JPH0491638A - Energy system - Google Patents

Abstract

PURPOSE:To use generated power and heat at a consumption district by transmitting power generated by natural energy to the district, electrolytically decomposing water if surplus power is generated to generate hydrogen, once storing it in hydrogen occlusion alloy, transporting it to the district, and operating a fuel battery. CONSTITUTION:A solar cell 1 is disposed in a desert district near the equator. A DC transmission system is provided in a real time system R, and power is transmitted through a high voltage transmission line 3. Then, hydrogen obtained from a water decomposing unit 7 is stored in a hydrogen storage unit 8 in a storage system S. Hydrogen discharged from the unit 8 is transported through a pipe line 9 to the vicinity of an energy consumption district 6. Transported hydrogen is used as fuel, power generated from a fuel battery power plant 10 is directly transmitted to the district 6, thermal energy generated in the case of the generation is transmitted to the consumption district for use. Thus, power generated based on clean natural energy can be used without waste.

Description

[Detailed description of the invention] (a) Industrial application field The present invention applies to wind power, water power, geothermal heat, tides, temperature differences, solar heat,
It relates to an energy system that transports electricity generated from natural energy such as sunlight to energy consumption areas.

(b) Conventional technology It has been a long time since people began to talk about the global environmental crisis, such as global warming and the occurrence of acid rain, along with the depletion of fossil energy. From this perspective, attempts have been made to develop energy systems that focus on non-polluting natural energies such as wind, water, geothermal, tides, temperature differences, solar heat, and sunlight, but overall progress has been slow. I am in a state where I have no choice but to say that.

Even under such circumstances, the technological development of solar cells that directly convert sunlight into electrical energy is relatively advanced, and the conversion efficiency alone is more than double what it was at one time. For example, ``Economist J '89.
8.15.22 Merger issue, or “Solar Energy Jo”
urnal of JSESJ '89 Vol, 15
As mentioned in ＼o, 5, etc., there was a grand proposal to place solar cells in desert areas near the equator and to transmit the electricity generated by the solar cells to energy consuming areas using superconducting cables. is being done.

On the other hand, there is also a proposal to use electric power generated by solar cells to electrolyze water to generate hydrogen and oxygen, and use the hydrogen as an energy source, for example, in JP-A-54-127890.
No. 55-116601, etc.

(c) Problems that the invention sought to solve However, the former proposal involves real-time power generation and consumption, and the latter proposal is based on the premise of energy storage, so the overall system-based concept is Nothing has been done.

(d) Means for Solving the Problems The present invention has been made in view of the above problems, and is capable of transmitting high-voltage DCat power generated based on natural energy to energy consuming areas in real time, and If the power exceeds the power consumption and there is surplus power,
Using the surplus electricity, water is electrolyzed at low voltage to generate hydrogen, the generated hydrogen is temporarily stored in a hydrogen storage alloy, and the stored hydrogen is transported to an energy consumption area. The idea was to use the transported hydrogen as fuel to operate a fuel cell, and to use the electricity and heat generated by the fuel cell operation at the consumption site.

(E) Function According to the present invention, the electric power generated in step 1 based on natural energy is utilized without wastage, and energy problems can be fundamentally solved.

(f) Embodiment FIG. 1 is a conceptual diagram of the energy system of the present invention,
The upper part of this figure shows a real-time system (R) in which power generation and consumption are performed simultaneously, and the lower part shows a storage system (S) in which the generated power is temporarily stored and then used when necessary. In Fig. 1 of the pillow lever, 1 is a solar cell, which is the most common means of collecting natural energy, and is placed over a large area on the order of several i to several 1100 square meters in desert areas near the equator. There is.

2 is a step-up device that boosts the voltage of the DC power generated by this solar cell 1 to a high DC voltage of about several 100 KV, 3 is a step-down device that steps down the voltage to a low voltage of several V to several tens of V, and 4 is a step-down device that steps down the voltage to a low voltage of several volts to several tens of volts. A power divider installed between the solar cell 1 and the booster 2 and bucker 3, giving priority to power to the booster 2 side, and when the power to the booster 2 side becomes surplus. It has the function of exclusively supplying power to the step-down converter 3 side.

