Intelligent power grid

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EEnergy SmartGrid.jpg
Change in network structure as part of the energy transition (schematic - as of 2019)

The term intelligent power grid ( English smart grid ) includes the communicative networking and control of power generators , storage , electrical consumers and network operating resources in energy transmission and distribution networks of the electricity supply. This enables optimization and monitoring of the interconnected components. The aim is to secure the energy supply on the basis of efficient and reliable system operation.

Background and motivation

While power grids with central power generation have dominated up to now, the trend is towards decentralized generation systems, both in the generation from fossil primary energy through small CHP systems and in the generation from renewable sources such as photovoltaic systems , solar thermal power plants, wind turbines and biogas systems . This leads to a much more complex structure, primarily in the area of load control , voltage maintenance in the distribution network and maintaining network stability . In contrast to medium-sized to larger power plants, smaller, decentralized generating plants also feed directly into the lower voltage levels such as the low-voltage network or the medium-voltage network .

In general, networks, including electrical energy supply networks, are designed for the maximum possible load. The reduction of the maximum load and the time shifting of the energy to be transmitted in times of lower utilization enables the necessary network infrastructure to be designed smaller and thus leads to cost advantages for the operator. The total amount of energy transferred remains roughly the same, only the utilization of the networks is optimized. For example, in 2009 power grids in Switzerland were only used at an annual average rate of 30 to 40%. Cost advantages and security of supply are therefore incentives for network operators to avoid expensive load peaks and, in the theoretical ideal case, only have a load share that is as constant as possible over time, which is above the so-called base load share . This leveling of the load can take place by means of intelligent networks through automatic controls and control of consumption systems as part of a load control .

One property of those networks is the ability to collect status information and load flow data from the individual network elements, such as B. generation plants, consumers (households or industrial plants) or transformer stations can be called up and processed in real time. In addition to the production systems, an intelligent power grid also includes larger consumers such as heat pumps, hot water storage tanks, freezers, car batteries, etc. in the network management.

In addition, with the support of Demand Side Management (DSM) , an intelligent power grid offers the advantage that forecasts of consumption and potential savings are identified on the consumer side. With this information, users can align their consumption to the current generation situation by using dynamic tariffs.

Building an intelligent power grid

An intelligent power grid integrates all actors through the interaction of generation, storage, network management and consumption in an overall system. Power plants (including storage) are already controlled in such a way that the same amount of electrical energy is produced as is used. Intelligent power grids include consumers as well as decentralized small energy suppliers and storage systems in this control, so that consumption is balanced in terms of time and space (see also intelligent power consumption ) and, on the other hand, non-disposable generation systems (e.g. wind energy and PV systems) and consumers (e.g. lighting) can be better integrated.

Electricity storage, which is gaining in importance due to the availability-dependent generation of renewable energies, has long been realized with the help of storage power plants . Decentralized battery storage systems including vehicle accumulators ( smart charging ) are also expected, but this is currently not an attractive business model for providing system services.

A major change at the end-user level is the installation of intelligent meters (also known as smart meters ). Their core tasks are remote reading and the possibility of billing time-variable prices. The data transfer between the individual components takes place via telephone modem , GSM , PLC or ADSL connections and much more.

However, the consumer can only realize price advantages without sacrificing convenience if he also has devices that work automatically, preferably during off- peak times. These are non-time-critical processes such as charging electric vehicles , operating heat pumps , freezing , heating (electric boilers ) , washing or dishwashing. This was already implemented decades ago with night storage heaters and fixed night tariffs, but modern systems can work more flexibly and more intelligently, which is particularly important for the inclusion of renewable energies. One technology that has been introduced for this is ripple control technology , which, however, due to the low bandwidth, does not allow individual addressing, but addresses system groups.

Supply and demand side

Since electrical energy grids cannot store energy and to maintain stability in the power grid, the demand for electrical power must always be the same as the supply of electrical power, either the supply side must be adapted to the demanded consumption, as is largely done in classic power grids by changing the power plant output , or through an adaptation by means of load shifts of the consumers to the current supply of the generating facilities, similar to how they are implemented with so-called load shedding customers in the event of supply bottlenecks since the beginning of the electrical energy supply.

