Multi-energy systems (MESs) use more than one energy vector to fulfil users’ electrical, thermal, and cooling demands. This paper examines the recent developments in the design, optimisation, and implementation of MESs, focusing on residential applications. Firstly, recent advances in the design and optimisation of MESs are explained and analysed. The field is characterised by the proliferation of bespoke optimisation methods suitable for this kind of problem. Secondly, practical implementation in the laboratory of MESs and microgrids supplying electrical and thermal loads is discussed. The hardware requirements, in terms of controllers and converters, are critically analysed. This is contrasted with the real-world implementation of MESs or multi-output microgrids in the real world. A description of the communication infrastructure required for real-world implementation is discussed. Finally, a critical review of the entire process, the areas of challenge, and potential research opportunities are presented.

In a bid to respond to the challenges being faced in the installation of flywheel-based electric energy storage systems (EESSs) in customer-side facilities, namely high safety, high energy/power densities and low cost, research work towards the development of a novel, one-body, laminated-rotor flywheel, based on a switched reluctance machine (OBOLAR-Fly SR machine) is presented, where the laminated rotor provides both the energy storage and motor/generator functions. The one-body architecture improves compactness and robustness. Besides, the rotor’s laminated body ensures inherently high safety. From the design perspective, the rotor’s dual purpose causes the traditional electrical machines design aspects, such as power development, cooling, losses, torque ripple, etc., to clash with the typical requirements of a flywheel, namely in-vacuum operation and moment of inertia. This results in six main trade-offs to be addressed during the design process: rotor material, speed ratio, number of drive phases, split ratio, optimal vacuum level, and controller hysteresis band. A 60 kW, 2.2 kWh OBOLAR-Fly SR system is developed with a twofold objective: (1) provide an in-depth description of the six bespoke design trade-offs and give some useful guidelines to tackle them; (2) prove the OBOLAR-Fly concept and compare the prototype’s performance with the current state of the art flywheels. Preliminary experimental results prove the viability of the OBOLAR idea and show its competitiveness in terms of efficiency and power density. On the other hand, a gap in energy density to be filled in future research works is highlighted.

This work presents a rigorous approach to simplify the design optimization process for Switched Reluctance Machines. First of all, the dimension of the Design Space is found to be equal to twelve, as the number of Independent Design Variables. Then, constraints and requirements in the design are represented as inequalities to determine the limit surfaces, which are nothing else than the boundaries of the Design Space. By applying constraints and requirements one by one, the paper shows how it is possible to find the Actual Design Space, which includes only feasible solutions to the design problem. A case study clearly shows how, by means of this methodology, the size of the Design Space can be decreased by orders of magnitude.

The island of Sark, located in the English Channel, has endured an electricity distribution crisis for the past few years, resulting in high electricity costs almost six times higher than UK mainland energy prices. This article is focused on a methodology for finding the best renewable energy system with the lowest levelized cost of energy (LCOE) in comparison to the current energy rate of 66 p/kWh. Three different main cases of study have been compared in performance for different levels of renewable energy integration and energy storage, evaluating the estimated size of the system, installation cost and CO₂ emissions. The results, which depend on the assumptions outlined, show that Case 2 renewable energy generation system is the most suitable in terms of reduction of CO₂ emissions and expected earnings from a lower LCOE. Uncertainty in the results could be minimized if actual data from the island is made available by following the same methodology to find the best solution to the island’s current energy generation problem. Due to non-available data for the load profiles and wind velocity a set of assumption were required to be implemented. As such, two different load profiles were selected—one with a peak of energy consumption in winter and the other with a summer peak.