Poiesis Prax (2009) 6:265–271 DOI 10.1007/s10202-009-0070-x FORUM
Current challenges for efficient electricity grids Ruth Klu¨ser
Published online: 13 February 2009 Ó Springer-Verlag 2009
Abstract The comprehensive liberalisation of the electricity market at the end of the last century has initiated a dynamic development. The politically determined disjunction of the network operation from generation, commerce and distribution which broke open the value added chain concerning the business organisation is to induce competition and consequently lower prices. Thus, besides a secure electricity supply, profitability, efficiency, quality and environmental aspects constitute present aims and have led to an enormous increase of complexity in the power supply. Furthermore, the imponderability and uncertainty of competition processes in a liberated market aggravate prognoses for future investment decisions. Not least the anymore rising electricity demand, the emerging of a single European power market as well as technically pushed changes in the production structure, due to the emergence of alternative forms of power generation such as wind or solar energy, biomass energy or fuel cells, account for electric networks which afford complex planning and regulation mechanisms. This article gives a survey of various requirements posed on electricity networks and concludes with a short description of solution approaches to safeguard a cost-saving and secured future electricity supply.
1 Power requirement in flux A modern industrial society competing with others is dependent on a cost-efficient provision of electrical energy by widely branched, stable networks. Diverse severe blackouts of the past years have hauntingly demonstrated the consequences of interruptions of supply. The quality of provisioning is at the same time crucial since R. Klu¨ser (&) Europa¨ische Akademie zur Erforschung von Folgen wissenschaftlich-technischer Entwicklungen, Bad Neuenahr-Ahrweiler GmbH, Germany e-mail:
[email protected]
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the application of communication and process technology enforces the dependency on uninterruptible electric power. Not only the global energy demand rises, but also the power consumption in Germany ascends continuously. In the past decade an accretion of one per cent per year on average of the production and consumption of electric energy could be ascertained. And this trend will continue. Until 2025 the current drain is assumed to increase about 30% (VDE 2008). Long-dated prognoses are rather difficult because of strong reorganisation processes and uncertainties applying the development of the economic system and the population. On the one hand the power consumption will gradually be uncoupled from the economic growth on account of amendments of proceedings and efficiency factors and new technologies. Apart from power-efficient devices the growing energyconscious attitude confines the increase of power wastage, especially in private households. Moreover, the structural change from an industrial to a service society decreases the specific power requirement (VDEW 2006). Information and communication systems on the other hand have a trend-setting influence on the boost of electricity consumption, at present and in future. They have become central components of society; the term ‘‘information society’’ is commonly used. The entirety of these systems forms an infrastructure of its own which is essential for private and public life. The modern, IT-based society already has an immense need for electricity by now. Without further efforts the electricity consumption of data centres in Germany will raise about 50% until 2010 (BMU/UBA 2007). The driving force of this expansion is the advancing cross linking of facilities and devices in households incited by the use of the internet, entertainment electronics and the coalescence of different media in private households. Product-lines are already available which provide the necessary interfaces to link electrical systems in households, actually to the point of a fully electronically controlled ‘‘intelligent’’ house (Bild der Wissenschaft 2006). This interconnectedness is regarded to be the most important element for the accretion of current consumption in households in industrial countries.
