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.     

Feasibility study of large scale hydrogen power-to-gas applications and cost of the systems evolving with scaling up in Germany,Belgium and Iceland

The use of hydrogen to store electricity is no longer utopian nor merely theoretical. Hydrogen applications such as Power-to-Gas systems are entering the market and some of them are ready to compete with other options in the near future. This means they have indeed a potential for profitability, especially if seen as large-scale storage solutions for the electricity surplus produced by variable renewable energy sources.In this study Power-to-Industry, Power-to-Mobility and Power-to-Power applications are chosen to be investigated and compared through levelized cost of hydrogen to identify the main cost drivers and consequently understand the possible solutions to reduce costs. The feasibility of the applications is discussed and analyzed in Germany, Belgium and Iceland, with mid and long-term perspectives, focusing the analysis on the advantage of scaling up.     

Power-to-Gas: Storing surplus electrical energy. Study of catalyst synthesis and operating conditions

Energy storage is needed in order to sustain the energy system on renewable energies like wind and solar power. Power-to-Gas (PtG) is a technology that enables the storage of the renewable electricity in a chemical carrier such as hydrogen, via water electrolysis, or methane, via carbon dioxide methanation. In this work a series of catalysts based on nickel and alumina, the catalyst commonly employed for carbon dioxide methanation, have been synthesised employing different calcination temperatures to study the influence of this parameter in the activity of the catalysts. As a result of this study 673 K was determined as the most suitable Moreover, the catalysts have also been tested at different pressures to determine the most suitable operating pressure. Although due to Le Chatelier's Principle a higher pressure results in an increasing yield, the study carried out proved that 10 bar is the most suitable pressure as the difference in the yield when increasing the pressure it is not high enough taking into account the costs and risks associated with higher pressures.     

Renewable Power-to-Gas: A technological and economic review

The Power-to-Gas (PtG) process chain could play a significant role in the future energy system. Renewable electric energy can be transformed into storable methane via electrolysis and subsequent methanation.This article compares the available electrolysis and methanation technologies with respect to the stringent requirements of the PtG chain such as low CAPEX, high efficiency, and high flexibility.Three water electrolysis technologies are considered: alkaline electrolysis, PEM electrolysis, and solid oxide electrolysis. Alkaline electrolysis is currently the cheapest technology; however, in the future PEM electrolysis could be better suited for the PtG process chain. Solid oxide electrolysis could also be an option in future, especially if heat sources are available.Several different reactor concepts can be used for the methanation reaction. For catalytic methanation, typically fixed-bed reactors are used; however, novel reactor concepts such as three-phase methanation and micro reactors are currently under development. Another approach is the biochemical conversion. The bioprocess takes place in aqueous solutions and close to ambient temperatures.Finally, the whole process chain is discussed. Critical aspects of the PtG process are the availability of CO₂ sources, the dynamic behaviour of the individual process steps, and especially the economics as well as the efficiency.     

Hybridization strategies of power-to-gas systems and battery storage using renewable energy

In this paper, the hybrid concept to use renewable electricity to produce hydrogen with an electrolyser in combination with a battery is introduced and analysed. This hybrid system opens the possibility to optimise operation and to increase operation times of the system and thus to improve the techno-economic performance. To analyse the performance, a model has been developed, which designs and operates a single or hybrid power-to-gas system in a cost optimal manner. The underlying method is a mixed integer linear programming (MILP) approach, which minimises total system costs. The cost optimisation modelling is performed by a case study for a hybrid electrolyser/battery system directly coupled with a large PV power plant without grid connection. The results show, that batteries can support electrolyser operation in a reasonable way. This is however associated with higher hydrogen production costs and not competitive compared to the installation of additional electrolyser capacity or curtailment of electricity.     

Rejecting renewables: The socio-technical impediments to renewable electricity in the United States

If renewable power systems deliver such impressive benefits, why do they still provide only 3 percent of national electricity generation in the United States? As an answer, this article demonstrates that the impediments to renewable power are socio-technical, a term that encompasses the technological, social, political, regulatory, and cultural aspects of electricity supply and use. Extensive interviews of public utility commissioners, utility managers, system operators, manufacturers, researchers, business owners, and ordinary consumers reveal that it is these socio-technical barriers that often explain why wind, solar, biomass, geothermal, and hydroelectric power sources are not embraced. Utility operators reject renewable resources because they are trained to think only in terms of big, conventional power plants. Consumers practically ignore renewable power systems because they are not given accurate price signals about electricity consumption. Intentional market distortions (such as subsidies), and unintentional market distortions (such as split incentives) prevent consumers from becoming fully invested in their electricity choices. As a result, newer and cleaner technologies that may offer social and environmental benefits but are not consistent with the dominant paradigm of the electricity industry continue to face comparative rejection.     

Renewable and nuclear power: A common future?

Nuclear power and renewable energy are the main options to bring down the carbon intensity of commercial energy supply. What technology is unlimited backstop supply depends on its performance on the sustainability criteria: democratic decided, globally accessible, environmental benign, low risk, affordable.     

System-level power-to-gas energy storage for high penetrations of variable renewables

According to outlooks by the IEA and the U.S. EIA, renewables will become the largest source of electricity by 2050 if global temperature rise is to be limited to 2 °C. However, at penetrations greater than 30%, curtailment of wind and solar can be significant in even the most flexible systems. Energy storage can reduce curtailment and increase utilisation of variable renewables. Power-to-gas is a form of long-term storage based on electrolytic production of hydrogen. This research models the co-sizing of wind and solar PV capacity and electrolyser capacity in a jurisdiction targeting 80% penetration of variable renewable electricity. Results indicate that power-to-gas can reduce required wind and solar capacity by as much as 23% and curtailment by as much as 87%. While the majority of charging events last less than 12 h, the majority of the total annual stored energy comes from longer-term events. Additional scenarios reveal that geographic diversity of wind farms reduces capacity requirements, but the same benefit is not found for distributing solar PV.     

Assessment of feasible strategies for seasonal underground hydrogen storage in a saline aquifer

Renewable energies fluctuate, resulting in temporary mismatches between demand and supply. The conversion of surplus energy to hydrogen and its storage in geological formations is one option to counteract this energy imbalance. This study evaluates the feasibility of seasonal storage of hydrogen produced from wind power in Castilla-León region (northern Spain). A 3D multiphase numerical model is used to test different extraction well configurations during three annual injection-production cycles in a saline aquifer. Results demonstrate that underground hydrogen storage in saline aquifers can be operated with reasonable recovery ratios. A maximum hydrogen recovery ratio of 78%, which represents a global energy efficiency of 30%, has been estimated. Hydrogen upconing emerges as the major risk on saline aquifer storage without using other cushion gases. However, shallow extraction wells can minimize its effects. Steeply dipping geological structures are key for an efficient hydrogen storage.     

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.     

The Japanese energy sector: Current situation,and future paths

As the world’s third leading economy and a major importer of fuels, the choice of future energy paths and policies that Japan makes in the next few years will have a significant influence on the energy security of the world as a whole, and of the Northeast Asia region in particular. In this article we describe the current status of and recent trends in the Japanese energy sector, including energy demand and supply by fuel and by sector. We then discuss the current energy policy situation in Japan, focusing on policies related to climate change targets, renewable energy development and deployment, liberalization of energy markets, and the evolution of the Japanese nuclear power sector. The final section of the article presents the structure of the Japan LEAP (long-range energy alternatives planning software system) dataset, describes several alternative energy paths for Japan – with an emphasis on alternative paths for nuclear power development and GHG emission abatement – and touches upon key current issues of energy policy facing Japan, as reflected in the modeling inputs and results.