The advent of deregulated electricity and the call for sustainable energy practices are major drivers for the continued increase of renewable energy systems within the modern day power network. Dominant among them is the wind energy system whose output is uncertain because of its dependence on the prevailing climatic conditions. This increases the level of uncertainty witnessed within the power system as such, as the penetration of renewable energy systems continue to increase, their effects cannot be trivialised. Probabilistic load flow (PLF) is employed by power system analysts to account for the effect of uncertainty within the power network. The common technique which is based on Monte Carlo Simulation (MCS), though accurate is very time consuming and for large systems it becomes unwieldy. Alternative approaches with the advantages of the MCS method but with reduced computational burden are required. A viable alternative method should therefore require minimum computational time and burden, be able to accurately model various network uncertainties, be applicable to practical small and large systems, be able to account for the effect of dependency among network variables and possess good overall accuracy. This thesis proposes a novel approximate approach referred to as the enhanced unscented transform method to meet the requirements of PLF. The method combines the Gaussian quadrature method and the Stieljes procedure with dimension reduction technique in deciding estimation points while the Cholesky decomposition is incorporated to account for the effect of dependency. The performance of the proposed technique is demonstrated using modified IEEE 6, 14, and 118 test systems and a practical distribution test system all incorporating wind farms. Results obtained for numerous scenarios show a good match between the proposed method and the MCS method but with significant computational burden saving. The performance of the method is also shown to compare favourably with other existing PLF methods.

An evaluation is made of the potential fuel and financial savings possible when a small, autonomous diesel system sized to meet the demands of an individual, domestic consumer is adapted to include: (1) combined heat and power (CUP) generation. (2) wind turbine generation. (3) direct load control. The potential of these three areas is investigated by means of time-step simulation modelling on a microcomputer. Models are used to evaluate performance and a Net Present Value analysis used to assess costs. A cost/benefit analysis then enables those areas, or combination of areas, that facilitate the greatest savings to be identified. The modelling work is supported by experience gained from the following: (1) field study of the Lundy Island wind/diesel system. (2) laboratory testing of a small diesel generator set. (3) study of a diesel based CUP unit. (4) study of a diesel based direct load control system. (5) statistical analysis of data obtained from the long-term monitoring of a large number of individual household's electricity consumption. Rather than consider the consumer's electrical demand in isolation, a more flexible approach is adopted, with consumer demand being regarded as the sum of primarily two components: a small, electricity demand for essential services and a large, reschedulable demand for heating/cooling. The results of the study indicate that: (1) operating a diesel set in a CUP mode is the best strategy for both financial and fuel savings. A simple retrofit enables overall conversion efficiencies to be increased from 25% to 60%, or greater, at little cost. (2) wind turbine generation in association with direct load control is a most effective combination. (3) A combination of both the above areas enables greatest overall financial savings, in favourable winds resulting in unit energy costs around 20% of those of diesel only operation.

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This paper focusses on the economic and socio-political preconditions and implications of low energy scenarios (LES) in the UK. It can be considered in two parts. The first section develops a generalised methodology for classifying and assessing alternative energy scenarios. Three scenario archetypes are identified: the conservation scenario; the renewable scenario; and the post-materialist scenario. The second part involves an examination of the various illustrative scenarios which have been advocated by the so-called low energy groups. In addition, since an assessment only has meaning if it allows for a comparison of a whole range of scenarios, a reference scenario (RES) has also been included. All these scenarios are subject to considerable uncertainties. These risks can be categorized as techno-economic, macro-economic, and socio-political uncertainties. LES in general are shown to have a greater techno-economic risk of failure than the RES since they incorporate a larger contribution from 'untried' energy supply and utilisation technologies. More importantly however, both the RES and LES would encounter the most serious obstacles in the socio-political spectrum. Since all LES embody a 'conservation scenario' they would be faced with a serious problem of providing an adequate incentive (whether carrot or whip) to ensure necessary take up of investments. This rests upon the assumption that individuals are myopic. A second fundamental socio-political risk concerns the acceptability of the energy supply facilities. In particular the expansion programmes for nuclear, synfuel and coal developments in the RES are not expected to be socially acceptable. On a less serious scale the 'renewable' LES would encounter obstacles in deploying wind, wave, solar and biomass technologies. With no evidence to suggest the development of post-materialist values the post-materialist scenarios must be considered the most implausible of all the scenarios.

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This Ph.D thesis describes an investigation into the operation of the Blue Circle Cauldon Works precalciner vessel. The vessel is part of the cement making plant and it serves the purpose of providing a furnace that is maintained at approximately 900C to calcine the limestone in the raw meal prior to cementation in the kiln. At Cauldon, tyre chips are used as a support fuel. It was the aim of this work to predict the likely behaviour of the gases and particles in the precalciner by using Computational Fluid Dynamics modelling. The commercial code Fluent was used. Investigation of the likely trajectories and combustion behaviour of tyre chips was particularly important. In this way it was hoped that a method of assessing the suitability of alternative waste fuels for incineration in the precalciner might be established. CFD models were constructed that simulated the precalciner with all main reactions and energy exchanges occurring. The first model predicted the behaviour of the precalciner burning coal and the full load of raw meal. Subsequent models assessed the sensitivity of the first model to changes in the boundary conditions. Further models were developed together with experimental work to assess the combustion and aerodynamic behaviour of the tyre chips. Alternative injection points for the tyre chips were investigated. This type of precalciner had not previously been modelled elsewhere. Similar models were found for the operation of the precalciner without tyre chips but the geometrical accuracy of the models was improved in this work due to improvements in commercial CFD code. No similar study of tyre chip combustion has been made elsewhere. CFD was used successfully to model a precalciner vessel with tyre chip and coal combustion and the full raw meal loading simulated. Adjustments can be made quickly to the model to assess minor geometrical alterations. Alternative fuel injection points can be quickly assessed using the model.