2 Power trading in Europe The intensification of the transnational exchange of electrical power and thus the creation of a truly Internal Electricity Market (IEM) belong to the main intentions of the European Commission regarding the energy sector. Since the beginning of the liberalisation in 1998 the volume of power trading within the European integrated network Union for the Co-ordination of Transmission of Electricity (UCTE) has more than doubled. Especially in Germany a strong emergence of trade can be determined in consequence of a high degree of interconnections with the UCTEnetwork, an entirely opened market, in contrast to most other EU countries, as well as the geographical location in the centre of Europe, between mainly Western European consumers and Eastern European producers. The intended integration of the national electricity markets undoubtedly affords adequate cross-border transmission capacities. In spite of advances on the upgrading
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of the electricity infrastructure the transmission capacities are still insufficient to cope with extensive amounts of electricity and to link formerly autarkic domestic markets. Consequently, bottlenecks at the borders of many member states arise. The transmission capacity allocation is market-based, i.e. within the scope of explicit auctions. The determination of the available capacities proceeds on the basis of a simulation of the entire European network. Nevertheless, a rising demand tightens the bottleneck problem. To mitigate this issue, the EU supports on the one hand measures to increase the transmission capacities by investments in new network facilities or by improvement and harmonisation of operating standards which allow a better exploitation of the networks. The expansion and annexe of capacities are cost-intensive and not realisable at short notice, so that, on the other hand, the rules applied for managing the existing capacities are particularly important in the short and medium term. Only a combination of upgrading of capacities and cross-border congestion management methods will provide for an efficient IEM. A relevant advancement in the congestion management is the coordination of auctions in central parts of the EU. This means that auctions are being carried out uniformly on a platform, so that additionally the determination of network capacities is facilitated by the exchange of relevant flux data. The first real market coupling between the Netherlands, Belgium and France is in process since 2007, a project between Germany and Denmark has started in 2008 and the regional market ‘‘Central-West’’ (Belgium, France, Germany, Luxembourg and the Netherlands) is to begin in 2009. In face of these measurements an upgrading of trans-border capacities is vital for an efficient use of the national networks and fair competition. The establishment of additional investment incentives for the network operators, who generally eschew stronger international rivalry, appears reasonable. The earnings from the auctions for example could be more closely linked to an investment obligation which is already given by EU-law. However, currently efficient investments can by nature become unprofitable in the future, for instance through changing flows of trade or modifications in the generating structure. Imponderables in the calculation are sharpened by a long duration (several decades) of depreciation. The intention of an integrated European market as such can in the long run lead to a problem situation as well: the demand for transport capacity will generally be reduced due to widely adjusted electricity tariffs. There is little or no incentive then to import electricity which makes formerly required high capacities obsolete. An expanding power trading has furthermore effects on the national economy and the energy sector which especially affect Germany as a transit country and can be seen critically. Even the question could be posed to what extent electricity transport can universally be seen as reasonable. So electrical ‘‘ring flows’’ result when connecting different network systems which diminish the available capacities. To avoid exceeding strain on the network, not only national arrangements of transmission providers are necessary, but also multilateral, mandatory agreements between all states concerned. The abandonment of transmission costs has led to an increasing occupation of extra-high voltage lines in particular for long-range electricity transports. The energy losses rise exponentially with respect to the degree of capacity utilisation and the advantage of the vicinity of production and
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consumption drops away. Besides, large amounts of electricity flows go along with an enlarged number of disturbances and hinder the claim for the stability of the network system and the security of supply.
3 Network lines: aspects of planning and environment The postulation of an integrated European electricity market makes the expansion of the electricity grids indispensable. To satisfy the market’s requests, the development of the production structure and the network have to take place co-ordinately. But changing political determining factors and the unbundling of production and transport in a liberated market lead to an uncertainty of the kind and primarily the location of prospective production facilities. Thus, scheduling and operation of production and grids do not proceed as aligned as in vertically integrated regimes. The transmission providers must though be able to attune the network construction promptly to new developments in the generating systems and provide sufficient transport capacities to promote competition on the electricity wholesale market. A long range design of the transmission grids therefore poses a high defiance, also in the light of long economic life-times (several decades) and amortisation times respectively of facilities. Complex approval procedures up to 10 years and considerable construction periods intensify the situation accessorily. The importance of a preferably precocious conception of the network planning becomes evident considering the fact that the structure of the energy supply in 10 years is already almost fixed at the present time. For the installation of new electric lines the legislator has envisaged comprehensive licensures to allow for environmental aspects and to mitigate harmful effects. Yet in the run-up to the authorisation procedure a regional planning procedure and an assessment of environmental impacts are scheduled. To tighten the long-winded proceedings a law came into force at the end of 2006 which is to lead to several simplifications and accelerations. The power network has naturally got different influences on humans and the environment which have to be considered within planning and assent. Overhead lines are in contrast to underground cables widely visible in the natural scenery and are often regarded as aesthetically distracting. Apart from that, zooming sounds (corona sounds) can appear during humid weather conditions and the flight of birds can be endangered. Below grade cables certainly find a greater public acceptance, but feature other hindrances. The surfaces above the lines must not be covered with buildings, the laying demands elaborate building works and long construction times, and the overall costs are up to ten times higher as aerial lines. The most serious influences of high-voltage lines are caused by their lowfrequency electromagnetic fields. Epidemiological studies have first shown in 1979 coherence between children’s cancer and the proximity of residential areas. Since then, a discussion is being led about the carcinogenic properties of these fields. Numerous studies have been accomplished with partially contradictory and ambiguous results; the International Agency for Research on Cancer (IARC) has classified low-frequency electromagnetic fields as potentially cancer-causing. Other
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biological implications have also been found in animal experiments, for example teratogene effects or a reduced production of melatonin. The relevance for humans is yet not fully clarified and has to be further examined. The German legislation has constituted maximum permissible values to protect the population from health damages through electromagnetic fields of electrical installations. These thresholds are considerably undercut by overhead and sub terrestrial lines (dena 2006). Nevertheless, the World Health Organization (WHO) recommends abstaining from housing underneath open wires owing to scientific uncertainty.
