Elektroautos in einer von erneuerbaren Energien geprägten Energiewirtschaft

The German Federal Government wants to establish Germany as a leading market for electric mobility. Potential environmental benefits and changes in the economic framework conditions of the energy sector are described in this paper. In order to quantify the electricity split which is actually used for charging electric vehicles, two economic models for the energy sector, a model for the market penetration of electric vehicles, a vehicle model and an LCA model are brought together. Based on an assumed dynamic increase of electric vehicles to 12 million in 2030, an additional electricity demand of about 18 TWh is calculated. If the vehicles are charged directly after their last daily trip, the peak load increases by 12%—despite the small increase in electricity demand. First model calculations for the development of the European power generation system show that the direct impact on the construction of new power plants remains low even until 2030. An impact of electric mobility on CO₂ certificate prices can only be seen from 2025 onwards and is limited to an increase in certificate prices by a maximum of 8 % in 2030. An optimisation is possible with intelligent charging strategies: The peak load without demand side management can be reduced by 5 GW and about 600 GWh of additional wind energy can used which would otherwise have been throttled due to feed-in management—about 3.5 % of the total electricity demand of electric vehicles. On the other hand, demand side management leads to more coal power plants instead of gas power plants being used to meet the additional electricity demand. If additional renewable sources are installed along with demand side management, the electricity for electric vehicles is almost carbon free. This is also reflected in the life cycle balance of electric vehicles which also includes vehicle and battery production: With today’s average electricity split in Germany, the greenhouse gas emissions of electric vehicles are about comparable to vehicles with conventional combustion engines. However, the electricity split in 2030 or the use of additional renewable energy sources lead to a significant advantage in the greenhouse gas balance.     

Bereitstellung von Regelleistung durch Elektrofahrzeuge: Modellrechnungen für Deutschland im Jahr 2035

The German government has set ambitious goals for both the expansion of renewable energy supply and electromobility. According to its Energiewende policy, electricity supply from fluctuating renewables is supposed to further increase considerably. This will tend to require a greater provision of balancing reserves. At the same time, supply from conventional dispatchable plants, which used to provide the bulk of reserves, will decrease. Against this background, this article analyzes the scope for an assumed fleet of 4.4 million electric vehicles to supply balancing reserves in 2035. Examining two different future power plant scenarios, it explores the potentials of reserve provision with and without the option of feeding electricity from vehicle batteries back to the grid. Results from an extended open-source power system simulation model show that the assumed vehicle fleet can efficiently provide a substantial share of reserve requirements, also in case the vehicle-to-grid option is not available. Arbitrage on wholesale markets, on the other hand, is negligible under basic assumptions. Likewise, total system cost savings are minor when compared to a pure cost-optimal loading of vehicle batteries. Under alternative assumptions on the future power plant portfolio as well as on battery degradation costs, however, wholesale arbitrage, reserve provision, and system cost savings can be substantial.     

Techno-ökonomische Bewertung von Energie-Autarkie für die Energieversorgung von Einfamilienhäusern

Many consumers currently follow the idea of energy self-sufficiency and try to contribute to meet their energy needs in order to become independent and self-sufficient from the central power supply system. In order to achieve load-oriented energy self-sufficiency the provision of energy must cover the full energy demand at any time. Against this background, in this paper the costs and potentials of a load-oriented energy self-sufficiency of single-family homes are analysed. Thereby it is differentiated between electricity-, heat- and energy self-sufficiency. The modelling is carried out with the simulation environment ?Polysun Designer“ which allows a high temporal dynamic simulation of the annual energy demand and supply.The results show that, within the investigated supply variations, the highest levels of energy self-sufficiency can be achieved by an energy supply system completely based on electricity using a combination of PV; heat pump and battery storage. Depending on the building standard, a maximum of 45 (existing buildings) and 71?% (new buildings) of the building’s energy demand can be covered with renewable energy. The economic evaluation however has shown that under present conditions, none of the investigated supply variants can compete with conventional energy supply (public grid connection + gas condensing boiler).     