Next, the real-time system (R) will be explained first. In the present invention, a DC power transmission system is adopted as the power transportation means. The reason for this is that in the case of DC power transmission, the ground return method can be used, which reduces the cost of installing transmission lines.
Reasons for this include that the power transmission line loss is lower than in the case of alternating current, and that the withstand voltage of the insulating material is stronger against direct current than against alternating current.

Reference numeral 5 denotes a high-voltage power transmission line that transmits the high-voltage DC boosted by the booster 2 to the energy consumption area 6 . For example, when the transmission voltage is 500 KV and the transmission current is 2 KA, the power transmission line 5 has a cross-sectional area of 2500 mm and a conductor resistance of 0.00732.
A copper wire of Ω,/km (20° C.) is used. When using this conductor, if the power transmission distance is, for example, 2251 On, the power transmission efficiency is 98.7%, and the power transmission distance is 700 km.
ffl, the power transmission efficiency is 95.9%. Of course, in the energy consumption area 6, the high-voltage DC that is sent is actually converted from DC to AC to obtain an AC voltage that is easy to use, but the details are omitted because it is not directly related to the gist of the present invention. ing.

Next, the storage system (S) will be explained. 7 is a water decomposition device that electrolyzes water using the low-voltage direct current stepped down by the step-down converter 3. It is necessary to supply a low voltage of about 1.5 V to a single cell for water decomposition, and normally, 10-20 single cells
A configuration is adopted in which a required number of cells are connected in series and arranged side by side. As for this water splitting device, the SPE method using an ion exchange membrane such as Nafion, or the method using a solid electrolyte such as zirconia, etc., is effective in terms of power efficiency and
That is, from the viewpoint of electricity-hydrogen conversion efficiency, this type of system is suitable for large-scale water splitting.

Reference numeral 8 denotes a hydrogen storage device for storing hydrogen obtained from the water splitting device 7, which contains rare earth-Nl alloys represented by LaNi5, MgNi alloys, Fe-Ti alloys, and Zr.
- It is made of a hydrogen storage alloy such as a Mn-based alloy.

9 is a pipeline that transports the hydrogen released from the hydrogen storage device 8 made of this hydrogen storage alloy to the vicinity of the energy consumption area 6, and the hydrogen transport pressure is 2 kg7/Cm.
, a gas flow rate of about 4 m%S is suitable for long-distance pipeline transportation. IO is a fuel cell power plant installed near an energy consumption area, which uses hydrogen transported via a pipeline 9 as fuel, and the electricity generated at the fuel cell power plant 10 is directly sent to an energy consumption area 6. At the same time, the thermal energy generated during power generation is also sent to the consumption area and used. Note that this fuel cell power plant 10 may perform power generation operation using hydrogen supplied via the pipeline 9 as fuel directly, but the fuel cell power plant 10 side may also have a similar hydrogen storage device 8 described in L. If a hydrogen storage section made of a hydrogen storage alloy is provided, it will be possible to stably continue power generation f111'.

Here, an example of the scale of this fuel cell power plant IO will be shown. If the fuel cell power plant 10 generates 2,400 KWh (200 KW x 12 hours), which is the amount of electricity required for a condominium consisting of about 100 houses, the power generation including the fuel cell, inverter for power adjustment, and control panel. The size of the section is 2-3m wide and 3-4m deep.
, the height is approximately 2 m, and the amount of hydrogen required at that time is approximately 800 m'', and the amount of hydrogen storage alloy constituting the hydrogen storage section to store this amount of hydrogen will be approximately 4 tons.

In this way, the advantage of installing a fuel cell power plant near an energy consumption area 6 in a scale commensurate with the electricity consumption of that consumption area is that it consumes not only power but also the heat generated during power generation. The advantage is that it can be used locally, improving overall energy efficiency. In other words, the efficiency of a fuel cell as a generator is at most 50
The efficiency of energy use, including the generated heat, can be expected to reach 80%.

In the above embodiment, the pipeline 9 is used as a means of transporting the hydrogen released from the hydrogen storage device 8 to the vicinity of the energy consumption area 6, but if the distance between the hydrogen storage device 8 and the energy consumption area 6 is If the length exceeds 10km, the hydrogen storage alloy that has absorbed hydrogen can be transported by sea instead of using the pipeline 9. Since the hydrogen transport efficiency will be higher, this ship transportation should be adopted.