Even if the temporal load shifts of selected consumers triggered in intelligent power grids in the form of load control are only possible in the range of hours to a few days, they are considered a useful way to compensate for the partially non-demand-oriented supply in renewable energy systems by means of controlled changes in current demand adapt. The advantage of the demand adjustment lies in their high energy efficiency , since in contrast to storage power plants they can be used with very little or no loss. Heating and cooling machines such as refrigerators, cold stores, heat pump heating systems, etc. are particularly well suited, but with restrictions, energy-intensive industrial processes such as aluminum production by electrolysis, electric steel production and the operation of cement mills and ventilation systems for load shifting are also possible. For example, the specific switch-on time of a correspondingly designed intelligent refrigerator can be shifted in a certain time interval so that it more closely matches the supply of electrical power without the cooled food being heated excessively. It can be controlled either indirectly via the price or directly via the energy supply or network operator; larger companies can also trade directly on the balancing energy market.

Data centers also offer considerable potential for load shifting . Since data centers are usually only partially used and some computing operations are not time-critical, computing power can be shifted both spatially and temporally if required. In this way, consumption can be specifically reduced or increased regionally without this having an impact on the services provided. Since the infrastructure is already in place, this would be possible with minimal adaptation of the infrastructure, and data centers, as large electricity consumers, could be an important factor in demand response. Further potential arises from the systems usually installed for uninterruptible power supply such as batteries and emergency power generators , which can also be used to provide control power or to cover peak loads. In this way, system costs could be minimized. Overall, it is considered possible that European data centers will have a load shift potential of a few GW to a few dozen GW in 2030. Other consumers, in particular consumers who need the purchased power directly, such as lighting , cannot in principle be shifted.

In terms of effects, the load shift achieves the same effects as the use of storage power plants to adjust the supply: The load increase (switching on the load in the event of excess electricity) corresponds to the charging of a storage system, the later load reduction corresponds to the storage tank discharge; therefore, load shifter acts as "virtual memory".

Current activities in Europe

There is a need for the EU's goals in relation to smart grids

  • a reduction in carbon dioxide emissions,
  • increased energy independence (see also energy self-sufficiency ),
  • increasing energy efficiency and
  • a planned increasing share of renewable energy, which must be integrated into the European energy networks,

underlying.

For example, the Italian energy supply company Enel installed an automated reading system for electricity meters for the first time as a step towards intelligent electricity networks in the late 1990s . This was done in particular to prevent the large losses caused by electricity theft , which was halted by modern meters.

For a completely different reason, the Federal Republic of Germany initiated an analysis in six so-called model regions as part of the E-Energy funding program, funded by the Federal Ministry of Economics and Technology and the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety , which investigated the effects of intelligent power grids and their practical ones Tested implementation in real power supply networks. According to the result of this project, intelligent energy networks are able to significantly reduce network expansion in the future . A first step in the implementation of smart grids in the Federal Republic of Germany is the nationwide introduction of smart metering . However, this building block is actually a component of the smart market and enables demand-oriented load reduction .

In January 2017, the German Federal Ministry for Economic Affairs and Energy (BMWi) sponsored the SINTEG program - Smart Energy Showcase - Digital Agenda for the Energy Transition . With a funding volume of 200 million euros and a total volume of 500 million euros, the five SINTEG shop windows form C / sells ; Designetz; enera; NEW4.0 and WindNODE the largest smart grid program in Europe. The program explicitly provides for five model regions that extend practically across Germany (with a few exceptions). In those, not only the theoretical basics are worked out, but also demonstration projects are realized. Furthermore, legal framework conditions and market models are researched. The projects are carried out by far-reaching consortia with around 60 members from energy suppliers , industry , research institutions and civil society actors, also using their own capital. The aim is to evaluate and develop smart grid technologies until they are ready for the market. With the funding volume, the large number of stakeholders and the depth of development, SINTEG is the most important smart grid program in Germany and the largest in Europe. Several German federal states have started their own smart grids activities, for example Baden-Württemberg has initiated the Smart Grids Platform Baden-Württemberg eV to network the relevant players.

There are also private-sector initiatives to promote electromobility in model municipalities. In Garmisch-Partenkirchen, for example, in addition to electromobility, the intelligent power grid is also being tested in a model experiment.

