Does renewable energy generation decrease the volatility of electricity prices? An analysis of Denmark and Germany

Although variable renewable energy (VRE) technologies with zero marginal costs decrease electricity prices, the literature is inconclusive about how the resulting shift in the supply curves impacts price volatility. Because the flexibility to respond to high peak and low off-peak prices is crucial for demand-response applications and may compensate for the losses of conventional generators caused by lower average prices, there is a need to understand how the penetration of VRE affects volatility. In this paper, we build distributed lag models with Danish and German data to estimate the impact of VRE generation on electricity price volatility. We find that in Denmark wind power decreases the daily volatility of prices by flattening the hourly price profile, but in Germany it increases the volatility because it has a stronger impact on off-peak prices. Our analysis suggests that access to flexible generation capacity and wind power generation patterns contribute to these differing impacts. Meanwhile, solar power decreases price volatility in Germany. By contrast, the weekly volatility of prices increases in both areas due to the intermittency of VRE. Thus, policy measures for facilitating the integration of VRE should be tailored to such region-specific patterns.     

Quantifying the effect of renewable generation on day–ahead electricity market prices: The Spanish case

The penetration of renewable generation has grown since the electricity sector has been deregulated. To account for that, this paper proposes a methodology to estimate the downward effect of renewable generation participation upon the day-ahead electricity market prices, since such an effect is quite intuitive observing the merit order of the generating units. The European Electricity Market Matching Algorithm (EMMA) is currently based on Euphemia (Price Coupling of Regions), though there are several differences among countries across Europe. The new algorithm proposed uses market orders, which include aggregate hourly orders such as aggregate supply and demand curves. These orders are simple orders and the marginal price is affected by complex orders, especially by the minimum income condition (MIC) used in the Iberian Electricity Market and considered in our proposed algorithm. A case study of the Spanish day-ahead electricity market is evaluated for 2015, for which a daily generation sample is composed of 16 days in 2015. The sample is created following the characteristics of thermal production, renewable production and inframarginal production. The conclusions are drawn comparing the simulations of the real marginal prices and the new marginal prices after incorporating renewable generation participation into the aggregate demand curve at the maximum price.     

Are the aims of increasing the share of green electricity generation and reducing GHG emissions always compatible?

Energy from waste (EfW) has been identified as a source of ‘green electricity’ and has been used as a way of reducing greenhouse gas (GHG) emissions. Nevertheless, selecting an EfW strategy for municipal solid waste management is a challenging task not least because of the uncertainty involved in quantifying the potential economic and environmental impacts. This paper analyses five alternatives for managing the municipal solid waste of Sydney for their ‘green electricity’ and GHG savings potential under conditions of uncertainty. The impact of paper recycling on the ranking of alternatives was investigated, too. Our analysis shows that maximizing EfW generation potential does not result in greater GHG saving. A combination of food and green waste composting, recycling of metals, paper, glass and plastics while only landfilling waste fractions that are not recyclable may result in the best GHG savings. Furthermore, recycling of paper does not always achieve the best outcome; anaerobic digestion or composting may yield better results from an environmental and energy generation perspective.     

Impact of the German nuclear phase-out on Europe's electricity generation—A comprehensive study

The combination of the ambitious German greenhouse gas reduction goals in the power sector and the nuclear phase-out raises many questions concerning the operational security of the German electricity generation system. This paper focusses on the technical feasibility (electricity generation and transmission) and CO₂-impact of the German nuclear phase-out on the short term (2012–2022).A detailed electricity generation simulation model is employed, including the German transmission grid and its international connections. A range of different conventional and renewable energy sources (RES) scenarios is considered. Results are presented for the change in generation mix, on the flows on the transmission network and on operational reliability issues.The scenario analysis shows that nuclear generation will be replaced mainly by coal- and lignite-based generation. This increases the CO₂-intensity of the German electricity sector. Furthermore, the results indicate that the German electricity export will decrease and under certain circumstances, the system becomes infeasible. Keeping some nuclear power plants online, would mitigate these effects. The amount of electricity generated from RES is shown to be the main driver for grid congestion.     

