WF-10-15 Waterfall Turbine FAQ
1. Please provide a high level description of your technology.
Our waterfall product is a cross-flow runner hydrokinetic turbine that can produce clean, reliable hydropower in industrial outfalls with highly variable flows. The self-contained units can be installed individually, or along the breadth of appropriate sites to increase total power. The non-fouling turbine features a self-clearing rotor and has been designed to be lowered into waterfalls without significantly impacting plant operation – installation within hours, and energy production within minutes. As the turbine is wholly contained within a manmade water channel, the permitting and engineering burdens are relatively light, making this an attractive and cost-effective distributed renewable energy generation technology.
2. What type of site would be most attractive for a pilot project using your technology?
The most attractive site would be a minimum 6 foot vertical drop in a waste water treatment plant that has minimum average flows of 5 million gallons per day, ideally with a weir or similar structure in place. While vertical drops are preferred, the turbine design can accommodate angled outfalls of up to 45 degrees. There are thousands of such sites throughout the United States, often found near chlorine contact tanks.
1. What is your nameplate? What is the velocity associated with this nameplate?
The nameplate for our waterfall turbine is 15 kW, achievable at 10 MGD with a 16 foot drop. We are developing a smaller version optimized for lower flows based upon our existing scale prototype. The nameplate on that unit would be 3-4 kW.
2. What velocity will make the system feasible?
Our 15kW nameplate turbine will not function at flows lower than 2.5 MGD; it operates with maximal efficiency at flows between 5-10 MGD. Flows greater than 10 MGD are not captured by the turbine and simply flow through the outfall as designed. Depending on site dimensions, greater flows may be captured by installing additional turbines.
3. What is the water depth required for generation? Will the turbine be damaged if not achieved?
The turbines need a minimum drop of six feet; higher drops increase power potential while lower drops don’t produce enough power to be economically feasible.
4. Hydraulic analyses of the impact of a string of turbines in the system?
The products are designed to deploy singly or en masse with no affect on plant operations.
5. Generator type and electrical output format
We use a variable speed permanent magnet generator. The turbine produces three-phase wild AC. To connect to the grid, one would rectify power output to DC and then invert it to AC for grid power as appropriate.
6. Interconnection: distribution or transmission system? What about micro-electric grids?
The system can be connected to an electrical grid using inverters that are standard for distributed renewable generation technology, such as those available for solar or wind. Due to the relatively small amounts of power produced, the system is optimized for “behind the meter” connections to the distribution grid. We don’t have any issues with micro-electric grids.
7. How is the turbine installed and anchored?
In most sites, the turbine “drops on” to the outfall structure. The system features a best-in-industry anchoring system that can be deployed in hours and with no permanent modifications required. In some sites, however, there is no weir upon which the turbine can be installed, and so the system will instead bolt onto existing concrete structures.
8. How does the turbine deal with debris?
Waste water treatment plants are highly regulated with no debris; this will not be a problem. Should the turbine be deployed in canals, off check structures, it is easy to install a debris screen in advance of the drop.
9. Operations and maintenance?
The turbine is easily lowered in by a simple gantry crane in as little as 90 minutes; it can quickly be removed using the same commonly available equipment. Hydrovolts anticipates annual maintenance to be completed by either plant engineers or a qualified third party, and has designed the turbine to be straightforward and include items such as tightening bearings and ensuring the speed increasers work correctly. Otherwise, operational needs are minimal: simply lower the turbine into a drop and watch it generate power.
10. Does your equipment have remote communications available to send alarms if the equipment is not working correctly?
All products come equipped with standard remote SCADA systems that can communicate distress.
11. What is the anticipated mean time between failures? Is there a typical failure mode that is expected?
We have built the product for a 20 year lifetime, and anticipate some parts getting switched out every five years as part of routine maintenance. With the exception of the penstock and the rotor, most parts are off-the-shelf and easily replaceable should a failure occur. The damage to power production wholly depends on which component was to fail.
1. How much does a turbine cost?
We have priced the waterfall turbines to be extremely competitive with both other renewable resources and, on a lifetime basis, with traditional power sources. Please contact us directly to learn more.
2. What is the anticipated annual capacity factor? Is this capacity factor based on estimated or measured performance of your system? How do you anticipate generation changing on a seasonal basis?
Our capacity factor is 91.5% – we anticipate there will be low points where the plant may not generate enough water to produce power, as well as requiring a week on average for maintenance. Generation is entirely dependent upon drop (consistent) and water flow (highly variable).
3. What is the anticipated useful life of these facilities?
We design turbines for a 20 year lifetime.
4. What are the typical fixed annual O&M costs on a $/kW-year basis?
The only fixed maintenance costs are a general inspection cleaning and changing the oil, both of which must occur annually. We anticipate an annual cost of approximately $10/nameplate kW for these two services, including labor.
5. What are the typical variable O&M costs on a $/kW-year basis?
We have modeled variable maintenance costs to be less than $200/kW/year, by looking at the anticipated lifespan of each component and factoring in the cost of both the part and labor for its repair.
6. How do you expect these costs to change over the next 5, 10, 15 years?
Maintenance costs for existing turbines will not change much. However, they should drop for newer generations as information about how parts endure multi-year trials improves.
7. What is the breakdown between development, permitting and construction time?
Hydrovolts needs an 8-12 week lead time to construct a turbine. All industrial sites we have targeted qualify for a FERC in-conduit exemption, which can take anywhere from 3-12 months. Or, a customer can choose to forego that process entirely and connect to a micro-grid instead. Site preparation and installation can be completed in two days at most.
1. Have you had any consultations with resource management agencies? If so, what environmental issues have they identified with regard to the deployment or operation of your technology?
Hydrovolts waterfall turbines produce hydrokinetic power and therefore must go through FERC and assorted agencies for either permits or exemptions. However, as waste water treatment plants and other industrial sites are entirely artificial, agency involvement is superficial. No waste water treatment plants have ever reported trouble securing the necessary letters from either agencies or FERC to install energy recovery devices in their plants.
2. Have you had to modify your design or approach in response to agency concerns?
We have never modified our design or approach in response to agency concerns. In fact, our entire business model is predicated on minimizing exposure to environmental and regulatory agencies.
3. Have your performed any environmental testing?
There is no environment or habitat in waste water treatment plants. The turbine does not have any chemical reactions and will not affect water quality.