Integration of renewable energies and nuclear power into North African Energy Systems: An analysis of energy import and export effects

The North African countries Morocco, Algeria, Tunisia, Libya and Egypt have been and are currently experiencing rapid growth in energy demand. This development confronts their political leaders with the question of how to expand or diversify their countries’ generation capacities. In this context, renewable energies and nuclear power constitute options that have rarely been exploited so far in the region. This article analyzes the drawbacks and benefits of both alternatives, with a special focus on import and export dynamics. When attempting to make the strategic decision between renewables and atomic power, North African regional specifics and circumstances have to be taken into account. Hence, in a first step, the article characterizes the energy systems of the North African countries and presents scenarios for their future development. In a second step, it scrutinizes the energy challenges these states face in terms of domestic concerns and foreign affairs. Finally, a case study of Algeria is used to demonstrate how renewable energies, but not nuclear power, are able to respond to North African energy challenges.     

De-regulated electric power markets and operating nuclear power plants: the case of British energy

One issue addressed in almost all electric power restructuring/de-regulation plans in both the United States (US) and the United Kingdom (UK) was the recovery of operating nuclear power plant's spent fuel disposal costs and the expenditures to decommission the units when they are retired. Prior to restructuring, in theory at least, in both countries, electricity consumers were paying for the back end costs from operating nuclear power plants. Moreover, in virtually all cases in the US, states included special provisions to insure that consumers would continue to do so after power markets were de-regulated. When power markets in the UK were initially restructured/de-regulated and nuclear power privatized, the shareholders of British Energy (BE) were initially responsible for these costs. However, after electricity prices fell and BE collapsed, the British government shifted many of the costs to future taxpayers, as much as a century forward. If this was not done, the book value of BE's equity would have been about −3.5 billion pounds. That is, BE's liabilities would have been about −3.5 billion pounds greater than their assets. It is difficult to see how BE could remain viable under such circumstances.     

Estimating the system efficiency of the multifunctional hydrogen complex at nuclear power plants

The paper deals with the primary current frequency regulation in the energy system (ES) as well as the basic requirements for NPP power units (PUs) under the conditions of involvement into the primary regulation. According to these requirements, NPP operation is related to the unloading and corresponding decrease in efficiency. It has been shown in this connection that combining NPP with a hydrogen complex (HEC) allows excluding the inefficient unloading mode. This enables the steam turbine and reactor equipment to operate in the basic mode at nominal power level. Besides, the conditions for producing and storing hydrogen and oxygen during the day as well as additionally during the night-time of off-peak electrical load may be created, which allows using them for generating peak power.In the paper, the systemic economic benefit as a result of involving NPP combined with HEC into primary regulation of the current frequency in ES with allowance for expending resources for the main equipment has been estimated. In this regard, the paper gives grounds for cyclic loadings of HEC main equipment including metal tanks for storing hydrogen and oxygen, compressors, hydrogen-oxygen combustion chamber (HOCC) for hydrogen-steam superheating of the actuating medium in the NPP steam turbine cycle. Methodological grounds for evaluating the equipment endurance under cyclic loading with involving into the primary frequency regulation by the criterion of the fatigue crack growth rate are described. It has been shown that in terms of HEC equipment, the highest load intensity occurs in HOCC due to high thermal stresses.Also, the systemic economic benefit has been estimated, and the impact of the equipment deterioration under conditions of cyclic loading has been demonstrated. It is shown that when combining NPP PUs with HEC, the efficiency of primary regulation may significantly depend on such factors as the cost of equipment exposed to cyclic loads, the frequency and intensity of cyclic loads, and the relation between the peak electricity tariff and the cost price of electric energy produced by NPP.It has been shown on the basis of novel methods for estimating the efficiency of involving NPP with HEC into the primary frequency regulation with allowance for damage to the equipment, that the use of HEC may provide a considerable economic benefit, as compared to the version of NPP unloading when involving directly into frequency regulation.     

