CN113424393A

CN113424393A - Method, device and system for stabilizing power grid

Info

Publication number: CN113424393A
Application number: CN201980091880.9A
Authority: CN
Inventors: P·沃尔克默
Original assignee: P Woerkemo
Current assignee: P Woerkemo
Priority date: 2018-12-17
Filing date: 2019-12-17
Publication date: 2021-09-21
Also published as: WO2020125868A1; DE112019006240A5

Abstract

The invention relates to a method, a device (1) and a system for stabilizing an electrical network by extracting surplus from the electrical network (DSN)On the one hand, converts the electrical energy into a storable energy source and stores it, and on the other hand reconverts the stored energy source and feeds it into the grid (DSN) in order to stabilize the production and consumption of electrical energy in a balanced manner. According to the invention, when the production of electric energy is higher than the consumption, by using the carbon dioxide (CO) formed by reforming in the previous cycle₂) Said energy being converted in chemical form and stored as at least one hydrocarbon as a storable chemical energy source by using carbon dioxide (CO)₂) And hydrogen (H)₂) To synthesize at least one hydrocarbon, hydrogen (H)₂) Is produced from water (H) by electrolysis using the electrical energy to be stored₂O) is obtained.

Description

Method, device and system for stabilizing power grid

Technical Field

The invention relates to a method and a device for stabilizing an electrical network, wherein the production and consumption of electrical energy are balanced for stabilization by means of extracting excess electrical energy from the electrical network, on the one hand converting the electrical energy into a storable energy carrier and storing it, and on the other hand reversing the stored energy carrier and feeding it into the electrical network. The invention also relates to a system for stabilizing an electrical network. The grid refers to a device for transmitting and distributing electric energy.

Background

By energy conversion, the generation of electrical energy will be completely converted to generation from renewable energy without further emission of CO₂. Such power generation is unstable in view of the daytime, weather, and season. Currently, there is a specific consumption of electrical energy per day for which a specific amount of electricity and power generation capacity must be provided.

There may be occasions when renewable energy power generation is not able to meet demand every hour or even every day (e.g. during periods of darkness, in the wind, or during periods of outages in power generation technology). There are also situations where the amount of electricity generated is too large and the power plant must be adjusted to reduce its power, which can reduce the efficiency of the power plant and can also result in negative costs for the electricity that is not being generated.

In order to realize more stable supply, the power consumption of the smart grid and the smart electric devices can be adjusted according to the current power supply situation. But this is not sufficient to overcome the electricity usage lull period, for example.

Physical storage in pumped storage plants, for example, is an effective option, in particular via storage lakes in the norway and alpine regions, but suitable locations are only available to a limited extent. Furthermore, it is also possible to store electrical energy chemically in a storage battery (also referred to as a battery pack). However, when they are implemented as large buffer storage facilities, they do not solve the task faced, since with them the storage capacity required for grid stabilization cannot even be approximately reached. They are well suited for the short term regulation necessary in the grid. For short-term storage, high-capacity capacitors known as supercapacitors are also increasingly used. This is again not able to substantially meet the storage capacity required for grid stability.

It is also planned to use high-power lines in domestic or adjacent countries, such as the northbound (Nordlink) formed with norway, to promote stability by exchanging renewable power. The exchange provides for discharging surplus and receiving power to meet domestic supply gaps. Since the line length is as long as 500km, the cost of such a system is very high and the actual overall storage efficiency is only 50%.

The above-described solution is not sufficient to guarantee the stability of the power supply by the necessary storage amount, and from the prediction of about 40% of annual consumption, i.e. a storage demand of about 60TWh, a large-capacity storage facility is therefore unavoidable for the required peak power generation amount of 30 GW.

It is therefore preferred to provide a method of storing electrical energy in chemical form in large quantities. The starting point is to produce hydrogen as an energy carrier, but storage and transport is expensive and risky. The specific energy density of hydrogen is very small compared to methane, for example. For this reason, there is currently and will not be a large hydrogen storage facility necessary for this purpose.

Based on hydrogen obtained from electricity and using CO according to the Sabati process₂A method for synthesizing methane or, in addition, methanol or other hydrocarbons, presents a sustainable, targeted solution for storing electricity.

A method for storing electrical energy is known from DE 102012105736 a 1. The proposed solution is aimed at utilizing CO from the exhaust gas of a brown coal power plant₂Will come fromThe electricity of the renewable energy is stored in the chemical energy carrier. However, this is ultimately not dependent on the stability of the power grid, but rather serves to reduce the specific CO of the brown coal power plant₂And (4) discharging the amount. The method for storing electrical energy in hydrocarbons using carbon dioxide formed in a technical installation is characterized in that the technical installation is provided with a synthesis of at least one hydrocarbon, in particular methane, using carbon dioxide, water and electrical energy. Electrical energy is stored in chemical form by hydrocarbons. However, in the process, fossil CO is finally released during combustion thereof₂Although there is less residue. However, a disadvantage of this solution is that it is CO₂The technical equipment of the source is imperatively necessary for the functionality of the proposed method. CO 2₂In technical installations, this results from the combustion of fossil energy carriers. Other noteworthy CO₂Sources not available, especially for obtaining CO from ambient air₂In other words, due to CO₂The very low content and the resulting high expenditure make it a technically meaningful, energy-and cost-effective alternative. In the conversion of the electricity supply to renewable energy sources, the technical equipment of burning fossil energy carriers is no longer part of the energy supply system.

