Conduit hydroelectricity

Conduit hydroelectricity (also known as conduit hydropower,{{cite book |last1=Vuuren |first1=SJ van |last2=Dijk |first2=M van |last3=Loots |first3=I |last4=Barta |first4=B |last5=Scharfetter |first5=BG |title=Conduit Hydropower Development Guide |publisher=Water Research Commission |isbn=978-1-4312-0550-9 |url=https://www.wrc.org.za/wp-content/uploads/mdocs/TT%20597-14.pdf |access-date=9 March 2025}} and in-pipe hydropower{{cite journal |last1=Saber |first1=Hossein |last2=Mazaheri |first2=Hesam |last3=Ranjbar |first3=Hossein |last4=Moeini-Aghtaie |first4=Moein |last5=Lehtonen |first5=Matti |title=Utilization of in-pipe hydropower renewable energy technology and energy storage systems in mountainous distribution networks |journal=Renewable Energy |date=July 2021 |volume=172 |pages=789–801 |doi=10.1016/j.renene.2021.03.072}}) is a method of using mechanical energy of water as part of the water delivery system through man-made conduits to generate electricity. Generally, the conduits are existing water pipelines such as in public water supply.{{cite web|title=Conduit Projects: Energy Recovery from Public Water Systems|url=http://www.canyonhydro.com/projects/conduit.html|publisher=Canyon Industries, Inc.|accessdate=14 September 2013}} Some definitions expand the definition of conduits to be existing tunnels, canals, or aqueducts that are used primarily for other water delivery purposes than electricity generation.{{cite web|title=Conduit Hydropower|url=http://www.hydro.org/tech-and-policy/technology/conduit/|publisher=National Hydropower Association|accessdate=14 September 2013|archive-url=https://web.archive.org/web/20130927214954/http://www.hydro.org/tech-and-policy/technology/conduit/|archive-date=27 September 2013|url-status=dead}}{{Cite web|url=https://www.hydroreview.com/2017/10/01/capturing-untapped-potential-small-hydro-in-irrigation-canals/|title=Capturing Untapped Potential: Small Hydro in Irrigation Canals|date=2017-10-01|website=Hydro Review|language=en-US|access-date=2019-09-28}}

Historically, electricity generation from water pipelines was rare because the water would have been pumped by other engines in the system prior to the intake of water turbines to generate electricity. The energy generated from the turbines would have been offset by the power used in pumping, canceling out the power generation benefit.{{cite journal|title=St. Louis Municipal Electric Power Plant|journal=Electrical World and Engineer|date=31 May 1902|volume=34|issue=12|page=961|url=https://books.google.com/books?id=OU9EAQAAIAAJ&pg=PA961|accessdate=14 September 2013}} However, there have been renewed interests to apply this method to recover energy when there is a need to reduce pressure in the water supply system that is normally done through pressure reducing valves. The conduit hydroelectricity generation in this case can be done by replacing the pressure reducing valves with small turbines and electrical generators.{{cite journal|title=Recovering energy from an existing conduit|journal=International Water Power & Dam Construction|date=May 2011|issue=306–400X|pages=18–20|url=http://www.canyonhydro.com/news/Dewitt_IWP_Jun2011.pdf|accessdate=14 September 2013}}

Since 2008, there has been considerable technological development in off-the-shelf "“water-to-wire” turbine technologies including reaction, impulse, and hydrokinetic turbines that target the sub 1-MW in-conduit hydroelectric market."{{Cite journal|last1=Sari|first1=Mutiara Ayu|last2=Badruzzaman|first2=Mohammad|last3=Cherchi|first3=Carla|last4=Swindle|first4=Matthew|last5=Ajami|first5=Newsha|last6=Jacangelo|first6=Joseph G.|date=2018-12-15|title=Recent innovations and trends in in-conduit hydropower technologies and their applications in water distribution systems|journal=Journal of Environmental Management|volume=228|pages=416–428|doi=10.1016/j.jenvman.2018.08.078|pmid=30243077|s2cid=52821294|issn=0301-4797}}{{Cite web|url=https://www.ge.com/reports/canal-plus-these-tiny-turbines-can-turn-man-made-waterways-into-miniature-power-plants/|title=Canal Plus: These Tiny Turbines Can Turn Man-Made Waterways Into Power Plants|last=Noon|first=Chris|date=2019-09-05|website=GE Reports|language=en-US|access-date=2019-09-28}}

Portland, Oregon uses conduit generation in its water pipes.{{Cite web|url=https://www.oregon.gov/energy/energy-oregon/Pages/Hydropower.aspx|title=Energy in Oregon - Hydropower|last=|first=|date=2018|website=State of Oregon|archive-url=|archive-date=|access-date=2019-09-28}} The Imperial Irrigation District had plans for 14 new conduit hydropower projects in 2016.{{Cite web|url=https://medium.com/the-hydroelectric/get-to-know-your-hydro-conduit-hydropower-28e290b6a953|title=Get to Know Your Hydro: Conduit Hydropower|last=National Hydropower Association|date=2016-12-13|website=Medium|language=en|archive-url=|archive-date=|access-date=2019-09-28}}

In 2013, the US had "a total of 236 FERC authorized conduit exemption projects."{{Cite web|url=http://cdnassets.hw.net/2e/fd/58ca4ccf465ab32ebb17ebc4c588/hydrop1.pdf|title=In-Conduit Hydropower Project – Phase I Report|last=Allen|first=Gregory S|date=2013|website=Alden Research Laboratory|archive-url=|archive-date=|access-date=2019-09-28}}