Developing performance-based design for foundation systems of WIND turbines in AFRICA (WindAfrica)

Lead Research Organisation: Durham University
Department Name: Engineering

Abstract

Africa is facing the challenge of generating more power to meet existing and future demand. Currently, about one-half Africa's total population is lacking access to electricity. However, the continent is well endowed with renewable energy resources; it is estimated that about 35% of the world resources for wind energy are located in the continent. There are many challenges which hinder the development of infrastructure for wind energy in Africa. Designing suitable foundations to sustain the loads typically applied by wind turbines represents a particular challenge. Most potential locations for wind turbines in Africa are in tropical zones where fluctuation in ground water level is severe. The cycling of water levels means that many deposits of interest are unsaturated for at least part of the year. Unsaturated soils exhibit complex mechanical behaviour, coupled to changes in water content. This research aims to provide design for the foundations of wind turbines in unsaturated soils.

Planned Impact

Africa has seen rapid economic growth in the last two decades, with a corresponding increase in the demand for energy. Generating more power to meet existing and future demand, is at the top of the agenda for policy makers in many African countries. The supply of electricity lags the demand in 30 African countries and there are about 600 million people in Africa who have no access to electricity. Three quarters of the population in East Africa, about half of the people in West Africa and most of those in Southern Africa lack access to electricity (although only 15% in South Africa lack electricity access). However, the continent is well endowed with renewable energy resources; it is estimated that 55% of the world's potential renewable energy sources are located in the African continent and about 35% of the world resources for wind energy. The theoretical potential for wind in Africa therefore exceeds current demand by orders of magnitude. A key challenge in Africa is to design economically viable foundations of wind turbines in unsaturated expansive soils subjected to drying/ wetting cycles. The timescale for the benefits of this proposal to be realised may be very quick as a consequence of the urgency of the need. This research project will lead to economic, social and environmental impacts as follows:
a) This project will accelerate the development of wind energy in Africa by providing reliable and economical foundation solutions. Many thousands of wind turbines are planned in the next ten years in Africa, so that small improvements in efficiency will result in significant overall savings. These reductions in the cost of foundations will lower the cost of generation and therefore the energy prices for consumers.
b) Half of all energy use in Africa involves traditional biomass consumption, which entails health risks due to smoke inhalation and social disparities in wood collection. Deployment of wind energy is not only beneficial for the economy, it will also improve human health, create social benefits and reduce environmental damage.
c) The proposed design guidelines will aid geotechnical engineers to select the most appropriate foundation solution to suit unsaturated expansive soil conditions subject to extreme weather conditions. This impact will not be confined to wind farms; ground movements cause significant damage to buildings and road pavements in Africa.
d) This study will enhance the ability of UK industry to respond to domestic and international needs to evaluate optimal foundation designs in unsaturated soils. It will improve the competitiveness of the UK companies in the African market of renewable energy. The size of the potential market can be judged by reference to the International Renewable Energy Agency (IRENA) Africa 2030 Roadmap which calls for 480 billion USD to be invested in the African renewable energy market by 2030.
e) The project will train young researchers in advanced experimental and computational techniques and will enable them to train the next generation of African and UK geotechnical engineers.

Publications

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Description Africa is facing the challenge of generating more power to meet existing and future demand. At the moment, there are over half a billion people on the continent lacking access to electricity, about one half Africa's total population. However, the continent is well endowed with renewable energy resources; it is estimated that 55% of the world's potential renewable energy sources are located in the African continent and about 35% of the world resources for wind energy. There are many challenges which hinder the development of infrastructure for wind energy in Africa. Designing suitable foundations to sustain the loads typically applied by wind turbines represents a particular challenge in Africa. Site investigations have shown that many areas that have been identified as suitable for wind turbines are underlain with expansive soils. These soils are particularly sensitive to soil moisture changes; as the water content of the soil increases during the wet season, the soil swells causing surface heave. This project aims to develop new design methods for foundations of wind turbines in these types of soil.
Exploitation Route The project recieved interest from several companies who are interested in wind turbine foundations (eg. Bart in USA).
Sectors Energy

 
Description Durham University (HEFCE/GCRF)
Amount £65,342 (GBP)
Organisation Higher Education Funding Council for England 
Sector Public
Country United Kingdom
Start 07/2017 
End 07/2018