ASouth African mining engineer aims to deploy low-cost and locally built hydroelectric generators on three major rivers in the Eastern Cape to generate power for the communities between East London and Port St Johns.

Retired mining engineer and inventor Bryce Pollock describes the hydroelectric system as a loop of buckets on a chain running over sprockets, a similar concept to waterwheels used throughout the ages, which drive generators to produce electricity.

However, compared with other water- wheels, such as the Pelton waterwheels his- torically used to drive pumps to dewater mines, the front of the unit is sealed so that buckets are carried down the sealed front shaft in an unbroken column of water, while a continuously variable transmission system ensures uniform speed and power produced by the generator. The empty buckets travel up the back of the unit.

The run-of-the-river hydroelectric system can also be installed on dam weirs that discharge constant flows to generate electricity cheaply. The bucket-conveyor design enables it to be installed at the angle of the water flow. The system is most effective, however, when the water drops straight down the sealed front shaft.

The system is designed to capture a single column of water from a flowing river, rapid or waterfall at its lowest yearly flow to ensure that electricity is generated throughout the year without impacting on the river system.

“The areas between East London and Port St Johns do not currently have access to cheap or readily available electricity. However, if we install three 5 MW systems on the Kei, Mbashe and Mthatha rivers on the Wild Coast, we can produce cheap electricity for these areas and spur development.”

In the 5 MW design, each of the 30 buckets on a single chain will hold about two tons of water, which means about 30 tons of water will be carried by the 15 buckets inside the water column within the sealed shaft at any given time.

The bucket-conveyor system turns at close to the rate of water flow because the single column of water bears the buckets down at a uniform speed. Therefore, a significant amount of the energy of the flowing water can be harvested using this simple method, he avers.

The 5 MW design, for example, has two bucket conveyors in parallel and the basic design can be modified to suit the width and length of the waterfall, rapid or river.

“The system can be built using local labour and manufacturing capacity. It is a simple system that is easily maintained and can be quickly adapted and deployed in large or small hydroelectric applications. Even if there is only a tiny river or stream flowing past, one could draw energy from that environmental flow to generate cheap electricity,” he concludes.

The bucket-conveyor system is patented under SA patent number 2007/02826. Pollock wants to enter into discussions with potential investors and partners to build and deploy the generators.

Future designs may include storage systems, a reservoir above the sealed shaft to ensure a uniform head of water pressure or energy conversion systems. For example, the hydro- electric systems can produce hydrogen through electrolysis to store energy chemically when the electricity is not used.