This leads to significant problems for all designs aimed at storing excess electrical energy from fluctuating sources in the form of hydrocarbons (especially methane gas), since CO is used₂Source of CO₂Still resulting from the combustion of fossil raw materials.

Although there is also a need for CO to circumvent this problem₂The design of the circulation guide is described, for example, in document US 5711770 a. There, use is made of CO separated from the flue gas of a combustion plant₂To subsequently synthesize methane with hydrogen from the electrolysis apparatus. Combustion devices use hydrocarbons to generate electricity. The methane thus produced is then used again for energy production, and then the clean, but fossil-containing CO is discharged from its combustion₂Of the exhaust gas of (1).

Disclosure of Invention

It is therefore an object of the present invention to provide a method and a device for effectively and cost-effectively stabilizing an electrical network or a system of such devices, wherein the stabilization is achieved by balancing the generation and consumption of electrical energy.

This object is achieved by a method for stabilizing an electrical network, wherein the stabilization is to be carried out in a balanced manner, wherein power is extracted as required when the capacity is surplus and fed in at a shortage after intermediate storage. On the one hand, excess power generated by the generator in excess of demand or consumption is extracted from the grid and converted into a storable chemical energy carrier. According to the invention, hydrocarbons, in particular methane, are provided as energy carriers. The storage is simple and takes place without additional investment in a containable, already existing natural gas network used as a large storage facility. On the other hand, in the case where the existing generator can no longer meet the demand for electricity due to low power or increased demand, by means of the feeding of electricity, electricity is obtained by the reverse generation of chemical energy carriers stored in a large storage facility. This avoids CO₂And (4) discharging.

According to the invention, the conversion and storage of electrical energy, electricity takes place in chemical form as at least one hydrocarbon using carbon dioxide (CO)₂) Is carried out, the carbon dioxide is formed in the previous cycle by reverse power generation and is stored or transported during this time when required. The hydrocarbon combustion process with the purpose of generating electricity is referred to as reverse power generation. In the conversion of electricity into chemical energy carriers, carbon dioxide (CO) is used₂) And hydrogen (H)₂) The synthesis of at least one hydrocarbon (chemical energy carrier) is carried out. Hydrogen (H)₂) Is produced from water (H) during electrolysis using excess electrical energy to be stored₂O) is obtained.

According to an advantageous development, in addition to hydrogen (H)₂) In addition, oxygen (O) also generated during the electrolysis process is stored₂) And is used in place of ambient air in combustion processes of reverse power generation, which are staggered in time, for the combustion air fed to the combustion process.

Advantageously, the device according to the invention also comprises twoCarbon Oxide (CO)₂) From a reverse power plant for producing electrical energy from hydrocarbons. According to a further advantageous embodiment, the device according to the invention comprises a separation and conditioning device for hydrocarbons produced in the synthesis plant and a hydrocarbon storage facility for the intermediate storage of hydrocarbons, in particular before combustion in the reverse power plant at the time of power demand. Also provided is a method for converting at least hydrocarbons from electrolysis and synthesized oxygen (O)₂) Device for feeding to a reverse power plant, adapted to use synthesized oxygen (O)₂) The hydrocarbons formed are combusted.

According to a further advantageous development, a device for conducting oxygen (O) in addition to a reverse power plant is provided₂) Other carbon dioxide (CO)₂) Is returned to replace the corresponding nitrogen (N) in the combustion air combusting the stored hydrocarbons₂) Means for portioning. A certain portion of CO is added₂Is mixed with the combustion air so that it is composed of oxygen (O) only in particularly advantageous cases₂) And carbon dioxide (CO)₂) And (4) forming. This proportion is selected such that it is advantageous for the combustion device used to ensure the operating mode. CO 2₂In this case, the CO is circulated in the combustion plant in such a way that it is introduced₂Separated from the exhaust gas and added to the combustion process. Using such artificial CO₂Combustion air, which in terms of energy and equipment significantly makes it possible to separate the desired CO from the combustion exhaust gases₂It becomes easy.

With CO₂The advantage of replacing the nitrogen present in the combustion air in excess of 70% by volume is that the nitrogen in the air is no longer a constituent of the combustion air and only CO is present in the flue gas₂、H₂O and other combustion gases present in small amounts. Due to the absence of foreign gases (e.g. NO)_x) Therefore, is used for CO₂The separation plant of (a) can be made much simpler and is expected to have only an investment requirement of about 1/10 compared to the investment requirement of working with the natural nitrogen share of air.

Very simplified CO₂The reason for the separation process technology is in H₂CO after condensation of O vapor₂Pressure-dividing tableThe yield is 100%. In normal combustion with ambient air, there is a very high partial pressure of nitrogen in the flue gas, up to 70%, while CO₂Is only about 20%.