Within the Web2Energy project, which is funded by the 7th Framework Program (FP7) of the European Commission, a non-discriminatory communication system for all market partners involved is set up and tested within an intelligent power grid in southern Hesse using the globally recognized IEC standards.

In the E2SG project, Energy to Smart Grid, 31 partners from 9 European countries have been working on central issues of intelligent supply networks since April 2012: Methods for secure communication in the supply network, optimized technologies for efficient current / voltage conversion and improved methods for determining requirements and network control should help renewable Better integrate energy sources and increase energy efficiency. E2SG is funded by ENIAC Joint undertaking and the national states of the project partners.

An initiative on intelligent power grids is also emerging in Austria. The Austrian Federal Ministry for Transport, Innovation and Technology is funding research and demonstration projects on the topic within the framework of the Energy Systems of the Future program and through the energy research program of the Climate and Energy Fund . Together with power grid operators and technology companies, several pioneering regions are emerging. The Salzburg AG has called for example, two projects to life. On the one hand the "ElectroDrive" project and on the other hand the "Smart Grids" project. These two projects were awarded and funded with 1.9 million and 1.7 million euros from the Austrian Climate and Energy Fund. They are almost inseparable because the electric vehicles serve as energy storage. There are currently 300 electric vehicles in Salzburg.

In Switzerland, Enercontract AG is working with Alpiq in the smart power project and Löpfe AG ​​on the concrete implementation of an intelligent power grid. The first pilot installations have been carried out at Jura Elektroapparate AG in Niederbuchsiten and in the supply area of ​​EWS Energie AG Aargau Süd.

According to the German Association of Electrical Engineering, Electronics and Information Technology , half the potential for load shifting lies with energy-intensive companies and half with private households, trade and commerce and services. Load management can balance demand and significantly reduce the costs of the energy transition.

Problems and challenges with intelligent power grids

In Switzerland, electricity measurement is the responsibility of the local electricity supply company (EVU) as part of the non-discriminatory grid connection. Non-discriminatory means that all electricity customers have the same conditions or Network connection and fee calculation received.

The measurement information is available to the energy supplier, i.e. In other words, they may not currently be made freely accessible, especially not to a competitor. Furthermore, data protection must be taken into account for the measurement data obtained, because this personal data can be used, for B. reconstruct the individual daily routine of an end consumer.

Another problem is that there are still no universally recognized standards for what is measured and how the data is transmitted to a destination. For this reason, proprietary measuring systems are currently used in test facilities that cannot easily be combined or interchanged with one another. After the introduction of standards, it may be necessary to change the systems at great expense. The standard ICT protocols are used in the smart power project . This means that any non-proprietary systems can be combined.

A popular approach to avoiding different standards, due to the use of different gateways, is harmonization using an open gateway platform OSGi .

Norms and standards

At the international level, data models and communication protocols of IEC 61850 are being further developed. Originally conceived for automation in substations, the field of application of this standard also extends to decentralized power generation in distribution networks.

In addition to ICT-related standardization, system-stabilizing electrotechnical properties are also important for the intelligent behavior of many smaller systems on the grid. H. the response to voltage and frequency changes. These were z. B. defined in Germany in the medium voltage directive , now replaced by the technical connection rule for medium voltage (VDE-AR-N 4110: 2018-11). The FNN application rule "Generation systems on the low-voltage network" (VDE-AR-N 4105: 2018-11) has existed since August 2011, meanwhile in a second revised version.

At European level, DIN EN 50438 (requirements for the connection of small generators to the public low-voltage network) and EN 50549: 2019 (requirements for generating plants intended for parallel operation with a distribution network) should be mentioned.

