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Concentration of CO2 in the Atmosphere

I Have a Stream: Conduit-Based Micro-Hydro

In this microhydro system, water is diverted into a penstock. Conduit-based systems use pipes that are already serving other purposes like irrigation or wastewater. Credit: U.S. Department of Energy

In this microhydro system, water is diverted into a penstock. Conduit-based systems use pipes that are already serving other purposes like irrigation or wastewater. Credit: U.S. Department of Energy

by Russell King

The classic picture of hydropower is that of a large concrete dam that spans the breadth of a river, providing water and electricity to thousands, if not millions. Hydroelectric dams are not merely physically big, however; their size manifests in two other ways as well. First, hydroelectric dams have a proportionally large environmental impact. Aside from the aesthetic harm of forever changing a river formally untouched by humans, the river ecology suffers. Whole valleys are flooded to provide reservoirs, destroying the riparian habitat. Water temperature changes, and downstream ecosystems do not receive the debris and sediment they need. Perhaps most importantly, fish cannot travel upstream to spawn, even with fish ladders. Second, large-scale hydropower comes with a correspondingly large set of regulatory and cost hurdles, which places it out of the hands of most. Licensing or exempting a hydroelectric dam through FERC with a capacity exceeding 10 MW can take years and requires technical expertise that is unavailable to the average citizen. NEPA is usually triggered, further extending the licensing period. And then there is the threat of litigation should a party object to what the developer is doing to the river. Simply put, everything about classic hydropower is big: with big dams, big impacts, big costs, and lots of regulation.

Yet there is another way – conduit-based micro-hydro. In 2013, Congress recognized that the licensing process for big hydro did not scale down, disincentivising any smaller projects. The regulation existed for a reason – large hydropower has large impacts. But small-hydro and micro-hydro have small and micro impacts, respectively. So Congress passed the Hydropower Regulatory Efficiency Act (HREA), which created several new programs to make the licensing or exemption process for small-scale hydropower more approachable. Amongst these programs is the qualified conduit hydropower facility program, which completely removes the need for a license or exemption from FERC. Finally, the power of moving water is back in the hands of the average citizen.

So what is a qualified conduit hydropower facility? These facilities must meet a few requirements. First, installed capacity must be less than 5 MW. Frequently, the capacity is less than 200 kW (which is small-hydro); systems as low as 2 kW to 10 kW (which is micro-hydro) make up a significant portion of these facilities. Second, the generator must be part of a conduit, which is any artificial conveyance of water, such as a ditch or a pipe. Third, that conduit must be primarily for agricultural, industrial, or municipal uses. On the ground, these are simple generators attached to already flowing water. They are irrigation conduits in Colorado. They are municipal wastewater pipes in Alaska. They are drinking water channels on farms in Vermont. They are, above all, hydropower for the little guys.

Unlike large hydropower, the environmental impact of these conduit facilities is limited. Firstly, they do not use a natural waterway, so there are no flooded rivers and stranded fish. Secondly, they use water that will be used anyway. Irrigation is the most common, but drinking water and wastewater are used, too. While watering crops, one might as well generate electricity. In the case of wastewater, micro-hydro turns a negative – polluted water headed for treatment – into power for a home or town, a positive. Essentially, the environmental impact is limited to that of the conduit itself, which is usually minimal.

The regulatory hurdles are just as limited, too. If the three requirements are met, the applicant sends in a notice of intent to FERC. Their user-friendly template can be found on their website. After a fifteen-day initial phase and a forty-five day comment period, FERC determines whether the facility qualifies. As the requirements are easy to meet, very few facilities are rejected. Once qualified, FERC no longer plays a role – once the applicant complies with any state laws, they’re free to generate hydropower. Gone are the mountains of work, environmental reports, and expert information. What is left is an easy-to-use application, accessible to just about anyone.

Micro-hydro is just that: micro. With it comes a micro environmental impact and a micro regulatory regime. What is not micro, however, is conduit-based hydropower’s promise: providing clean, low-impact energy using water for another purpose, all while being in reach of the average citizen. To be sure, residential users may not be able to use it (so it will not replace solar panels), but for New England’s farms, towns, and industry, the promise of green power is as far away as the nearest pipe.

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