribution network  30  or a power transmission line  300  line (which can be either a super conductive power transmitting system  12  or a conventional power transmission line) provided along a natural gas pipe, so that electric power can be transmitted between a thermal power generation system  10  of a coal field side, which comprises a thermal power plant  10   a  provided in the vicinity of a coal (including peat) field, such as in an inland of Siberia, and a AC load system of demand end side  110  comprising AC loads at big city area, such as in Japan, which receives supply of electric power.  
         [0064]     Until now, coal energy in cold remote districts such as inland Siberia has been unable to be developed because of bad logistics condition of cold remote districts although there are coal fields having abundant deposits. The thermal power generation system  10  having the thermal power plant  10   a  is constructed to convert coal energy to electric energy. The super conductive power transmitting system  12  or the conventional ordinary-temperature power transmitting line  300  can be installed on the ground or under the ground as a feeding line to the existing power distribution network  30 .  
         [0065]     When the power transmission line  300  is provided on the thermal power generation system  10  and the power transmission line  300  is connected to the conventional power distribution network  30  in this case, a super conductive power storage facility can be provided at the connecting end shown in  FIG. 6 (A).  
         [0066]     Thus, electric power can be smoothly supplied even if power transmission is temporarily stopped at the side of the power transmission line  300  or load fluctuation occurs.  
         [0067]     When the DC super conductive power transmitting system  12  is provided on the thermal power generation system  10  and the DC super conductive power transmitting system  12  is connected to the conventional power distribution network  30 , it is only necessary to provide an AC-DC converter  13  at the connecting end, since the super conductive power transmitting system  12  itself has a function of storing electric power.  
         [0068]     Because an installation cost of the super conductive power transmitting system  12  is high, it cannot be installed for a very long distance. Hence, a conventional existing power distribution network  30  is utilized or a power transmission line  300  is provided along a natural gas pipeline  50 , such as those installed in Siberia and Sakhalin district. A natural gas pipeline in Siberia or Sakhalin is as long as over 1000 km, so that it is necessary to dispose delivery-with-pressure stations every  20  km distance along the pipeline.  
         [0069]     A delivery-with-pressure compressor  41  of 100,000 horse powers is driven with a gas turbine  43  taking natural gas into a combustor  42  at the delivery-with-pressure station  40 . Waste heat of the gas turbine, however, is not utilized, but discarded. If a power transmission line  300  is provided along a natural gas pipeline  50 , electric power can be generated by Rankine cycle with waste heat from the gas turbine at the delivery station  40  SO as to feed the electric power to the power distribution network  30 .  
         [0070]     Particularly, if electric current is flowed for a long distance on the ordinary power distribution network  30 , power loss is great, leading to big energy loss. However, power can be transmitted without loss when a steam turbine  46  connected to a generator  45  is driven with steam recovered from waste heat of a gas turbine by a boiler  44  so as to feed the power to the power distribution network  30 , utilizing effectively the delivery-with-pressure station disposed every 20 km distance along the pipeline. In this case, a power generator  45  can be provided at the out put end of a delivery compressor  41  and the electric power can be fed to the power distribution network  30 .  
         [0071]     As shown in  FIG. 4 (B), an AC-DC converter  13  and a super conductive power storage facility  70  can be provided between a power distribution network  30  disposed on along a natural gas pipe line  50  and the connecting end of a feeding line  300 A of delivery station side. As shown in  FIG. 4 (A), the feeding line itself can be a super conductive power transmitting system  12  so as to be connected to the conventional existing power distribution network  30 . In this case, as the super conductive power transmitting system itself  12  has a power storage function, only an AC-DC converter need be provided on the connecting end.  
         [0072]     If the heat efficiency of a gas turbine of 100,000 horse powers (75,000 kw) is 25-30%, when electric power is generated using 75-70% of waste heat with heat efficiency of 20%, electric power of 75,000 kw×3×0.2=45,000 kw is obtained without loss.  
         [0073]     Specifically, a natural gas pipe line  50  of inland Siberia in the vicinity of coal fields extends between Siberia and Sakhalin having its length of 3000 km. 150 delivery stations  40  are provided to obtain 6,750,000 kw power of electricity. The generated power is transmitted using the pipe line network.  
