Canal hydropower covers three distinct ways of turning water movement into electricity: conventional low-head turbines at a drop or weir, hydrokinetic turbines that capture energy from current speed alone, and “power canals” (hydel channels) that divert river water to a powerhouse. If you are looking for how to generate free electricity with water using an existing canal, the short answer is that it is rarely free. You need licences, capital and a buyer for the power.
This technology sits at the intersection of hydropower and small-scale renewable generation. It is not a single product but a family of approaches that share one advantage: they use existing water infrastructure rather than requiring new dams.
How it works
Canal-based systems generally fall into two categories based on how they extract energy.
Conventional low-head hydro
Conventional hydro depends on flow (the volume of water) and head (the height it falls). The standard hydraulic power relation is P = water density × gravity × flow × head × efficiency.
Archimedes screws are the most common technology for low heads. According to the consultancy Renewables First, they work efficiently on heads as low as 1 metre but are generally not used below 1.5 metres, mainly for economic reasons. Single screws suit heads up to 8 metres; above that, multiple screws or other turbines are used. The smallest screw is about 1 metre in diameter, passing 250 litres per second. The largest reach 5 metres in diameter, passing about 14.5 cubic metres per second, although practical delivery limits often cap screws at 3 metres. Power output ranges from about 5 kW for the smallest screw to 500 kW for the largest.
The drivetrain includes a gearbox, generator and inverter, with losses totalling about 15%. The design life is 30 years, extendable with overhaul. Because screws turn slowly and have large open passages, they are considered fish-friendly, though a dedicated fish pass is still required where upstream passage is needed. They only need coarse screens with 100–150 mm bar spacing, and they avoid the fine screens, draft tubes and deep concrete associated with Kaplan turbines, which simplifies civil works.
Hydrokinetic turbines
Hydrokinetic turbines need no dam or drop. They sit in the flowing channel and take energy from current speed alone. An example is Emrgy’s module, a U-shaped concrete box resting on the canal bed, anchored by its own weight, holding two rotors. Water flowing faster than about 1 metre per second turns them.
The company says the system does not anchor to or modify existing infrastructure and is removable by crane or forklift. It is modular, so units can be added over time. Unlike solar panels mounted over a canal, which are not hydropower, these turbines sit in the water and generate power from the kinetic energy of the flow.
Real-world examples
Hydrokinetic in canals (USA)
In 2017 Denver Water announced plans to install 10 Emrgy turbines in a section of the 9-mile South Boulder Canal from Gross Dam to Ralston Reservoir, near Golden, Colorado. The cost was about $330,000. Denver Water said each turbine would produce about 80 MWh per year in continuous operation, roughly the annual use of seven average US homes. Data was to be collected with NREL, the Bureau of Reclamation and Colorado School of Mines.
GE reported Emrgy’s output as up to 10 kW in 2019, while an AP report in 2023 cited 5–25 kW per module, with whole installations of 2–10 MW. In the GE example, modules are spaced every 50–100 metres, and 100 modules equal about 1 MW, which GE described as enough to supply nearly 1,000 households. Nicolas Serrie of GE stated in 2019 that above a 70–80% capacity factor, the levelised costs of energy are on a par with solar and wind, though no specific cost figures were given.
Emrgy received $18.4 million in Series A funding in April 2023. The US Department of Energy said in November 2023 that Emrgy had received more than $6 million from DOE offices since 2015 and generates distributed hydropower in four US states and New Zealand. In August 2026, the Arvin-Edison Water Storage District in California filed an exemption notice for temporary, fully removable performance testing of Emrgy “Twin EM3.1” turbines in a concrete-lined canal. The European Patent Office listed Emrgy’s founders as 2026 European Inventor Award finalists; its profile says the company has agreements with 48 water and irrigation districts covering about 19,000 km of canals, a company-supplied figure.
Conventional hydro at canal drops
In the USA, Drop 5 on the South Canal in the Uncompahgre Project (Montrose, Colorado) is rated at 2.4 MW. It has been operating since March 2017 and generated about 8.9 GWh per year, according to data to October 2025. The project used irrigation water already in the canal, with no new diversions.
In India, the Punjab irrigation network includes large hydel channels. The Mukerian Hydel Channel has four powerhouses with a total capacity of 207 MW, commissioned between 1983 and 1989, according to the Central Electricity Authority’s 2021 station list.
