DE202007016024U1 - Hybrid plant with a biogas plant - Google Patents

Abstract

Hybrid plant for the provision of electrical energy from regenerative energy sources, comprising:
a biogas plant having a generator (62) which provides electrical energy and is powered by combustion of the biogas produced by the biogas plant, and
at least one further energy converter (64, 66) which provides electrical energy and whose retrievable power is dependent on external influencing factors, in particular the wind supply and / or solar radiation,
wherein the electrical energy of the generator (62) and the electrical energy of the at least one further energy converter (64, 66) are fed into a common supply network (76), characterized in that
a heat accumulator (82), to which heat from the combustion process of the biogas can be supplied via a heat exchanger (26), and at least one electrical heating element (48, 124, 126) is present which is connected to electrical energy of the at least one further energy converter (64, 66 ) and can supply heat to the biogas plant.

Description

The The invention relates to a hybrid system for providing electrical Energy from renewable energy sources, which is a biogas plant with a generator that provides electrical energy and through Combustion of the biogas produced by the biogas plant driven is, and at least one further energy converter, the electrical Provides energy and its retrievable power from external sources Influencing factors, especially depending on the wind supply and / or solar radiation, the electric energy of the generator and the electric Energy of the at least one other energy converter in a common supply network be fed.

biogas plants have a so-called fermenter, in the biomass-containing residues such sewage sludge, Biowaste or leftovers, manure, manure, Wood schnitzel or specifically grown energy crops such as Corn, cereals and grass are implemented in a multi-stage process. This produces biogas, its essential high-energy component Methane is. The biogas can, for example, in a combined heat and power plant for Drive an internal combustion engine used, which is a generator drives. The provided electrical energy can be in a supply network be fed while the waste heat of the internal combustion engine for the heating of a building can be used. Due to the drive of the generator used combustion process arises When operating a biogas plant always electrical energy and heat at the same time, especially it is not possible provide electrical energy without generating heat at the same time. The thermal and electrical power of a biogas plant is up at a maximum value determined by the sizing of the installation available at any time. If sufficient biogas is available, can the performance of the plant by controlling the internal combustion engine be increased in a short time to its maximum value.

Other known energy converters can be immediate Provide electrical energy without a significant waste heat arises. Which includes in particular wind energy and photovoltaic systems. However, that is the availability the provided electrical energy of such energy converters from external influencing factors dependent, in the examples mentioned by the wind supply or solar radiation. In certain circumstances can over longer periods no or only a fraction of the rated output of such systems be available.

Hybrid systems for the provision of electrical energy from renewable energy sources combine different energy converters. Such a hybrid system is known from the German patent application DE 10 2004 046 701 A1 known. It is referred to as a renewable energy system and combines a wind turbine that generates electrical energy and feeds into a grid, with an internal combustion engine, which is operated with a fuel derived from renewable resources, such as rapeseed oil. The internal combustion engine drives a generator and thus generates electrical energy, which is also fed into the supply network. Essentially, the known hybrid system is intended for a supply of isolated networks. The combustion engine, which is driven by rapeseed oil, replaces a diesel generator that is traditionally used and can thus improve the environmental compatibility. In one embodiment, it is intended to operate the internal combustion engine with biogas. The heat generated during operation of the internal combustion engine is not used in the known hybrid system. Electric energy produced by the wind energy plant, which exceeds the consumption in the supply network, can be fed to a rapeseed mill. As a result, excess electrical energy can be used to produce a supply of rapeseed oil. However, this recovery of excess electrical energy requires equally that sufficient rapeseed is available for the mill and that sufficient storage capacity is provided for the rapeseed oil obtained.

From that Based on the object of the invention, a hybrid system of initially mentioned type available independent of the energy sources used current needs of the supply network uses more efficiently.

These Task is solved by the hybrid system with the features of claim 1.