         [0074]     In addition, a measure for avoiding transmitting loss of power can be taken in such a manner that power is fed until the power distribution network  30  by combining an ordinary power transmission line  300  with a super conductive power transmitting system  12  through an AC-DC converter  13 .  
         [0075]     When a power distribution network  30  provided along a natural gas pipe line in the Russian side or an existing conventional power distribution network  30  is connected to a power distribution network in Japan, power is lowered or stopped on account of snow and others while passing in such remote area as Siberia or Sakhalin. Consequently, a relay station  31  at the connecting end between the Russian side and the Japanese side can be provided with a AC-DC converter  13  in conjunction with a super conductive power storage facility  70 . Otherwise, a feeding line itself of the channel is made as a DC super conductive power transmitting system  12  through an AC-DC converter  13  and connected to the power distribution networks in the Russian side and the Japanese side. In this case, as the DC super conductive power transmitting system  12  itself has a power storage function, an AC-DC converter needs to be provided at the relay station of each connecting end between the Russian side and the Japanese side.  
         [0076]     Means for adjusting the power load  15  is preferably provided at the connecting end to grasp the necessary power amount of a demand end in case a feeding line itself of a channel is a DC super conductive transmitting system  12 .  
         [0077]     As shown in FIGS.  5 (A)- 5 (B), the means for adjusting power load  15  of a super conductive transmitting system  12  side comprises an electric power converting device  92 , a flow divider  91 , and current bypass circuits  92   s ,  94   s  ; means for adjusting power load  15  of a down stream side comprises an electric power converting device  94 , a current bypass circuit  94   s , and a connector  93 .  
         [0078]     In other words, since a power generating amount of a coal field side is independent from a necessary power amount of a demand end, a power storage function is inevitable for adjusting the load balance of both sides. If the function is formed at a coal field side, investment in the coal field side increases. If the function is formed at the demand end side, transmitting loss increases as power is stored through its power distribution network.  
         [0079]     Hence, according to the present invention, current bypass circuits  92   s ,  94   s  are provided at each upstream end and down stream end of a super conductive transmitting system  12 , which is laid down over a channel, and are utilized as a function of means for adjusting power load  15 . Meanwhile, a power distribution network  30  of a power company in each district is connected to an AC load system  11  in a big city area, which is a demand end. Generally, AC flows in the power distribution network  30  so that any power distribution network  30  can be connected aside from voltage condition.  
         [0080]     Thus, new power plants are not necessary to be constructed in the vicinity of a city area in a district where power accommodation such as the AC load system  11  in a city area of Japan is necessary, so that it contributes to environmental protection and the exhaust of carbon dioxide can be decreased. Particularly, surcharge for excess exhaust of carbon dioxide against a right of exhaust of carbon dioxide in a developed country needs not to be paid.  
         [0081]     A feeding line itself over a channel between the main land and Hokkaido in Japan can be a DC super conductive transmitting system  12 , the connecting end side (the relay station  31 ) of which is provided with means for adjusting power load  15  for grasping a necessary amount of power at a demand end.  
         [0082]     In the present embodiment, feeding lines over a border with Russia and over Tsugaru channel can be DC super conductive transmitting systems  12 , a relay station  31  side of the connecting end of which is provided with means for adjusting power load  15  for grasping a necessary amount of power at a demand end. However, further fluctuation of power demand can be coped with when several feeding lines between a relay station  31  as a power receiving point of the Japanese side and an AC load system  11  in a city area are provided with super conductive power transmitting systems  12  having a power storage function for connecting a commercial power transmission system comprising an AC power distribution network through an AC-DC converter  13 .  
         [0083]     Further, an AC-DC converter  13  shown in  FIG. 4 (B) and a super conductive power storage facility  70  can be provided at the down stream side of a transformer  301 , or a DC super conductive power transmitting system  12  is provided as a feeding line itself as shown in  FIG. 4 (A) to connect to a existing power distribution network  30 . In this case, as the super conductive power transmitting system  12  itself has a function to store electric power, only an AC-DC converter  13  is necessary to be provided. In this case, it can cope with a fluctuation of power load system in a city area.  
         [0084]     When there is a natural gas field in the Russian side between a thermal plant  10   a  near coal fields and a relay station  31  as a power receiving point of the Russian side and the Japanese side, a power transmission line is provided along a natural gas pipe line  50 . As described before, power fluctuation between both nations can be coped with by providing a super conductive cable  16  at an international boundary between Russia and Japan.  