Distribution of costs induced by the integration of RES-E power

This article focuses on the distribution of costs induced by the integration of electricity generation from renewable energy sources (RES-E). The treatment to distribute these costs on different market actors is crucial for its development. For this purpose, individual actors of electricity markets and several cost categories are identified. According to the defined cost structure, possible treatments to distribute the individual cost categories on different relevant actors are described. Finally, an evaluation of the cost distribution treatments based on an economic analysis is given. Economic efficiency recommends that clearly attributable (shallow) grid connection as well as (deep) grid costs are charged to the corresponding RES-E producer and that the RES-E producers are also charged the regulating power costs. However, deep grid integration costs should be updated to reflect evolving scarcities. Also regulating power costs should reflect actual scarcity and thus be symmetric and based on real-time prices, taking into account the overall system imbalance. Moreover, the time span between the closure of the spot market and actual delivery should be chosen as short as possible to enable accurate RES-E production forecasts.     

A portfolio analysis model of the demand for nuclear power plants

Electric utilities are characterized as timid risk averters that select coal or nuclear plants or both, where the levellized cost of each is characterized by considerable risk. A portfolio selection model is developed to explain the historical demand for nuclear reactors by region. Some qualitative policy implications are derived with respect to the DOE's objective of reviving the nuclear power market.     

Factors influencing the public intention to use renewable energy technologies in South Korea: Effects of the Fukushima nuclear accident

The Fukushima accident has influenced public attitudes toward energy sources and technologies, including not only nuclear energy, but also other energy sources. Therefore, it is worth investigating how the accident influenced public perceptions of renewable energy and its technologies, between the time before the accident and after the accident. This study aims to explore the effects of the Fukushima accident on the public perceptions of renewable energy technologies in South Korea, the closest nation to Japan. This study found that there were notable differences of public perceptions, including public attitudes, perceived benefits, trust, intention to use, knowledge and risks between before and after the earthquake. In addition, the perceived cost of renewable energy technologies was the primary determinant of the intention to use the technologies before the accident, whereas public attitudes toward the technologies became the main antecedents of the intention after the accident. After the accident, we found that there is a multi-dimensional matrix of perceived trust-benefits (with risks)-attitude-intention to use, in explaining the public acceptance of renewable energy technologies. Moreover, we found significant roles of the perceived trust, benefits and risks in the research model. Based on the empirical findings, both implications and suggestions are presented.     

Licensing of nuclear power plants: The case of Sweden in an international comparison

Efficient power plant licensing procedures are essential for the functioning of deregulated electricity markets. The purpose of this paper is to review and analyse the licensing process for nuclear power plants in Sweden, and in part contrast the Swedish case with the corresponding approaches in a selection of other countries. This approach permits a discussion of how licensing processes can be altered and what the benefits and drawbacks of such changes are. The paper highlights and discusses a number of important legal issues and implications, including, for instance: (a) the role of political versus impartial decision-making bodies; (b) the tension between national policy goals and implementation at the local level; (c) public participation and access to justice; (d) consistency and clarity of the legal system; and (e) the introduction of license time limits.     

Primary frequency regulation in the power system by nuclear power plants based on hydrogen-thermal storage

