Analysing the impact of renewable electricity support schemes on power prices: The case of wind electricity in Spain

It is sometimes argued that renewables are “expensive”. However, although it is generally true that the private costs of renewable electricity generation are certainly above those of conventional electricity, that statement fails to consider the social benefits provided by electricity from renewable energy sources (RES-E), including environmental and socioeconomic ones. This paper empirically analyses an additional albeit usually neglected benefit: the reduction in the wholesale price of electricity as a result of more RES-E generation being fed into the grid. The case of wind generation in Spain shows that this reduction is greater than the increase in the costs for the consumers arising from the RES-E support scheme (the feed-in tariffs), which are charged to the final consumer. Therefore, a net reduction in the retail electricity price results, which is positive from a consumer point of view. This provides an additional argument for RES-E support and contradicts one of the usual arguments against RES-E deployment: the excessive burden on the consumer.     

Feed-in tariff and market electricity price comparison: The case of cogeneration units in Croatia

In August 2007, the Government of the Republic of Croatia instituted a feed-in tariff system, requiring the Croatian Electricity Market Operator (HROTE) to off-take the electricity produced from renewable energy sources or cogeneration units fueled by natural gas. Analysis of the off-take electricity price range, which depends on the net electrical output and electricity market trends, indicates that it is more cost effective for cogeneration units greater than 1 MW to sell their electricity on the exchange market. This was confirmed by developing a mathematical model to calculate the cost-effectiveness ratio of a cogeneration unit. This ratio represents the relation between the profit spread, i.e. the difference between the profit generated from selling the electricity on the exchange market and the profit made from dispatching the electricity to HROTE, as well as the total investment costs. The model can be applied for changes in certain parameters, such as the net electrical output, volatility and spot electricity price. The Monte Carlo method is used to obtain the most probable cost-effectiveness ratio and average future electricity price. Together with these two economic parameters and market price analysis, it is possible to calculate and calibrate an acceptable off-take electricity price.     

Life-cycle energy consumption and greenhouse gas emissions for electricity generation and supply in China

The Well-to-Meter (WTM) analysis module in the Tsinghua-CA3EM model has been used to examine the primary fossil energy consumption (PFEC) and greenhouse gas (GHG) emissions for electricity generation and supply in China. The results show that (1) the WTM PFEC and GHG emission intensities for the 2007 Chinese electricity mix are 3.247 MJ/MJ and 297.688 g carbon dioxide of equivalent (gCO_2,e)/MJ, respectively; (2) power generation is the main contributing sub-stage; (3) the coal-power pathway is the only major contributor of PFEC (96.23%) and GHG emissions (97.08%) in the 2007 mix; and (4) GHG emissions intensity in 2020 will be reduced to 220.470 gCO_2,e/MJ with the development of nuclear and renewable energy and to 169.014 gCO_2,e/MJ if carbon dioxide capture and storage (CCS) technology is employed. It is concluded that (1) the current high levels of PFEC and GHG emission for electricity in China are largely due to the dominant role of coal in the power-generation sector and the relatively low efficiencies during all the sub-stages from resource extraction to final energy consumption and (2) the development of nuclear and renewable energy as well as low carbon technologies such as CCS can significantly reduce GHG emissions from electricity.     

Tracking electricity generation attributes in Europe

Tracking electricity generation attributes can yield detailed information on the used electricity generating technologies, such as per unit fuel consumption and emissions to the environment. The policy context matters for defining the attributes to be tracked. Evolving experience with tracking greatly facilitates the implementation of reliable tracking systems. Some EU Member States have already gained experience with electronically tracked generation attributes for the purpose of disclosing the generation mix to the consumer. Another major application is the use for facilitation of support systems for renewable electricity. There are factors rendering the introduction of tracking generation attributes in Europe no easy task. The main problem is the widely varying initiatives among EU Member States to implement legislation on Guarantees of Origin and disclosure, as this greatly complicates trans-border transfers of generation attributes. The amount of electricity traded makes it difficult to link generation to consumption under “contract-tied tracking”, while this is of no concern under “de-linked tracking”. The key towards overcoming the aforementioned barriers is harmonisation of schemes for tracking generation attributes.     

