Smart power grid

It all started when a high-voltage power line was disconnected in Emsland, Lower Saxony, setting off a chain reaction throughout the grid. Many experts see the reason for this type of incident in the diversity of power-generation sources. Instead of having a small number of large power stations that feed their output into the grid in accordance with demand, the deregulation of the power-utility market has given rise to a situation where the electricity supply depends on a large number of smaller producers.

The solution to avoiding such blackouts lies in a “smart power grid”, as researchers from the Fraunhofer Energy Alliance will be demonstrating to visitors to the Hannover Fair, from April 16 to 20. Other exhibits at the Fraunhofer stand will focus on energy-saving and micro power engineering.

Thomas Schlegl, who heads the Fraunhofer Energy Alliance, prefers to see the diversity of power-generation sources in a positive light. “An intelligently managed power grid would make it possible to reduce energy costs and encourage power users to help to spread the load on the network through a flexible system of real-time pricing.” What this means in practice is demonstrated by a trial project in Stutensee, near Karlsruhe. Without increasing its capacity, the network is capable of accepting input from a larger number of distributed sources – mainly solar – thanks to intelligent control and management. “The power management system serving the community of around 100 households prevents peaks from occurring at the medium-high voltage level of the grid,” Schlegl explains. The local power utility, MVV of Mannheim, confirms that the peak load has been reduced by 35 percent as predicted.

The intelligent control system is built around a set of algorithms that provide scope for the network to adapt to demand – it takes into account how much power is being fed into the network at different points and how much is being consumed. A typical example of the way in which peaks in production capacity can be put to optimum use is illustrated by a local project undertaken by the Fraunhofer Institute for Solar Energy Systems ISE. Their project entitled “Waschen mit der Sonne”, which roughly translates as “washing laundry with the sun”, involves sending a text message to alert users at times when a generous amount of solar energy is being produced. Any-one who responded to this call to smooth out peaks in energy consumption was rewarded with a financial incentive.

In order to be able to make such offers, utilities need a sophisticated electronic communication system. This is why the Fraunhofer Energy Alliance has made energy management one of the focuses of its work. “Such systems enable the various distributed power producers in a region to be linked together to form a virtual centralized power plant,” Schlegl explains.

Power management is one way of using energy resources more efficiently. But how can power producers test new systems before they go online? At the Hannover Fair, the Fraunhofer Applications Center for Systems Technology AST and the Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT will be presenting a new laboratory that they are in the process of building up, where power grids and the concepts used to manage them can be simulated as a means of optimizing the algorithms on which they are based.

To improve the control of low-voltage power distribution networks, the ISE has teamed up with a number of European partners to draw up the concept for a Power Flow and Power Quality Management System (PoMS). This system can help to integrate the growing number of distributed generation sites into the existing power grid and manage them there. Power management can be optimized on the basis of a wide variety of criteria, including minimizing operating costs, reducing the need for surplus capacity to meet peaks in demand, and minimizing the consumption of primary energy sources.

The deregulation of the energy market has led to radical changes that confront grid operators with increasingly complex challenges. The research teams at the Fraunhofer Applications Center for Systems Technology can provide flexible, automated solutions for power management and related data communication needs – to support power producers, grid operators and their sales and marketing departments.