Over the last century wind pumps have been particularly popular in America and Australia to provide water for the agricultural industry. More recently, wind pump technology has been increasingly used in developing countries.
They are quite site-specific, requiring a steady moderate wind to start up and keep turning, so you'll need to monitor and evaluate the site to properly size one.
Wind pumps have a relatively low capital cost and long lifetime (about 25 years). They are good for off-grid sites, as they're entirely mechanical - no need for electricity to run a controllor, for example. However, they do require a 6-monthly service, and the pumping efficiency drops off in high wind speeds.
A wind pump will cost about £3,000 (with complete installation up to £10,000) but is a cost-effective solution for a large scale application - A 3.5 metre diameter rotor operating in a windspeed of 3 metres per second will pump 45,000 litres a day through 5 metres.
For more information, the books How to Build a Wind Pump and Windpumps - a Guide for Development Workers are available from CAT Mail Order.If you need to find a supplier, get in touch and we can send you some contacts.