The hybrid system according to the invention serves to provide electrical energy from regenerative energy sources and has a biogas plant with a generator that provides electrical energy and is powered by combustion of the biogas produced by the biogas plant, and at least one other energy converter that provides electrical energy and its retrievable power is dependent on external influencing factors, in particular the wind supply and / or solar radiation, wherein the electrical energy of the generator and the electrical energy of the at least one further energy converter are fed into a common supply network, and wherein a heat storage, the heat from the combustion process of the biogas is supplied via a heat exchanger, and at least one electric heating element is provided which can be operated with electrical energy of the at least one further energy converter. The dependence of the Callable performance of at least one other energy converter may also relate to the availability of other, ultimately solar fuels, such as geothermal or hydropower plants. The supply network may be a public power grid and / or a stand-alone grid. In the case of an island network, the hybrid plant according to the invention allows a self-sufficient supply, which represents a sensible alternative for connection to a public supply network, for example, for remote farms. The heat storage may be any means for storing heat, such as a thermally insulated water tank. The heat released in the combustion process of the biogas, which can not be converted into electrical energy with the aid of the generator, can be supplied to the heat accumulator, ie it does not escape unused but can be stored for later use. As a second possibility of heat supply is the electric heating element, which can be operated with electrical energy from the at least one other energy converter. As a result, excess electrical energy can be converted into heat by one or more of the further energy converters and supplied to the biogas plant. As a rule, the biogas plant must be constantly heated to maintain methane production, depending on the process engineering design to between 20 ° and 50 ° C substrate temperature. The solution found is particularly advantageous if the other energy converters generate more electrical energy than the consumers connected to the supply network need. If the electrical energy can not otherwise be stored, for example in an electrical energy store, the other energy converters would have to be switched off if necessary. However, this is unfavorable because it puts the hybrid system in an unfavorable working position for the overall operation and requires a relatively complex operation. Furthermore, in the case of a wind turbine, for example, the load on the components of the wind turbine can increase compared to a steady operation. As an alternative to a shutdown, it is known to convert the excess electrical energy into heat and supply it to the ground. For this purpose, however, a complex device is required and the excess energy is lost for later use. The hybrid system is equipped with an additional, controllable consumer, which can even out fluctuating demand for electrical energy in the supply network with the at least one, if necessary switchable over a long period of time heating element.

Basically the at least one heating element to meet the heat demand contribute to the biogas plant in any way. In one embodiment is at least one of the electrical heating elements in the heat accumulator arranged. The heat storage is part of the biogas plant. Because in this case for storage the waste heat from the combustion process and the heat provided by the electric heating element common heat storage can be used, an internal or external heat consumer in a simple way from the heat storage be supplied and thus benefit from both heat sources.

In a further embodiment is at least one of the electrical Heating elements in a fermenter of the biogas plant, a heating circuit for Heating a fermenter of the biogas plant or in a heat exchanger arranged for heating a fermenter biogas plant. In this case So the electrical heating element is used without intermediate heat storage directly to the fermenter. In particular, in the arrangement a heating element in the fermenter may require action the one local overheating prevent the substrate, for example, a large-scale execution of Heating elements.

In a further embodiment is at least one of the electrical Heating elements in a storage tank the biogas plant arranged. A storage tank is used to heat Fresh substrate, then the fermenter is supplied.

Of the Drive of the generator can basically with any Internal combustion engine done, for example, with a piston engine. In one embodiment of the invention is a gas turbine for driving provided the generator. A gas turbine is characterized by a higher Efficiency as a conventional Internal combustion engine off. This can make biogas from the same amount a larger amount electrical energy can be obtained. Accordingly reduced the amount of heat which released when burning a certain amount of biogas becomes.

According to one Another embodiment of the invention, heat is the heat storage for heating a Removable fermenter biogas plant. This allows the biogas plant on one for cheap biogas production Temperature be brought. Preferably, the liberated in the combustion process Heat the Exhaust gas with a heat exchanger taken and the fermenter biogas plant via another heat exchanger fed. In Combination with one in the heat exchanger for the heat to the fermenter arranged heating element is created as a "hybrid Heat exchanger ", both electrical as well as with heat from the heat storage can be supplied.

In In one embodiment of the invention, the biogas plant has a gas tank for storing biogas. This can provide a sufficient supply be kept on biogas to the biogas plant even if lacking Biogas production, perhaps as a result of maintenance or a Resource shortages, for to be able to operate for a certain period of time. Furthermore, the biogas production due to the buffer effect of the gas tank even with fluctuating performance the gas turbine on a steady, cheap Level continued become.