Optimierte Integration der Elektromobilität in das Stromversorgungssystem bei hohen Anteilen erneuerbarer Energien

Electric mobility will play a key role for the transformation of the energy supply in Germany [the “Energiewende”]. A successful market development of plug-in hybrids and battery electric vehicles and a full fleet penetration in the long-term are the most efficient and effective measure for integrating large amounts of renewable energy into the transport sector and for reaching the efficiency targets. These new electricity consumers in the supply system will cause additional electricity loads strongly dependent on the mobility needs of the vehicle users. A controlled battery charging is able to avoid new peak demands and to increase the efficiency of the power generation system by using excess power. By scenario analysis, the German Aerospace Center (DLR) in cooperation with the Fraunhofer Institute for Solar Energy Systems (ISE) and the Institute for High Voltage Technology of the RWTH Aachen investigated a possible successful development path of electric mobility in Germany and its integration into and interaction with the future power supply system. From both perspectives—the one of the total supply system as well as the other of local distribution grids—the results show promising potentials but also limits.     

Monetäre Anreize zur Steuerung der Ladelast von Elektrofahrzeugen – eine modellgestützte Optimierung

Electric mobility is supposed to contribute to climate policy targets by reducing CO₂-emissions in the transportation sector. Increasing penetration rates of electric vehicles (EV) can lead to new challenges in the electricity sector, especially with regard to local distribution networks. Thus the management of charging loads is discussed as a key issue in energy economics. Due to their long parking times, high electricity and power demand, EV seem to be predestined for load management. Monetary incentives as dynamic pricing can be suitable for that: They reflect the current supply situation, pass the information to the consumers and can thus lead to a corresponding charging behaviour. In this article we analyse this interaction between dynamic pricing and charging loads. For this reason we have developed the optimization model DS-Opt+. It models a total number of 4,000 households in two residential areas of a major city with regard to its electricity demand, its mobility behaviour and its equipment of photovoltaic systems. Four different pricing models are tested for their effects on charging behaviour and thus the total load of the residential area. The results illustrate that only fairly high penetration rates of EV lead to remarkably higher electricity demand and require some load management. The tested dynamic pricing models are suitable for influencing charging loads; load-based tariffs are best in achieving a balanced load curve. In our analysis uncontrolled charging strategies are superior regarding a balanced load curve than controlled strategies by time-varying tariffs. Our results lead to several implications relevant for the energy industry and further research.     

Dezentrale Steuerung eines Pools von Wärmepumpen auf Basis spieltheoretischer Methoden

An intelligent coupling of the power and the heat sector offers huge possibilities for the integration of electric energy from fluctuating, renewable energies. In this regard heat pumps depict a highly efficient way of power-heat-coupling. However, for a pool of heat pumps this potential can only be exploited effectively with a suitable control methodology. Such a control methodology makes it possible to enforce – depending on the specific case of application – a system-compatible behavior of the pool of heat pumps. In this respect a decentralized control approach offers a higher scalability compared with a centralized control approach. Thus a decentralized control approach based on game-theoretic methods is developed and presented here. For this purpose three game-theoretic optimization algorithms are examined. Their performance is analyzed and evaluated for two specific cases of application (reduction of peak load and tracking of a predefined load profile) by means of simulation. The results of both case studies illustrate, that game-theoretic control is easily applicable and can effectively be used to control a pool of heat pumps. Furthermore the developed control methodology can principally be adapted and utilized for all other electric loads with inherent storage functionality.     

Die Berücksichtigung von Spitzenkappung in der Anreizregulierung

The model of temporary disconnection of renewable energy in case of high energy injection and low demand is thought to be an effective method for reducing investments in electricity networks. However, plant owners need to be reimbursed for foregone sales. According to the currently discussed draft of the Amendment of the German Incentive Regulation Ordinance, these costs can be rolled over to the consumer on a yearly basis, but are part of the cost benchmark with their base year values. This paper shows that this model sets incentives for optimal investments in electricity networks, but violates the participation constraint: Net operators will be exposed to a severe risk of worsening their position in the cost benchmark. In expectation, they will generate losses and investors have no incentive to invest in electricity networks. This problem can be solved by allowing net operators to roll over costs to customers, while considering average reimbursement fees in the cost benchmark.     

