Smart grid

The term smart grid ( smart grid english ) includes communication over a network and control power generators, storage, electrical loads and network resources in power transmission and distribution networks of electricity supply. This enables optimization and monitoring of the interconnected components. The aim is to secure the energy supplies in an efficient and reliable system operation.

Background and Motivation

While in the past dominate power grids with centralized power generation, the trend towards decentralized production plants, both in the production of fossil primary energy by small CHP plants as well as in the generation from renewable sources like photovoltaic systems, solar thermal power plants, wind power plants and biogas plants. This leads to a much more complex structure, primarily in the area of ​​load regulation, voltage support in the distribution network and to maintain network stability. Smaller, distributed generation systems feed directly into a lower voltage levels as the low voltage network or the medium voltage grid in contrast to medium to large power plants.

Generally, networks, and electrical power grids, designed for the maximum possible load. The reduction of those peak load and re-timing of the transmitted energy in busy times allows the necessary network infrastructure to be interpreted as smaller and thus leads to cost savings on operator side. Here, the total amount of energy transmitted is approximately equal, it is only the capacity of the networks to optimize. For example, in 2009 electricity networks in Switzerland were utilized in the annual average only between 30 to 40% a year. Cost benefits and security of supply should therefore be avoided incentives for network operators, expensive peak loads and to have only the theoretical ideal case, a possible time-constant proportion of the load, which is higher than the base load so-called. This leveling of the load can be done by automatic controls and control of consumer assets acquired in a load control using intelligent networks.

A property of those networks is the ability to state information and load flow data from the individual network elements, such as generating plants, consumers (households or industrial plants ) or transformer stations to retrieve and process in real time. A smart grid account of both the production and larger consumers such as heat pumps, hot water tanks, freezer, car batteries, etc. in the network management with a.

Building a smart grid

A smart grid integrates all actors in the electricity market by the interaction of generation, storage, network management and consumption in an overall system. Power and storage plants are already being controlled so that always produces only as much power as is needed. Smart grids refer to this control, the consumer and small decentral energy suppliers and locations with one, so on the one hand a temporally and spatially homogeneous consumption arises and on the other hand, in principle inhomogeneous generators (eg, wind power) and loads (eg lighting) better integrated can be.

The electricity storage, which is gaining importance due to the fluctuating renewable energy production, has long been realized with the help of storage power plants. In addition, for example, decentralized storage such as car batteries, but what currently is still far from cost recovery.

For consumers, a significant change is the installation of intelligent meters (including smart meters). Its core tasks are remote reading and the ability to short in one day realize fluctuating prices. All electricity meters must therefore be replaced by those with long-distance data transmission. The data transfer between the different components running in pilot projects mostly via telephone modem - the smart power project in Switzerland, however, is already working with ADSL connections.

However, consumers may realize price advantages only comfort without penalty if it also has devices that automatically preferably work during off-peak times. It is non-time processes such as heat pumps with latent heat storage, freezing, heating ( electric boiler ), washing or dishwashing. With night storage heaters and fixed overnight rates this was realized decades ago, but modern systems can work flexible and intelligent, which is particularly important for the integration of renewable energies.

Current activities in Europe

The objectives of the EU in terms of Smart Grids is the need for

• A reduction in carbon dioxide emissions
• The desire for increased energy independence (see energy self-sufficiency )
• The increase of energy efficiency
• Planned a rising share of renewable energy, which must be integrated into the European energy networks

Based.

For the first time installed the Italian power company Enel as a step towards smart grids since the late 1990s, an automated reading system for electricity meters. This happened especially to prevent the large losses due to electricity theft, which was offered by the modern counter stop.

From an entirely different reason, the Federal Republic of Germany initiated 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, an analysis in six so-called model regions which limit the impact of smart grids and their practical implementation tested in real power grids. Result of this project, according to the smart grids are able to significantly reduce the 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. This block is but actually a component of the Smart Market and enables the demand- load reduction.