According to the Technical Requirements for Generating Equipment of Participants in the Wholesale Market of the Unified Energy System (UES) of Russia, from 2016 to participate in the general primary frequency regulation (PFR), the maneuverable characteristics of generating equipment of nuclear power plants with VVER reactors put into operation before 2009 should ensure frequency deviations guaranteed realization of the required primary power for loading up to 2% of the nominal electric power. For this, the current capacity of the reactor installation should be maintained at a level of not more than 98% of the nominal thermal power. The fulfillment of this requirement significantly reduces the installed capacity utilization factor (ICUF) of reactor plant.In addition, at present in the UES of the Russian Federation there is a tendency towards an increase in the deficit of peak and half-peak capacities. The majority of fossil fuel-fired thermal stations are switched to the half-peak mode, which negatively affects their efficiency and reliability. In addition, the rise in price of natural gas makes it more profitable to sell it abroad instead of burning at power plants. On the other hand, an increase in the share of nuclear power plants is observed in the UES, which exacerbates the problems associated with the passage of minima and maxima of the daily load in the power system, due to the economically and technically justified need to load NPPs with maximum CUF.The authors developed an approach to solving this problem by combining NPPs with an environmentally friendly energy source – an autonomous hydrogen power complex (AHPC), which includes heat accumulators and an additional multifunctional steam turbine unit. The developed energy complex will allow energy to be accumulated during hours of minima load in the power system due to the electrolysis of water to produce hydrogen and oxygen, as well as the accumulation of hot water in the storage tanks. The accumulated energy can be used to generate super-nominal electricity to cover the half-peak load zone in the power system. In addition, the presence of a low-power steam turbine installation will ensure uninterrupted power supply to consumers of their own needs at the NPP by using the energy of the residual heat from the reactor when the station is completely de-energized.Based on the proposed power complex, a method has been developed to ensure the participation of NPPs in the PFR in an energy system with a constant CUF. To assess the effectiveness of the proposed solution, a methodology for thermodynamic analysis of the power complex based on the combination of NPPs with AHPC was developed. The dependence of the required hydrogen fuel consumption and the efficiency of using off-peak electricity on the temperature of the feed water supplied to the hydrogen-oxygen steam generator from the hot water tanks is constructed.Based on the results obtained, the technical and economic efficiency of the developed power complex is considered. The accumulated net present value was determined depending on off-peak electricity tariffs with three variants of the forecast dynamics of the half-peak electricity tariff, taking into account natural gas savings, reduced investment in NPP safety systems and the economic effect of ensuring the participation of NPPs in the PFR with the plant load at 100%.     

Predictive economic efficiency of combining nuclear power plants with autonomous hydrogen power complex

Currently, the United Energy System (UEC) of Russia is trending in the deficit of peak and half-peak capacity with a simultaneous increase in the number of nuclear power plants (NPPs), which will require the participation of the NPPs in the variable part of the schedule of electrical loads.In addition to the economic need to maintain the high-level utilization rate, there are technological limitations of maneuverability for NPPs.The authors developed an approach to solving this problem by combining with an environmentally friendly energy source – an autonomous hydrogen power complex, which includes thermal batteries and an additional multifunctional low-power steam turbine installation.The developed energy complex can also provide reliable reservation of electricity supply to consumers of their own needs of the nuclear power plant in case of complete blackout of the plant.The feasibility study of the main equipment of the autonomous hydrogen power complex, which is necessary for combining with a two-unit nuclear power plant with WWER-1000, has been evaluated.On the basis of the assessment of the inflation indicators of the Russian economy over the past 11 years, three variants of fuel cost dynamics and tariff rates for electricity (capacity) as well as the size of operating costs, including depreciation deductions to the main equipment, are defined, taking into account the current principles of price formation.The result is a value for accumulated net present value, depending on the ratio of the cost of the half-peak and off-peak electricity at different inflation rates.The positive economic effect of reducing the risk of the core damage accident, replacing the construction of the gas turbine unit as a maneuverable source of electricity in the power grid and increasing the income of the Russian federal budget from the savings of natural gas has been taken into account.The greatest economic efficiency is achieved with maximum projected inflation, which is associated with the maximum rate of discounting and the high rate of growth of electricity tariffs.Reducing the risk of the core damage accident ensures that the proposed approach is competitive in all the inflation options under consideration and the ratio of electricity tariffs.     

An international comparison of regulatory organizations and licensing procedures for new nuclear power plants

This paper considers measures needed to license new nuclear power plants efficiently. We base our analysis on international standards and a comparison of the national regulatory and licensing framework in seven countries (Canada, France, Germany, Japan, Switzerland, the UK and the USA). We split the review into the organization of regulatory responsibilities and the licensing process. We propose a set of considerations that should be incorporated into national solutions. While conscious of the different cultural fundamentals of each region, we hope this paper will help fuel an emerging debate on this highly topical issue.     

Overview of JSME flaw evaluation code for nuclear power plants

A Japanese flaw evaluation code for nuclear power plant components has been developed at the Japan Society of Mechanical Engineers (JSME). The code prescribes methods for the evaluation of flaws, which are detected during inservice inspection for pressure vessels and pipes in nuclear power plants. This paper describes the basic flow chart, methods of evaluation and allowable flaw sizes for acceptance standards and criteria, including comparisons with the ASME Code Section XI.     

