US20100236253A1

US20100236253A1 - Method and system for using renewable energy sources

Info

Publication number: US20100236253A1
Application number: US12/613,910
Authority: US
Inventors: Dirk Adam
Original assignee: Natcon7 GmbH
Current assignee: Natcon7 GmbH
Priority date: 2008-12-23
Filing date: 2009-11-06
Publication date: 2010-09-23
Also published as: PL2202470T3; DE102008063250A1; ES2428788T3; EP2202679A1; HRP20130629T1; EP2202470A1; CY1114302T1; DK2202470T3; US9543764B2; US20100161147A1; PT2202470E; SI2202470T1; DE202008017271U1; SMT201300079B; EP2202470B1; EP2202470B8

Abstract

Method for using renewable energy sources comprising at least one remote energy generation plant which may be operated by a renewable energy source,

- a production measurement unit at the location of the at least one remote energy generation plant which measures the production of the at least one remote energy generation plant,
- a central control unit,
  the method comprising the following steps:
a) producing a production forecast for the production of the at least one remote energy generation plant in a future time period,
b) transmitting the production forecast to the central control unit via a computer network,
c) operating the remote energy generation plant and measuring the production using the production measurement unit,
d) comparing the measured production with the production forecast,
e) notifying an operator of the at least one energy generation plant, if the measured production deviates from the production forecast beyond a predetermined level.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not applicable

BACKGROUND OF THE INVENTION

The invention relates to a method and a system for using renewable energy sources. To this end, various energy generation plants are used which are operated by a renewable energy source. These include, in particular, biogas plants, geothermal plants, photovoltaic plants or solar collectors, water power plants and wind energy plants. Said energy generation plants convert the energy provided by the renewable energy sources, in particular, into electrical energy or thermal energy, which is easily available for further use.
Both when using the aforementioned energy sources in separate networks and when supplying the energy made available to public power supply grids, the ability to control and predict the energy generation, which is only possible to a limited extent, represents a considerable challenge. A significant reason for the limited ability to control and predict the energy production is in the fluctuating availability of “solar fuel”, for example with a fluctuating wind supply. For remedying these problems, it is known to produce forecasts which, for example, are based on a weather prediction. The production of such forecasts is, however, difficult and whether the desired result is produced, namely a correct forecast of the energy actually provided in the forecast time period, is dependent on many factors.
A further reason for the limited ability to plan and predict the energy generated is the generally remote structure. For example, the energy generation of a biogas plant located in a remote agricultural business is additionally dependent on how the locally responsible operator operates the plant. Generally, the operator substantially only considers process engineering and plant engineering characteristics and the given boundary conditions at its location. Additionally, as a result of many other constraints which are not due to the technology, the operator may be prevented from fully exhausting the potential energy generated which is based on the available renewable raw material.
The aforementioned difficulties in the ability to plan and predict energy generation are a drawback for the use and acceptability of renewable energy sources. In particular, they may make the availability of rapidly accessible reserve energy and an upgrading of the power supply grids necessary.
Proceeding therefrom, it is the object of the invention to provide a method and a system for using renewable energy sources, which simplifies the planned use of the renewable energy sources and improves the ability to plan and predict the energy actually available.

BRIEF SUMMARY OF THE INVENTION

The method according to the invention serves for using renewable energy sources and requires at least one remote energy generation plant, which may be operated by a renewable energy source, a production measurement unit at the location of the at least one remote energy generation plant, which measures the production of the at least one remote energy generation plant, and a central control unit. The method comprises the following steps:

a) producing a production forecast for the production of the at least one remote energy generation plant in a future time period,
b) transmitting the production forecast to the central control unit via a computer network,
c) operating the remote energy generation plant and measuring the production using the production measurement unit,
d) comparing the measured production with the production forecast,
e) automatically notifying an operator of the at least one energy generation plant, if the measured production deviates from the production forecast beyond a predetermined level.