A particularly advantageous effect of the proposed method is that of passing CO₂In such an amount that the CO-containing feed to the combustion process₂Has a cooling effect. Thus, CO can be passed through₂The portion is adjusted in such a way that the combustion temperature does not exceed a value that is permissible by the combustion technology used in each case. At the same time, the invention enables the use and integration of conventional combustion technologies which cannot be used for high combustion temperatures, as they occur, for example, in the combustion with almost pure oxygen (oxy-fuel process), for plant technologies which require special and expensive equipment technology which can withstand the elevated temperatures in the combustion chamber, which combustion with oxygen only.

The reverse power plant advantageously has a device for the thermal coupling of forces. The device for the thermal-mechanical coupling is preferably designed as a gas and steam power plant, an internal combustion engine, for example a gas engine or a gas turbine, for use in a central heating station (blockheizwradk) for burning natural gas and obtaining electric heat, or as a fuel cell system.

Advantageously, the hydrocarbons to be stored are present in gaseous form and the hydrocarbon storage facility is implemented as a gas storage assembly. In this respect, it has proved to be particularly advantageous if the gas storage assembly comprises an existing natural gas network NGN with an associated existing natural gas storage facility to which at least methane gas is supplied. Hydrogen (H) directly from electrolysis may additionally be added₂) A certain fraction of (c).

For a particularly advantageous energy storage with a large capacity and without significant technical additional equipment, therefore, the existing, widely distributed natural gas network NGN, which is connected to a gas storage facility (for example a cavern), is used as an energy storage facility for the chemical energy carrier, advantageously the synthesis of methane SNG, formed according to the invention. Significantly more energy can thus be stored in the NGN than in other energy storage facilities. The currently available storage capacity of an NGN may also be extended even significantly by simple means. With pressure increases around a few mmWS in existing gas storage facilities, additional amounts of energy may be stored in a range equivalent to a few TWh.

Therefore, hydrogen (H) is preferably used₂) And carbon dioxide (CO) available in the storage system in terms of process technology₂) The synthesized gaseous methane SNG acts as an energy carrier for storage. Hydrogen (H)₂) From electrolysis operating on excess electricity. In addition, time-shifted, necessary reverse power generation carbon dioxide (CO) from natural gas or gaseous methane SNG that is gradually synthesized in the future is used at gas power plants₂). Carbon dioxide (CO)₂) Is intermediately stored before being used for combustion, so that no CO is produced₂Emissions, as NG is currently largely fossil-sourced in natural gas networks NGNs. Carbon dioxide (CO)₂) Only afterwards can renewable energy sources be derived at least partly and on an increased scale. The process of the present invention contributes to "low carbonization (Dekartoniaerung)" because there is no further CO left₂From the related art process into the atmosphere.

Another aspect of the invention relates to a device for stabilizing an electrical network, wherein the production and consumption of electrical energy are balanced for stabilization by means of extracting excess electrical energy from the electrical network, on the one hand converting the electrical energy into a storable energy carrier and storing it, and on the other hand reversing the stored energy carrier and feeding it into the electrical network. According to the invention, for converting electrical energy into hydrocarbons, a device for generating at least hydrogen (H) is provided₂) For using hydrogen (H) in the electrolysis installation, synthesis device preferably embodied as an installation for methane synthesis₂) And carbon dioxide (CO)₂) At least one hydrocarbon, preferably methane, is produced. Furthermore, a reverse power plant for generating power is provided, which is fed into the power grid when required to stabilize the power grid.

Furthermore, an advantageous embodiment of the device according to the invention comprises: for carbon dioxide (CO) from reverse power plants₂) For production from hydrocarbonsA conditioning plant for generating electrical energy, a separation and conditioning plant for the hydrocarbons produced, and/or a hydrocarbon storage facility NGN. Furthermore, a device for mixing at least hydrocarbons and synthetic oxygen (O)₂) To synthesis oxygen (O) suitable for use in₂) A reverse power plant that combusts the hydrocarbons formed.

According to a further advantageous embodiment, provision is made for conducting oxygen (O) in addition to the reverse power plant₂) Other carbon dioxide (CO)₂) Is returned to replace the corresponding nitrogen (N) in the combustion air used to combust the hydrocarbons₂) Means for portioning. The hydrocarbon storage facility NGN is preferably implemented as a gas storage assembly. Methane is provided in particular as the hydrocarbon, and the reverse power plant has a device for the force-thermal coupling. Particularly preferably, the device for the thermal mechanical coupling is embodied as a gas and steam power plant, as a central heating station for natural gas combustion, or as a fuel cell system. Furthermore, it has proven advantageous that the gas storage assembly comprises an existing natural gas network NGN with an existing natural gas storage facility to which at least methane is supplied.

The system for stabilizing an electric grid according to the present invention is another aspect of the invention and comprises a plurality of devices for stabilizing an electric grid, said devices comprising respectively a power storage unit SSE and a reverse power generation unit RSE. The system according to the invention is thus composed of a combination of planar distributed power storage unit SSE elements and associated reverse power generating elements RSE, these elements being connected to a power grid (e.g. a german domestic power grid DSN) which is also internationally connected to other countries, and to a natural gas network NGN which is also internationally connected to natural gas networks of other countries.

