Integral Resource Optimisation Network - Concept
In the context of the emergency situation in the energy domain (Energy-independence of the EU, CO2 reduction, shortage in resource availability), it is necessary to improve the efficiency of electric energy systems. The research project IRON Concept (Integral Resource Optimisation Network - Concept) analyses market-oriented options for efficiency increase by more information exchange between the grid users (loads, small generators). In the electric power system, communication to the demand side as well as to small generators is mostly non-existing. However, for talking influence on the consumption patterns of loads (load management/demand side management), an information infrastructure is needed.
The costs of this infrastructure, for its setup, its operation and for setting incentives for users, must be covered by the advantage gained from its application. In this project, electrical load management is primarily used to shift consumption times, not for reducing the energy demand in total. Efficiency improvements are achieved by a better correlation between generation and demand achieved by management measure, resulting in the use of more efficient power plants and a reduction of line losses. A reduction of the load at one time is usually followed by an increased demand at a later time (rebound effect).
In contrast to the state-of-the-art load shedding, which is performed today in grid emergency situations, the load management measures proposed in this project are targeted for the normal operation of the grid. Therefore, it has to be taken care that the impact on the energy service which the consumer receives from the grid is not too high. Load management measures have to be performed automatically and hidden. Consequently, only those electrical loads with a certain amount of flexibility in their consumption behaviour are targeted. These are primarily systems where electrical energy is converted into some other form of energy (thermal, potential energy etc.), which then can be stored for some time (thermal capacity of air-conditioned rooms, water heaters and so on).
Four different market models have been developed and examined in the course of the project. All four target to utilise load management economically under the current or mid-term expectable legal framework.
These models are:
- Optimisation of transport costs: Reduction of line losses und grid extension costs by local consumption of distributed generation.
- Renewable Energy: Better time-correlation between generation from renewables and demand.
- Time-varying energy tariff: Offering a time-varying, transparent electricity tariff the end user which reflects the price changes on the energy stock market
- Control energy: Integrating many small load management resources to one single large "virtual energy storage" that is used to provide primary control energy which is needed for the real-time balancing of demand and supply in the electric power grid.
Closer examinations have shown that only the last two market models, time-varying energy tariff and control energy, are economically viable. Especially the control energy model is very attractive, since control energy is already sold for comparably high prices and a rise of control energy demand can be expected due to the increase of wind energy generation in the grid, making this model even more attractive. By providing control energy by load management, less conventional control capacities have to be allocated and consequently CO2 emissions are reduced.
For providing control energy by a pool of electric loads taking part in a load management program, also complete technical concept had been developed (the "IRON-Box"). A further advantageous aspect of the control energy model is, that the demand for primary control energy is "broadcasted" by the grid frequency, more precisely by its deviation from the nominal 50 Hz, which can cheaply be measured anywhere in the grid. Therefore, the communication infrastructure has only to fulfil very moderate requirements, since the real-time communication is provided by the grid itself. Internet communication or the emerging infrastructure for smart metering can be used to fulfil the communication demands.
For an effective and efficient realisation of the proposed IRON-Technology it is of very high importance that the aspects of communication, business processes and hardware integration are strictly standardised. Open standards are the prerequisite for a broad support by different suppliers. The project team concludes that it will be necessary in future to integrate the smart technology, which currently is implemented in the stand-alone "IRON-Box", into the end user equipment itself. Only by this measure, demand side management can be used to change our power grids from centralised and passive structures to active or "smart" grids.
DI Friederich Kupzog
Institut für Computertechnik, Technische Universität Wien
DI Stefan Grobbelaar, Marcus Meisel
Project or cooperation partner
- LINZ STROM GmbH
- Sonnenplatz Großschönau GmbH
- Lawrence Berkeley National Laboratory (Berkeley)
- Envidatec GmbH (Hamburg)