What are the benefits of lidar-assisted control in the design of a wind turbine?

This paper explores the potential benefits brought by the integration of lidar-assisted control (LAC) in the design of a wind turbine. The study identifies which design drivers can be relaxed by LAC, as well as by how much these drivers could be reduced before other conditions become the drivers. A generic LAC load-reduction model is defined and used to redesign the rotor and tower of three representative turbines, differing in terms of wind class, size, and power rating. The load reductions enabled by LAC are used to save mass, increase hub height, or extend lifetime. For the first two strategies, results suggest only modest reductions in the levelized cost of energy, with potential benefits essentially limited to the tower of a large offshore machine. On the other hand, lifetime extension appears to be the most effective way of exploiting the effects of LAC.

Radio-Oxidation Ageing of XLPE Containing Different Additives and Filler: Effect on the Gases Emission and Consumption

In the lifetime extension of nuclear power plants (NPPs) context, aging of electric cables has to be very well understood in order to predict their end-of-life and thus to replace them on time. Therefore, evaluation and understanding of the ageing mechanism of the cable insulating material is mandatory under conditions as close as possible of those encountered in NPPs. In this context, different formulated crosslinked polyethylenes (XLPE)—one of the polymers used nowadays to manufacture the insulator layer—have been irradiated under oxidative conditions, at two different dose rates and at different aging doses. Gases emitted and consumed from the irradiated polymers were quantified to identify the primary processes happening in the materials and thus the interactions involved between the different molecules composing the formulated polymers.

On Lifetime Extension of Wind Turbine Drivetrains

The focused shift to reduce carbon emissions by substituting fossil fuels with renewable energy sources, including wind, is increasing. This means that more and more wind turbines are being installed, both onshore and offshore and as this number increases, more and more turbines are reaching their end of designed service life. Extending this designed service life, which is commonly referred to as lifetime extension (LTE), is particularly favoured by owner/operators, due to economic reasons. Whilst there are relatively well-established practices for lifetime extension of structural members or those preserving structural integrity, the electro-mechanical and drivetrain systems are often overlooked. Therefore, this paper reviews lifetime extension assessment practices executed within a variety of industries, such as oil and gas, marine vessels, electrical machines, mechanical rotating equipment and bearings, to determine if any of these practices can be implemented or adapted within the wind industry, particularly on wind turbine drivetrains.

Latrine characteristics and maintenance practices associated with pit latrine lifetime in an informal settlement in Kampala, Uganda

This study assessed latrine characteristics and maintenance practices associated with an extended pit latrine lifetime in an informal settlement in Kampala, Uganda. Data were obtained from 306 respondents on sociodemographic characteristics, their private pit latrine characteristics and latrine lifetime. A modified Poisson regression was used to model the latrine characteristics and maintenance practices associated with the pit latrine lifetime. All analyses were performed using Stata 14 software. Approximately 23.5% of the pit latrines had a lifetime of less than 2 years, and most latrines were reportedly desludged (64.7%) or regularly cleaned for maintenance (27.1%) as a way of extending lifetime. Pit latrine lifetime extension was higher in male-headed households (prevalence ratio (PR) 1.12, 95% confidence interval (CI) 1.00–1.25), households with a smaller number of users (unshared vs shared latrines) (PR 1.15, 95% CI 1.02–1.29) and where desludging of pits was regularly done (PR 1.53, 95% CI 1.17–1.99), while post-primary education level was negatively associated with extended latrine lifetime (PR 0.88, 95% CI 0.77–0.99). Deliberate efforts, including sensitizing communities on desludging and provision of non-shared household sanitary facilities, are needed to improve latrine maintenance and consequently extend latrine lifetime.