LCA of renewable energy for electricity generation systems—A review

Sustainable development requires methods and tools to measure and compare the environmental impacts of human activities for various products (goods and services). Providing society with goods and services contributes to a wide range of environmental impacts. Environmental impacts include emissions into the environment and the consumption of resources as well as other interventions such as land use, etc. Life cycle assessment (LCA) is a technique for assessing environmental loads of a product or a system. The aim of this paper is to review existing energy and CO₂ life cycle analyses of renewable sources based electricity generation systems.The paper points out that carbon emission from renewable energy (RE) systems are not nil, as is generally assumed while evaluating carbon credits. Further the range of carbon emissions from RE systems have been found out from existing literature and compared with those from fossil fuel based systems, so as to assist in a rational choice of energy supply systems.     

Quantifying the impacts of national renewable electricity ambitions using a North–West European electricity market model

This work builds a comprehensive North–West European Electricity Market model for the year 2020 and uses it to quantify the impacts of ambitious national renewable electricity targets. The geographical coverage of the model comprises Germany, France, Belgium, Netherlands, Luxemburg, Great Britain and Ireland. The model simulates the electricity market operation for the entire region at half hourly resolution and produces results in terms of electricity prices, cross border flows, emissions and associated total system costs. The impact of two carbon prices is examined within the model. Results highlight the policy challenges that arise when individual Member States formulate renewable energy plans in isolation in the absence of integrated modelling of interconnected regions as cross border power flows play a more significant role in market dynamics especially in the presence of geographically dispersed variable renewable generation sources such as wind and solar. From a policy perspective results suggest that based on these national plans, congestion will be present on a number of key lines at long periods during the year.     

Estimation of Japanese price elasticities of residential electricity demand, 1990–2007

This paper estimates elasticities of Japanese residential price electricity from 1990 to 2007. The first difference generalized method of moment estimator is employed to avoid dynamic panel bias, which is not considered in most previous studies. The results show that while short-run elasticities are similar to those in previous studies, long-run elasticities are significantly lower in our study. We also find that the price elasticity of Japanese residential electricity consumption is notably affected by income inequality and severe weather. Based on these results, we provide some insights to tailor environmental taxation so as to effectively attain the Kyoto Protocol.     

Is there a water–energy nexus in electricity generation? Long-term scenarios for the western United States

Water is required for energy supply, and energy is required for water supply, creating problems as demand for both resources grows. We analyze this “water–energy nexus” as it affects long-run electricity planning in the western United States. We develop four scenarios assuming: no new constraints; limits on carbon emissions; limits on water use; and combined carbon and water limits.We evaluate these scenarios through 2100 under a range of carbon and water prices. The carbon-reducing scenarios become cost-effective at carbon prices of about $50–$70 per ton of CO₂, moderately high but plausible within the century. In contrast, the water-conserving scenarios are not cost-effective until water prices reach thousands of dollars per acre-foot, well beyond foreseeable levels. This is due in part to the modest available water savings: our most and least water-intensive scenarios differ by less than 1% of the region's water consumption.Under our assumptions, Western electricity generation could be reshaped by the cost of carbon emissions, but not by the cost of water, over the course of this century. Both climate change and water scarcity are of critical importance, but only in the former is electricity generation central to the problem and its solutions.     

Fine structure of the price–demand relationship in the electricity market: Multi-scale correlation analysis

In this research we investigate the problems of dynamic relationship between electricity price and demand over different time scales for two largest price zones of the Russian wholesale electricity market. We use multi-scale correlation analysis based on a modified method of time-dependent intrinsic correlation and the complete ensemble empirical mode decomposition with adaptive noise for this purpose. Three hypotheses on the type and strength of correlations in the short-, medium- and long-runs were tested. It is shown that price zones significantly differ in internal price–demand correlation structure over the comparable time scales, and not each of the theoretically formulated hypotheses is true for each of them. We can conclude that the answer to the question whether it is necessary to take into account the influence of demand-side on electricity spot prices over different time scales, is significantly dependent on the structure of electricity generation and consumption on the corresponding market.     