The production measurement unit measures a variable which is meaningful for the production of the energy generation plant, for example an amount of electrical energy supplied to a power supply grid, or an amount of heat, provided in a specific time interval. Preferably, the power provided by the energy generation plant is continuously measured, for example a gross electrical output measured on a current transformer or generator, or power supplied to an electrical network. Such a measurement of the load profile, i.e. the measurement of power at the current time, provides a particularly accurate image of the operating conditions of the energy generation plant.
The central control unit may, in particular, be a computer which is connected to an electronic network. The control unit has a coordinating function when managing a production forecast transmitted thereto and when automatically notifying the operator. The central control unit has a function going beyond the scope of this, which is a controlling function in a narrower sense, but only in specific embodiments of the invention. The term control unit is thus understood in a broad sense.
The future time period covered by the production forecast is fixedly predetermined and may, for example, be an hour, a week or preferably a day. Thus the time period is subdivided into smaller time intervals, which for example encompass a minute, an hour or preferably 15 minutes. The production forecast contains for each time interval information about the predictable production of the energy generation plant. The information, in a similar manner to the production measured by the production measurement unit, may be an amount of energy available in the time interval or power provided for the respective time interval. The production forecast may be restricted to this production data and/or power data and, independently of meteorological data, may be produced solely based on the information and empirical values of the respective energy generation plant.
For transmitting the production forecast which has been produced to the central control unit, a computer network is provided, in particular, by incorporating the Internet. However, any other Wide Area Network (WAN) may also be used, for example a mobile radio network or a wired telephone network.
The production measured during the operation of the remote energy generation plant by the production measurement unit is compared in a further method step with the corresponding information of the production forecast. This comparison may either take place in the central control unit which requires a transmission of the production measured by the production measurement unit from the remote energy generation plant to the central control unit, in particular via a computer network.
Preferably, the comparison takes place at the location of the at least one remote energy generation plant, i.e. locally, in particular within the production measurement unit or another control unit connected thereto. In this case, the production forecast is transmitted, in particular via a computer network, from the central control unit to the location of the energy generation plant, in particular to the production measurement unit or another control unit arranged there. If the production forecast is for a time period of, for example, one day at the location of the energy generation plant, the comparison within this time period may take place irrespective of the availability of the communication with the central control unit. Even when in the event of a communication fault no notification of the operator is possible via the central control unit, uninterrupted monitoring may nevertheless take place, by deviations between the production forecast and the actual production being recorded locally. Expediently, the continuously calculated values of the difference between measured production and the production forecast may be continuously recorded and stored.
If the measured production deviates by a predeterminable level beyond the production forecast, an operator who is responsible for the operation of the at least one remote energy generation plant is automatically notified. The predeterminable level of deviation may, in particular, be predetermined via upper and lower limit values. The maximum permissible deviation from the production forecast may, for example, be predetermined in the form of a percentage deviation from the predicted production, different presettings being able to be made for the maximum permissible deviations upwards and downwards. Also, two or more different limit values may be predetermined in any direction (deviation upwards or downwards). For example, when exceeding a first limit value, which corresponds to a relatively small deviation from the production forecast, and when exceeding a second limit value which corresponds to a relatively large deviation, different types of notification can be provided, for example a warning and an alarm, or a specific call for action.
The automatic notification takes place preferably via a computer network, in particular a telephone network or mobile radio network may be used. The notification may, for example, be transmitted in the form of an email or an SMS to the operator.
By means of the method according to the invention, the ability to plan the energy generation is substantially improved. Firstly, the production of a production forecast forces the responsible person in each case to deal with the operation of the plant in a very specific manner for each time interval of the planned time period.
Secondly, the automatic notification of the operator makes it possible to react immediately to a deviation from the expected operating conditions of the energy generation plant. As a result, for example a technical fault of the plant may be very rapidly identified and wherever possible corrected by the operator.
