Aristides Kiprakis

• Professor
• Chair of Agile Energy Systems at University of Edinburgh

A bottom-up modeling approach is presented that uses a Markov chain Monte Carlo (MCMC) method to develop demand profiles. The demand profiles are combined with the electrical characteristics of the appliance to create detailed time-varying models of residential loads suitable for the analysis of smart grid applications and low-voltage (LV) demand-s...

A detailed study of the potential impact of low voltage (LV) residential demand-side management (DSM) on the cost and greenhouse gas (GHG) emissions is presented. The proposed optimisation algorithm is used to shift non-critical residential loads, with the wet load category used as a case study, in order to minimise the total daily cost and emissio...

Buildings are responsible for some 40% of the total final energy consumption in the European Union and about 40% of the world's primary energy consumption. Hence, the reduction of primary energy consumption is important for the overall energy chain. The scope of the current work is to assess the energy efficiency measures in the residential and sma...

This paper describes a fully coupled, wave-to-wire time-domain model that can simulate the hydrodynamic, mechanical, and electrical response of an array of wave energy converters. Arrays of any configuration can be simulated to explore both the effects of the array on the electricity network and of network events on the devices within the array. St...

With the rapid increase in distributed generation (DG), the issue of voltage regulation in the distribution network becomes more significant, and centralized voltage control (or active network management) is one of the proposed methods. Alternative work on intelligent distributed voltage and reactive power control of DG has also demonstrated benefi...

Due to the increasing installation of residential electric vehicle (EV) chargers to benefit from the low tariff rates during off-peak hours, the simultaneous charging of a large number of EVs affects the voltage profile and the transformer loading of a radial distribution network. Hence, this paper presents a virtual power plant (VPP) configuration...

Unleashing the potential of distributed renewable energy sources (RESs), intelligent and autonomous microgrids are becoming pivotal in attaining net‐zero carbon emission goals. Hybrid AC/DC microgrids rise as cutting‐edge microgrid topologies, capitalising on the best of both AC and DC systems. However, the integration of intermittent renewables an...

Macro-energy system modelling is used by decision-makers to steer the global energy transition towards an affordable, sustainable and reliable future. Closed-source models are the current standard for most policy and industry decisions. However, open models have proven to be competitive alternatives that promote science, robust technical analysis,...

As the world seeks to transition to a sustainable energy future, energy storage technologies are increasingly recognized as critical enablers. However, the macro-energy system assessment of energy storage has often focused on isolated storage technologies and neglected competition between them, thus leaving out which energy storage to prioritise. T...

When deploying robots in shallow ocean waters, wave disturbances can be significant, highly dynamic and pose problems when operating near structures; this is a key limitation of current control strategies, restricting the range of conditions in which subsea vehicles can be deployed. To improve dynamic control and offer a higher level of robustness,...

The penetration of electrical vehicles (EVs) is exponentially rising to decarbonize the transport sector resulting in the research problem regarding the future of their retired batteries. Landfill disposal poses an environmental hazard, therefore, recycling or reusing them as second-life batteries (SLBs) are the inevitable options. Reusing the EV b...

Energy system models are used for policy decisions and technology designs. If not carefully used, models give implausible outputs and mislead decision-making. One implausible effect is ’unintended storage cycling’, which is observable as simultaneous storage charging and discharging. Methods to remove such misleading effects exist, but are computat...

A fundamental strategy for utilizing green energy from renewable sources to tackle global warming is the microgrid (MG). Due to the predominance of AC microgrids in the existing power system and the substantial increase in DC power generation and DC load demand, the development of AC/DC hybrid microgrids (HMG) is inevitable. Despite increased theor...

The domestic sector accounts for a third of the UK's energy consumption and with increasing pressure from net-zero targets, the potential of residential flexibility is more widely recognised by consumers, aggregators and governments. The development of near real-time metering systems and home energy management technologies provide new possibilities...

Macro-energy system modelling is used by decision-makers to steer the global energy transition toward an affordable, sustainable and reliable future. Closed-source models are the current standard for most policy and industry decisions. However, open models have proven to be competitive alternatives that promote science, robust technical analysis, c...

The gradual decommissioning of fossil fuel-driven power plants, that traditionally provide most operational flexibility in power systems, has led to more frequent grid stability issues. To compensate for the lack of flexible resources, Distributed Energy Resources (DERs) in distribution networks can be employed. To facilitate the use of DERs, the a...

Given the ongoing transition towards a more decentralised and adaptive energy system, the potential of blockchain-enabled smart contracts for the energy sector is being increasingly recognised. Due to their self-executing, customisable and tamper-proof nature, they are seen as a key technology for enabling the transition to a more efficient, transp...

