A bright idea from Lucid Energy, with help from Siemens motors and regenerative drives with natural water flow, will produce 1.1GWh per year or 1100 MWh, enough to power 150 homes in Oregon
The use of regenerative energy has ramped up quickly in American industry due largely to advancements in drives technology. Through various mechanical components, coupled with regenerative drives, energy can be captured or created and used in three ways:
- Stored in batteries for subsequent use
- Redirected immediately to other electrical power requirements
- Fed back to the power company on a contract basis
All this can be done without losing host system performance, mechanical component integrity, or creating safety issues.
Typically, regenerative power is produced by a motor turning during braking or stopping; but what if the motor turned as the result of something other than an electrical power supply? This question was asked and answered by the City of Portland, Oregon’s water bureau, which worked with a local firm—Lucid Energy—to create a unique method of power generation. The renewable energy and smart water management solution they used is Lucid Energy’s patented LucidPipe™ Power System that enables industrial, municipal, and agricultural water facilities to generate clean, reliable, and low-cost energy from gravity-fed water pipeline and stream flow.
The Conduit 3 Hydroelectric Project
For a recent installation under the road at SW 147th Avenue and Powell Boulevard in Portland, Lucid Energy provided their system, which comprises four 42” lift-based turbines spun by the gravity-fed water flow inside the Portland Water Bureau pipeline. These turbines turn four Siemens torque motors as 50kW generators for a 200kW nameplate capacity project. The electricity generated by this system is captured and fed to the Portland General Electric (PGE) grid by four Siemens regenerative drives. In a 20-year power purchase agreement, this project will generate approximately $2 million in renewable energy capacity, to be used for development, installation, and operational maintenance costs.
The project investor, Harbourton Alternative Energy, will share the revenue with the City of Portland and Portland Water Bureau to reduce the cost of water operations. Upon completion of the agreement, Portland Water Bureau has the right to purchase the system and the power produced. Since the pipeline is expected to have a lifespan of more than 50 years, this project represents a mutually beneficial arrangement for both the investor and city.
Reaching Out for Proven Expertise
“For the execution of this project, we reached out to Siemens, in tandem with their solution partner in our area, Applied Motion Systems, who wrote the software for the regenerative operational protocols, connecting the hardware to the grid,” says Lucid Energy’s director of operations, Susan Priddy.
In addition to the drives and motors on this project, Siemens also provided the motion controller, transformers, circuit breakers, and all power supplies. The master control cabinet is installed underground, in close proximity to the pipeline and the four LucidPipe turbines.
How the System Works
Functionally, the water being fed from reservoirs flows downhill to turn the torque motors into generators, which supply power back onto the Siemens Sinamics S120 drive system, which in turn feeds it to the PGE electrical grid. The electricity is generated by the water flow with no other power source. The pipeline performance is unaffected and there is no environmental impact.
The Lucid Energy system has been tested and certified by NSF International to meet the NSF/ANSI Standard 61 for potable water systems. It extracts very little head pressure, typically 1-5 PSI, so the turbine units can be installed in sequence without disrupting the water flow. The system does not require installation in a pressure-transient zone or where extreme differential pressures are necessary.
Lucid Energy developed its patented, lift-based, vertical axis spherical turbine technology at the end of the generator’s flange to maximize the use of the water’s gravitational flow to put work back onto the motor. Units can be installed in pipes with 24” to 96” diameters. For this project, Lucid Energy was able to use standard motor and drive components that typically require external power supply to control the motion of a machine, as part of its LucidPipe power-generation system.
Siemens’ regenerative, active infeed drives efficiently return the energy created back into the supply system, rather than losing it in the form of heat or inertial load losses. The regenerative operation is combined with power quality management, improving the overall operational system efficiency. By virtually eliminating harmonics and optionally providing power factor control to compensate for poor power factor from other loads, active infeed drives offer more stable operation on the load in weak supply systems with voltage and frequency fluctuations and can actually help stabilize the supply system. Motor performance is also improved significantly with active infeed (also called active front end) regenerative drives technology.
Working As Promised
The Conduit 3 Hydroelectric Project system was final tested in February 2015 and is producing power to full expectations today. Based on subsequent performance metrics analyses, Portland Water Bureau is considering additional installations of the LucidPipe system. The project is a model application for successful regenerative energy. The initial system had an added benefit for Portland: it is located entirely underground, protecting the beauty and aesthetics of the Rose City.
To see the Lucid Energy system in action, you can go to www.lucidenergy.com/how-it-works.Have an Inquiry for Siemens about this article? Click Here >>