Furthermore, the SSE and RSE are connected via higher-level classical or internet communication and act together proactively in regulating the stability of the entire grid. In each unit, at least the hydrocarbons for storage in the hydrocarbon storage facility (preferably embodied as a natural gas network NGN) can be produced from an electrical energy surplus, or at least the stored hydrocarbons are extracted from the hydrocarbon storage facility at the time of electrical power demand and electrical energy is thereby produced for feeding into the electrical network.

NGNs are used as large capacity storage facilities. In the event of excess power, SSE is fed by the DSN for storage of power in the form of methane (SNG), where hydrogen (H) is used as hydrogen₂) And carbon dioxide (CO) produced₂) Synthesized and sent to NGN. When power is needed in the DSN, power is obtained from natural gas or SNG in the NGN by reverse power generation and fed into the DSN.

According to an advantageous development, the network also comprises at least in part a device for introducing carbon dioxide (CO)₂) CO transported from a reverse power plant between the combined plants₂Gas network, and/or for the supply of hydrogen (H)₂) A network of hydrogen gas transported from the electrolysis apparatus between the combined apparatuses. In a further advantageous development, the CO is provided at least in part₂Storage facilities and/or hydrogen storage facilities where gas may be stored before or after transportation or at an advantageous location on the transportation path.

In a preferred embodiment, the RSE jointly consists of the following basic elements:

suitable interfaces at the NGN for extracting gas, natural gas or SNG,

a power plant for obtaining electricity by using the gas in the NGN through a facility for using the generated waste heat,

for separating H from exhaust or combustion gases of power plants₂O and CO₂The apparatus of (1) is described,

CO with input line to SSE₂The storage facilities are used for storing the information,

an oxygen line from the SSE to the RSE for oxygen from electrolysis;

device for mixing artificial combustion air, consisting of oxygen from electrolysis and CO from separated recycle₂Composition is carried out;

a suitable feed interface for supplying power to the DSN.

In a preferred embodiment, the SSE consists of the following basic elements:

a suitable interface for extracting power from the DSN,

an apparatus for the electrolysis of water comprising a water supply,

a plant for methane synthesis having a plant for conditioning methane gas and a plant for extracting high temperature waste heat for further use,

for hydrogen (H)₂) The buffer storage facility(s) of (c),

for oxygen (O)₂) Having an input pipeline to the RSE,

CO from RSE₂Storing facility to SSE COs₂The inlet pipe of (a) the inlet pipe,

a suitable SNG feed interface to the NGN.

The RSE and SSE may be placed directly side-by-side or spatially separated, connected by piping, for example, to use waste heat on site.

When the reserve methane is synthesized and stored in large storage natural gas networks NGN, the stored hydrogen is used. The mode of operation of the interconnected SSE and RSE is centrally controlled together with the grid regulation.

The purpose of the control is:

storing the SNG form of electricity into the NGN for storage by the connected SSE,

in the event of a surplus of power, the power in the form of SNG is stored in the NGN by the connected SRE,

if necessary, electricity is fed from the SNG or methane in the NGN via the connected SRE to the grid via reverse power generation, and

ensuring CO emissions in reverse SNG power generation in gas power plants₂。

Thus, the present invention demonstrates a CO-based catalyst₂Has a minimum of CO to the atmosphere₂Emission, or complete absence of CO₂And (5) discharging. The process according to the invention uses CO₂To store energy without additional emission of CO₂. The method mimics natural plant processes in which CO is present₂As a working material for storing energy.

The central approach is good availability of wind and solar energyHydrogen is produced by means of electrolysis to be used as a base material for the synthesis of methane gas. Carbon dioxide is added to hydrogen to obtain artificially synthesized methane gas SNG as an energy-rich substance. On the other hand, artificially synthesized methane is stored in places where natural gas has been stored according to the prior art: in existing natural gas networks. The natural gas network has such a large storage capacity that it can also easily accommodate a quantity of gas that can be used to reverse power generation in a weather-neutral manner in an efficient, well-regulated gas power plant on calm and cloudy days. This is sufficient, for example, in germany to compensate for at least two weeks of adverse, restricted or hampered weather from renewable energy generation. Finally, CO₂Is a working material for energy storage, as in nature, which remains in the storage system according to the invention and does not need to be discharged nor a new supply.

As long as the usage gains from stored electricity and heat are not sufficient to run the storage system cost-effectively in a cost-covering manner at the enterprise, the system according to the invention may be used for regulation and stabilization of the power grid from a cost point of view. Only by this regulation and stabilization can the renewable energy source meet the requirements under different load conditions despite the fluctuations.

The national overall economic calculation as the basis of economic evaluation must simultaneously consider the following effects:

national economic requirements for stabilizing the grid;

the load of the transmission line is reduced or new equipment is saved and the corresponding cost is saved;

influence of structural changes: providing new and maintaining existing industrial workstations, providing industrial prospects in the field as a means for migratory (Abwandering), developing new export economies; and

significant national trade to reduce the growing disappointment for politics.