A particular advantage of the method, therefore, is that it may be carried out using very simple means. The monitoring of the plant operation is carried out by utilising the production measurement unit which is already present in existing energy generation plants which supply the generated energy to a public power supply grid. Thus no additional measuring technology is required for the monitoring of the energy generation plant. The production and transmission of the production forecast as well as the implementation of a suitable central control unit is also possible with a low equipment cost.
In one embodiment of the method, the production forecast is produced by a person who is locally responsible for the operation of the at least one remote energy generation plant. Due to the transmission of the production forecast, which is provided according to the invention, to the central control unit via a computer network, the production forecast may, in principle, be produced at any location. Preferably, the production forecast takes into account characteristics specific to the plant and location, about which those responsible for the local operation of the plant according to the invention are kept informed substantially more accurately than other groups of people considered for producing the production forecasts, namely sales executives of an operating company or marketing company. The method makes it possible to use this local know-how in a simple manner to improve the ability to plan the operation of the plant.
An embodiment of the method provides that the production forecast is produced by means of a computer network. In addition to the transmission of the production forecast provided via a computer network, the production of the production forecast itself is also simplified as a result. In particular, it is conceivable to provide a Web interface, which makes it possible to produce the production forecast using a conventional Internet browser. As a result, the technical provisions for producing the production forecast are very simple and immediately available anywhere. For example, a person responsible for the local operation of the energy generation plant may produce a production forecast at the weekend from home or during a business trip from a hotel.
In one embodiment, the production forecast comprises an active power and/or reactive power to be generated and/or network system services to be provided. In principle, the information of the production forecast for the operation of the remote energy generation plant may be very simple, namely merely consisting of on/off information. It is, however, also possible to provide subtly different information, namely numerical values for the active power or reactive power. Moreover, it is also conceivable to use the method for improving the ability to plan network system services. These comprise, in particular, controlling the active power, reactive power, frequency and/or a voltage. During the operation of separate networks and also during the operation of public networks, the aforementioned network system services are, under some circumstances, in high demand and absolutely necessary in order to permit stable network operation. The network system services may, in principle, also be produced by remote energy generation plants, which are operated by renewable energy sources. Therefore, the invention provides for the incorporation of corresponding information into the production forecast. As a result, the ability to plan even the network system services may be optimised.
In one embodiment the central control unit based on the production forecast produces a schedule for the at least one remote energy generation device and the schedule is transmitted from the central control unit via a computer network to a remote control unit, which controls the at least one remote energy generation plant automatically according to the schedule.
The schedule contains information which corresponds to that of the previously produced production forecast, i.e. for example specific presettings for the desired power and reactive power in the individual time intervals of the planning time period. In the simplest case, the presettings of the schedule are the same as the information of the production forecast. However in the schedule, deviating presettings may also be made. Thus the comparison of the measured production does not take place with the production forecast, but with the schedule based thereon. The operator is notified if the schedule is not observed.
The automatic control of the at least one remote energy generation plant takes place by means of the remote control unit. In other words, in principle, the schedule may be executed automatically without further manual intervention. At least when altering a presetting for the operation of the plant from one given time interval to the next time interval, no manual intervention is necessary in the management of the plant. However, for the operation of the remote energy generation plant according to the schedule, the involvement of an operator may be necessary, for example in order to introduce renewable raw materials into the fermenter of a biogas plant.
As a result of the automatic execution of the schedule, the actual plant operation is less affected by everyday, unforeseeable circumstances. For example, a power increase which is predetermined for a specific time by the schedule is reliably implemented, even when the plant operator is indisposed due to illness or even a telephone conversation. This contributes substantially to the fact that the energy generation takes place as planned. At the same time, the operation of the energy generation plant is substantially simplified and the operator is relieved of his control tasks.
