This paper is an overview of a program that is in the final stages of developing a modular set of cost-effective microhydro schemes for site heads below those currently serviced by Pelton Wheels. The rationale has been that there is a multitude of viable low-head sites in isolated areas where microhydro is a realistic energy option, and where conventional economics are not appropriate, especially in Third World countries. The goals of this project have been to provide low-cost, soundly based turbine design solutions that systematically cover the 0.2-20 kW supply, that are uniquely resistant to debris blockage and are easily built by tradesmen of medium skills in regional workshops. The paper presents the results as a matrix of the most cost-effective penstocks matched to modular turbines using established electronic controls. It discusses practical issues of site selection and options for sites where exact matches are not achieved. It has been an object of the program to establish a benchmark for cost-effectiveness in the microhydro field. (C) 2007 Elsevier Ltd. All rights reserved.