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This paper is an Editorial for the special issue (SI) of Energy Reviews (RSER) dedicated to the 10th International Conference on Sustainable Energy and Environmental Protection SEEP, held in Bled-Slovenia. During the conference more than 300 papers were presented, around 25% of these papers were accepted for this special issue. Papers discussed different topics related to renewable energy, energy storage systems and some environmental issues related to transportation. During this conference Prof Olabi presented a keynote talk on the relation between circular economy and renewable energy, case studies about implementing this concept in Scotland were included in his presentation. This editorial will give a short description on the relation between circular economy and renewable energy, then it will be followed by addressing the accepted papers in this special issue. [ABSTRACT FROM AUTHOR]

This paper presents an investigation of the potential for coordinated charging of electric vehicles to i) reduce the CO 2 emissions associated with their charging by selectively charging when grid carbon intensity (gCO2/kWh) is low and ii) absorb excess wind generation in times when it would otherwise be curtailed. A method of scheduling charge events that seeks the minimum carbon intensity of charging while respecting EV and network constraints is presented via a time-coupled linearised optimal power flow formulation, based on plugging-in periods derived from a large travel dataset. Schedules are derived using real half-hourly grid intensity data; if charging in a particular event can be done entirely through use of renewable energy that would otherwise have been curtailed, its carbon intensity is zero. It was found that if 'dumb' charged from the current UK mainland (GB) grid, average emissions related to electric vehicle (EV) charging are in the range 35–56 gCO2/km; this can be reduced to 28–40 gCO2/km by controlled charging – approximately 20–30% of the tailpipe emissions of an average new petrol or diesel car sold in Europe. There is potential for EVs to absorb excess wind generation; based on the modelled charging behaviour, 500,000 EVs (20% of Scotland's current car fleet) could absorb around three quarters of curtailment at Scotland's largest onshore wind farm. • Electric vehicle (EV) charging is scheduled for minimum carbon intensity. • EVs' potential to absorb excess renewables by charging selectively is investigated. • Real GB grid carbon intensity (gCO 2 /kWh) and wind curtailment data used. • Scheduling can reduce EV emissions from 35 to 56 gCO 2 /km to 28–40 gCO 2 /km. • 500,000 EVs can absorb 75% of curtailment at GB's largest onshore wind farm. [ABSTRACT FROM AUTHOR]

The concept of off-grid hybrid wind energy system is financially attractive and more reliable than stand-alone power systems since it is based on more than one electricity generation source. One of the most expensive components in a stand-alone wind-power system is the energy storage system as very often it is oversized to increase system autonomy. In this work, we consider a hybrid system which consists of wind turbines, photovoltaic panels, diesel generator and battery storage. One of the main challenges experienced by project managers is the sizing of components for different sites. This challenge is due to the variability of the renewable energy resource and the load demand for different sites. This paper introduces a sizing model that has been developed and implemented as a graphical user interface, which predicts the optimum configuration of a hybrid system. In particular, this paper focuses on seeking the optimal size of the batteries and the diesel generator usage. Both of these components are seen to be trade-offs from each other. The model simulates real time operation of the hybrid system, using the annual measured hourly wind speed and solar irradiation. The benefit of using time series approach is that it reflects a more realistic situation; here, the peaks and troughs of the renewable energy resource are a central part of the sizing model. Finally, load sensitivity and hybrid system performance analysis are demonstrated. [ABSTRACT FROM AUTHOR]

To promote the transition towards a low carbon economy, the Scottish Government has adopted ambitious energy-related targets, including generating all electricity from renewable sources by 2020. To achieve this, continued investment will be required across a range of sustainable technologies. Hydropower has a long history in Scotland and the present-day operational capacity of ~1.5 GW already makes a substantial contribution to the national energy budget. In addition, there remains potential for ~500 MW of further development, mostly in the form of small to medium size run-of-river schemes. Climate change is expected to lead to an intensification of the global hydrological cycle, leading to changes in both the magnitude and seasonality of river flows. There may also be indirect effects on water flows, such as changing land use, enhanced evapotranspiration rates and an increased demand for irrigation, all of which could affect the water available for energy generation. In this paper we describe Scotland׳s currently installed hydropower capacity and present a review of the scope for future development. We also review the potential impacts of climate change, highlighting possible adaptation measures as well as key factors likely to determine financial viability over the coming decades. We present a summary of the present state of knowledge regarding the resilience of Scotland׳s hydropower resource to a changing climate, and identify key areas where further research is required. [ABSTRACT FROM AUTHOR]

A large deployment of energy storage solutions will be required by the stochastic and non-controllable nature of most renewable energy sources when planning for higher penetration of renewable electricity into the energy mix. Various solutions have been suggested for dealing with medium- and long-term energy storage. Hydrogen and ammonia are two of the most frequently discussed as they are both carbon-free fuels. In this paper, the authors analyse the energy and cost efficiency of hydrogen and ammonia-based pathways for the storage, transportation, and final use of excess electricity from an offshore wind farm. The problem is solved as a linear programming problem, simultaneously optimising the size of each problem unit and the respective time-dependent operational conditions. As a case study, we consider an offshore wind farm of 1.5 GW size located in a reference location North of Scotland. The energy efficiency and cost of the whole chain are evaluated and compared with competitive alternatives, namely, batteries and liquid hydrogen storage. The results show that hydrogen and ammonia storage can be part of the optimal solution. Moreover, their use for long-term energy storage can provide a significant, cost-effective contribution to an extensive penetration of renewable energy sources in national energy systems. • Assessment of hydrogen and ammonia for wind energy storage. • Accounts the effects of electricity price variability and renewable penetration. • Realistic case study to showcase the proposed framework. • Hydrogen and ammonia selected for high fuel prices and wind power penetration. • Specific policies need to promote renewable-based capacity market infrastructure. [ABSTRACT FROM AUTHOR]

Abstract: This paper assists in determining the realistic amount of power available from tidal range generation on the Solway Firth, utilising the latest turbine information for the estimates. The barrage location that is to yield the largest amount of energy output has been highlighted, standing between Workington and Abbey Head at a length of 30 km, spanning the outermost part of the estuary. Double regulated turbine models from Sulzer Escher Wyss of Zurich and also Andritz Hydro are used to determine the flow and power characteristics for individual turbines over a range of heads. Combining the up to date Andritz model with bathymetry sourced from the Department of Energy, and tidal characteristics (modelled from tidal constituents), the model for the behaviour of a barrage on the Solway for ebb generation is constructed. [Copyright &y& Elsevier]