Operating Strategies for Battery Storage Systems in Low-Voltage Grids to Limit the Feed-In Power of Solar Power Systems Using Fuzzy Control

Germany’s energy turnaround is leading to an increasing integration of photovoltaics (PVs) throughout its distribution grid. To ensure safe grid operation in times of high solar radiation, PV plants must either be throttled back to comply with the feed-in limitation or store a portion of their excess electricity in batteries. This paper presents a grid-optimized operating strategy for PV storage systems based on a Fuzzy Logic Controller that reduces peak feed-in and thus also PV curtailment losses. The Fuzzy Logic Controller uses data on PV power surplus and battery charge level as input variables. To obtain good results, the set of numerical parameters of the membership functions is enhanced by evolutionary programming.The energetic assessment shows that even small electrical storage capacities (<<5?kWh) reduce curtailment losses considerably when using the grid-optimized operating strategy. The economic assessment shows that, in 2016, investments in PV storage systems with large PV plants and small batteries have small (positive) Internal Rates of Return. The system efficiency of the battery storage has a small impact on the profitability of PV storage systems, whereas the cycle stability and the electricity purchase price have a large impact. Moreover, there is an economic benefit for plant operators to switch from the simple to the grid-optimized operating strategy. Solar forecast inaccuracies and variations in load and generation profiles have a negligible impact on the performance of the control algorithm.     

Bioenergie – Beitrag zum heutigen und zukünftigen Energiesystem

The introduction and establishment of renewable energies is still discussed intensively with the focus on climate-neutral coverage of the global energy demand. In this regard it is a valid option to use biomass as a feedstock. Already today biomass contributes significantly to cover the energy demand in the global energy system. Therefore, the present and future global bioenergy potentials are investigated in the following and compared to the respective biomass use. The results show, amongst others, that the share of biomass for heat, electricity and fuel production will increase worldwide until 2030, although the availability of biomass for energy production is likely to decline in the future.     

World Energy Council’s Global Energy Scenarios to 2060

Since 1970, global energy consumption has more than doubled. Conventional resources, in particular oil, gas and coal, had a dominant share in supply and covered most of the growth in demand in the past. Even in 2015, these fossil fuels still accounted for more than 80% of global primary energy consumption. The contribution of renewable energies to the total electricity generation was 23% in 2015, the same share as in 1970. Developments in the coming decades will differ substantially, however. Total energy consumption will rise at a much more moderate pace than in the past, e.?g. by up to one third by 2060. Electricity consumption will double during this period. But even this is a considerable slowdown in growth compared with the five-fold increase seen between 1970 and 2015. And, unlike in the past, the emerging rise in consumption will essentially be covered by renewable energy sources. This is true especially for the electricity sector. This comparison with developments in the past shows the extent of the global energy transformation that may be expected in future. These developments are reflected in three global scenarios, which were published by the World Energy Council in October 2016. The results of this flagship study World Energy Scenarios to 2060 are mirrored with the main findings of the IEA’s World Energy Outlook and the U.S. EIA’s International Energy Outlook. The most important challenge indicated by the results of the mentioned studies is: the transformation, which is expected in the covered scenarios is not sufficient, in order to achieve the target of limiting the global temperature increase to less than 2 degrees Celsius compared to pre-industrial levels that was agreed by the international community of states in Paris at the end of 2015. It will be highlighted, which strategies could meet the requirement cost-efficiently—a prerequisite for its success.     

Zur Akzeptanz von Stromspeichern in Unternehmen

The German Energy Transition challenges the German Energy System with the integration of renewable energy and its mainly fluctuating nature (especially wind and PV-energy). In order to balance energy demand and supply scholars critically discuss decentralized electric energy storages as an option to introduce more flexibility to the system. In an industrial setting electric energy storage solutions are especially of interest to implement load management, meaning a temporal deferral of load capacity, for peak-shaving activities and the possibility to achieve higher consumption rates of self-generated electricity. One question arises: What do companies think about the use of energy storage solutions in their companies as of today? This article offers an empirical starting point in looking further into detail concerning the overall attitude and the level of knowledge with regard to electrical energy storage solutions based on guided interviews with companies of the manufacturing and processing industry in Germany.     

