Hydroelectric Power: Run-of-the-River Projects

This article relates to The Wallcreeper

The Wallcreeper shows how complicated even seemingly benign environmental projects can be.

For example, the hydroelectric projects discussed in The Wallcreeper are what are known as run-of-the-river. They are smaller and carried out without the creation of dams. ROR stations are seemingly benign and widely perceived as less environmentally damaging than their larger cousins such as the Three Gorges Dam project in China where entire communities were displaced.

Like any hydroelectric power station, the ROR model also works by channeling the force of flowing water to create electricity. While the principle can be used on any river, it is obvious that for the largest amount of power to be generated, one needs both volume and height. Here's how an ROR plant works: water is diverted from a fast-flowing river to a holding station called a weir that is at a certain height way above the generating power plant. The water then flows down, following the principle of gravity, through a pipe called the penstock and made to work turbines, which then generates electricity. The water is finally released back to the river.

It should be noted that while the ROR model might be smaller than large dam projects, they're still intrusive and not without their downsides. For example, the alteration of water flow by diversion does cause significant changes to the river's ecosystem. Water temperature, depth and vegetation can all morph in different ways affecting fish populations. Also, while large dams might not be needed for ROR, a supporting infrastructure to create power stations and access roads, is required. These projects also don't produce as much power as their larger brethren - the difference of output between the two can often be described in terms of orders of magnitude.

A video that shows how run-of-the-river works:

Panorama of the Three Gorges Dam, courtesy of Shizhao
Diagram of a run-of-the-river project, courtesy of cleantechinvestor.com
Hydroelectric power at the Robert Moses Generating facility at Niagra Falls, courtesy of Dickbauch

Filed under Medicine, Science and Tech

This article relates to The Wallcreeper. It first ran in the October 15, 2014 issue of BookBrowse Recommends.

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