The impact of the EU ETS on the sectoral innovation system for power generation technologies – Findings for Germany

This paper provides an overview of early changes in the sectoral innovation system for power generation technologies which have been triggered by the European Emission Trading System (EU ETS). Based on a broad definition of the sector, our research analyses the impact of the EU ETS on the four building blocks ‘knowledge and technologies’, ‘actors and networks’, ‘institutions’, and ‘demand’ by combining two streams of literature, namely systems of innovation and environmental economics. Our analysis for Germany is based on 42 exploratory interviews with experts in the field of the EU ETS, the power sector, and technological innovation. We find that the EU ETS mainly affects the rate and direction of technological change of power generation technologies within the large-scale, coal-based power generation technological regime, to which carbon capture technologies are added as a new technological trajectory. While this impact can be interpreted as the defensive behaviour of incumbents, the observed changes should not be underestimated. We argue that the EU ETS’ impact on corporate CO₂ culture and routines may prepare the ground for the transition to a low-carbon sectoral innovation system for power generation technologies.     

Hydrogen generation by the hydrolysis of magnesium–aluminum–iron material in aqueous solutions

Highly activated Mg–Al–Fe materials are prepared from powder by mechanical ball milling method for hydrogen generation. The hydrolysis characteristics of Mg–Al–Fe materials in aqueous solutions under different experimental conditions are carefully investigated. The results show that the hydrolysis reactivity of Mg–Al–Fe material can be significantly improved by increasing the ball milling time and Fe content. The increase of NaCl solution concentration and initial temperature is also found to promote the hydrogen generation reaction. At 25 °C, the Mg60–Al30–Fe10 (wt%) material ball-milled for 4 h shows the best performance in 0.6 mol L⁻¹ NaCl solution, and the reaction can produce 1013.33 ml g⁻¹ hydrogen with a maximum hydrogen generation rate of 499.50 ml min⁻¹ g⁻¹. In comparison to NaCl solution, natural seawater is found to have an inhibiting effect on the hydrolysis of Mg–Al–Fe material. Especially, the presence of Mg²⁺ and Ca²⁺ in seawater can greatly reduce the hydrogen conversion yield, and the SO₄²⁻ can decrease the hydrogen generation rate.     

Hydrogen generation from the hydrolysis of aluminum promoted by Ni–Li–B catalyst

In this study, the high activity Ni–Li–B catalysts were fabricated through wet chemical reduction method. Their morphological structures, crystallinity, surface area and composition were examined by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) method and energy-dispersive X-ray spectroscopy (EDS). The aluminum-water reaction tests were explored in the range of temperatures from 35–75 °C. It was found that water could react with aluminum to generate hydrogen gas. The yield and hydrogen generation rate were significantly increased when all prepared catalysts were added into the reaction. The Ni–Li–B (X_LiCl = 0.1 g) catalyst exhibited the highest cumulative hydrogen volume of 201.3 ml with an average hydrogen production rate of 0.50 ml min⁻¹ at 55 °C. This phenomenon could be pointed to the emergence of the micro galvanic cell formed by the Ni–Li–B, Li/Ni–Li–B, Li and Al, which accelerated aluminum to rapidly react with water.     

Wind power and photovoltaic power: How to improve the accommodation capability of renewable electricity generation in China?