In a further embodiment of the invention, the gas turbine is a micro gas turbine with an electrical power of 100 kW or less. Microturbines are specially optimized for the mentioned, relatively low power range and have a high efficiency. Therefore, a hybrid system with high efficiency can be offered in a relatively low power range sufficient for many applications. Another advantage is that such micro gas turbines can be operated with non-treated, in particular not desulfurized biogas. An example of a micro gas turbine is off DE 202 20 621 U1 known.

In Another embodiment of the invention is the total electrical power of at least one other energy converter maximum 50% of electrical Power of the generator. The total electrical power relates on the electrical power of all connected others Energy converters. This allows the total of the hybrid system Provided electric power even in strongly fluctuating Power of the at least one other energy converter constant being held. In particular, the gas turbine at an operating point be operated, which is a quick balancing of power fluctuations the at least one other energy converter allows. simultaneously can the gas turbine in a favorable in terms of efficiency Power range to be operated.

According to one Embodiment of the invention is one of at least one other Energy converter a wind turbine. Also preferred is the Use of a photovoltaic system. Both variants are proven, robust Energy converters that provide immediate electrical energy can.

In Another embodiment of the invention are several others Energy converters provided the different renewable energy sources use. By combining different regenerative energy sources for the Provision of electrical energy with a biogas plant can cause power fluctuations the individual energy sources are partially compensated. Besides, that will available Energy supply, for example in the form of solar and wind energy, better exploited. The combination of different energy sources also offers an increased Operational safety in the case of technical failures of individual Energy converters.

According to one Embodiment of the invention are the other energy converter a common DC circuit or to a common DC circuit AC voltage circuit connected. If only energy converters are combined, the nature of a DC voltage supply, then they are connected to a common DC circuit connected. If only energy converters are combined, they naturally have an alternating voltage supply, then these are connected to a common AC circuit connected. Are energy converters delivering a DC voltage, with energy converters that supply an alternating voltage combined, can supply the supplied AC voltage with a suitable power supply unit in DC voltage being transformed. Alternatively you can the energy converters that supply a DC voltage with an inverter be combined, which converts the DC voltage into an AC voltage transforms. Mains connection devices exist essentially of a rectifier and a sieve member and supply a direct current with a supply of alternating current only slight residual ripple. Such power supply units are from devices and plants that are powered by AC mains. You can for different Voltage and current ranges be built. An advantage of using power supply units is in their robustness opposite Load fluctuations and variations in the input voltage of, for example up to +/- 10%. In a connection of the other Energy converter to a common DC voltage circuit all energy converters that naturally supply a DC voltage, with suitable protection against unwanted effects from the DC circuit fitted.

In one embodiment of the invention, the common DC voltage circuit or the common AC voltage circuit is connected to an energy store. The energy storage can provide electrical energy either directly or by energy conversion from a thermal, chemical or mechanical energy storage. The direct provision of electrical energy can be done for example via a capacitor bank, while the provision of electrical energy by energy conversion from thermal energy can be done for example from a heat storage. The provision of electrical energy from chemical energy can via a rechargeable battery, a battery, a galvanic cell or a redox flow cell. The provision of electrical energy from mechanical energy can be either from kinetic energy via a flywheel or from potential energy via a spring, a pumped storage, a compressed air reservoir, a gas storage or a weight. The stored energy can be used to compensate for power fluctuations of the other energy converters in the DC or AC voltage circuit and thus stabilize the electrical energy flow directly provided by the other energy converters. Furthermore, the stored energy can be used to restart the hybrid system after a break in operation independently of an external supply voltage. For this purpose, it may be necessary, for example, to restart auxiliary drives of the biogas plant, of the gas turbine or of the further energy converter or to move or track it in a specific working position. In addition, the power supply for the entire monitoring, control and regulation of the hybrid system during a break in operation can be ensured via the energy storage. The hybrid system is equipped with an additional, controllable energy source with the electrical energy from the energy store, which can be switched on as required over a relatively long period of time.

In A further embodiment of the invention converts an inverter electrical energy from the common DC voltage circuit in AC voltage um and feeds them into the supply network. By the change judge can control the power fed into the utility grid become. Furthermore, that of different energy converters provided electrical energy to the conditions of the respective supply network customized become.

