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Highlights • Increasing variable renewable electricity sources has shown to lower market prices. • Researchers have investigated this effect using historical data electricity markets. • Here holistic energy system analyses are done with an energy system simulation tool. • The analyses are used to quantify the effect on a specific case. Abstract Variable renewable electricity sources have been shown to reduce wholesale electricity market prices. This is expected to reduce the incentive for investments in new electricity production capacity, and might even make these investments infeasible, if relying only on the income from trade on the current electricity market paradigms. In this paper, a novel approach for quantifying this effect in future energy systems is developed using a holistic energy system approach. The approach is applied to the case of Denmark in 2015, which is part of the Nordic and Baltic wholesale electricity market Nord Pool Spot. A holistic energy system model is created and verified according to both the Danish energy balance and the Nord Pool Spot system price in 2015. Using this verified model, the Nord Pool Spot system price is quantified at increasing amounts of onshore wind power, offshore wind power and photovoltaic in Denmark. It is found that regardless of which variable renewable electricity source is implemented, including a combination of the three, the Nord Pool Spot system price decreases as the amount of energy produced by these sources increases, and this effect occurs immediately as more is introduced. [ABSTRACT FROM AUTHOR]

Future renewable energy systems with high shares of variable renewable energy production must also include technologies and measures to balance these production fluctuations. This could be in the form of electricity storage, energy demand adaptation (also known as demand-side management), or sector coupling. Industry electrification couples electricity and industry sectors by replacing the fossil fuel demand with electricity demands, thus enabling further integration of renewable electricity and transitioning the hard-to-abate energy sector. The effects of electrification on 100% renewable energy systems are rarely investigated. When investigated, one 100% renewable energy system scenario is used, which is often created by the same author, actor or organisation and may result in a narrow view of the possibilities for future energy systems. This study quantifies the role of industry electrification in the context of different 100% renewable energy system scenarios created by different relevant actors, to identify how its role may differ based on the scenario investigated. It is found that direct electrification of industrial process heat demands should be favoured over, e.g., a fuel shift to hydrogen-based process systems, even when these provide more flexibility. • Future renewable energy systems must balance variable production fluctuations. • Industry electrification enables integration of renewable electricity. • Industry electrification is analysed in three renewable energy system scenarios. • Direct electrification should be favoured over hydrogen-based process systems. [ABSTRACT FROM AUTHOR]

Moving towards carbon-neutral societies, both nuclear and renewable energy can potentially supply CO 2 -free electricity. While the cost of renewable energy has decreased significantly, the cost of nuclear has, however, increased in the past decades and now in general exceeds the cost of renewables. However, one cannot compare directly the per unit cost of electricity since temporal behavior in the electricity production differs substantially between the two groups of technologies. Nuclear power inherently aims to provide a constant base load supply of electricity, while renewables generally depend on weather patterns. Thus, the two have different requirements and impact the overall system costs differently regarding flexibility and system design. Focusing on the case of Denmark, this article investigates a future fully sector-coupled energy system in a carbon-neutral society and compares the operation and costs of renewables and nuclear-based energy systems. The study finds that investments in flexibility in the electricity supply are needed in both systems due to the constant production pattern of nuclear and the variability of renewable energy sources. However, the scenario with high nuclear implementation is 1.2 billion EUR more expensive annually compared to a scenario only based on renewables, with all systems completely balancing supply and demand across all energy sectors in every hour. For nuclear power to be cost competitive with renewables an investment cost of 1.55 MEUR/MW must be achieved, which is substantially below any cost projection for nuclear power. • Both renewable energy and nuclear power benefits from sector coupling. • Hourly modelling is required to capture system effects. • Nuclear systems require less flexibility capacity than renewable only systems. • A renewable energy system is cheaper than a nuclear based system. • Lower flexibility costs do not offset the high investment costs in nuclear energy. [ABSTRACT FROM AUTHOR]

• Focusing on the trade-off problem between industrial excess heat and heat pumps in DH system. • A novel hybrid framework for optimal DH strategy in 100% renewable smart energy systems. • The real energy system of Aalborg, Denmark is employed for technical–economic analysis. • Sector synergies between the DH network, power grid, and gas grid are revealed. • 40% IEH and 20% HP in DH bring Aalborg a balanced near carbon–neutral system with minimum cost. The literature emphasizes the important role of industrial excess heat (IEH) and heat pumps (HP) in future 4th generation district heating and smart energy systems. However, they can potentially have negative or positive effects on the integration of renewable energy sources (RES). It is necessary to find a trade-off between IEH and HP in the transition towards a 100% renewable energy system yet has not been discussed in the literature. This paper presents a comprehensive techno-economic analysis for the optimal district heating (DH) strategy in a 100% renewable energy system. It is conducted based on a novel hybrid methodology framework that couples hourly smart energy system simulation, multi-objective optimization, and multiple-criteria decision making. The optimal share between IEH and HP and associated RES capacity can be determined considering the preferences of policymakers. A scenario for 2050 for Aalborg Municipality in Denmark is used as a case study. Results show that an appropriate mix of IEH and HP, 40% and 20% respectively in the DH supply, should be employed to obtain a balanced near carbon–neutral system with the least cost. Also, the cross-sector effective interactivities between the DH network, power grid, and gas grid are revealed in the smart energy system context. The proposed framework is designed in a general way that can be used in other cities, regions, or countries. [ABSTRACT FROM AUTHOR]

EnergyPLAN is an energy system analysis tool used worldwide for scientific analyses of national and regional energy planning strategies and alternatives. This work describes the MATLAB Toolbox for EnergyPLAN (MaT4EnergyPLAN), a set of functions developed to manage the EnergyPLAN software using MATLAB. The tool allows the user to take advantage of the energy system analysis capabilities of EnergyPLAN in combination with the computational advantages of MATLAB. This allows the user to easily manage EnergyPLAN files and analyse a large number of EnergyPLAN simulations. • A new MATLAB Toolbox for improving energy planning studies is presented. • The toolbox increases the potentialities of EnergyPLAN analyses. • A method to develop smart renewable energy strategies on islands is presented. • A large number of EnergyPLAN simulations can be analysed and managed from MATLAB. [ABSTRACT FROM AUTHOR]