光伏发电系统高效逆变器的研制

太阳能作为一种取之不尽、用之不竭的环保能源 ,已成为人们的共识 ,在我国其研究被列入高科技领域。此类系统结构简单、成本低廉 ,特别是为边远贫困地区、解决医疗、电视差转等远离电源地方使用 ,带来方便     

Dynamics of productivity change in the Australian electricity industry: Assessing the impacts of electricity reform

The Australian electricity industry has undergone a significant reform, since the mid-1990s. Key changes comprised functional unbundling, market restructuring, regulatory reform, public corporatisation and privatisation. Technological development has been another indisputable constituent of these changes, in the wake of ICT revolution. The principle rationale behind these changes has been that they would improve productivity of the industry and social well-being of people. This paper examines the dynamics of productivity changes in the Australian electricity industry and conducts several hypotheses-testings to identify whether industry's efficiency measures are truly improved as a result of the reform-driven changes. Malmquist Total Factor Productivity Index approach and ANOVA are used for this purpose. The results reveal that the productivity gains in the industry have been largely driven by technological improvements and, to a lesser extent, by reform-induced comparative efficiency gains. On average at national level and for the entire industry, there are efficiency gains that, to large extents, can be attributed to functional unbundling and public corporatisation and, to a lesser extent, to market restructuring and privatisation. The results, however, reveal that the reform-driven changes have made insignificant contribution to comparative efficiency, at the level of thermal generation.     

Power generation from pulverized coal in China

The growth of power generation in China since the 1980s has been reviewed by analyzing the relationship between demand and supply of power, the increasing in installed capacity, and the variations in power-resource structure. Currently, the power generation from pulverized coal (PC) is dominant in the China's power industry, with relevant PC-power-generation technologies being introduced in the past two decades; such technologies were introduced to tackle various issues such as economy, reliability, and pollutant emissions. Furthermore, some of the problems related to PC-power generation in China have been discussed herein. Accordingly, the prospects of PC-power generation in China are predicted, considering the aspects of emission reduction and improvements in efficiency and reliability.     

Power system economics : The value of natural gas in electricity generation

The study reported in this paper is concerned with assessing the value of natural gas in power generation. It had previously been assumed that this value is equal to price(s) of displaced fuel(s). A methodology is derived to assess this value in integrated supply systems and results are derived for a hypothetical system. It is shown that the value is system specific and may be equal to, greater than or less than the value of displaced fuel. The methodology and results reported are relevant to the debate on gas parity pricing.     

Present situation and prospects for lignite in the Polish power-generation industry

In Poland, lignite is mined in open pits and four deep mines, producing totally about 60–65 million tons a year. Extracted lignite constitutes a fuel for power plants with a total installed capacity of 8833 MW, which generate some 35% of electric energy nationally. This energy is cheaper compared with that from other sources. Poland, with its huge deposits of lignite, is placed in a privileged position, for apart from at present mined deposits, which constitute only about 15% of workable reserves, some abundant areas exist, where mining working can be started. At present, the mined deposits allow us to maintain a current yearly output for the forthcoming 15 years, whereas through the subsequent 30 years, it will decline. In order to maintain supplies of lignite, which is a significant fuel in Poland, it is necessary to fully utilize deposits in the existing areas, and develop new zones where lignite occurs.     

