• Energy Research

The development of the North Sea Supergrid is closely linked to three main topological ideas: (i) Business as Usual; (ii) Local Coordination; and (iii) Fully Integrated. In this paper, the three proposed topologies were simplified, analysed and compared for power export from offshore wind farms unto onshore grids. A review on the state-of-the-art HVAC and HVDC offshore transmission technologies was carried out. The national offshore network development strategies of the six countries surrounding the North Sea were summarised. The number of HVAC and HVDC assets required for all three topologies were calculated. It was evident from calculations that, by 2030, the Fully Integrated Topology will achieve approximately 8% asset savings than the Local Coordination Topology.

AbstractThe carbon constrained design of energy supply infrastructure for new build schemes was investigated. This was considered as an optimization problem with the objective of finding the mix of on-site energy supply technologies that meet green house gas emissions targets at a minimum build cost to the developer. An integrated design tool was developed by combining a social cognitive optimisation solver, an infrastructure model and a set of analysis modules to provide the technical design, the evaluation of greenhouse gas emissions and the financial appraisal for the scheme. The integrated design tool was applied to a new build scheme in the UK with a 60% target reduction of regulated emissions. It was shown that the optimal design and corresponding cost was sensitive to the year of build completion and to the assumptions applied when determining the emissions intensity of the marginal central generators.

AbstractThe protection of wind turbines from lightning damage is increasingly important as they increase in size and are placed in locations where access to carry out repairs may be difficult. As blades are the most common attachment point of lightning, they must be adequately protected. In addition, the passage of lightning current through wind turbine bearings introduces a risk of lightning damage to these vital components. Investigations relating to the improvement of blade lightning protection systems have been carried out, including experiments designed to address the difficult problems involved in the protection of hydraulic cylinders used for tip brake control. Work has also focused on the ability of lightning current to cause damage to wind turbine bearings. The work has been a mixture of computer simulations and experimental testing using high‐voltage and high‐current facilities. Copyright © 2001 John Wiley & Sons, Ltd.

AbstractIn order to meet greenhouse gas emissions targets the Great Britain (GB) future electricity supply will include a higher fraction of non-dispatchable generation, increasing opportunities for demand side management to maintain a supply/demand balance. This paper examines the extent of flexible domestic demand (FDD) in GB, its usefulness in system balancing and appropriate incentives to encourage consumers to participate. FDD, classified as electric space and water heating (ESWH), and cold and wet appliances, amounts to 59TWh in 2012 (113TWh total domestic demand) and is calculated to increase to 67TWh in 2030. Summer and winter daily load profiles for flexible loads show significant seasonal and diurnal variations in the total flexible load and between load categories. Low levels of reflective consumer engagement with electricity consumption and a resistance to automation present barriers to effective access to FDD. A value of £1.97/household/year has been calculated for cold appliance loads used for frequency response in 2030, using 2013 market rates. The introduction of smart meters in GB by 2020 will allow access to FDD for system balancing. The low commercial value of individual domestic loads increases the attractiveness of non-financial incentives to fully exploit FDD. It was shown that appliance loads have different characteristics which can contribute to an efficient power system in different ways.

AbstractActive demand side response (DSR) will provide a significant opportunity to enhance the power system flexibility in the Great Britain (GB). Although electricity peak shaving has a clear reduction on required investments in the power system, the benefits on the gas supply network have not been examined. Using a Combined Gas and Electricity Networks expansion model (CGEN+), the impact of DSR on the electricity and gas supply systems in GB was investigated for the time horizon from 2010 to 2050s. The results showed a significant reduction in the capacity of new gas-fired power plants, caused by electricity peak shaving. The reduction of gas-fired power plants achieved through DSR consequently reduced the requirements for gas import capacity up to 90 million cubic meter per day by 2050. The cost savings resulted from the deployment of DSR over a 50-year time horizon from 2010 was estimated to be around £60 billion for the GB power system. Although, the cost saving achieved in the gas network was not significant, it was shown that the DSR will have a crucial role to play in the improvement of security of gas supply.

AbstractThe modelling and control of a wide‐range variable speed wind turbine based on a synchronous generator are presented. Two different methods to control the operation of the synchronous generator are investigated, i.e. load angle control and instantaneous vector control. The dynamic performance characteristics of these control strategies are evaluated and compared using three model representations of the generator: a non‐reduced order model including both stator and rotor transients, a reduced order model with stator transients neglected, and a steady‐state model that neglects generator electrical dynamics. Assessment on the performance of grid‐side controller is shown during network fault and frequency variation. A simplified wind turbine model representation is also developed and proposed for large‐scale power system studies. Simulation results in Matlab/Simulink are presented and discussed. Copyright © 2007 John Wiley & Sons, Ltd.

A method for estimating the heat demand of different types of dwellings is described. Furthermore, an optimal heat supply mix for a local area was determined considering gas and electricity prices and the unique characteristics of the local area in terms of the heat demand and potential heat supply options. These methods were demonstrated on the local authority area of Neath Port Talbot in the UK. The estimated heat demand was validated against real data. The modelling results obtained show that significant financial support is required for low carbon heating technologies such as heat pumps and district heating networks for them to play a major role in the decarbonisation of heat.