Process losses occur in the form of heat, which can be utilized in other ways. In this process, the losses occurring are therefore of the thermal type. It is generated based on electricity drawn from the grid, which is based on renewable energy.

As such, there is a need to ensure that enterprises requiring storage facilities operate economically and efficiently. This can be achieved either by matching the gas prices for the stored SNG or by associating the storage facility with the grid to be stabilized and being taken up by an additional fee for the grid fee, to thereby ensure economic feasibility of the enterprise. The network operator may prestore operational tools on the network technology to ensure the safety and reliability of the power supply system.

The economic situation can be further improved if a gas-fired power plant operating on fossil natural gas, which is also to be shut down in the future, is functional to convert into a reverse power generation KW for the method according to the invention. Thus, for the device according to the invention, considerable expenses or costs for new devices will be saved, which represents a basic effect of the invention. The conversion of the function of a gas power plant operating with fossil natural gas can be achieved only by the method according to the invention.

The invention is explained in detail below with the aid of a description of exemplary embodiments and their illustrations in the associated drawings.

A prediction is made as to what power storage capacity is required for stabilizing the grid DSN with the fluctuating power supply of current renewable energy producers during the period 2017 to 2037. From this prediction, in 2037, the electricity storage facility needs to have a total of 30GW_elPower sum 52TWh_elOutput size of/a capacity. This order of magnitude can only be covered by the vast storage facilities exhibited by existing natural gas networks.

If the method according to the invention is used to convert power to SNG due to the storage size, a 76GW is expected_elInput size of 131TWh_elExtracted power in the/a range. Taking a storage facility as an example, as a storage facility having a power of 100MW according to the invention_elPower and 1GWh_elThe method is illustrated as part of one embodiment of an apparatus for the containment. The storage facility is composed of two components, namely an RSE and an SSE, which operate in a time-staggered and, if necessary, spatially separated manner:

the reverse power generating unit RSE for the power supply is embodied in particular as a reverse power generating plant RVKW, for example in the form of a gas and steam power plant GuD, which is operated with SNG (currently balanced) stored in the natural gas network. GuD uses a gas turbine followed by a steam turbine and thus achieves power generation efficiencies of up to 60%. RVKW uses the oxygen obtained in electrolysis instead of air for combustion. Thus, separating CO from flue gases₂It is very easy. The RVKW feeds power into the grid DSN when required for stability. CO separated out₂Stored in a storage facility at a pressure of 30bar for the time-staggered use in methane synthesis. The volume of the storage facility depends on how high the storage capacity is to be designed.

Power storage unit SSE: hydrogen and oxygen are obtained by electrolysis using the stored electricity. Oxygen is stored in a pressure storage facility for time-staggered use in RVKW. Together with CO from the storage facility of the RSE₂Together, in the synthesis plant, methane was formed using the hydrogen produced at 30bar and 300 ℃. Methane is fed to the natural gas network after conditioning as synthetic natural gas, SNG.

In order to meet the overall requirements, a flat distribution device 1 according to the invention is installed. In each of the two components present in the plant 1, namely the RSE and the SSE, no fossil waste heat of larger scale is generated. This can be utilized in situ, thereby significantly improving the efficiency of the process as a whole.

Drawings

In the process configuration diagram according to fig. 1, the device scale and mass flow of a 100MW/1GWh power storage facility is shown implemented as an embodiment of a process technology and device technology design for a power storage facility with 100MW_elInstalled power and 1GWh_elCapacity storage facilities.

Description of the reference numerals

bar overpressure (1bar 105N/m)²)

DSN German domestic power grid

GuD/GuD-KW gas and steam power plant

GW_elGigawatt electric power (10 giga)⁹)

Ki, i ═ 1..5 main component

K1 GuD power plant

K1.1 condensate storage facility

K2 CO₂Storage facility

K3 O₂Storage facility

K4 Electrolysis

K4.1 oxygen excess

K4.2 hydrogen buffer storage facility

K5 methane Synthesis

mmWS mm water column (pressure)

MW_elMegawatt electric power (megawatt-10)⁶)

NG natural gas

NGN natural gas network

RSE reverse power generation unit

RVKW reverse power generation power plant

SNG Synthetic Natural Gas (Synthetic Natural Gas)

SSE power storage unit

TWh_elElectric energy in takah (10-tai)¹²)

Detailed Description

In nature, CO is not utilized₂In the case of (2), solar energy incident on the earth cannot be stored. For its metabolism, plants emit CO₂To maintain its function when the sun is not shining. However, in biomass, CO is used₂So much solar energy is stored that the entire population of humans is ultimately supported thereby. In CO₂In cooperation, the use of solar radiation enables the production of human life energy, of course also for plants and animals.

Application of biomass to end products having CO-based basis₂Human energy process of nutrition (and of plants and animals), resulting in CO₂Emission of CO₂And then reused for solar energy storage in the biomass. However, in general, the solar radiation-CO₂The biomass process does not lead to atmospheric CO₂Is increased.

The natural gas network exhibits a large technical coal to hydrogen system, similar to the storage system of biomass in nature, in particular, electricity and CO produced by solar energy₂The synthesized methane is stored therein and is extracted again when electricity is needed. CO produced in regeneration₂Is reserved for reuse in methane synthesis.