Network investments and the integration of distributed generation: Regulatory recommendations for the Dutch electricity industry

An increase in the distributed generation of electricity necessitates investments in the distribution network. The current tariff regulation in the Dutch electricity industry, with its ex post evaluation of the efficiency of investments, average benchmarking and a frontier shift in the x-factor, delays these investments. In the unbundled electricity industry, the investments in the network need to be coordinated with those in the distributed generation of electricity to enable the system operators to build enough network capacity. The current Dutch regulations do not provide for a sufficient information exchange between the generators and the system operators to coordinate the investments. This paper analyses these two effects of the Dutch regulations, and suggests improvements to the regulation of the network connection and transportation tariffs to allow for sufficient network capacity and coordination between the investments in the network and in the generation of electricity. These improvements include locally differentiated tariffs that increase with an increasing concentration of distributed generation.     

Conditions and costs for renewables electricity grid connection: Examples in Europe

This paper compares conditions and costs for RES-E grid connection in selected European countries. These are Germany, the Netherlands, the United Kingdom, Sweden, Austria, Lithuania and Slovenia. Country specific case studies are presented for wind onshore and offshore, biomass and photovoltaic power systems, as based on literature reviews and stakeholder interviews. It is shown that, especially for wind offshore, the allocation of grid connection costs can form a significant barrier for the installation of new RES-E generation if the developer has to bear all such costs. If energy policy makers want to reduce the barriers for new large-scale RES-E deployment, then it is concluded that the grid connection costs should be covered by the respective grid operator. These costs may then be recouped by increasing consumer tariffs for the use of the grid.     

Changes in industrial electricity consumption in china from 1998 to 2007

Electricity consumption in the industrial sector experienced a dramatic increase between 1998 and 2007, accounting for approximately 75% of China’s total electricity consumption. This study analyzes the potential factors influencing the growth of electricity consumption in China’s industrial sector over the past decade using a logarithmic mean Divisia index I decomposition method. Results show that activity effect and shift effect (caused by the change in the electricity’s share of industrial energy use) are the major factors responsible for the rise in electricity consumption between 1998 and 2007. It is found that structural change also contributed to the increase in electricity consumption, it had only a small effect. In contrast, the technological effect is responsible for a decrease in electricity consumption during this period. The influences of technological effects and shift effects followed approximately an inverse-U-shaped and U-shaped curve, respectively. Furthermore, the results show that the main contributors to incremental electricity consumption among industrial subsectors were manufacturing of raw chemical material and products, manufacturing of non-metal mineral products, smelting and pressing of ferrous and non-ferrous metals, and production and supply of electric power and heat power. These sectors should take priority for industrial restructuring in order to implement policies for energy and electricity savings.     

The benefits of transmission expansions in the competitive electricity markets

The paper presents an innovative method for assessing simultaneously technical and economic benefits of transmission expansions. This method takes into account the new needs of the transmission planning process for competitive electricity markets, in which benefits of major transmission expansions include: (a) improved reliability, (b) increased availability of efficient supply and (c) increased competition among suppliers.     

Long-term trends of electric efficiencies in electricity generation in developing countries

This analysis provides time-series data on electric efficiencies for 138 countries and regions, covering all fossil fuels for the period 1971–2005, with an emphasis on non-Organization for Economic Cooperation and Development (OECD) countries. Fossil fuel consumption for electricity generation in non-OECD countries now exceeds that in the OECD. The historical performance of the top five non-OECD consumers of each fossil fuel for which reliable data are available is presented and discussed. For each fuel, the countries that lead the world in efficiency are used for benchmarks; bringing the rest of the world up to these standards would result in energy savings of 26 EJ (equivalent to 5% of global energy consumption) and CO₂ emissions reduction of 2.1 Pg (equivalent to 8% of global CO₂ emissions). Coal showed the largest potential margin of improvement for both energy and CO₂, with possible savings equivalent to 3% of current global energy consumption and 5% of global CO₂ emissions. The gap in electric efficiency between OECD and non-OECD countries over the past 35 years has widened for coal-fired generation, stayed relatively constant for natural gas, but has shrunk for petroleum. The results show the very gradual nature of overall efficiency improvements and the significant differences among regions and countries.     