Also from private industry, there are initiatives to promote electric mobility in pilot communities. So even the smart grid is tested in a model experiment for example, in Garmisch- Partenkirchen next electric mobility.

Within the project Web2Energy, which is funded by the 7th Framework Programme ( FP7) of the European Commission, a discrimination-free communication system for all participating market partners within a smart grid in southern Hesse is built and tested using the internationally recognized IEC standards.

In the project E2SG, Energy to Smart Grid, 31 partners from 9 European countries since April 2012 to the central themes of smart grids: help methods for secure communication in the supply network, optimized technologies for efficient Strom-/Spannungswandlung and improved methods for identification of needs and network control are renewable better integrate energy sources and increase energy efficiency. E2SG is funded by the ENIAC joint undertaking and the nation states of the project partners.

In Austria also created an initiative on smart grids. The Austrian Federal Ministry for Transport, Innovation and Technology under the program promotes energy systems of the future as well as on the energy research program of the climate and energy fund research and demonstration projects on the subject. Together with electricity network operators and technology companies created several pioneering regions. Salzburg AG has launched, for example, two projects to life. Firstly, the project " Electro Drive" and on the other the project " Smart Grids". These two projects were awarded and promoted with 1.9 million and 1.7 million euros from the Austrian rich generic climate and energy fund. You are almost inseparable, as the electric vehicles are used for energy storage. Currently drive 300 electric vehicles in Salzburg.

Enercontract AG Working in Switzerland with the participation of Alpiq in the project and the smart power Löpfe AG to set about implementing a smart grid. The first pilot installations Electrical Appliances Ltd. in Niederbuchsiten and in the supply area of the EMS Energy Ltd Aargau South are carried out at the company law.

According to the German Association for Electrical, Electronic & Information Technologies lies the potential for load shifting half in energy-intensive companies and half in private households, trade and commerce, and services. Load management could offset the demand and reduce the cost of energy turnaround significantly.

Issues and challenges in smart grids

In Switzerland, the current measurement to the local electricity supply company (PSC ) is responsible under the discriminatory network connection. Discrimination -free means that all electricity customers receive the same conditions (ie individual customers neither special discount nor may relate special services).

The measurement information is available here to the energy supplier, that is, they must not be made freely available at the moment, especially not a competitor. Furthermore, in the measurement data obtained is data protection should be noted ( since this can be seen from the electricity consumption of coffee, for example, when someone gets up in the morning).

A further problem is that there is still no widely accepted standards of what is measured and how the data is transferred to a destination. Thus, proprietary measurement systems are used currently in pilot plants, which are not easily combined with each other or exchangeable. After the introduction of standards possibly an expensive change of systems is necessary. When smart power project working with customary in ICT protocols. Thus any non- proprietary systems can be combined.

A popular approach to avoid different standards, due to the use of different gateways, the harmonization through an open gateway platform OSGi.

Although the development and standardization is still running, you can install a simple own " Smart Grid" at home already. A beautiful example of this consumption display devices and " standby killers" the Switzerland of the canton of work. With these devices, which operate wirelessly via a radio link, the customer can

• See the power consumption
• The current performance
• And may the evening 's consumer ( TV, video, etc.) from the power supply ( thus saving you 20-30 euros per year).

Standardization

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

In addition to the ICT-related standardization are for intelligent behavior of many smaller systems on the grid and system-stabilizing electrical properties are important, that is, the response to voltage and frequency variations. These are defined, for example, in Germany in the medium-voltage directive. The FNN - application rule " Generating plants connected to low-voltage network " ( E VDE -AR-N 4105:2010-07 ) has also been revised and is in draft form (as of Jan 2011).

At European level, this is DIN EN 50438 (Requirements for the connection of micro - generators in parallel with public low -voltage grid ) should be mentioned, as well as larger feeders from 11 kVA DIN CLC / TS 50549 ( Requirements for the connection of generators above 16 A per phase to the low voltage distribution network or to the medium voltage distribution network).

In the U.S., the IEEE 1547 ( Standard for Interconnecting Distributed Resources with Electric Power Systems ) of relevance.