In In another embodiment of the invention, the electrical Energy from the common AC circuit via a Transformer fed into the supply network. Possibly can also be taken from a common DC circuit Energy after conversion to AC voltage with the help of an inverter combined with a transformer for feeding into the supply network become.

According to one Another embodiment of the invention, the heat exchanger via a first heat circulation with the heat storage connected. The heat can the heat storage then be taken as needed by the biogas production process, if she needs becomes.

In a further embodiment of the invention is the heat of Heat storage over a second Heat medium circuit removable. This can also heat energy, not for the operation the biogas plant is recoverable, be used meaningfully. Especially can a building how a house or a stable is supplied with heat. Thereby the energy resources used are exploited even more efficiently. The extracted heat can also with the help of a suitable refrigeration system, such as a adsorption or a heat pump, for the cooling of buildings be used for example in the summer months. Also possible it does not, the excess heat the heat storage but with the help of another heat exchanger directly to the first Heat medium circuit refer to.

According to one Another embodiment of the invention, the biogas plant a Fermenter, which is provided with a heating circuit, which has a Valve arrangement with the first heat medium circuit is connectable. about the heating circuit, the fermenter with the in the heat storage stored heat be supplied.

In In another embodiment of the invention, a controller is provided, which the the drive of the generator in dependence of an externally or internally specified setpoint for the electrical power of the hybrid system and / or depending another externally or internally specified setpoint for the thermal Performance of the hybrid system controls. The two setpoints can be based on the requested electrical and / or thermal power set become. By controlling the drive of the generator, the Hybrid plant, for example, a constant electric power provide power fluctuations of the other energy converters be compensated by the control of the generator drive. Possibly the control of the generator drive can intervene only if the power fluctuations of the other energy converters are not or not completely with the help of energy storage or by switching on the heating element be compensated. Also possible is a setpoint for the specify thermal performance of the hybrid system and thus always a certain amount of heat to disposal to deliver. Specifying a setpoint for the electrical or the thermal power is known in the field of combined heat and power plants, the corresponding as heat-guided or current-controlled combined heat and power plants be designated. However, these known systems can not independent of each other Setpoints for the electrical and the thermal power are given. This is according to the invention possible, because the provision of electrical energy within certain Limits of the provision of heat is decoupled. It revealed This opens up new possibilities for one needs-based control of the hybrid system.

In In another embodiment of the invention, the controller detects the electrical Power of the generator and / or the electrical power of each the at least one further energy converter and / or the heat storage extracted thermal power. Optionally, in addition to the in the supply network fed electrical power to be detected. The collection of the mentioned data forms the basis for the control the drive of the generator. Also possible is a recording of from an inverter or a transformer into the electrical Supply network fed electrical power and / or of the electrical energy absorbed or discharged electrical Power and / or of the heating element or the heating elements absorbed electrical power. In particular, that of a electric heating element also absorbed electric power in dependence of the requested electrical power in the supply network and the from the other energy converters provided electrical energy be managed.

According to one In another embodiment, the controller controls the electrical power one of the at least one further energy converter. This can additionally to the control of the drive of the generator that of the other Energy converter provided electrical power can be influenced. This is for example in accordance with controllable wind turbines possible, whose power is e.g. in the interest of low noise emission can be lowered. Depending on the location of the wind turbine can this particular during the night's sleep be beneficial. Another motivation for lowering performance may be due to low demand for electrical energy result. It is also envisaged that the controller will power the heating elements or a heating element controls. This can be targeted a certain electrical power is converted into heat.

In a further embodiment of the invention, the at least one Further energy converters and / or the biogas plant modular expandable. The Extension can be used, for example, to supplement other solar modules, another wind turbine or an additional wind turbine Gas turbine for the biogas plant exist. This makes the hybrid system flexible to a changing one Demand for electrical and / or thermal power to be adjusted. Preferably, the hybrid system is already prepared for the addition of additional modules, for example, by appropriate larger sizing electrical Links.