Prognose der Day-Ahead Wind- und Photovoltaikstromerzeugung – Einflussgrößen und Zuverlässigkeit

In the future, the percentage of renewable energies in the electricity generation is expected to increase continuously. Especially weather-dependent wind and solar power plays a substantial role. These energy sources are partly characterized by a fluctuating and imprecisely predictable power generation. To cover the residual load and to balance the forecast errors a rising number of flexible producers and consumers will be needed in the future. This is necessary to ensure the high security of supply of the German electricity grid.Against this background, the objective of the following investigation is to analyse the day-ahead forecasting quality of the feed-in from wind and photovoltaic systems in the control areas of Germany’s transmission system operators and in the entire area of Germany for the years 2010 to 15. The aim of this analysis is to identify the crucial parameters that influence the forecast error. Subsequently, the share of the wind and photovoltaic power forecast which can be considered as reliably predictable for the following day is estimated. In addition, the increase in this reliable prediction through a higher level of detail in the assessment of the forecast error is quantified. Based on these results, the need of flexibilities through the weather-dependent electricity supply from wind and photovoltaic systems can be estimated, and the impact on the electricity system can be evaluated.     

Induktives Laden von Elektromobilen – Eine techno-ökonomische Bewertung

Conductive (wired) charging, where the user has to plug or unplug a cable, dominates the concepts discussed for electric vehicles up to now. Apart from the reduced range of the electric vehicle, frequent charging and especially short charging times make this plugging and unplugging appear impractical. In contrast, inductive (wireless) energy transfer makes it possible to charge without user intervention. This article attempts to answer questions on whether inductive energy transfer can already be used to charge electric vehicles and where this represents an economically attractive solution for users. To do so, first the charging technologies are presented and contrasted. It is also possible to compare the two charging technologies economically based on a cost analysis. It can be shown that no widespread use of the inductive technology is to be expected for the time being from an economic point of view due to its significant extra costs. Under certain conditions, however, there is a limited field of application as a niche technology in certain commercial areas, such as taxis, for example.     

Energieversorgung als Innovationsbranche vor dem Hintergrund der Energiewende: Ein Fragezeichen

The energy transition includes some technical challenges for the economy. A long-term increase in the demand for energy must be met, whereas proven technologies are no longer opportune. This requires a huge amount of research and development. Is the energy industry facing this challenge? To what extent the additional R & D need is reflected in the official statistics?     

Germany’s Energy Supply

Germany has only very limited domestic energy resources. Seventy percent of primary energy needs must be covered by imports. The markets for energy are marked by a wide diversity and a large number of providers. The oil market has been intensely competitive for decades now. Lignite and hard coal are subjected to fierce substitution competition, especially with natural gas. The natural gas and electricity markets were fully liberalized in 1998. Consumers can freely choose from a vast number of suppliers. Since the beginning of this century, however, state interference particularly in the electricity market has increased. The expansion of renewables has been promoted since the year 2000 by feed-in priority and feed-in remunerations regulated by the state. The energy transition initiated in 2011 is characterized by ambitious energy and climate policy targets. Key pillars include the conversion of electricity generation from production on the basis of conventional energy sources to a system based mainly on renewable energies combined with stringent requirements designed to enhance energy efficiency and what are probably the most ambitious climate protection targets worldwide. As regards the expansion of renewables and the phase-out of nuclear energy, Germany is keeping to its target path. By contrast, there are no signs yet that the objectives formulated in terms of the lowering of primary energy consumption and the reduction in greenhouse gas emissions will be achieved.     