Cogeneration of power and substitute of natural gas using biomass and electrolytic hydrogen

Storing renewable energy sources is becoming a very important issue to allow a further reduction of greenhouse gas emissions. Most of such energy sources generate electric power which not always can be conveniently transferred to the grid and also its conversion to hydrogen presents some critical aspects connected mainly to hydrogen distribution and storage.Electrolysis generates not only hydrogen, but also oxygen which could be used to burn biomass or waste products (oxycombustion) in power plants with the result to obtain an exhaust gas containing mainly water and CO₂. This last can be converted into a mixture of methane and hydrogen by reacting with electrolytic hydrogen, so that the power used for electrolysis is stored into a fuel which can be distributed and stored just like natural gas.In this paper, an innovative biomass fuelled plant has been designed and simulated for different layouts with an internal combustion engine as a main power system. Utilizing hydrogen and oxygen produced through electrolysis and applying a hydrogasification process, the plant produces electricity and a substitute of natural gas. The result of such simulations is that the electricity can be stored in a useful and versatile fuel with a marginal efficiency up to 60%.     

Cost evaluation of two potential nuclear power plants for hydrogen production

Hydrogen is recognized as one of the most promising alternative fuels to meet the energy demand for the future by providing a carbon-free solution. In regards to hydrogen production, there has been increasing interest to develop, innovate and commercialize more efficient, effective and economic methods, systems and applications. Nuclear based hydrogen production options through electrolysis and thermochemical cycles appear to be potentially attractive and sustainable for the expanding hydrogen sector. In the current study, two potential nuclear power plants, which are planned to be built in Akkuyu and Sinop in Turkey, are evaluated for hydrogen production scenarios and cost aspects. These two plants will employ the pressurized water reactors with the electricity production capacities of 4800 MW (consisting of 4 units of 1200 MW) for Akkuyu nuclear power plant and 4480 MW (consisting of 4 units of 1120 MW) for Sinop nuclear power plant. Each of these plants are expected to cost about 20 billion US dollars. In the present study, these two plants are considered for hydrogen production and their cost evaluations by employing the special software entitled “Hydrogen Economic Evaluation Program (HEEP)” developed by International Atomic Energy Agency (IAEA) which includes numerous options for hydrogen generation, storage and transportation. The costs of capital, fuel, electricity, decommissioning and consumables are calculated and evaluated in detail for hydrogen generation, storage and transportation in Turkey. The results show that the amount of hydrogen cost varies from 3.18 $/kg H₂ to 6.17 $/kg H₂.     

Economic analysis of power generation from parabolic trough solar thermal plants for the Mediterranean region—A case study for the island of Cyprus

In this work a feasibility study is carried out in order to investigate whether the installation of a parabolic trough solar thermal technology for power generation in the Mediterranean region is economically feasible. The case study takes into account the available solar potential for Cyprus, as well as all available data concerning current renewable energy sources policy of the Cyprus Government, including the relevant feed-in tariff. In order to identify the least cost feasible option for the installation of the parabolic trough solar thermal plant a parametric cost–benefit analysis is carried out by varying parameters, such as, parabolic trough solar thermal plant capacity, parabolic trough solar thermal capital investment, operating hours, carbon dioxide emission trading system price, etc. For all above cases the electricity unit cost or benefit before tax, as well as after tax cash flow, net present value, internal rate of return and payback period are calculated. The results indicate that under certain conditions such projects can be profitable.     

Toward the clean production of hydrogen: Competition among renewable energy sources and nuclear power

This study elucidates the competition among renewable and nuclear energy sources for the production of hydrogen. These involve the use of solar, wind, biological process, tidal, geothermal and nuclear power to generate hydrogen. A comprehensive economic model, the Taiwan General Equilibrium Model-Clean Energy (TAIGEM-CE) model, is used for forecasting. Based on certain assumptions, the analytical results reveal that the most promising means of generating hydrogen is using wind power. Geothermal power is the most sensitive to external investment as a source of power for producing hydrogen. Solar hydrogen also benefits greatly from investment. Production of biohydrogen will be favorable without external investment, and they are less sensitive to investment than other renewable energy sources. Based on the assumptions made in this study, nuclear energy is not as competitive as most renewable energy sources for hydrogen production.     