Coupled blade element momentum-computational fluid dynamic (BEM-CFD) approaches have been extensively used to study tidal stream turbine performance and wake development. These approaches have shown to be accurate when compared to tests conducted in tow-tanks or in regulated flumes with uniform flows across the turbine. Whilst such studies can be v...

Active surface morphing is a nonintrusive flow control technique that can delay separation in laminar and turbulent boundary layers. Most of the experimental studies of such control strategy have been carried out in wind tunnels at low Reynolds numbers with costly actuators. In contrast, the implementation of such a control strategy at low cost for...

Unintended storage cycling is a modelling artifact that may unknowingly appear in many energy system models. It is observable through simultaneous charging and discharging of the same storage unit, when instead of curtailing renewable surplus electricity, unintended storage cycling creates energy losses that distort optimal dispatch decisions acros...

Electricity network modelling and grid simulations form a key enabling element for the integration of newer and cleaner technologies such as renewable energy generation and electric vehicles into the existing grid and energy system infrastructure. This paper reviews the models of the African electricity systems and highlights the gaps in the open m...

Tidal stream turbines (TST) are subject to large unsteady hydrodynamic loads which will result in fatigue of components and potentially failure. Control algorithms, if used effectively, have the ability to reduce these unsteady loads without affecting overall performance. To examine the effect of control strategy on performance and loads, experimen...

Remotely Operated (underwater) Vehicles (ROV) have a wide range of maritime applications, including repair and maintenance. Quantifying hydrodynamic loads is important for the design and control of these ROVs. A novel approach with eight tethers was used to restrain a commercially available ROV, namely the BlueROV2 (Blue Robotics, Torrance, USA), i...

An energy storage technology is valuable if it makes energy systems cheaper. Traditional ways to improve storage technologies are to reduce their costs; however, the cheapest energy storage is not always the most valuable in energy systems. Modern techno-economical evaluation methods try to address the cost and value situation but do not judge the...

Predictive control methods can substantially improve the performance of Unmanned Underwater Vehicles (UUVs), particularly in shallow water environments or near the free surface where wave induced disturbance are of magnitude comparable to the vehicle characteristic inertia. To facilitate the adoption of these methods, a fast estimation of the time...

The outbreak of SARS-COV-2 disease 2019 (COVID-19) abruptly changed the patterns in electricity consumption, challenging the system operations of forecasting and balancing supply and demand. This is mainly due to the mitigation measures that include lockdown and work from home (WFH), which decreased the aggregated demand and remarkably altered its...

The outbreak of SARS-COV-2 disease 2019 (COVID-19) abruptly changed the patterns in electricity consumption, challenging the system operations of forecasting and balancing supply and demand. This is due to the mitigation measures that include lockdown and Work from Home (WFH), which decreased the aggregated demand and remarkably altered its profile...

The frequency of power outages being experienced in Sub-Saharan Africa mean that traditional methods of electricity demand forecasting which rely on directly observed demand data are inadequate for use in projections. Nevertheless, accurate forecasting methods are urgently required to ensure efficient power system operations and expansion planning....

The remotely operated vehicles (ROVs) are important to provide the technology support for both the traditional offshore structures and rapidly-growing renewable energy facilities during their full-lifecycles, such as site survey, installation, inspection, maintenance and repair. Regarding the motion and performance of a ROV, the understanding of it...

Recent years have seen an increasing interest in Demand Response (DR) as a means to provide flexibility, and hence improve the reliability of energy systems in a cost-effective way. Yet, the high complexity of the tasks associated with DR, combined with their use of large-scale data and the frequent need for near real-time decisions, means that Art...

Remotely Operated underwater Vehicles (ROVs) are growing in importance in the ocean environment for observation and manipulation tasks, particularly when used to maintain offshore energy and offshore renewable energy assets. Many such tasks require the dynamic positioning of ROV in challenging sea conditions with multiple disturbances resulting fro...

Batteries offer a combination of balancing and regulation services within a smart grid to improve its resilience and flexibility. Maintaining an acceptable state of health and the highest rate of return requires dynamic modelling of the asset and rigorous optimisation. We compare the technical cost and economic benefit of battery employment in dyna...

Hydrodynamic forces are an important input value for the design, navigation and station keeping of underwater Remotely Operated Vehicles (ROVs). The experiment investigated the forces imparted by currents (with representative real world turbulence) and waves on a commercially available ROV, namely the BlueROV2 (Blue Robotics, Torrance, USA). Three...

In this study, a topology defragmentation method is developed for co-placements of phasor measurement units (PMUs) and their communication infrastructure. Electric power networks are defragmented into sets of branches and a realistic cost model, based on reports from industry, is developed. Instead of considering channel limitations, more practical...