According to one embodiment, when producing the schedule in the central control unit, a comparison of the production forecast takes place with a forecast demand and the schedule is produced, adapted to the forecast demand, optionally deviating from the proposed schedule. This makes it possible in a simple manner to take into account a centrally available demand forecast during the operation of the plant. In particular, with a production forecast which exceeds a forecast demand, the information for the schedule may be easily reduced, without this jeopardising the planned execution of the schedule. It is also possible, in addition, to store the reduction of the presettings which has been carried out in the schedule relative to the production forecast, in particular in the central control unit. It may be assumed, therefore, that the reduction which has been carried out corresponds to an available reserve, which may be called upon if required.
In one embodiment, the remote control unit comprises a monitoring device which monitors operating data and/or environmental conditions of the at least one remote energy generation plant and transmits this information to the central control unit via a computer network. The monitored operating data comprise, for example, the generated active power and/or reactive power or a quantity of gas stored in a gas store of a biogas plant. The operating data may exceed the data relevant to the production made available by the production measurement unit. The environmental conditions include among other things meteorological data such as temperature or wind strength. The monitoring of the aforementioned data permits additional monitoring as to whether the operation of the plant takes place corresponding to the production forecast and/or corresponding to the schedule. Moreover, additional monitoring measures of the plant operation may be carried out and possibly relevant circumstances automatically communicated to the operator by means of notification.
According to one embodiment, a plurality of remote energy generation plants are present which are operated by renewable energy sources, a corresponding number of production forecasts and/or schedules being produced. On the one hand, the advantages of the method already set forth in detail are therefore achieved simultaneously in a plurality of energy generation plants, only one central control unit being necessary. On the other hand, by grouping together a plurality of remote energy generation plants, the ability to plan the energy generation is further improved, as deviations which may be present of individual production forecasts and/or schedules are less crucial. It is possible to control automatically a proportion of the plants by predetermining schedules and merely by detecting the production forecast and monitoring using the production measurement unit, it is possible to incorporate a further proportion of the plants into the system. As a result, energy generation plants may be incorporated with different technical prerequisites.
In one embodiment, no notification of the operator takes place when, using the data transmitted from the monitoring device, a cause may be identified for the deviation of the measured production from the production forecast and/or from a schedule produced which is based on the production forecast, over which the operator has no influence. If, for example, there is a production forecast which provides for the operation of a wind energy plant at nominal power, and if the data for the wind speed of the monitoring device exhibit a decrease in wind speed, it is clear that the operator is not able to observe the production forecast due to the current wind conditions. In this case, a notification of the operator may be dispensed with.
In one embodiment, a schedule is adapted when the comparison of a measured production and/or of operating data monitored by the monitoring device exhibits deviations from a production forecast and/or a schedule which has been produced, based on the production forecast. As a result, it is possible to counteract the established deviations from the schedule. If, for example, a remote energy production plant falls short of the associated production forecast and/or the associated schedule, a compensation may be carried out by altering the schedule of a further remote energy generation plant.
In this case, in particular, the information present in the central control unit about the possibility of increasing the presettings of the other energy generation plant may be utilised, namely when, as set forth above, a reduction of the production forecast which is present for the other energy generation plant has been previously carried out. By alternatively or additionally considering the operating conditions, during the comparison it is also possible to forecast which further sequence the established deviations will adopt. If the monitored operating conditions reveal a technical fault of the plant, it may be concluded therefrom that an operation according to the schedule will no longer be possible for a specific time period. It is then possible to adapt accordingly the schedule of the plant affected by the fault, i.e. for example to set all presettings to zero. At the same time, compensation may take place by means of a further energy generation plant already in operation or an energy generation plant to be additionally put into operation, which again takes place by altering the respective schedules. As the schedule of the energy generation plant affected by the deviation is also adapted, the energy may be generated as a whole according to the schedules present in the central control unit. It is impossible that a plant affected by a fault, for example, is put into operation again without this previously being able to be taken into account by a corresponding schedule. It may be provided to notify the operators affected by the alteration of individual schedules automatically about the alterations.
The system is used for using renewable energy sources and comprises