The UK angle
UK navigation canals are largely still water held in level pounds between locks, so they offer little usable flow for hydropower. The Canal & River Trust’s hydro programme is on river weirs on its navigations, not on the canals themselves.
Knottingley weir on the River Aire was built by Northern Hydropower with Barn Energy and commissioned in 2017. The Trust said in 2024 that it had generated about 2.8 GWh in the previous year, enough for 700–800 homes, with most of the output going to a nearby flour mill. The turbines are dual Kaplan turbines, 2 metres in diameter. A fish pass was built into the scheme. Reported costs range from £6.5 million to £7.5 million depending on the source.
Linton Lock on the River Ouse uses Archimedes screws commissioned in 2012 and 2017, with a combined output of 380 kW. The second, 5-metre screw is described as the world’s largest Archimedes screw for hydro. Kilnhurst on the River Don has a 260 kW Archimedes screw plant by Barn Energy.
The Trust says the hydro schemes on its network generate around 20 GWh per year, equivalent to about 6,200 homes. In 2024, it said 10 more schemes were fully consented but income from grid export was too low to justify building them.
What the numbers say
Small hydro installed costs vary widely. IRENA reported global costs of USD 1,300–8,000 per kW in 2012. German data cited in Water Power Magazine suggests Archimedes screws cost about USD 8,250–8,730 per kW installed, compared with USD 14,500–15,500 per kW for low-head Kaplan turbines, with payback estimated at 14.5–15.4 years under the article’s assumptions. No current UK cost per kW for low-head hydro is published in the sources used here.
In Great Britain, the Smart Export Guarantee covers hydro installations up to 5 MW, with suppliers setting the export rate. Ofgem’s Year 5 annual report (December 2025) recorded 25 hydro generators among non-solar installations. However, the Canal & River Trust said in 2024 that export income was too low to support new builds.
Performance depends on the technology. For hydrokinetic modules, GE’s 2019 cost comparison hinges on a capacity factor above 70–80%; no independent figures for achieved capacity factors are given. Conventional screws have a design life of 30 years with about 15% drivetrain losses.
Limitations / honest assessment
Canal hydropower is not a silver bullet. It is niche and often unproven at scale.
First, flow is the limiting factor. UK canals are largely still water, and hydrokinetic turbines require flow speeds above about 1 metre per second. Without a drop or weir, many canals cannot support these systems.
Second, costs can be high. While screws are cheaper than Kaplans, the total installed cost remains significant. The Knottingley project cost £6.5–7.5 million, depending on the source, for roughly 2.8 GWh of annual output.
Third, regulation is complex. In England, you need an abstraction licence, an impounding licence, fish pass approval and a flood risk permit, plus planning permission. The Environment Agency usually decides within 4 months, says new upland weirs over 1.5 metres are likely to be rejected and new lowland weirs are unlikely to get permission.
Finally, the technology is still developing. Emrgy’s turbines are being performance-tested in California in 2026, with no results published as of October 2026.
Frequently asked questions
What is a power canal?
A power canal (or hydel channel) diverts river water to a powerhouse or to water-powered industry. Examples include the Dundee Canal in New Jersey and the Mukerian Hydel Channel in Punjab, India.
Can you put a hydro turbine in a canal?
Yes, but it depends on the type. Hydrokinetic turbines like Emrgy’s work in flowing water. Conventional turbines need a drop or weir. UK navigation canals have little flow, so they are not well suited to hydrokinetic systems.
How much power does a canal hydrokinetic turbine produce?
Reported figures vary: GE cited up to 10 kW in 2019, and a 2023 AP report cited 5–25 kW per module. Denver Water expected each of its turbines to produce about 80 MWh per year in continuous operation.
Is canal-top solar the same as canal hydropower?
No. Solar panels on canals, like the 2012 Chandrasan pilot in Gujarat, are photovoltaic systems. They save land and reduce evaporation but do not use water flow for energy. See our guide to solar energy for how they work.
Do I need a licence to generate hydropower from a river or canal in the UK?
Yes. In England you need an abstraction licence if taking more than 20 cubic metres a day, an impounding licence for weirs, fish pass approval, flood risk consent and planning permission. Wales has its own regime through Natural Resources Wales. On Canal & River Trust waterways, you also need the Trust’s agreement.
Which canal supplied hydro-power and water for manufacturing?
The Dundee Canal in New Jersey, built 1858–1861, supplied hydro-power and water for manufacturing in Passaic. It was never used for navigation.