Contribution of green energy sources to electrical power production of Turkey: A review

Green power products may be seen as a means of fostering renewable energy sources (RES) because they create and channel consumer demand for environmentally sound power generation. Turkey also has a large potential for renewable energy exploitation in a number of areas. Clean, domestic and renewable energy is commonly accepted as the key for future life, not only for Turkey but also for the world. The renewable energy contribution in the total primary energy production is insignificant. The alternative and renewable energy systems have been neglected so far in Turkey but must be included in the new energy programs. In this context, Renewable Energy Law was enacted in 2005 in order to encourage renewable-based generation in competitive market conditions. Supporting mechanisms such as feed-in tariffs and purchase obligation are defined in the law, in conformity with the EU legislation and practice. These mechanisms are envisaged to facilitate the development of power plants based on RES.     

An improved method for hydrogen deflagration to detonation transition prediction under severe accidents in nuclear power plants

This work proposed a new method for prediction of hydrogen Deflagration to Detonation Transition (DDT) on the basis of oxygen concentration in the presence of inerting diluents. Whereas previously, the traditional criterion for deflagration to detonation transition hypothesized an unchanged air composition, it now seems appropriate to question the assumption and consider possible situations in which the presence of inerting gas components incapacitates the old criterion for applications. Under some circumstances (severe accidents in nuclear power plants), hydrogen may be massively generated by intense chemical reactions between zirconium cladding and overheated coolant in the nuclear reactor vessel. In order to prevent hydrogen explosions, Passive Autocatalytic Recombiners (PARs) that mitigate hydrogen risk by hydrogen oxidations have been implemented in the nuclear energy industry worldwide. It consumes a large amount of oxygen as the reactant and gives rise to an increased ratio of inert gas nitrogen to oxygen in the air, the product of which, water mist, also alleviates explosion hazards. The new method addressed on the variation of oxidant volume fraction and proposed new parameters: the equivalent air and the equivalent inert gases concentrations in deflagration to detonation transition criterion. The HYDRAGON code, that has been specially developed for hydrogen analysis in nuclear power plants, implemented both new and original criteria and has been applied to assessments. Close agreements between numerical simulations and a large number of experimental data sets: a wide variety of fuel gases and inert diluents, suggested that such new technique was viable and applicable to predict deflagration to detonation transition for various combustible gases. A hydrogen risk analysis of an advanced pressurized water reactor using the new method was also demonstrated in this paper.     

Effect of using nanofluids on efficiency of parabolic trough collectors in solar thermal electric power plants

In this paper, forced convection heat transfer nanofluid flow inside the receiver tube of solar parabolic trough collector is numerically simulated. Computational Fluid Dynamics (CFD) simulations are carried out to study the influence of using nanofluid as heat transfer fluid on thermal efficiency of the solar system. The three-dimensional steady, turbulent flow and heat transfer governing equations are solved using Finite Volume Method (FVM) with the SIMPLEC algorithm. The results show that the numerical simulation are in good agreement with the experimental data. Also, the effect of various nanoparticle volume fraction on thermal and hydrodynamic characteristics of the solar parabolic collector is discussed in details. The results indicate that, using of nanofluid instead of base fluid as a working fluid leads to enhanced heat transfer performance. Furthermore, the results reveal that by increasing of the nanoparticle volume fraction, the average Nusselt number increases.     

Procedure for optimal design of hydrogen production plants with reserve storage and a stand-alone photovoltaic power system

A procedure for sizing an electrolytic hydrogen production plant powered by a stand-alone photovoltaic system is described in this study. Our fundamental proposal is to compensate the loss of load probability of the photovoltaic system, by means of a hydrogen complementary storage. We compute the necessary hydrogen volume of that reserve storage. Using the isoreliability map of curves that characterizes a given location, we determine the size of the photovoltaic system that would be needed to generate a predetermined flow of hydrogen. Finally, we share information on our own experience relating to the design of the experimental installation at Villafría, located in the city of Burgos, Spain.