Most present wind, wave, and tidal energy systems require expensive power conditioning systems that reduce overall efficiency. This new design eliminates power conditioning all, or nearly all, of the time.
Wind, wave, and tidal energy systems can transmit their energy to pumps that send high-pressure fluid to a central power production area. The central power production area can consist of a series of hydraulic generators. The hydraulic generators can be variable displacement generators such that the RPM, and thus the voltage, remains constant, eliminating the need for further power conditioning.
A series of wind blades is attached to a series of radial piston pumps, which pump fluid to a series of axial piston motors attached to generators. As the wind is reduced, the amount of energy is reduced, and the number of active hydraulic generators can be reduced to maintain a nearly constant RPM. If the axial piston motors have variable displacement, an exact RPM can be maintained for all, or nearly all, wind speeds. Analyses have been performed that show over 20% performance improvements with this technique over conventional wind turbines.
This work was done by Jack A. Jones of Caltech for NASA’s Jet Propulsion Laboratory. NPO-48620
This Brief includes a Technical Support Package (TSP).
Wind, Wave, and Tidal Energy Without Power Conditioning
(reference NPO-48620) is currently available for download from the TSP library.
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Overview
The document presents advancements in hydraulic energy transfer systems developed by NASA's Jet Propulsion Laboratory (JPL) and Sunlight Photonics, focusing on wind, wave, and tidal energy technologies. It emphasizes a novel hydraulic wind energy design that offers significant performance and cost advantages over conventional systems. This design eliminates failure-prone gears and centralizes electronics in a ground-level power generating station, enhancing maintenance and efficiency.
Key benefits of the hydraulic energy transfer system include a nearly constant generator RPM, which leads to higher efficiency and a typical efficiency increase of 20%. The levelized cost of energy is also reduced by about 30%, making it competitive with traditional energy sources like coal, especially after accounting for carbon tax rebates. The system utilizes environmentally-friendly, biodegradable vegetable oil, making it suitable for both offshore and onshore wind applications.
The document highlights the potential of various renewable energy sources, noting that the United States could theoretically meet its annual electricity consumption of approximately 4,000 terawatt-hours (TW-Hrs) entirely through wave, tidal, and offshore wind energy. Onshore wind energy has the potential to supply nearly ten times that amount, showcasing the vast opportunities for renewable energy development.
The JPL's hydraulic wind energy design has demonstrated up to a 23% performance improvement in 5 m/sec wind conditions compared to traditional wind turbine systems. This innovative approach is also applicable to tidal energy systems, having passed preliminary laboratory proof-of-performance tests funded by the Department of Energy.
Overall, the document underscores the importance of advancing renewable energy technologies to meet growing energy demands sustainably. It serves as a technical support package under NASA's Commercial Technology Program, aiming to disseminate aerospace-related developments with broader technological, scientific, and commercial applications. The information is intended to encourage further exploration and collaboration in the field of renewable energy, highlighting the potential for significant contributions to energy sustainability and environmental protection.