For controlling Unmanned Underwater Vehicles (UUVs) in deep water, Proportional-Integral-Derivative (PID) control has previously been proposed. Disturbances due to waves are minimal at high depths, so PID provides an acceptable level of control for performing tasks such as station-keeping. In shallow water, disturbances from waves are considerably...

Tidal stream turbines are subject to complex flow conditions, particularly when installed in staggered array configurations where the downstream turbines are affected by the wake and/or bypass flow of upstream turbines. This work presents, for the first time, methods for and results from the physical testing of three 1/15 scale instrumented turbine...

This dataset presents a set of turbine loading and performance measurements carried out at the FloWave Ocean Energy Research Facility, around a closely spaced staggered array of three nominally 1:15 scale tidal turbines, with a 1.2m rotor diameter. Measurements were made at different rotation speeds, with the three turbine array compared to just th...

This dataset presents a comprehensive set of flow measurements carried out at the FloWave Ocean Energy Research Facility, around a closely spaced staggered array of three nominally 1:15 scale tidal turbines, with a 1.2m rotor diameter, including empty tank baseline data.

Demand response (DR) is an integral component of smart grid operations that offers the necessary flexibility to support its decarbonisation. In incentive-based DR programs, deviations from the scheduled DR capacity affect the grid’s energy balance and result in revenue losses for the DR participants. This issue aggravates with increasing DR deliver...

The use of battery energy storage system (BESS) is one of the methods employed in solving the major challenge of overvoltage, experienced on distribution networks with high penetration of photovoltaics (PV). The overvoltage problem limits the penetration levels of PV into the distribution network, and the benefits that could be gained. This study p...

The use of battery energy storage systems (BESS) is one of the methods employed in solving the major challenge of overvoltage, experienced on low voltage (LV) distribution networks with high penetration of photovoltaics (PV). The overvoltage problem limits the penetration levels of PV into the LV network, and the benefits that could be gained. This...

This paper proposes an optimisation program for scheduling the operations of battery energy storage system (BESS) in a distribution network, in order to maximise energy arbitrage gains. BESS are increasingly being deployed for stationary applications in power systems globally. Due to the high capital cost of BESS deployment, it is necessary to have...

Demand Response (DR) is a Smart Grid technology aiming to provide demand regulation for dynamic pricing and ancillary services to the grid. Thermostatically controlled loads (TCLs) are among those with the highest potential for DR. Some of the challenges in modelling TCLs is the various factors that affect their duty cycle, mainly human behaviour a...

This paper presents a review of the main electrical components that are expected to be present in marine renewable energy arrays. The review is put in context by appraising the current needs of the industry and identifying the key components required in both device and array-scale developments. For each component, electrical, mechanical and cost co...

This study presents an economical distributed control scheme for operations in the low-voltage network. The scheme aims to keep bus voltages within the desired statutory range of values while increasing the penetration of solar photovoltaic (PV) renewable energy within the network. Rather than curtailment, battery energy storage system (BESS) is fi...

Great Britain has begun to implement significant modifications that are ought to change the national electricity generation. Adding a large amount of renewable capacity to the energy mix will impact different areas of energy use from the landscape used for installation to the electricity market. This study presents an approach to determine the opti...

Current developments in wave energy conversion have focused on locations where the wave energy resource is the highest; using large devices to generate hundreds of kilowatts of power. However, it is possible to generate power from low power waves using smaller wave energy devices. These lower rated wave energy converters can form arrays to supply p...

Nowadays, with the introduction of different types of variable renewable energy sources, generators and other actors in the electricity market are faced with a new layer of complexity they have to adapt to. This upsets the electrical consumption profile power generation production has mostly followed and the established merit order, which was assum...

This paper introduces a techno-economic analysis framework to assess different transmission options for marine energy converter (MEC) farms. On the technical front, the feasibility of the transmission options considering supply quality constraints and the optimal sizing of reactive power compensation to allow maximum real power transfer capability...

Domestic heating has a large share in the UK total energy consumption and significant contribution to the greenhouse gas emissions since it is mainly fulfilled by fossil fuels. Therefore, decarbonising the heating system is essential and an option to achieve this is by heating system electrification through heat pumps (HP) installation in combinati...

This paper explores smoothing in the net real power generated by arrays of point absorber type wave energy converters (WECs) brought about by spacing WECs appropriately within the array. Smoothing is measured by assessing the voltage flicker introduced by injecting the generated power into electricity networks. Uniformly spacing WECs at 0.25Opeak,...

A better understanding of the process of setting wholesale electricity prices does benefit not only the generating companies but also the end users as it forces them to be responsible with their energy use in the time of peak electricity demand leading to smaller fluctuations in demand. Determining when a generator could maximise the profit based o...