In the USA, the IEEE 1547 (Standard for Interconnecting Distributed Resources with Electric Power Systems) is relevant.

literature

  • Aichele, C., Doleski, OD (Ed.): Smart Market - From Smart Grid to Intelligent Energy Market . Springer Fachmedien, Wiesbaden 2014, ISBN 978-3-658-02778-0 .
  • European Commission: JRC-IET : JRC Scientific and Policy Reports. Smart Grid projects in Europe: Lessons learned and current developments . European Commission, 2013 ( overview , long version (PDF; 5.0 MB) ).
  • Sebastian Knab, Kai Strunz, Heiko Lehmann: Smart Grid: The Central Nervous System for Power Supply - New Paradigms, New Challenges, New Services (= Scientific Series of the Innovation Center Energy at the Technische Universität Berlin . Volume 2). University Press of the TU Berlin, Berlin 2010 (PDF; 451 kB) .
  • VDE | FNN: Challenges in converting the networks . Berlin 2011 (PDF; 531 kB) .
  • Friedrich Augenstein, Ludwig Einhellig, Ingmar Kohl: The realization of the “Smart Grid” - on everyone's lips, but not in the implementation . In: Energiewirtschaftliche Tagesfragen , Volume 61, Issue 7, etv Energieverlag GmbH, Essen 2011, pp. 28–31, (PDF; 264 kB) .
  • Christian Neureiter: A Domain-Specific, Model Driven Engineering Approach For Systems Engineering In The Smart Grid . 2017, ISBN 978-3-9818529-2-9 (MBSE4U).

Web links

Individual evidence

  1. NIST Smart Grid Interoperability Standards Roadmap (PDF; 6.0 MB)
  2. §1 (purpose of the law) EnWG
  3. Hans-Jürgen Appelrath, Henning Kagermann and Christoph Mayer (eds.): Future Energy Grid. Migration paths to the Internet of Energy. acatech - German Academy of Science and Engineering, 2012, p. 48.
  4. Roman Uhlig: Use of charging flexibility for the optimal system integration of electromobility . 2nd Edition. Wuppertal 2017, ISBN 978-3-7450-5959-5 .
  5. Matthias Günther, Energy efficiency through renewable energies. Possibilities, potentials, systems , Wiesbaden 2015, p. 141.
  6. Carolina Koronen et al .: Data centers in future European energy systems - energy efficiency, integration and policy . In: Energy Efficiency . 2019, doi : 10.1007 / s12053-019-09833-8 .
  7. Nele Friedrichsen, consumption control , in: Martin Wietschel, Sandra Ullrich, Peter Markewitz, Friedrich Schulte, Fabio Genoese (ed.), Energy technologies of the future. Generation, storage, efficiency and networks , Wiesbaden 2015, pp. 417–446, p. 418.
  8. E-Energy homepage
  9. a b Federal Ministry for Economic Affairs and Energy: SINTEG funding program: "Smart Energy Showcase - Digital Agenda for the Energy Transition". Retrieved March 1, 2018 .
  10. All partners with whom the C / sells project is driving the energy transition. Accessed March 1, 2018 (German).
  11. Ministry for the Environment, Climate Protection and the Energy Sector: Kick-off event for the Smart Grids platform Baden-Württemberg. November 29, 2012, accessed August 17, 2020 .
  12. http://www.e-gap.de/intelligentes-stromnetz/
  13. http://www.ffe.de/die-themen/mobilitaet/410-e-gap-modellkommune-garmisch-partenkirchen
  14. Energy to Smart Grid
  15. Project profile - E2SG - Energy to smart grid ( Memento of the original from April 11, 2014 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. on eniac.eu from January 2011, accessed on February 24, 2014 @1@ 2Template: Webachiv / IABot / www.eniac.eu
  16. Technology platform Smart Grids ( Memento of the original from November 13, 2009 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.smartgrids.at
  17. Archive link ( Memento of the original from January 9, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / www.energiesystemederzukunft.at
  18. Salzburg model region ( Memento of the original from June 13, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / www.salzburg-ag.at
  19. Intelligent grids can drastically reduce electricity consumption, SPIEGEL Online, June 8, 2012
  20. VDE application rules (FNN) 4110 : Technical rules for the connection of customer systems to the medium-voltage network and their operation
  21. Forum Network Technology / Network Operation: Drafts of VDE application rules (FNN)
  22. VDE-Verlag: VDE 0435-901, DIN EN 50438: 2008-08
  23. Beuth-Verlag: EN 50549-1: 2019
  24. ^ IEEE Standards Association: IEEE 1547 Standard for Interconnecting Distributed Resources with Electric Power Systems