Potential of solar electricity generation in the European Union member states and candidate countries

During the years 2001–2005, a European solar radiation database was developed using a solar radiation model and climatic data integrated within the Photovoltaic Geographic Information System (PVGIS). The database, with a resolution of 1 km × 1 km, consists of monthly and yearly averages of global irradiation and related climatic parameters, representing the period 1981–1990. The database has been used to analyse regional and national differences of solar energy resource and to assess the photovoltaic (PV) potential in the 25 European Union member states and 5 candidate countries. The calculation of electricity generation potential by contemporary PV technology is a basic step in analysing scenarios for the future energy supply and for a rational implementation of legal and financial frameworks to support the developing industrial production of PV. Three aspects are explored within this paper: (1) the expected average annual electricity generation of a ‘standard’ 1 kW_p grid-connected PV system; (2) the theoretical potential of PV electricity generation; (3) determination of required installed capacity for each country to supply 1% of the national electricity consumption from PV. The analysis shows that PV can already provide a significant contribution to a mixed renewable energy portfolio in the present and future European Union.     

State-scale evaluation of renewable electricity policy: The role of renewable electricity credits and carbon taxes

We have developed a state-scale version of the MARKAL energy optimization model, commonly used to model energy policy at the US national scale and internationally. We apply the model to address state-scale impacts of a renewable electricity standard (RES) and a carbon tax in one southeastern state, Georgia. Biomass is the lowest cost option for large-scale renewable generation in Georgia; we find that electricity can be generated from biomass co-firing at existing coal plants for a marginal cost above baseline of 0.2–2.2 cents/kWh and from dedicated biomass facilities for 3.0–5.5 cents/kWh above baseline. We evaluate the cost and amount of renewable electricity that would be produced in-state and the amount of out-of-state renewable electricity credits (RECs) that would be purchased as a function of the REC price. We find that in Georgia, a constant carbon tax to 2030 primarily promotes a shift from coal to natural gas and does not result in substantial renewable electricity generation. We also find that the option to offset a RES with renewable electricity credits would push renewable investment out-of-state. The tradeoff for keeping renewable investment in-state by not offering RECs is an approximately 1% additional increase in the levelized cost of electricity.     

Wind electricity in Greece: recent developments, problems and prospects

Electricity generation from renewable energy sources (RES) in Greece is regulated by the energy law 2244/94 which provides incentives to attract private investments in the RES sector. The wind energy sector is highly attractive due to the verified large wind potential in many regions of the country. This paper presents the current situation concerning wind energy exploitation, analyses the technical problems following the penetration of wind power into electricity grids, and the consequent technical solutions proposed by the Public Power Corporation (PPC). It also describes the perspectives for high wind power penetration into Greek power system.     

Role of the GB-France electricity interconnectors in integration of variable renewable generation

The integration of large capacities of wind and solar generation into the France and Great Britain (GB) power systems is expected to pose significant operational challenges. Electricity interconnectors can play a role in facilitating the integration of renewable generation in neighbouring countries by allowing power to flow freely between power systems and therefore smooth the net electricity demand. In this paper, role of the electricity interconnectors in efficient balancing of supply and demand in the France and GB power systems was evaluated in terms of overall reduction in the operational costs and curtailment of renewable generation, and also its impact on operation of gas-fired plants. The value of the France-GB interconnectors was studied for two generation mix scenarios in 2030 using PLEXOS. The outputs of the modelling showed the interconnectors will result in larger amount of wind and solar to be absorbed by both power systems which consequently will reduce overall operational costs and CO₂ emissions. In addition, the interconnectors will reduce burden on gas-fired plants compensating for variation in wind and solar generation. This can have a significant value in operation and required investment of gas networks in both countries.     

中国实施电力市场的可行性探讨

介绍了中国电力市场的发展过程和现状,探讨了中国实施电力市场的可能性,通过国内外电力体制发展趋势的观察,总结出了我国电力市场未来发展的三个阶段。