This paper discusses the potential of the domestic sector to provide Demand Side Management (DSM) services. The inherent drawback of the domestic sector is its structure, consisting of numerous small loads, the high variety of sub-types, the deviation of consumption profiles between households but also the daily variation of each household’s demand...

Domestic heating which is dominated by fossil fuels has a large share in the UK total energy consumption. Heat pumps (HP) with thermal energy storage (TES) in combination with renewable electricity generation are a viable low carbon heating option. TES allows the shifting of heating demand to off peak periods or periods with surplus renewable elect...

A better understanding of the process of setting wholesale electricity prices does benefit not only the generating companies but also the end users as it forces them to be responsible with their energy use in the time of peak electricity demand leading to smaller fluctuations in demand. Determining when a generator could maximise the profit based o...

Direct drive permanent magnet linear generator have been proposed as an alternative to conventional generators due to the simplification they introduce in a wave energy converter system. Due to the ability of the permanent magnet generators to generate power at low speeds it is possible to generate power from low power waves using small wave energy...

This paper presents a simulation tool for the design and analysis of offshore ocean energy array networks. The tool integrates a number of modules which are divided into two core functions: the automation of the cable laying algorithm and subsequent creation of the network model, and the other performing the power flow analysis. The results of the...

A Nortek Aquadopp current profiler was tested at the University of Strathclyde's Kelvin Hydrodynamics Laboratory. To evaluate both the accuracy and precision of the instrument, it was towed on a carriage at a range of speeds up to 3.5ms-1. The effect of the spatial resolution and range parameter settings on these uncertainties has also been studied...

More effective energy production requires a greater penetration of storage technologies. This paper takes a looks at and compares the landscape of energy storage devices. Solutions across four categories of storage, namely: mechanical, chemical, electromagnetic and thermal storage are compared on the basis of energy/power density, specific energy/p...

Despite the significant share of heat demand in the UK energy consumption, the management and storage of thermal energy have been overlooked relative to its electrical counterpart. However, Thermal Energy Storage (TES) is one of the key technologies to enable more efficient heating systems and the decarbonisation of the heating sector. The domestic...

This paper presents a component-based modelling approach for developing time-varying harmonic current injection models of the residential load sector. Some initial results of the model are also presented to demonstrate the temporal variations in low-voltage (LV) residential harmonics. The level of detail afforded by the model is illustrated using t...

The paper presents a detailed study of the potential impact on the cost and greenhouse gas emissions (GHG) through low voltage (LV) residential demand-side management (DSM). The proposed optimisation algorithm is used to shift non-critical residential loads, with the wet load category used as a case study, in order to minimise the total daily cost...

This article presents a comprehensive statistical analysis of data obtained from a wide range of literature on the most widely used appliances in the UK residential load sector, as well as a comprehensive technology and market survey conducted by the authors. The article focuses on the individual appliances and begins by consideration of the electr...

This paper presents a comprehensive statistical review of data obtained from a wide range of literature on the most widely used electrical appliances in the UK residential load sector. It focuses on individual appliances and begins by consideration of the electrical operations performed by the load. This approach allows for the loads to be categori...

Reducing peak system demand is generally regarded as a crucial step in deferring investment in electricity networks and improving overall performance. Several utilities have explored the used of voltage control for peak reduction but the results are inconclusive. This paper presents results of an ongoing study of the potential of voltage control fo...

Flywheel energy storage (FES) provides high density storage. Traditional systems relied on mechanical bearings. Bearings can be replaced by electromagnetic variations. Modern FES systems levitate inertial mass on electromagnetic cushions. Levitation consumes energy, so FES systems are confined to short-term power quality applications. An FES system...

This paper presents a Markov chain approach for developing low-voltage (LV) residential load models for use in the analysis of future smart grids. The motivation is to obtain a better understanding of load use and user behaviour at the LV level which will allow future electricity network performance to be improved by understanding the impact of ene...

To fully assess the impact of possible demand-side management (DSM) actions on a system-wide scale, detailed low-voltage (LV) load models are required. This paper describes the development of a flexible, bottom-up approached profiling tool that transforms user activity profiles into load models. That will allow studying the grid and the influence o...

This paper presents the work program of DESIMAX, a collaborative research project looking at wide-scale implementation of demand side management (DSM) within electricity networks. To fully understand the implications of extended use of DSM, it is important to develop multi-scale models that will be able to capture, predict and demonstrate the respo...

This paper describes a wave-to-wire model of an array of wave energy converters developed in MATLAB/Simulink. The effects of connecting a 1 MW wave farm to a weak, rural electricity network are investigated. Impacts of the wave farm on voltage quality are examined and both conventional and more intelligent control methods by which these impacts can...