Betriebsoptimierung großtechnischer Kälteversorgungsverbunde bei limitierter Datengrundlage

Energy in the form of cold is required by many commercial and industrial companies in Germany. The demand ranges from space cooling to food refrigeration up to applications with very specific requirements, as it is the case with medical devices. From a certain size of the company, the cooling supply usually takes place in a central refrigeration network fed by several cooling units. The operation of several cooling units allows the individual systems to be controlled in such a way that they operate within the optimum range of operating. In practice, the primary goal is often only to cover the required cooling demand to ensure the underlying processes, so that there is a high potential for operational optimization. Existing models usually require lots of measurement points or historical data to model the efficiency behavior of cooling machines. Therefore, a methodological approach is presented in this work, which, on the one hand, models the efficiency profile of cooling units as a function of the ambient temperature and the utilization, and on the other hand, an energetically optimized schedule for the cooling units can be assessed underlying a limited data basis. The developed approach is subsequently applied to a specific application and validated.     

Markt- und Systemintegration von erneuerbaren Energien im Rahmen der Systemtransformation – Ein Beitrag zur definitorischen Abgrenzung

The reconstruction of the electricity system is one of the main challenges of the German energy transition (Energiewende). The expansion of renewable electricity generation should enable the phase out of nuclear and fossil power generators in the long run. The Renewable Energy Sources Act (Erneuerbare Energien Gesetz) aims at increasing renewable generation up to a share of at least 80?% in gross electricity consumption by the year 2050. There are many possible ways to reach this target. Today, the characteristics of the future energy systems become apparent through the legal framework and long term energy scenarios.Economic, social and regulatory hurdles will need to be overcome to enable the transition of the electricity system. In this context, specific measures are evaluated with respect to their contribution on the system transformation, system integration and market integration. Up until now a consistent framework for evaluating political actions and scientific that should effectively support the energy political objectives is not present. The concepts of power system transformation, power system integration and market integration are differentiated and defined to close this gap. Based on this framework, a practical example is evaluated. The exact definitions will help to objectify the political and scientific debate. Furthermore, it contributes to develop regulatory and market mechanisms.     

Die Verteilung der Kosten des Ausbaus der Erneuerbaren

Germany’s private and industrial consumers have to bear electricity prices that are among the highest in Europe, a major reason being the massive subsidization of green electricity via feed-in tariffs. To dampen future electricity cost increases, numerous suggestions were published recently. They differ substantially with respect to their distributional impacts, transaction costs, political feasibility, and their impact on the cost-effectiveness of the future promotion of renewable technologies. This article’s qualitative evaluation of the most prominent proposals indicates that, more or less, they all fall short with respect to these evaluation criteria. In conclusion, decision-makers would be well advised to reconsider Germany’s renewable energy goals. Consideration should be given to either abolishing these ambitious goals or to improving the cost-effectiveness of the future expansion of renewable energy technologies to dampen the likely continued increase in electricity prices.     

Behavioral and Attitudinal Customer Loyalty in the Power Sector

The emergence of smart grids changes the customer-utility relationship. To facilitate the transition towards a sustainable, reliable and economically viable energy system, utilities need to develop smart grid products and services that have strong customer acceptance and enable different customer segments to engage in energy efficiency. Thus, integrating customer feedback on innovative smart grid services early in the innovation process is of crucial importance. Further, energy providers need to increase customer loyalty and invest in relationship marketing in order to survive and be successful in a competitive market environment.This article presents the findings of a five-month field experiment that investigated the effectiveness of different reward programs in increasing customer loyalty and customer feedback provision in the energy sector. The results demonstrate that reward programs have a positive effect on behavioral (customer feedback provision) and attitudinal (e.?g. satisfaction with the energy provider) aspects of customer loyalty. The reward type matters, however. While monetary reward programs are effective in increasing customer feedback provision, only social reward programs can improve attitudinal aspects of customer loyalty. Energy providers should therefore consider tailoring the reward type to meet their program objectives when employing reward programs.     

以技术动力学视角看电动汽车的发展前景

在目前能源短缺、环境污染严重、节能减排的巨大压力下,先进的电动汽车技术成为人们关注的热点.基于技术动力学的一般规律,针对电动汽车发展涉及的电池技术发展、充电基础设施及其与电动汽车的协调等问题,对电动汽车作为新生事物具有的学习效应、网络与路径依赖以及其中的不确定性、技术路线与政府的角色等方面进行了分析,可为电动汽车发展战略与政策的制定提供参考.