China's wind curtailment and photovoltaic curtailment was one of the prominent issues in 2014, and the renewable curtailment worsened in 2015. With the rapid growth of renewables, the phenomenon of the insufficiency in renewable accommodation capability is becoming more and more serious in 2016. In that case, the problem of the insufficient accommodation capability is pointed out by analyzing China's development requirements. The renewable power generation scale, the renewable power consumption, and the restrictions on the renewable electricity generation are discussed from the China's market perspective. Meanwhile, the legal environment, the planning requirement, the institutional setting, and the policy tools are introduced from the perspective of governmental regulation. An empirical analysis, a cause analysis and a trend analysis are illustrated before explaining the problem of renewable curtailment and proposing a solution for enhancing the accommodation capability. According to the analysis results, the solution for addressing the wind curtailment and PV curtailment is offered with respect to the technology, the institution, the legislation, and the political aspect. Through the research, the research conclusions are drew finally and the corresponding policy recommendations are put forward.     

Privatization of electricity distribution in the Northeast of Brazil: The good,the bad,the ugly or the naïve?

This paper analyzes the evolution of five electricity distribution companies in the Northeast of Brazil using technical and financial indicators. Three privatized and two public firms were analyzed between 1997 and 2008. The financial indicators are used as proxies for the capacity of the business to generate value for shareholders, while the technical indicators are used as proxies for service quality provided to consumers. We observed that the privatized firms had their financial indicators improved after privatization, increasing the value of the firm for the shareholders. However, there is no evidence that privatization affected the quality of service provided to consumers.     

Market power versus regulatory power in the Spanish electricity system, 1973–1996

This study not only establishes that the institutional changes (the change of political regime) and economic changes (the energy crisis) that occurred during the 70s and 80s had an important effect on business strategies within the Spanish electricity sector, but, above all, it shows how the resulting regulatory model was not the product of any clearly defined plan on the part of the Spanish authorities (as the majority of authors seem to implicitly or explicitly maintain), but rather it arose from the dialectical interaction between companies which resisted losing the power of the market, and institutions which, in order to define any medium term energy policy in the future European domestic electricity market, required an increase in their regulatory power.     

Integrated energy in Germany–A critical look at the development and state of integrated energies in Germany

In the face of global warming and a scarcity of resources, future energy systems are urged to undergo a major and radical transformation. The recognition of the need to embrace renewable energy technologies and to move toward decarbonization has led to significant changes in the German energy generation, consumption and infrastructure. Ambitious German national plans to decrease carbon dioxide emissions on one side, and the unpredictable and volatile nature of renewable energy sources on the other side have elevated the importance of integrated energies in recent years. The deployment of integrated technologies as a solution to interlink various infrastructures creates opportunities for increasing the reliability of energy systems, minimizing environmental impacts and maximizing the share of renewable resources. This paper discusses the role of integrated energy systems in supporting of sustainable solutions for future energy transitions. Moreover, the reinforcement of this movement with the help of different technologies will be discussed and the development of integrated energy systems in Germany will be reviewed.     

Features of the exponential form of internal heat generation,Cattaneo–Christov heat theory on water-based graphene–CNT–titanium ternary hybrid nanofluid flow

To increase energy efficiency, the flow of fluids containing nanoparticles is crucial in industrial applications notably in nuclear reactors and nuclear system cooling. In light of this, this study examines the flow of a water-based ternary hybrid nanofluid (graphene, single-walled carbon nanotubes, and titanium dioxide) across a curved stretching sheet with suction. The non-Fourier heat flux model is also considered in the modeling. The existing partial differential equations are converted into ordinary differential equations through the use of similarity variables. These ordinary differential equations are then numerically solved using the Runge–Kutta–Fehlberg fourth- and fifth-order method along with a shooting approach. The collection of graphical findings for the key variables on the temperature and velocity profiles is investigated. Results reveal that the heat transport in ternary hybrid nanoliquid rises as the heat source/sink parameter rises. The Biot number influences the thermal profile positively, whereas the increasing curvature parameter values reduce heat transport. The curvature parameter has a positive impact on skin friction but the suction parameter has a negative impact on skin friction.     

