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The uptake of renewable energy sources has increased dramatically in recent decades, in response to the contribution to climate change attributed to CO2 emissions from the burning of fossil fuels, the need for governments to maximise the use of domestic energy forms with depleting conventional sources, and to reduce exposure to fuel price volatility. Renewable energy targets set by the European Union have been supported by legislation and economic incentives, and have resulted in a sharp increase in installed wind power capacity in particular. Wind power is seen as a particularly attractive source of renewable energy capacity in the UK due to favourable resources and a competitive cost of energy for onshore sites, with 8.8 GW of capacity currently installed [1]. Constraints from visual and environmental impacts, together with improved wind resources, have led to the acceptance of greater financial costs and the exploitation of offshore sites, with over 5 GW installed to date [1]. Both onshore and offshore, the wind industry now has significant operational experience, with some of the earliest wind farms approaching the end of their design life. Material fatigue is a design critical factor which dictates the safe operational life of wind turbines, but is subjected to numerous areas of uncertainty in the level of environmental loading and structural response, as well as material properties and manufacturing methods. Therefore, a conservative design must be ensured from the outset, which presents the potential for fatigue life extension of installed assets if improved knowledge of their operational experience can be obtained. This thesis details the methodology for a fatigue load assessment of operational offshore wind turbine support structures using measured data, and attempts to quantify areas of loading which contribute to total fatigue damage. The methodologies developed build on existing recommendations for onshore wind turbines to incorporate the additional effects of the offshore environment. Results from measured loading suggest that design fatigue levels can be reduced if operational monitoring is included. Operational experience can allow design conservatism, which is necessary due to uncertainties in structural properties and in levels of stochastic loading, to be more accurately quantified.

Aerosols are an important factor of the Earth climatic system and they play a key role for air quality and public health. Observations of the Oxygen A-Band at 760 nm can provide information on the vertical distribution of aerosols from passive sensors, that can be of great interest for operational monitoring applications with high spatial coverage if the aerosol information is obtained with sufficient precision, accuracy and vertical resolution. To address this issue, retrieval simulations of the aerosol vertical profile retrieval from Oxygen A-Band observations by GOSAT, the upcoming OCO-2 and Sentinel 5-P mission and the proposed CarbonSat mission have been carried out. These simulations suggest that such observations will be useful in the measurement of uplifted aerosols such as volcanic plumes and forest fires. Retrievals from GOSAT were also undertaken that showed promising results in challenging conditions, warranting further study. The Fabry-Perot Etalon spectrometer provides a compact, robust and affordable alternative to grating or Fourier transform spectrometers. Such an instrument was designed and optimised for the measurement of aerosol in the Oxygen A-Band and its performance simulated in comparison to GOSAT, where it competed well despite its low cost. Initial calibrations of the instrument were undertaken and showed promising results in the instrument operation concept. Following on from this simulations were used to study the performance of groundbased observations showing that using and combining a range of viewing angles would contribute significantly to the vertical information content whereas polarisation proved not to be useful except possibly in extreme circumstances.

The aim of this dissertation was to investigate the potential for building ground energy systems (BGESs) in the UK by analysing key country specific attributes. More recently these systems have been presented in the UK as having the ability to reduce carbon emissions in comparison to conventional heating and cooling plant. Due to the essential transition to a low carbon economy, this was the main driver and motivation to conduct the research in this field. An initial distinction was made between closed and open loop systems. The former system type utilises a network of pipes installed in the ground to abstract and reject heat via a circulating fluid. Using existing well technology, open loop systems abstract and discharge groundwater whereby the heat transfer between the ground and building effectively occurs within the building via a heat exchanger. Both technology approaches are relevant in the UK where the temperate climate provides a thermodynamic advantage for heat rejection and abstraction from a building, i.e. to aid cooling and heating respectively. A reversible heat pump unit is commonly used in non-domestic installations to allow the prevailing temperature from the ground side system to be reduced or increased accordingly. The research project was split into three main themes. Firstly, a technology specific spatial review of the geology, hydrogeology and climatic effects throughout the UK was conducted using a GIS software package. Secondly, a design phase analysis concentrated on the impact of climate change by applying different weather files to thermal models, different carbon factor projections for electricity, part load sizing, energy prices and the marginal cost of carbon abatement over the lifetime of the system. Finally, an operational phase analysis concentrated on the actual performance of four existing systems monitored over a 12 month period. Four different case study buildings were used for the design phase analysis, and a different set of four building for the operational phase analysis. Using referenced values for the thermal properties of the geology, the resulting heat exchanger length for vertical closed loop systems is primarily led by the respective heating and cooling loads. For the same building type this varied significantly in the three different UK climate types. Following this the thermal conductivity and starting borehole temperature was also shown to make significant differences. For horizontal closed loop systems the heat exchanger length is again led by the building location. The lead ground related parameter is the saturation of the ground as this is likely to vary considerably from location to location. A high thermal conductivity is not necessarily beneficial as this can increase the alignment with the prevailing air temperature and reduce the thermodynamic advantage. There is limited potential for open loop systems due to availability of productive aquifers. The yield analysis showed very large ranges in yield and hence the peak heating and cooling capacity from a single well. This was true when analysing particular aquifer zones and also when comparing sub regions of different aquifer types. The percentage change in peak heating and cooling capacity and annual demand due to climate change was very significant for all the four buildings analysed. The use of dynamic carbon dioxide projections in comparison to static factors currently stated in government publications also highlighted significant variations in projected carbon dioxide savings for a BGES over a 20 year period. The bivalent energy and economic assessment underlined the difference in marginal utilisation and cost effectiveness by varying the size of the BGES relative to the peak load. As the utilisation reduced the cost effectiveness also reduced. These results were translated through to huge variances in the marginal cost of carbon abatement. The operational monitoring results showed that existing BGESs are not performing according to efficiencies quoted by manufacturers. This sometimes led to marginal or negative carbon reduction and operational cost savings versus conventional plant. The poor performance was linked to the commissioned flow rates through the heat pump, buffer tank sizing, the heating distribution installation, maintenance and servicing frequency, insufficient owner knowledge and part load efficiency of heat pump plant.