In Another embodiment of the invention is a gas treatment plant Provided and treated biogas will be in a gas supply network fed. The gas treatment plant, for example, a Desulfurization and drying of the biogas produced. The Gas supply network may be a pipeline network to which a variety connected by gas consumers. Also possible however, that that Biogas first cached in a gas tank and by truck or boat another place is spent on the processed biogas is fed into a pipeline network. In this way, the generated and processed biogas also a variety of consumers accessible made. This also makes a larger amount of biogas useful be used as needed locally becomes. Especially with larger agricultural Companies are often too big Quantities of biomass available, so that biogas that can not be produced from it completely for the agricultural Operation can be recycled.

According to one Embodiment of the invention is only a part of the biogas produced as fuel for used the drive of the generator, the part being so dimensioned is that the provided by the hybrid electric and / or thermal Energy for the autonomous operation of the biogas and gas treatment plant is sufficient. In this embodiment, the hybrid system according to the invention thus serves primarily the production and treatment of biogas for feeding into a Gas supply network. Depending on the proportion of the other energy converters provided electrical energy is only a small amount used the generated biogas as fuel.

According to one Another embodiment of the invention, the biogas plant essential more biogas ready than for the autonomous energy supply, biogas and gas treatment plant is required. To the amount of generated To increase biogas, either the fermenter can be dimensioned much larger be required to operate the drive of the generator. Also possible is the use of additional Fermenter whose biogas is exclusive to the gas treatment plant supplied becomes. Furthermore, the amount of biogas produced can also be characterized decisively be increased that the Biomass, a high-energy co-substrate, for example in shape high-energy plants such as corn, is added.

In a further embodiment of the invention, the gas supply network is taken at any other point gas in fuel or heat equivalent to the injected biogas and fed there a gas turbine, an internal combustion engine or a gas extraction station. As a result, the energy contained in the injected biogas by removing an energy-equivalent amount of gas from the supply network at any be recycled elsewhere.

In a further embodiment, at least one further electrical heating element is provided which is connected to electrical energy of the at least one further energy converter 64 . 66 operated and used for other heating purposes. For example, excess electrical energy can thereby be used to heat an operating room of the biogas plant, a container or an accommodation.

The The invention will be described below with reference to exemplary embodiments illustrated in FIGS explained in more detail. It demonstrate:

1 a hybrid system according to the invention in a highly simplified, schematic representation,

2 a simplified block diagram for controlling the hybrid system from 1 .

3 a further simplified block diagram for controlling a further hybrid system according to the invention.

4 another hybrid system according to the invention in a highly simplified, schematic representation.

1 shows a hybrid system with a fermenter 10 , in which biogas is generated from residues that are in the upper range 12 of the fermenter 10 accumulates. The biogas enters a gas tank via a pipeline system 14 , Further processing steps of the biogas, such as desulfurization, compression or drying of the gas are in the simplified representation of 1 not shown, but may nevertheless be provided.

The biogas is discharged from the gas tank 14 in a micro gas turbine 60 which is powered by combustion of biogas. The also for micro gas turbine 60 leading arrow 44 indicates the supply of fresh air for the combustion process. The micro gas turbine 60 is about a wave with a generator 62 connected, which can provide an electrical power of preferably 100 kW or less.

The from the generator 62 provided electrical power is transmitted via a line 72 into a supply network 76 fed. The supply network 76 supplies several electrical consumers, not shown, and has no connection to the network of a power company. As an alternative to this so-called island operation of the supply network 76 For example, the electrical energy provided by the hybrid system can also be fed into a public grid. The resulting in the combustion process of the biogas exhaust gases are from the micro gas turbine 60 over a line 36 a heat exchanger 26 fed. In the heat exchanger 26 the heat of the exhaust gas from the heating means of a first heat medium circuit 28 added. In the illustrated embodiment, water is used as a heating means. The exhaust gases are from an outlet of the heat exchanger 26 via an exhaust system 38 discharged into the ambient air. The first heat circulation 28 transports the heat taken from the exhaust gas into a heat storage tank 82 , which is formed in the illustrated embodiment of a water tank.

Via a valve arrangement 30 it is possible to use the first heat recovery circuit 28 with a heating circuit 32 to connect one inside the fermenter 10 located second heat exchanger 34 flows through. In this way, the heat taken from the exhaust gas can be the biogas production process within the fermenter 10 be supplied. At the same time, the valve system becomes 30 preferably controlled so that in the fermenter 10 sets a constant temperature, depending on the process engineering design.