- at least one remote energy generation plant, which may be operated by a renewable energy source,
- a production measurement unit at the location of the at least one remote energy generation plant, which measures the production of the at least one remote energy generation plant,
- a device for detecting a production forecast for the production of the at least one remote energy generation plant in a future time period,
- a device for transmitting the production forecast to the central control unit via a computer network,
- a device for comparing the measured production with the production forecast and
- a device for notifying an operator of the at least one energy generation plant which is configured such that a notification of the operator automatically takes place, if the measured production deviates from the production forecast beyond a predeterminable level.

The system is suitable, in particular, for carrying out the method according to the invention. With regard to the explanation of the terms used and the advantage achievable by the system, reference is made to the above explanations of the method.
In one embodiment, the at least one remote energy production plant is a biogas plant and/or a plurality of remote energy generation plants are present, which may be operated by renewable energy sources. A biogas plant offers the particular advantage that its operation may be more easily planned within certain limits than, for example, that of a photovoltaic plant. This is due to the fact that the biogas plant is namely very much dependent on locally available, renewable raw materials to be converted in the biogas plant, but which are frequently obtained with a certain regularity and additionally are capable of storage. The same applies to the biogas produced, which optionally may be temporarily stored in the plant. For this reason, a production forecast may be produced in a particularly reliable manner and/or a predetermined schedule may be executed in a particularly reliable manner.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention is described in more detail hereinafter with reference to two embodiments shown in the figures, in which:

FIG. 1 shows a first embodiment of a simple system according to the invention; and

FIG. 2 shows a second embodiment of a more complex system according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

While this invention may be embodied in many different forms, there are described in detail herein a specific preferred embodiment of the invention. This description is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiment illustrated.
FIG. 1 shows a system comprising an energy generation plant 10 which is operated by a renewable energy source. As indicated by the dotted line, the energy generation plant 10 is operated by an operator 12 who controls the energy generation plant 10.
The operator 12 produces a production forecast 100 via a Web interface 18. This takes place by means of a computer network and an Internet browser 16.
The production forecast 100 is transmitted via a wide area network 104, in the example via the Internet, to a central control unit 24. A production measurement unit 102 is connected to the energy generation plant 10 and measures continuously the electrical active power and/or reactive power supplied to a public power supply grid by the energy generation plant 10. These data are transmitted to a remote control unit 36, which is arranged at the location of the energy generation plant 10. From the remote control unit 36, the data is transmitted via a computer network 106, in the example again via the Internet, to the central control unit 24. As the second arrow between the central control unit 24 and the remote control unit 36 indicates, data are also transmitted in the opposite direction, namely those of the production forecast 100. In the remote control unit 36 a comparison takes place of the measured productions with the production forecast 100. Thus the production forecast 100 may be present for the entire forecast time period in the remote control unit 36 or merely for part of the forecast time period which is valid for a current time period. For example, the production forecasts 100 may be produced for one respective week and transmitted to the central control unit 24 and for the comparison in the remote control unit 36 only one day time period of the production forecast 100 is transmitted from the central control unit 24 to the remote control unit 36. If, therefore, a deviation is established, i.e. the measured production deviates upwards or downwards beyond a predetermined level from the production forecast 100, an automatic notification of the operator 12 of the energy generation plant 10 takes place via a computer network 108, in the example via a mobile radio network. The notification may take place, for example, by sending an SMS.
The system shown in FIG. 2 has an energy generation plant 10 which is operated by renewable energy. In the example it is a biogas plant. The operator 12 is responsible for the operation of the energy generation plant 10. In this case, the operation of the energy generation plant 10 is subjected to environmental conditions 14, for example to a specific external temperature. The energy generation plant 10 may be connected to a separate network or to a public power supply grid.
The operator 12 locally responsible for the operation of the energy generation plant 10 produces, by means of an Internet browser 16 via a Web interface 18, a production forecast which at the same time is a proposal for the operation of his plant in the forecast time period. Thus the production forecast is denoted hereinafter as the proposed schedule 20. The proposed schedule contains presettings for the operation of the energy generation plant 10. In the example shown, these presettings refer to the electrical power available from the energy generation plant 10 as well as thermal power. For both power values, the schedule has desired values which are respectively constant for a time interval of fifteen minutes. The entire proposed schedule 20 covers a time period of one day and thus contains 96 presettings for each of the two power values. The Internet browser 16 is connected via a computer network 22, in this case the Internet, to the central control unit 24. The central control unit 24 comprises a control module 26, a monitoring module 28 and a reporting module 30.
In the central control unit 24, the proposed schedule 20 is used as a basis for producing a schedule 32 by considering forecasts for the operating conditions of the energy generation plant 10 and by considering a forecast demand. This schedule 32 is transmitted via a computer network 34 to a remote control unit 36.
The transmitted schedule 32 is initially stored in the remote control unit 36. The remote control unit 36 contains a further schedule 38, which is denoted as “Schedule 1”, and which is still executed at the time of the transmission of the schedule 32. This relates to the current day, whilst the schedule 32 applies to the following day. The remote control unit 36 has a control module 40 which, based on the information of the current “Schedule 1” 38, transmits control commands directly to the management of the energy generation plant 10. In this manner it is ensured that the energy generation plant 10 is operated according to the current schedule 33.
Also shown in the figure is the monitoring which has been provided of the status of the energy generation plant 10. To this end, the remote control unit 36 has a monitoring device 42 which by means of sensors, not shown, on the one hand detects the environmental conditions 14. Additionally, the monitoring device 42 detects operating data of the energy generation plant 10. Amongst these are included, in particular, the currently available active power, the currently available reactive power or other factors important for the operation of the energy generation plant, namely the quantity of an available fuel or the temperature in a fermenter. Relative to this is shown in the figure that the monitoring device 42 provides the monitored variables separately according to variables 44 and other operating conditions 46 relevant to the production of the energy generation plant, and via separate computer networks 48 and 50 forwards said variables to the central control unit 24, more specifically to the monitoring module 28 located therein. Naturally, the aforementioned data may also be transmitted together via a single computer network.
The data of the status monitoring received in the central control unit 24 from the monitoring module 28 are made available to the control unit 26 of the central control unit 24. This may immediately cause, therefore, an alteration to the schedule. At the same time, the data from the monitoring module 28 are forwarded to the reporting module 30, which is also connected to the control unit 26, in order to obtain information about the schedules. Based thereon, the reporting module 30 produces a report which compares the presettings of a schedule and the data provided by the monitoring device 42 with one another and produces a report about the deviations established. This report is made available via a computer network 52 to the operator 12 of the energy generation plant 10.
As a further possibility for producing proposed schedules, and the influence on the schedules, a further input device is shown in FIG. 2 which, in turn, substantially consists of an Internet browser 54. It comprises a Web interface 56 and a proposed pool schedule 58 which groups together a plurality of individual proposed schedules and relates to a group of energy generation plants which are operated by a primary coordination point 60. This primary coordination point 60 has the possibility of producing or altering proposed pool schedules 58 itself. The proposed pool schedules 58 are, in turn, transmitted via a computer network 62 to the central control unit 24. The report produced by the reporting module 30 is also forwarded via a further computer network 64 to the primary coordination point 60.

Claims

1. Method for using renewable energy sources comprising

at least one remote energy generation plant (10) which may be operated by a renewable energy source,

a production measurement unit (102, 42) at the location of the at least one remote energy generation plant (10) which measures the production of the at least one remote energy generation plant,

a central control unit (24),

the method comprising the following steps:

a) producing a production forecast (100, 20) for the production of the at least one remote energy generation plant (10) in a future time period,

b) transmitting the production forecast (100, 20) to the central control unit (24) via a computer network (104, 22),

c) operating the remote energy generation plant (10) and measuring the production using the production measurement unit (102, 42),

d) comparing the measured production with the production forecast (100, 20),

e) notifying an operator (12) of the at least one energy generation plant (10), if the measured production deviates from the production forecast (100, 20) beyond a predetermined level.