Therefore, the power generated by the solar cell 1 installed in the desert area near the equator is first given priority to the real-time system (R) at the power divider 4, and the power is matched to the power consumption at the energy consumption area 6. Electric power is boosted by a booster 2 and sent to an energy consumption area 6 via a power transmission line 5. If the amount of power generated by the solar cell 1 is equal to or less than the amount of power required in the energy consumption area 6, all of the power generated by the solar cell 1 is consumed in this real-time system (R) and stored in the storage system (S).
) will not be sent.

On the other hand, if the amount of power generated by the solar cell 1 exceeds the amount of power required by the energy consumption area 6, the power distributor 4 distributes the surplus power to the step-down converter 3 side, and the water splitter 7 Step down to low voltage direct current suitable for decomposition. Water splitting device 7
receives the low-pressure direct current and electrolyzes water to produce hydrogen and oxygen. The hydrogen thus obtained is sent to the hydrogen storage device 8 and stored. Furthermore, the hydrogen stored in this hydrogen storage device 8 is transferred to an energy consumption area 6 via a pipeline 9.
For example, when there is a shortage of power directly transmitted from the solar cell 1 in the real-time system (R), the power generation operation at the fuel cell power plant 10 is performed as appropriate. and supplies the insufficient power and heat to the energy consuming area 6.

In addition, although FIG. 1 shows the case where the solar cell 1 and the energy consumption area 6 correspond on a one-to-one basis for the sake of simplicity,
In fact, as shown in Figure 2, the energy consuming area 6 is not only supplied with electricity from a single solar cell 1, but is also provided by multiple electricity sources, such as nuclear power plants, etc. It is conceivable that power generation systems such as thermal power plants depend on power generation systems other than solar cells. Furthermore, as shown in Fig. 3, the energy consumption area 6 to which power is supplied via the real-time system (R) and the energy consumption area 6 to which electricity is supplied via the storage system (S) may be different. Diversification of supply routes is considered.

Also, in the above explanation, we have described the case where solar cells that directly convert solar energy into electricity are used.
Power generation methods that utilize various natural phenomena that occur based on energy supplied by the sun can also be used in the same way, such as wind power generation, hydroelectric power generation, geothermal power generation, tidal power generation, seawater temperature difference power generation, and solar thermal power generation. .

(g) Effects of the Invention As is clear from the above description, the present invention transmits high-voltage DC power generated based on natural energy to energy consuming areas in real time, and generates surplus power when the generated power exceeds the consumed power. If this occurs, the surplus electricity will be used to generate hydrogen by low-voltage electrolysis of water, and at the same time, the hydrogen will be temporarily stored in a 7-ton storage alloy, and the stored hydrogen will be transported to the energy consumption area. The transported hydrogen is used as fuel to operate a fuel cell at the consumption area, and the electricity and heat generated by the fuel cell operation are supplied to the consumption area, so power generation is based on clean natural energy. The generated electricity will be used without wastage, and it will be possible to fundamentally solve global environmental problems such as the depletion of fossil energy, global warming, and the occurrence of acid rain.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing the configuration of the system of the present invention, FIG.
FIG. 3 is a conceptual diagram showing another configuration of the system of the present invention. 1. Solar cells, 2. Boost, 3. Step down, power divider, 5. Transmission lines, energy consumption areas, 7. Water splitting equipment, hydrogen storage equipment,
9 ・Pipelines, ・Fuel cell power plants.

Claims (2)

[Claims] (1) In addition to transmitting high-voltage DC power generated based on natural energy to energy consuming areas in real time, if the generated power exceeds the power consumption in the energy consuming areas and surplus power arises, that surplus power will be used. Hydrogen is generated by low-voltage electrolysis of water, the generated hydrogen is temporarily stored in a hydrogen storage alloy, and the stored hydrogen is transported to an energy consuming area, and at the same time, the transported hydrogen is An energy system characterized by operating a fuel cell using fuel as fuel, and using the electricity and heat generated by the operation of the fuel cell at an energy consumption area. (2) Claim (1) characterized in that the natural energy is any one of wind energy, hydraulic energy, geothermal energy, tidal energy, temperature difference energy, solar energy, or a combination thereof.
Energy system described.