         [0085]     As described above, in the relay station  31  between the super conductive power transmitting system  12  and the power distribution network, an excess power is stored in the super conductive cable  16  and short AC power supply is covered by discharging AC power through the AC-DC converter  14   b , corresponding to a power demand of the demand end of the AC load system  11  with the means for adjusting power load  15 . Since the super conductive cable  16 , the AC-DC converter  14   b , and the means for adjusting power load  15  need to be maintained as a super conductive state, a cooling energy supplying system  113  shown in  FIG. 2  is provided along the power transmitting system  12 , which delivers cooling agent comprising extreme low temperature brine or liquid nitrogen.  
         [0086]     The above cooling agent is not limited to liquid nitrogen, but slush nitrogen, which is a mixture of liquid nitrogen and fine particles of solid nitrogen can be used. As a result, slush nitrogen brings about excellent capacity for absorbing heat load so that it can effectively cools high temperature super conductive power transmitting cables or super conductive apparatuses.  
         [0087]     The above slush nitrogen is produced by mixing liquid nitrogen with fine particles of solid nitrogen that is formed by sucking and blowing liquid nitrogen together with low temperature cooling gas such as helium.  
         [0088]     Since the above cooling energy supplying system  113  enables delivery of the cooling agent all over the region of the super conductive transmitting system  12 , as shown in  FIG. 2 (A), cooling energy supplying stations  13   a  are provided at various points such as the AC-DC converters  14   a ,  14   b  or relay stations  31   a ,  31   b ,  31   c.    
         [0089]     Further, as shown in  FIG. 3 , the above cooling energy supplying station  13   a  comprises a low temperature refrigerator  17 , a storage tank  24 , and a pump  26  for delivering cooling agent.  
         [0090]     The low temperature refrigerator  17  comprises a compressor  20 , a condenser  22 , an expansion valve  23 , and an evaporator  21  for generating cooling agent  24   a . The generated cooling agent  24   a  is stored in the storage tank  24  and introduced to super conductive apparatuses such as the AC-DC converters  14   a ,  14   b  and the means for adjusting power load  15 .  
         [0091]     As shown in  FIG. 2 (B) and  FIG. 3 , a heat supplying system  18  is preferably installed by providing a heat supplying station  18   b  so that heat of condensation generated in the condenser  22  is supplied to an inhabited area around the cooling energy supplying station through a pump  18   a.    
         [0092]     The above low temperature refrigerator contributes to environment protection because carbon dioxide generated from exhaust gas of the thermal plants and the delivery stations in the thermal power generation system  10  in the vicinity of the coal fields. Heat of condensation of the carbon dioxide of the condenser side is utilized as heat for the heat supplying station  18 .  
         [0093]     Although extreme low temperature brine can be used as a cooling agent  24   a , super conductive state can be maintained using liquid nitrogen in case of using oxide type high temperature super conductive material.  
       INDUSTRIAL APPLICABILITY  
       [0094]     Industrial applicability according to the present invention arises as follows because of the above mentioned construction.  
         [0095]     a. Coal, which is inferior to petroleum or natural gas in terms of logistics but is superior in terms of amount of deposits by several times that of petroleum or natural gas, is converted to electric power, which is advantageous for logistics, by thermal power generation to enable supplying stable coal energy.  
         [0096]     b. A problem of utilization of energy in wide region and measures for environmental protection can be performed intensively by thermally generating power on coal production sites. Further, recovered carbon dioxide, which is exhausted from thermal plants, can be used as refrigerant of a low temperature refrigerator for cooling super conductive material, which results in contributing to environmental protection.  
         [0097]     Although the present invention has been described in connection with the illustrated embodiments, given the disclosure of the present invention, one versed in the art would appreciate that there can be other embodiments and modifications within the scope and spirit of the present invention. All modifications and equivalents attainable by one versed in the art from the present disclosure within the scope and spirit of the present invention are to be included as further embodiments of the present invention. The scope of the present invention accordingly is to be defined as set forth in the appended claims.  
         [0098]     This application is based on, and claims priority to, Japanese Application No. 2003-093954, filed on 31 Mar. 2003, and the disclosure of the priority application, in its entirety, including the drawings, claims, and the specification thereof, is incorporated herein by reference.