2. Method according to claim 1, characterised in that the production forecast (100, 20) is produced by a person who is locally responsible for the operation of the at least one remote energy generation plant (10).

3. Method according to claim 1, characterised in that the production forecast (100, 20) is produced by means of a computer network.

4. Method according to claim 1, characterised in that the production forecast (100, 20) comprises an active power and/or reactive power to be generated and/or network system services to be provided.

5. Method according to claim 1, characterised in that the comparison of the measured production with the production forecast (100, 20) takes place at the location of the at least one remote energy generation plant (10).

6. Method according to claim 1, characterised in that the central control unit (24) based on the production forecast (20) produces a schedule (32) for the at least one remote energy generation device (10), the schedule (32) being transmitted from the central control unit (24) via a computer network (34) to a remote control unit (36), which controls the at least one remote energy generation plant (10) automatically according to the schedule (32).

7. Method according to claim 1, characterised in that when producing the schedule (32) in the central control unit (24) a comparison of the production forecast (20) takes place with a forecast demand and the schedule (32) is produced, adapted to the forecast demand, optionally deviating from the production forecast (20).

8. Method according to claim 1, characterised in that the remote control unit comprises a monitoring device (42), which monitors operating data (44) and/or environmental conditions (46) of the at least one remote energy generation plant (10) and transmits this information to the central control unit (24) via a computer network (48, 50).

9. Method according to claim 1, characterised in that a plurality of remote energy generation plants (10) are present which are operated by renewable energy sources, a corresponding number of production forecasts (100, 20) and/or schedules (32) being produced.

10. Method according to claim 8, characterised in that no notification of the operator (12) takes place when, using the data transmitted from the monitoring device (42) a cause may be identified for the deviation of the measured production from the production forecast (20) and/or from a schedule (32) produced based on the production forecast (20), over which the operator (12) has no influence.

11. Method according to claim 8, characterised in that a schedule (32) is adapted when the comparison of a measured production and/or operating data (44) monitored by the monitoring device (42) with a production forecast (100, 20) and/or a schedule (32) produced based on the production forecast (100, 20) exhibits deviations.

12. System for using renewable energy sources comprising

at least one remote energy generation plant (10), which may be operated by a renewable energy source,

a production measurement unit (102) at the location of the at least one remote energy generation plant (10) which measures the production of the at least one remote energy generation plant (10),

a device (16, 18) for detecting a production forecast (100, 20) for the production of the at least one remote energy generation plant (10) in a future time period,

a device for transmitting the production forecast (100, 20) to the central control unit (24) via a computer network (104, 22),

a device for comparing the measured production with the production forecast (100, 20),

a device for notifying an operator (12) of the at least one energy generation plant (10) which is configured such that a notification of the operator (12) automatically takes place, if the measured production deviates from the production forecast (100, 20) beyond a predeterminable level.

13. System according to claim 12, characterised in that the at least one remote energy generation plant (10) is a biogas plant and/or a plurality of remote energy generation plants (10) are present, which may be operated by renewable energy sources.

14. System according to claim 12, characterised in that the central control unit (24) is configured for producing a schedule (32) based on the production forecast (20) and a device for transmitting the schedule (32) to a remote control unit (36) via a computer network (34) is present which is configured for automatic control of the at least one remote energy generation plant (10) according to the schedule (32).

15. System according to claim 14, characterised in that the remote control unit (36) comprises a monitoring device (42) which is connected to the remote energy generation plant (10) and/or to sensors and is configured for monitoring operating data (44) and/or environmental conditions (46) of the at least one remote energy generation plant (10).

16. System according to claim 15, characterised in that the monitoring device (42) may be connected via a computer network (48, 50) to the central control unit, and is configured for transmitting the monitored operating data (44) and/or environmental conditions (46) to the central control unit (24).