The need for storage is apparent. The power obtained from renewable energy sources, for example from solar radiation by means of photovoltaic systems, from the wind by means of wind energy systems, from flowing water by means of hydraulic systems, is unstable or fluctuating. The power production is affected by naturally occurring daily and seasonal and weather conditions, significant fluctuations in power generally related to each renewable energy carrier. As the share of renewable energy power increases, the problem of unstable power supply becomes more serious. This problem is serious in the german target, i.e. reaching at least 95% in all regions by year 2050.

Gross electricity consumption in 2017 in Germany is 654TWh/a, wherein 244TWh comes from renewable energy, 148TWh comes from lignite, 76TWh comes from stone coal, and 86TWh comes from fossil fuel gas. In 2017, the installed power of renewable energy used by power plants for power generation was 112.537MW, where 50.291 was wind (onshore) and 42.339MW was photovoltaic. The installed power of the power plant of the non-renewable energy source is 103.046MW, wherein 9.848MW of pumped storage power plants are included.

It has now been considered that in the event of an oversupply of power from renewable energy sources, despite the existence of an overall, nationwide grid, a complete blackout of the supply can still result in large pieces in the middle of the period. On the other hand, this can lead to flooding during the generation in wind and photovoltaic installations, so that this must be adjusted downward in order not to impair the stability of the network. This approach is costly, as has now been determined, because unutilized power is paid for on a legal basis.

At present, the occasional power shortage problem is compensated by a renewable energy power plant through some pumped storage power plant, a standby or operating coal power plant or a gas power plant. In the future, fluctuations can also be buffered by means of more intelligent networks and more intelligent consumers coordinated with one another.

However, with the shift of energy sources to renewable energy sources, there is an inevitable demand for providing large-capacity long-term power storage, particularly surplus power and backup power, to the grid while expanding the amount of electricity generated by renewable energy sources, and for providing high-efficiency large-capacity power generation from these power storage facilities. According to the data of 2017, the needed power storage facilities are predicted, and rough balance simulation is designed for power supply of the time series of 2017, 2022, 2027, 2032, 2037.

The power demand is maintained at a value of 654 TWh. It can be assumed that the energy efficiency of the power application will increase by at least 50% and thus the power usage will exist within this range. The number of full hours of all plants, especially renewable energy power plants, since 2017 were then used in concert to establish a ratio of generated to installed power. As the share of offshore wind power plants increases, this situation can be improved. Storage facilities, which must increasingly strongly protect the stability of the power grid (DSN) to prevent the increasing fluctuations of the renewable energy power generation, play an important role in the supply safety. Here, from the storage facility that existed in 2017, the increase rate of the storage facility performance was determined according to the increase demand of the renewable energy power generation amount.

Based on the prediction, a 76GW input and a 30GW are required_elThe exported back-generation gas power plant storage facility is initially capacity to ensure adequate and stable power supply. Through 30GW_elThe storage facility exports power to make up for the gap to ensure the hypothetical demand of 650TWh/a, which comes only from the use of renewable energy sources.

Some storage technologies including these (which can be protected in germany, taking germany as an example here) are the existing natural gas networks as storage facilities for SNG and can be re-extracted from the storage facilities in germany for reverse power generation. It is capable of storing SNG obtained from a storage facility of 130TWh, for example, on the scale of 80TWh from renewable energy sources. Regardless of the storage facility configuration involved, one basic conclusion is that the power generation system must have a higher generation capacity than is required for consumption to cover storage facility losses.

For implementation in process technology, the system for storing electrical energy in hydrocarbons according to the invention comprises two basic components, namely a reverse power generation unit RSE and a power storage unit SSE:

the RSE comprises a reverse power plant RVKW, in particular a gas and steam power plant GuD, which uses the SNG in the existing natural gas network (in balance, actually with natural gas) to generate storage facility output power from reverse power generation and for feeding into the power grid DSN. Separating CO needed by methane synthesis from flue gas of reverse power generation power plant₂。

The separation can be designed simply if the RVKW is operated with pure oxygen instead of combustion air from the environment, or preferably with artificial air (instead of air) in the context of the invention. Replacing air by oxygen and CO₂Composition of mixture of CO₂Are carried in a cycle. For this purpose, the oxygen comes from the electrolysis of the SSE described below.

CO due to the reduction in volume and the working pressure of 30bar required for methane synthesis₂Stored in the RSE in a pressure storage facility.

An SSE is an electric power storage device consisting of a pressure electrolysis device that produces hydrogen (and oxygen) at a pressure of 30bar from the electric power to be stored. In SNG synthesis plants (also called methane synthesis plants), hydrogen is used with CO from the storage facilities of the RSE₂To synthesize methane and, in each case, feed into the natural gas network NGN as required after conditioning.

The SSE also comprises a pressure storage facility of 30bar for the obtained oxygen, which is used for the RSE described above. An oxygen excess K4.1 may also occur, which is supplied to other technical applications.

