Our Method
The problem: Under-utilized Clean Energy Resources
There are 80,000 dams in the U.S. and less than 3% generate electricity. Most were built for other purposes: Flood control, navigation, drinking water reservoirs and recreation. Wisconsin alone has over 800 non-powered dams, with several scavenger sites that once operated feed or lumber mill machinery. The high cost of retrofitting these sites with small turbines is a clear barrier to entry.
Cadens’ target market is small low-head hydropower plants. There are currently over 1,700 small hydropower plants in the country providing low-carbon, reliable electricity. A resource assessment indicated the presence of an additional 29 GW of new technical potential across 10,000 sites. However, the DOE modeled the deployment of this potential and predicted 0 GW will be developed by 2050, unless the industry can radically reduce costs. DOE suggested exploring the use of new materials and manufacturing methods as one cost reduction pathway, a pathway Cadens was already investigating. ORNL has also suggested using standardization and modularity as strategies to make small low-head hydropower development affordable.
Our Solution: Initial Cadens S-Turbine Product
Cadens’ initial minimum viable product (MVP) units are micro-to-small hydropower S-turbine systems, with stator vanes, runner, shaft, bearings and seals, curved conveyance including intake and diffuser, as well as a generator located out of the flow path for simplicity in assembly, installation, and maintenance. The system is modular in that several sub-components are manufactured and then assembled to make the final integrated machine: a powertrain plus conveyance system.
The electrical generator hardware will be based on a modular design, so that a minimum number of components can be used to cover the largest possible range of applications. The resulting family of generator sizes will be taken into account in the turbine design in order to get an optimal matched design for best energy output. A critical aspect of the electrical part of the system, however, is the control of the generator over a relatively wide range of flows. Traditionally, generator sets are designed at specific load points where efficiency is maximized. In the present case, efficiency optimization will be done over the expected load cycle of the system, using the same flow data gathered for the turbine design. In this respect, recent advances in wind generator and vehicular control systems will be adapted to water flow scenarios.
Where we are today – Ultra-low Head Micro-Hydropower AM Test Bed:
Cadens’ AM Micro-hydro Test Bed (Figure 3) allows further advancement in the state-of-the-art of the runner and turbine as well as energy conversion methods and system optimization. This test bed is the first and only of its kind, supporting industry in testing system components, materials, and energy conversion/storage regimes. With a first prototype of the system successfully tested in 2020 at its operating mill, Cadens can now move to refining and productionizing this product.
Cadens unique testing capabilities have been at the core of the business development. It is now used to demonstrate the feasibility and affordability of large format additive manufacturing and other AM technologies for small hydro components.