4 Feed-in of renewable energies Regenerative energies are of increasing importance for the power market and have reached a rate of over ten per cent of the current consumption in Germany; as a medium-term aim for the year 2020 a proportion of at least 20% is determined. Long-run prospects even assume that a fourth of the current supply in 2030 will be based on renewable energies, with wind power being the prevalent energy source. The rising part of alternative forms of energy and lawfully fixed preferential feeding pose a huge challenge for the stability of the networks. The choice of location for wind power stations (and solar power stations) complies with the availability of the most lucrative offer of primary energy which often lies in sparsely populated areas. In the case of wind energy this means a shifting of the electricity production centre to the high-wind north of Germany and a reversal from the existing network topology which is optimised for a transport direction from the south and the middle of the country to the north. To comply with these changes the extra high-voltage transmission lines have to be aggravated (400 km) and 850 km of new lines have to be built additionally until 2015, with a contribution of 20% of renewable energies assumed (dena 2005, ‘‘dena-network-study I’’). The costs are put at 1.1 billion Euros. The renewal and the expansion have to begin without delay and to be carried out quickly to retain the security of supply. A new study will give further perspectives for the integration of wind energy until 2025 (‘‘dena-network-study II’’, published presumably at the end of 2009). A long-run view is essential since novel technologies will become necessary for an effective integration. For the network design the unsteady performance profile of wind power plants is of basic relevance. Wind energy, fed to the electrical grid, needs chargeback power provided by conventional power stations for balancing fluctuations; this causes energy losses in thermal power stations and limits the degree of energy substitution. Present plans for huge off-shore generation in Europe will intensify this problem. The dena-study assesses that about 94% of the wind power performance will have to be rendered by conventional power plants. The short-run reserves must be assured as well as to back up massive generation collapses. Here, the application of capable prognosis tools is inevitable to optimize the allocation of balance reserves. Widearea monitoring systems are moreover capable of giving a precise copy of the dynamic system status to allow for an efficient system management during quick load flows.
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Regenerative energies play a decisive role in the drastic change of the power supply system which is characterised by peripheral input of a growing number of small electricity producers. The decentralisation requires a local compensation of production and usage, all the more if the back feeding of electricity is considerable. In the long run, an upgrading and an increased cross linking of the network seem unavoidable. In addition, the coordination of the local producers and the communication between the suppliers and the superordinate network management are vital, so that ‘‘decentralised intelligence’’ can optimise the feeding of energy. The concept of virtual power plants which comprises an interconnection of harmonised power producing devices is used for the integration of decentralised generators and for the economic optimisation of the operations. Small power producers should become a confirmed element in the electricity system and be more intensely incorporated in the power market. Energy management systems are up to route production and collection of power in real-time and can embed small-sized producers as active partners into the network management (Leprich 2006). Advanced plans design an electricity network patterned after the internet (‘‘energy internet’’) which acts independently and clears faults unassistedly, but demands highly productive controlling systems and communication technologies.