As another energy converter, the hybrid system has the 1 via a wind turbine 66 and a photovoltaic system 64 , The wind turbine 66 generates an alternating electrical current, which is generated by means of a rectifier 16 is converted into direct current. About the rectifier 16 is the wind turbine with a DC voltage circuit 18 connected. The photovoltaic system 64 Immediately provides a DC voltage, which is also the DC voltage circuit 18 is supplied. To stabilize the DC voltage is the DC voltage circuit 18 additionally with an accumulator 20 connected, which stores electrical energy. The in the accumulator 20 stored electrical energy can also be used to start the hybrid system after a break in operation (black start). The DC voltage circuit 18 is about an inverter 22 to the supply network 76 tethered. About the "detour" of the DC circuit 18 can the electrical energy of different energy converters 64 and 66 via a common inverter 22 the supply network 76 be supplied.

The biogas leading pipe from the fermenter 10 to the gas tank 14 is with a further valve arrangement 40 provided over the excess biogas, neither from the gas tank 14 still taken by the micro gas turbine 60 can be recycled, a torch head 42 fed to where it can be burned.

By the flaring off of biogas, which consists essentially of methane, will the environmental impact across from a release of methane into the atmosphere significantly improved.

The in the heat storage 82 Stored heat can not only be used to heat the fermenter 10 be used, but also via a in the drawing only indicated second heat medium cycle 46 for other purposes. For example, in this way, an equipped with the hybrid plant agricultural operation can be supplied with sufficient heat energy, which can be used both for heating and - with a suitable chiller - for cooling.

Alternatively, required heat energy can also be transferred via another heat exchanger 24 directly to the first heat recovery circuit 28 be removed. In the exemplary embodiment, this heat energy extraction is used to operate a refrigeration machine for the air conditioning of agricultural operating rooms.

The administration 72 to the supply network 76 is via an electrical line 50 with a heating element 48 connected to the heat storage 82 is used. The heating element 48 becomes with the electric energy of the further energy converter 64 and 66 operated. This can be done in the heat storage 82 be additionally heated. From the other energy converters 64 . 66 Provided electrical energy can thus be utilized even if there is no demand for electrical energy in the supply network 46 exists and the electrical energy storage 20 already filled.

In the block diagram of 2 is the control of the hybrid system off 1 shown schematically and greatly simplified. The generator 62 is via an electrical line 72 with a node 74 connected. The node 74 is also via an electrical line 70 with the photovoltaic system 64 and via an electrical line 68 with the wind turbine 66 connected. The electrical energy gets over the node 74 into the supply network 76 fed. Also indicated schematically is the heat transfer from the micro gas turbine 60 that with biogas 78 is supplied by a wire 80 to the heat storage 82 from which a consumer 84 is supplied with thermal energy.

The control 86 records the following quantities via the dotted connections: Via the connection 88 that of the photovoltaic system 64 provided electrical power, over the connection 90 the one from the generator 62 provided electrical power, over the line 92 that of the wind turbine 66 provided electrical power and over the line 94 the total in the supply network 76 fed electrical power. The control 86 evaluates the acquired data and compares the provided electrical power with an externally or internally set value 98 who in the supply network 76 requested electrical power describes. Represents the controller 86 a deviation from the setpoint fixed, via the control connection shown in dashed lines 102 a control command to the micro gas turbine 60 output whose output is then adjusted so that the total electrical power supplied to the setpoint 98 equivalent. In this way, always the required electrical power can be provided, even if the electrical power of the photovoltaic system 64 or the wind turbine 66 fluctuates greatly due to external influences. By the type of control mentioned, the electrical power of the other energy converter 64 and 66 prioritized to the biogas plant, so that a combustion of the biogas takes place only to the extent required.