The RSE draws its operating energy from the natural gas network NGN used as a storage facility, feeds electric power into the power grid DSN as required and can export waste heat, in particular when the operation of the RVKW is implemented in a force-heat coupling. In reverse power generation, 40% (efficiency according to the prior art) of the electrical energy stored in the SSE can be recovered.

The SSE and RSE may be co-located at or near one location. However, in an alternative embodiment, it is expedient to arrange the SSE separately from the RSE and to arrange the CO₂Preferably via a pipeline from the RSE to the SSE. Likewise, O must be removed from SSE₂The pipe leads to the RSE. In this case, the CO must be decided according to the project₂Where the storage facility should be. Separation is particularly suitable when large amounts of waste heat from electrolysis (20-30% at low temperatures) and from exothermic synthesis (20-30% at 300 ℃) can be used well at the selected location. This is very advantageous for economic operation of the system and also improves energy efficiency.

In principle, the operating times of the RSE and the SSE are also separated in time, resulting in different operating situations. The most important operating conditions are described below. The RSE comprises main components K1 and K2 and the SSE comprises main components, K2 and, if possible, K3, K4 and K5, as shown in fig. 1.

Operating conditions 1-stabilization of the grid by power feed:

the operating situation is shown in fig. 1 by dashed lines. The RSE is running because there is a need for power feeding in the grid DSN. For this purpose, NG is extracted from the NG network, and O₂From SSE and stored in SSE, O₂Extracted from the storage facility K3. CO 2₂Separated from the flue gas of GuD K1 and sent to CO₂Storage facility K2 where it is stored under pressure for later use in the SSE. In this case, the SSE is not running. Or, CO₂May be added to the combustion in the RSE first and be recycled.

Operating scenario 2-stabilization of the grid by receiving excess power:

there is surplus power in the grid DSN. The RSE is stopped and the SSE is running. O is obtained from the surplus electric power by electrolysis in the main component K4₂And H₂. From CO₂CO of storage facility K2₂With the H obtained₂Methane was synthesized in the SNG synthesis plant K5 and stored in the NGN.

Operating scenario 3-stabilization of the grid by receiving a load:

this operating situation is illustrated in fig. 1 by a dashed line. There is no surplus power yet in the grid DSN, but it makes sense to show the disconnection of large consumers, or to purchase cheap power from renewable energy sources from abroad via the grid DSN. The RSE is stopped and the SSE is put into operation. O is₂And H₂Are obtained electrolytically from electricity, which can be intermediately stored in buffer storage facilities K2, K4.2, respectively. In the SNG Synthesis device K5, the obtained H was used₂With CO₂CO in storage facility K2₂Methane is synthesized and stored in the NGN.

With the device 1 according to the invention for stabilizing a power grid (DSN), it is possible to use an existing gas power plant as a reverse power plant, which can be expanded in a simple manner and with continued use of the main group to an RSE in the sense of an embodiment. To do this, the SSE must be reconstructed to produce a storage system according to the present invention.

The device 1 for stabilizing a power network (DSN) according to the invention should be distributed over a large area (for example germany) and be set up with up to 100MW_elModule size of reverse generated power. For a required storage power of 30GW, 300 of each 100MW according to the invention for storing electrical energy in hydrocarbons are required_elThe system of (1). One group of which may be formed by already existing gas power plants, in the sense of the present invention the electricity storage unit SSE is set up at the gas power plant or installed elsewhere.

The following is a description of the process of the above example, having a MW of 100_elModule of power feed power and 1GWh capacity:

for 100MW with installation_elRSE of electrical power regeneration, at 62% efficiency would require 162MW for GuD K1 combustion calculations_thermH, it will consume 14.600Nm³H of natural gas. When GuD uses electricity fromWhen the oxygen is dissolved, the exhaust gas is 14.600Nm³ CO₂H and 29.208,27Nm³/hH₂O vapor composition condensable to 23.5m³Water/h and is reusable for electrolysis of K4. The condensation waste heat produced can be used for the process or for external heat consumers. Is arranged to store water in the condensed water storage facility K1.1 and is ready for the aforementioned use.

CO separation from GuD K1 combustion exhaust gas₂Compressed to a synthesis pressure of 30bar and stored in CO₂In the storage facility K2, for example in a tray gas storage facility. At 30bar, CO₂The necessary intermediate storage volume is reduced to about 4.400m³/h。

Such stored CO₂Forming the basis for the synthesis of SNG. If CO is present₂The storage facility K2 is designed for a feed capacity of 1Gwh, and then a total of 44.000m is required³CO of₂A storage volume. Required CO₂The storage facility K2 will have a side length of 35m as a cube, a diameter of 44m as a sphere, or a height of 35m and a diameter of 40m as a cylinder.

The oxygen produced in electrolysis K4 is used in GuD K1 and is used, for example, for pure oxygen fuel combustion processes or for combustion in alternative air consisting of oxygen (O)₂) With CO₂The composition of the mixture. Thus, CO is compared to combustion with ambient air₂The separation is in particular greatly simplified. At 100MW_elNext, 14.600Nm is also required³/h O₂. The oxygen originates from the facility K4 for electrolysis, preferably designed for pressure electrolysis, and is at a pressure of at least 30 bar. Thus, oxygen and CO₂The storage facility K3 is required to be equally large. The main components K1 and K4 give off waste heat for further use.