Optimization of hydrogen generation process from the hydrolysis of activated Al–NaCl–SiC composites using Taguchi method

Novel Al–NaCl–SiC composites for hydrogen generation were prepared by mechanical ball milling. NaCl is a well-known salt for the activation of Al. SiC, which is much harder and more rigid than NaCl, was added as a milling aid. In this optimization study Taguchi method was used for design of experiments. In the experimental design using the L16 (4 ? 3) orthogonal array, 4-levels of NaCl and SiC ratios and mechanical milling times were used. Confirmation tests were carried out for the optimum levels determined by Taguchi method. An analysis of variance was performed to determine the relative importance of the control factors and their contribution to the performance characteristic. It was found that NaCl has the greatest effect on hydrogen generation performance, followed by mechanical milling time and SiC ratio. The highest values of these parameters were determined as optimum levels for maximum hydrogen generation. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) analyzes were performed to investigate the relation between hydrogen generation performance and morphology of milled powders. The grain (crystal) dimensions of some milled powders were calculated from the XRD data using the Scherrer equation. Grain refinement, reduction in grain size during mechanical milling was used as a measure of the severity of plastic deformation. It was observed that the grain sizes were reduced to a few tens of nanometers with the ball milling process.     

Large-scale fuelwood production on agricultural fields in mesoscale river catchments – GIS-based determination of potentials in the Dahme river catchment (Brandenburg,NE Germany)

Woody biomass (dendromass) today already has an important role in bioenergy production and will even increase in the future as a renewable resource for energetic as well as for material use. In eastern Germany, an increasing demand for dendromass in renewable energy production is unlikely to be covered by sustainable forest wood production. Hence, a deficit for the federal state of Brandenburg of 4.02 million tonnes per year is predicted. Besides imports, one option of increasing dendromass supply in Brandenburg is short rotation coppice (SRC) on arable land. The potential of SRC on arable land is determined by the economic competitiveness of SRC compared to conventional annual crops. This factor is strongly influenced by the water supply, expressed as the transpiration water supply (TWS) in the growing season, and the soil quality.First evaluations of SRC potentials in Brandenburg identify large areas of arable land where SRC seems to be able to compete with annual crops.Potential areas in the Dahme river catchment, located in the south of Berlin, were identified at a regional scale through a GIS-based approach. The results indicate that lowland river catchments like the Dahme basin have great potentials for fuelwood production. Especially the large amount of arable land with accessible groundwater resources offers water for transpiration in a region where average annual precipitation and water storage capacity of soils is relatively low (550 mm and 100–150 mm m⁻¹ resp.) and thus too small to meet the demands of optimal SRC growth. In total, 340,000 tonnes fuelwood could be produced annually in the Dahme river catchment, if all potential sites were transformed into SRC. This accounts for 8.5% of the deficit produced on just 1.8% of the federal state of Brandenburg's total agricultural area by 2030 and meet the heating energy demand of approximately 130,000 people. The results show that the applied method is an effective way to identify biomass potentials in mesoscale river basins and demonstrates the relevance of the Dahme catchment for a sustainable energy supply in the future.     

Which is the best solar thermal collection technology for electricity generation in north-west India? Evaluation of options using the analytical hierarchy process

This study of concentrating solar thermal power generation sets out to evaluate the main existing collection technologies using the framework of the Analytical Hierarchy Process (AHP). It encompasses parabolic troughs, heliostat fields, linear Fresnel reflectors, parabolic dishes, compound parabolic concentrators and linear Fresnel lenses. These technologies are compared based on technical, economic and environmental criteria. Within these three categories, numerous sub-criteria are identified; similarly sub-alternatives are considered for each technology. A literature review, thermodynamic calculations and an expert workshop have been used to arrive at quantitative and qualitative assessments. The methodology is applied principally to a case study in Gujarat in north-west India, though case studies based on the Sahara Desert, Southern Spain and California are included for comparison. A sensitivity analysis is carried out for Gujarat. The study concludes that the linear Fresnel lens with a secondary compound parabolic collector, or the parabolic dish reflector, is the preferred technology for north-west India.