How can small energy sources be integrated to form stable power grids? To answer this question the scientists working on the "SmartNord" project are looking to colony-forming insects. An interview with spokesman for the project Michael Sonnenschein and energy informatics expert Sebastian Lehnhoff.
What is the goal of the "Smart Grids Research Group Norddeutschland SmartNord"(Forschungsverbunds Intelligente Netze Norddeutschland SmartNord")?
Prof. Dr. Michael Sonnenschein: Our electricity-supply system is undergoing great changes: electricity supplies from a small number of large-scale power plants are being replaced by supplies from many different, small-scale power plants such as wind energy farms, photovoltaic systems and combined heating and power plants. This however requires that we make our power grids "smart", even in the area of medium and low voltage. A basic prerequisite for a stable supply of electricity is that the amounts of electricity generated and consumed correspond to each other as precisely as possible at any given time, because the power grid can't store electricity.
This is where the intelligent grids of the future, the so-called "smart grids" come into play.
Prof. Dr. Michael Sonnenschein: Exactly. To ensure a stable electricity supply they must take over the tasks of balancing active power as well as facilitating so called ancillary services to stabilize the grid. These until now have been performed by large conventional power plants – in a situation in which the amount of electricity fed into the grid from wind energy or solar energy varies and is somewhat unpredictable. Achieving this calls for new methods from the field of computer science and communications technology for coordinating the many new agents in the grid, as well as studies to determine the stability of the grids in terms of power supply. This is the main goal of SmartNord.
How can such diverse energy sources be integrated to form a stable electricity-supply system?
Prof. Dr. Sebastian Lehnhoff: In the SmartNord consortium we are studying the possibilities for integrating a large number of small energy sources into grids in which the unstable power supplies of certain sources are balanced out by others. In this way the grid turns an initially unpredictable supply from individual plants into a reliable service for the electricity market, providing both the so-called active power and also short-term extra power in order to maintain the stability of the electricity-supply system. A good prognosis of behaviour is a crucial prerequisite here.
And is that enough?
Prof. Dr. Sebastian Lehnhoff: No, not yet. In addition we need to develop mechanisms for balancing out short-term variations caused by other agents in the event that an electricity generator deviates from its predicted behaviour. This necessitates the integration of storage facilities and methods for controlling consumption.
What role do the University's more than 30 years of experience in the field of renewable energies play in your current research?
Prof. Dr. Michael Sonnenschein: Energy research is given high priority at the University of Oldenburg, and the research here has been of superior quality for many years now, achieving international visibility and relevance. As well as the "classic" subjects such as wind energy, photovoltaic, fuel cells, energy economy, energy storage and sustainability management, Oldenburg's areas of expertise also include energy informatics and in the present case the research and development of smart grids. The systematic access to the subject "future intelligent energy supply systems" which energy informatics provides is given a substantial boost by the broad range of research disciplines active in this area at Oldenburg.
You place an increased emphasis on nature-inspired approaches in the SmartNord project. How does this work?
Prof. Dr. Sebastian Lehnhoff: Nature provides us with excellent examples of how highly complex systems can be coordinated and controlled. Nature-inspired approaches try to transfer the mechanisms observed for instance in complex biological systems to technical systems. It is generally not possible to mimic them entirely, instead it's more about transferring the basic ideas rather than their concrete application in nature. One such idea is swarm behaviour. Here, large numbers of individuals display highly coordinated behavioural patterns in order to achieve a common goal – for example reducing energy expenditure when moving from one place to another, or protecting themselves against predators. And they perform all these feats without central supervision or leadership. That’s what we want to learn from!
What do colony-forming insects have to do with energy supplies?
Prof. Dr. Sebastian Lehnhoff: Eusocial insects like bees or ants have developed highly efficient mechanisms for working together on complex tasks such as keeping an ant colony supplied with food, without the individual organisms having to be very intelligent and without relying on central coordination. These are precisely the processes of self-organisation which we want to study in SmartNord, with an eye to coordinating large numbers of small electricity generators. Here, too, we have a huge number of decentralised energy consumers and suppliers all in pursuit of the same goal, namely a secure and reliable energy supply. Already today, only in exceptional circumstances it is possible to determine the overall system status of a power grid, let alone take that status into consideration for active control while it is up and running. So the question is which rules of behaviour can enable all these decentralised systems to adjust to each other in such a way that they keep the power grid stable without central coordination?
What do you see as the next steps for the research group?
Prof. Dr. Michael Sonnenschein: In a way "SmartNord" is itself a complex system. The research group is divided into six sub-projects that study different aspects of the problem. Within each sub-project there are precisely defined work packages within which in turn specific studies are performed. So for example two work packages deal with mechanisms for grouping electricity producers according to the different services they provide on the market. However hardly any of the work packages can be successful independently of the others: intensive cooperation in particular between computer scientists and electrical energy experts is required in order to understand the problems and develop adequate solutions. To a large extent we rely on simulation technologies for developing new techniques: new methods are first tried out in different scenarios on the computer.