Projects |
Unlocking distributed hydropower
IWP&DC learns more about InPipe Energy’s scalable solution for pressure recovery in water infrastructure
Above: InPipe Energy’s HydroXS pressure management and energy recovery system
HYDROPOWER ENGINEERS KNOW BETTER than most that water doesn’t just sustain life – it protects and creates grid security. Yet, for all the innovation in turbines, storage, and dam optimization, one massive opportunity remains largely untapped: the enormous amounts of energy embedded in pressurized water pipelines. Gregg Semler, CEO and founder of InPipe Energy, is changing that so utilities can reduce their energy costs and carbon emissions. Since Semler launched InPipe Energy in 2016, he has led the development of the HydroXS, a modular, in-conduit energy recovery system that generates grid-connected electricity by harvesting pressure differentials within water pipelines – without the environmental permitting hurdles associated with traditional hydro. “At a time when the demand for energy is
growing globally and infrastructure is aging, we’ve demonstrated how easy it is to retrofit water pipeline infrastructure to generate a new source of renewable energy,” says Semler. “It has all the benefits of hydroelectricity but it’s from an existing pipeline, so there is no environmental impact.“
A new approach to pressure
Key specs of the HydroXS System
Power capacity: 10 kW to 2 MW
Flow range: 75–2,500 L/s
Operating pressure drop: 1.6 bar
Pipe diameters supported: 5 cm to 2.8 m
Grid connection: Net metering, grid- compliant via standard interconnection
Maintenance: Quarterly, similar to pumps/valves
Cost of energy: $0.05–$0.06/kWh
management At its core, InPipe’s HydroXS technology replaces traditional control valves with a micro-hydro turbine and generator designed to recover energy from pressure drops while maintaining flow regulation. The HydroXS is engineered to replicate the pressure- reducing function of control valves, integrating seamlessly into municipal, industrial, or agricultural pipeline infrastructure. “Control valves in water systems reduce pressure by using a diaphragm or similar mechanism to burn off pressure through friction,” Semler explains. “We see that as wasted potential energy. We designed the HydroXS to precisely take that same pressure drop to spin a micro hydroelectric turbine and generate low- cost electricity – up to 2MW per unit, depending on hydraulic conditions.” The HydroXS is available in seven standard configurations, accommodating pipe diameters from 5cm to 2.8m and flow rates between 75 and 2,500 liters per second, with operating pressure drops of 1.6 bar or more. These ranges make it viable for both high- capacity industrial infrastructure and smaller-scale municipal systems. Each HydroXS unit comprises: A hydro turbine and permanent magnet generator housed in a pressure-rated enclosure An automated flow-control valve engineered to meet the same hydraulic standards as existing pressure regulation equipment
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A smart control system with real-time telemetry on flow, pressure, generation output, and carbon offset A grid-tied power panel that interfaces with utility systems via industry-standard net metering protocols
To minimize any adverse impact, the HydroXS is typically co-located in a bypass with existing valves, allowing for either manual or automated switching between traditional pressure management and power- generating operation. Crucially, InPipe’s systems are designed for minimal civil works. In many cases, they’re retrofitted into existing vaults or installed in compact adjacent chambers, eliminating the need for above-ground infrastructure. This approach not only streamlines permitting but also reduces installation timelines and CAPEX. “From the customer’s perspective, there is no operational impact on their operations,” says Semler. “The HydroXS mimics the impact of a valve only with added economic benefits.”
Performance and reliability With over 10 years of runtime across multiple
U.S. installations, the HydroXS has demonstrated >99% availability and minimal O&M requirements. Maintenance routines mirror those of standard valve and pump systems - quarterly inspections, basic lubrication, and filter changes—allowing utilities to rely on in-house personnel. Case studies from Oregon and Washington illustrate both the reliability and versatility of the system: In Hillsboro, Oregon, a HydroXS unit retrofitted into a municipal pipeline has generated 200,000 kWh annually for over five years with no outages. The energy offsets grid electricity demand from an adjacent sports complex, including EV charging, concessions and lighting systems. In Skagit County, Washington, another installation delivers 104,000 kWh per year, feeding electricity back into the pumping station itself to reduce operational electricity costs from pumping. Each installation is tailored to the hydraulic characteristics of the site – pipe diameter, head pressure, flow variability – and InPipe collaborates closely with operators to optimize energy recovery while maintaining system safety and water quality compliance.
InPipe offers multiple deployment models.
Customers can purchase the system outright or opt for a power purchase agreement (PPA) under which InPipe installs, operates, and maintains the equipment and sells the electricity at a fixed rate over 15–20 years. “This structure is familiar in the solar energy space, but it makes the economics very compelling compared to solar – especially for utilities or municipalities with tight capital budgets,” says Semler. Depending on flow rate and energy prices, payback
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