Claims

1. A method for stabilizing an electrical network, wherein the electrical energy is converted into a storable energy carrier and stored on the one hand and the stored energy carrier is reversed on the other hand by extracting excess electrical energy from the electrical networkElectricity and fed into the grid to balance the production and consumption of electric energy to achieve stability, characterized in that, in the case of a higher production than consumption of electric energy, the carbon dioxide (CO) formed by reverse power generation in the previous cycle is used₂) In the case of (1), as storable chemical energy carrier, at least one hydrocarbon is converted and stored in chemical form, wherein carbon dioxide (CO) is used₂) And hydrogen (H)₂) In the case of at least one hydrocarbon synthesis, hydrogen (H)₂) In the electrolysis method, water (H) is used as the electrical energy to be stored₂O) is obtained.

2. The method according to claim 1, wherein at least the oxygen (O) likewise produced in the electrolysis (K4) is fed to the combustion process₂) Added to reverse power generation so that the corresponding nitrogen (N) in the combustion air₂) The fraction is at least partially substituted by oxygen (O)₂) And (4) replacing.

3. The method according to claim 1 or 2, wherein a portion of the available carbon dioxide (CO) is provided during reverse power generation₂) And by carbon dioxide (CO)₂) Completely replacing oxygen (O) in combustion air₂) Nitrogen (N) present in corresponding proportions₂) Said oxygen (O)₂) Is necessary for the combustion of hydrocarbons for reverse power generation.

4. The method according to any of the preceding claims, wherein the combustion of hydrocarbons is carried out in a gas and steam power plant (K1) or in a fuel cell plant for the reverse power generation.

5. The method according to any of the preceding claims, wherein during synthesis and/or in flue gas cleaning and/or carbon dioxide (CO)₂) During the separation, the water obtained from the flue gas is utilized in the method steps of electrolysis and/or conditioning.

6. The method of any preceding claim, wherein the step of converting the input signal from the input signal is performed using a converterHydrogen (H) from electrolysis unit (K4)₂) Directly mixed into the gaseous hydrocarbon.

7. A device for stabilizing an electric network, wherein the production and consumption of electric energy are balanced to provide stabilization by extracting surplus electric energy from the network, on the one hand converting said electric energy into a storable energy carrier and storing it, and on the other hand reversing the stored energy carrier to generate electricity and feeding it into the network, characterized in that for converting the electric energy into hydrocarbons, means are provided for generating at least hydrogen (H) gas₂) An electrolysis apparatus (K4) for using hydrogen (H) gas₂) And carbon dioxide (CO)₂) A synthesis plant (K5) for producing at least one hydrocarbon, wherein a reverse power plant (K1, RVKW) for producing electrical energy from the hydrocarbon is additionally provided.

8. The arrangement of claim 7, wherein there is further provided for carbon dioxide (CO) from the reverse power plant (K1)₂) A separation and conditioning plant for produced hydrocarbons and/or a hydrocarbon storage facility (NGN), wherein at least hydrocarbons and synthetic oxygen (O) are provided₂) To synthesis oxygen (O) suitable for use in₂) The reverse power plant (K1, RVKW) combusting the formed hydrocarbons.

9. An arrangement according to claim 7 or 8, wherein oxygen (O) is also conducted in addition to the reverse power plant (K1, RVKW)₂) Other carbon dioxide (CO)₂) To replace the corresponding nitrogen (N) in the combustion air used for the combustion of hydrocarbons₂) And (4) shares.

10. The plant according to any one of claims 7 to 9, wherein the hydrocarbons are gaseous and the hydrocarbon storage facility (NGN) is implemented as a gas storage assembly.

11. An apparatus according to claim 10, wherein methane is provided as a hydrocarbon and the reverse power plant (K1, RVKW) has equipment for the force-heat coupling.

12. The plant according to claim 11, wherein the means for force-thermal coupling are implemented as a gas and steam power plant (K1), a central heating station for burning natural gas or a fuel cell plant.

13. The plant of claim 12 wherein the gas storage component comprises an existing Natural Gas Network (NGN) having an existing natural gas storage facility that is supplied at least with methane.

14. A system for stabilizing an electric network, characterized in that a plurality of plants (1) for stabilizing an electric network (DSN) according to any one of claims 7 to 13 are coupled in combination in such a way that in each of said plants (1) at least hydrocarbons stored in said hydrocarbon storage facility (NGN) are produced from surplus electric energy or at least stored hydrocarbons are extracted from said hydrocarbon storage facility (NGN) upon demand for electric power and electric energy is produced therefrom.

15. The system of claim 14, wherein the combining further comprises, at least in part, for combining the carbon dioxide (CO)₂) CO transported from the reverse power plant (K1, RVKW) to between the combined plants (1)₂Gas network and/or for supplying the hydrogen (H)₂) From the electrolysis device (K4) to the hydrogen network between the combined devices (1).

16. The system of claim 14 or 15, wherein the CO is provided at least in part₂A storage facility (K2) and/or a hydrogen storage facility (K4.2).