Another variant of the control is based on the 3 be explained. In the illustrated embodiment is a wind turbine 66 intended as the only other energy converter. The elements provided with the same reference numerals correspond to those of 2 , In contrast to 2 receives the control 86 of the 3 a second setpoint specification 100 which the requested thermal power of the consumer or consumers 84 describes. Further receives the control 86 about the connection 96 Information about the heat storage 82 extracted thermal power. With increased demand for thermal power, the controller can 86 the performance of the micro gas turbine 60 increase accordingly, so that the heat storage 82 a sufficient amount of heat is supplied. Should this cause the electric power of the generator 62 about that in the supply network 76 Increasing the demanded measure, the excess electrical power can optionally also via a corresponding heating element the heat storage 82 be supplied. Alternatively, the controller has 86 over the control line 102 the possibility of the electrical power provided by a reduction in power of the wind turbine 66 to influence.

In the 4 schematically a section of another hybrid system according to the invention is shown. The exemplary embodiment particularly shows different arrangements of the electrical heating elements. The other energy converters and the biogas-powered generator are not shown in the section. Components corresponding to those of the first embodiment in 1 are identical with the same reference numerals and will not be explained again. Deviating from the first Ausfüh approximately example, there is in the variant of 4 a hybrid heat exchanger 110 , which is used to heat the substrate in the fermenter 10 serves. The hybrid heat exchanger 110 is outside the fermenter 10 arranged and is going through a cycle 118 flows through the substrate to be heated. The hybrid heat exchanger 110 it draws heat energy either, similar to the heat exchanger 34 from the first embodiment, from the heating circuit 32 , or over the two electrical heating elements 124 , which can be operated with electrical energy of the other energy converter, not shown. As the hybrid heat exchanger 110 Part of the heating circuit 32 is, are the two electric heating elements 124 also in the heating circuit 32 ,

The two other electrical heating elements 126 are in the storage container 112 arranged. The original container 112 is double-walled and includes an inner container 114 in which there is fresh substrate. The inner container 114 is from an outer container 116 surrounded, which is filled with water. In this water are the two electric heating elements 126 , which can also be operated with electrical energy of other energy converters. This allows the fresh substrate in the inner container 114 be heated, without causing local overheating in the field of heating elements 126 comes. The preheated in this way fresh substrate from the container 114 passes over a line 130 and a valve 132 in the cycle 118 and is about this the fermenter 10 fed. Consumed substrate becomes the fermenter 10 over a line 136 withdrawn and a discharge container 134 fed. The spent substrate from the discharge container 134 can by tanker truck 138 be transported away.

In the inner container 114 of the original container 112 and inside the fermenter 10 each is a circulating device 140 respectively. 142 , which ensures a thorough mixing of the substrate.

Another pair of additional heating elements 128 , which can also be supplied with energy of other electrical energy converters, is in an accommodation 120 arranged. These heating elements 128 For example, they can be radiant heaters.

Claims (28)