This thesis describes work aimed at developing practical methods for determining the best docking locations for an underwater remotely operated vehicle (ROV) when inspecting an offshore platform. ROVs are used extensively in the offshore oil and gas industry to conduct a large variety of intervention tasks such as visual inspection, operational monitoring, equipment installation and operation, debris recovery, and so on. However, they have found only limited use in the more difficult tasks such as the detailed inspection of complex weld geometries. These complex welds are, however, found extensively in the construction of the majority of offshore structures and platforms ('oil rigs'). Furthermore, there is a safety requirement to have them inspected regularly since failure of these welds can potentially lead to catastrophic failure of the structures, the majority of which are manned. A number of specialist ROV systems have been developed that are able to attach onto platform structures and use their manipulators to conduct inspection. However, due to the short reach of the manipulators and the complex geometry of the welds (often encumbered with protruding pipes and other fittings) the success of any inspection is crucially dependent on a good initial choice of ROV docking position. This thesis will describe the problems and current manual planning methods, and then detail the development of two new methods for automated optimisation of docking positions - firstly using neural networks, and secondly using more conventional numerical processing. This thesis will also review related work in the field, such as the development of neural networks and their applications in the general offshore environment and in the control of ROVs and robot manipulator arms, and other approaches to ROV docking. It will further describe the use of the system developed here for planning docking positions on example commercial ROV inspection work programmes.

The monitoring of vegetation resources is of vital importance for Southern African countries because of the dominance of agriculture in the economy. The use of remote sensing techniques in a national or local planning context is particularly adapted to the Southern African conditions because large areas can be covered regularly with minimal requirements for field based infrastructure. Furthermore, relatively low-cost receiving stations have been installed in the meteorological departments and other local institutions, which makes satellite data available in realtime. Real-time acquisition is essential for the operational monitoring of vegetation development and remote sensing plays a significant role in three main areas: • Inventory or mapping of cover types • Monitoring of vegetation conditions relative to the norm • Estimates of biomass In this research operational techniques were developed in each of these areas with the participation and involvement of users. Remote sensing and field survey techniques for inventory and mapping of cover types were adapted and developed from existing experience in the European context to match the requirements in Southern Africa. The need for an unbiased sample of field observations, for the calibration of digital classification of satellite imagery was identified and methodology for its collection demonstrated. Methods developed for the inventory of crop types in Europe were successfully adapted to the African rangeland. The levels of classification accuracy achieved were similar to that obtained in the European context for a classification scheme of equivalent complexity. A Vegetation Productivity Indicator (VPI) was developed for monitoring vegetation conditions based on real-time acquisition of NOAA HRPT imagery from a local receiving station and a historical Normalised Difference Vegetation Index (NDVI) archive. The VPI maps show departure from normal vegetation response using methodology similar to the analysis of extreme events in hydrology, in near real-time. The method was successfully implemented in Zambia to monitor maize production and in Namibia to monitor rangeland. The VPI was significantly correlated with rainfall. The technique was successfully transferred to the Department of Meteorological Services in Botswana where VPI maps are produced routinely and presented to the inter-ministerial drought committee for assessing rangeland conditions. Methodology for rapid biomass assessment was developed using simple physiognomic plant parameters. Field Measurements were taken in four different cover types (grassland, steppe and shrub and tree savanna) and correlated with the NDVI derived from the satellite observations in Etosha National Park, Namibia in near real-time. The pooled regression relationship which was obtained was highly statistically significant. However, the regression model excluding the two savanna types exhibited a higher correlation suggesting that there might be a separate relationship between savanna biomass and NDVI. Biomass maps were produced using the pooled relationship and their potential for operational targeting of areas suitable for prescribed burning was illustrated. Although the methods and techniques in this work were developed using time series of NOAA-AVHRR and the NDVI, they can all be adapted to include data from new sensors systems and other vegetation indices as they become available. Methods demonstrated in this work can be integrated to form a suitable framework for a national vegetation resources monitoring system. This would assist Southern African governments in making decisions related to vegetation resources by providing sound and timely technical advice.