5 Methods of resolution within the regulation of electricity grids The process of liberalising the electricity sector and of regulating the natural monopoly of the grid in Europe and Germany has had and still has vast impact on the power economy. The dynamic transformation from an integrated public utility monopoly to a competitive generation and sales of electricity with a regulation of the networks is highly complex and far from being completed. Within an interdisciplinary research project Steger et al. (2008) have analysed the regulatory design, in particular specific points that sometimes run counter to conventional knowledge and which are important for the effectiveness of the future incentivebased regulation (came into force on January 1st 2009) to ensure non-discriminatory competition before and behind the electricity grid. The given recommendations should assure the functioning of the network, in the light of the described challenges such as growing power requirement and power trading, unsure and complex power system planning and the expanding insertion of renewable energies. Against the background of the high costs of blackouts (direct and still higher indirect costs) and the high demand it has to be ensured that the regulatory framework encourages investments in the upper range of reasonable expectations to maintain the high quality of electricity supply. Additionally, it seems useful to impose fines for violating service standards to prevent an excessive cost reduction of the quality of supply during the incentive-based regulation. Interruptible contracts, which commit the participants to deactivations upon request, have played a minor role in Germany so far. But their application can reduce the sensibility of the network caused for example by the fluctuating feed-in of renewable energies or international dependencies. Appropriate treaty structures
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are able to diminish demand peaks and therefore reduce the risk and the consequences of large-area cut-offs, also at a given dimension and quality of the network. The costs for additional acquisitions for request peaks on the spot market would as well be lower. The principle of electricity generation close to the consumer is still economically and ecologically reasonable. Power generators however have no incentive to consider the impact of their site choice on the grid as they do not have to pay any user fee. This subsidises long-distance electricity transmission and also cross-border export and import flows. Especially in transit countries, such as Germany, the consumer has to shoulder higher transit costs without having benefits. A generalised distance-base user fee and input fee respectively (at least for conventional energies) could reduce non-grid-optimal power plant sites and long-distance electricity transports which endanger the aim of an overall cost-effective supply. An economic provisioning should in addition be supported by a wider use of auctions. These constitute the most effective way of allocating scarce capacities and can not only be deployed for cross-border congestion management, but also for physical transmission rights from the generation site to the point of demand site. The broader employment of auctions, in Europe and in Germany, under specific conditions is to be further developed and integrated into the regulatory framework in the coming years. In any case, the EU Commission’s intention of creating a common electricity market by stimulating competition through massive cross-border flows and the site choice of power plants can easily endanger the goal of low electricity prices and should therefore be monitored carefully.
References Bild der Wissenschaft (2006) Heim mit Hirn. Report Haustechnik. 8/2006:102–105 BMU/UBA (2007) Zukunftsmarkt Energieeffiziente Rechenzentren. Fallstudie im Auftrag des Bundesministeriums fu¨r Umwelt, Naturschutz und Reaktorsicherheit. Umweltbundesamt, Berlin dena (2005) Energiewirtschaftliche Planung fu¨r die Netzintegration von Windenergie in Deutschland an Land und Offshore bis zum Jahr 2020. Deutsche Energie-Agentur GmbH, Ko¨ln dena (2006) Ausbau des Stromtransportnetzes: Technische Varianten im Vergleich. Deutsche EnergieAgentur GmbH, Berlin Leprich (2006) Vom Durchleitungsgehilfen zum aktiven Netzbetreiber. Energie and Management (E&M), 1 April 2006, vol 4 Steger U, Bu¨denbender U, Feess E, Nelles D (2008) Die Regulierung elektrischer Netze. Offene Fragen und Lo¨sungsansa¨tze. Springer, Berlin VDE (2008) Effizienz- und Einsparpotentiale elektrischer Energie in Deutschland––Perspektiven bis 2025 und Handlungsbedarf. Verband der Elektrotechnik, Elektronik und Informationstechnik e.V VDEW (2006) Pressemitteilung 29 March 2006, Verband der Elektrizita¨tswirtschaft e.V., Berlin
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