Hybrid plant for the provision of electrical energy from regenerative energy sources, comprising: - a biogas plant with a generator ( 62 ), which provides electrical energy and is driven by combustion of the biogas produced by the biogas plant, and - at least one further energy converter ( 64 . 66 ), which provides electrical energy and whose retrievable power is dependent on external influencing factors, in particular the wind supply and / or solar radiation, - the electric energy of the generator ( 62 ) and the electrical energy of the at least one further energy converter ( 64 . 66 ) into a common supply network ( 76 ) are fed, characterized in that - a heat storage ( 82 ), the heat from the combustion process of the biogas via a heat exchanger ( 26 ), and at least one electric heating element ( 48 . 124 . 126 ) is present, which with electrical energy of at least one other energy converter ( 64 . 66 ) and can supply heat to the biogas plant. Hybrid installation according to claim 1, characterized in that at least one of the electrical heating elements ( 48 ) in the heat storage ( 82 ) is arranged. Hybrid installation according to claim 1 or 2, characterized in that at least one of the electrical heating elements ( 124 . 126 ) in a fermenter ( 10 ) of the biogas plant, a heating circuit ( 32 ) for heating a fermenter ( 10 ) of the biogas plant or in a heat exchanger ( 34 . 110 ) for heating a fermenter ( 10 ) of the biogas plant is arranged. Hybrid installation according to one of claims 1 to 3, characterized in that at least one of the electrical heating elements ( 126 ) in a storage container ( 112 ) of the biogas plant is arranged. Hybrid installation according to one of claims 1 to 4, characterized that one Gas turbine is provided for driving the generator. Hybrid installation according to one of Claims 1 to 5, characterized in that heat is transferred to the heat store ( 82 ) for heating a fermenter ( 10 ) of the biogas plant is removable. Hybrid installation according to one of claims 1 to 6, characterized in that the biogas plant comprises a gas tank ( 14 ) for storing biogas. Hybrid installation according to one of Claims 5 to 7, characterized in that the gas turbine has a micro gas turbine ( 60 ) having an electric power of 100 kW or less. Hybrid installation according to one of claims 1 to 8, characterized in that the total electrical power of the at least one further energy giewandler ( 64 . 66 ) maximum 50% of the electrical power of the generator ( 62 ) is. Hybrid installation according to one of claims 1 to 9, characterized in that one of the at least one further energy converter is a wind energy plant ( 66 ). Hybrid installation according to one of Claims 1 to 10, characterized in that one of the at least one further energy converter has a photovoltaic system ( 64 ). Hybrid installation according to one of Claims 1 to 11, characterized in that a plurality of further energy converters ( 64 . 66 ) are provided which use different renewable energy sources. Hybrid installation according to one of Claims 1 to 12, characterized in that the further energy converters are connected to a common DC circuit ( 18 ) or connected to a common AC circuit. Hybrid installation according to claim 13, characterized in that the common DC circuit ( 18 ) or the common AC voltage circuit to an energy store ( 20 ) connected. Hybrid installation according to claim 13 or 14, characterized in that an inverter ( 22 ) electrical energy from the common DC circuit ( 18 ) converted into AC voltage and into the supply network ( 76 ) feeds. Hybrid system according to claim 13 or 14, characterized in that the electrical energy from the common AC circuit via a transformer in the supply network ( 76 ) is fed. Hybrid installation according to one of Claims 1 to 16, characterized in that the heat exchanger ( 26 ) via a first heat medium circuit ( 28 ) with the heat storage ( 82 ) connected is. Hybrid installation according to claim 17, characterized in that the heat of the heat accumulator ( 82 ) via a second heat medium circuit ( 46 ) is removable. Hybrid installation according to claim 17 or 18, characterized in that the biogas plant has a fermenter ( 10 ) having a heating circuit ( 32 ) provided with a valve arrangement ( 30 ) with the first heat medium circuit ( 28 ) is connectable. Hybrid installation according to one of Claims 1 to 19, characterized in that a control system ( 86 ) is provided, which drives the generator ( 60 ) as a function of an externally or internally specified reference value ( 98 ) for the electrical power of the hybrid system and / or in dependence on a further externally or internally predetermined setpoint ( 100 ) controls the thermal performance of the hybrid system. Hybrid system according to claim 20, characterized in that the controller ( 86 ) the electric power of the generator ( 62 ) and / or the electrical power of each of the at least one further energy converter ( 64 . 66 ) and / or the heat storage ( 82 ) detected thermal power detected. Hybrid system according to claim 20 or 21, characterized in that the controller ( 86 ) the electrical power of one of the at least one further energy converter ( 64 . 66 ) controls. Hybrid installation according to one of Claims 1 to 22, characterized in that the at least one further energy converter ( 64 . 66 ) and the biogas plant are modular expandable. Hybrid system according to one of claims 1 to 23, characterized in that a Gas treatment plant is provided and processed biogas in a gas supply network is fed. Hybrid installation according to Claim 24, characterized in that only a part of the biogas produced is used as fuel for the drive of the generator ( 60 ) is used, wherein the part is dimensioned so that the provided by the hybrid system electrical and / or thermal energy sufficient for the autonomous operation of the gas treatment plant. Hybrid installation according to claim 24 or 25, characterized that the Biogas plant provides significantly more biogas than autonomous operation the gas treatment plant is required. Hybrid system according to one of claims 24 to 26, characterized in that the Gas supply network at any other place Gas in the fuel or heat equivalent taken to the fed biogas and there a gas turbine or an internal combustion engine or a gas extraction station is supplied. Hybrid installation according to one of Claims 1 to 27, characterized in that at least one further electrical heating element ( 128 ) provided with electrical energy of the at least one further energy converter ( 64 . 66 ) and can be used for other heating purposes.