Avista is partnering with Washington State University and American Governor Company to develop an environmentally biodegradable hydraulic fluid alternative for use in its hydro facilities.
By Steve Wenke
Avista Utilities is an investor-owned utility based in Spokane, Wash., U.S., that has a total company-owned generating capacity of 1,862 MW, which includes 1,029 MW of hydropower, as well as natural gas, coal, biomass and wind. In 2009, we experienced a small uncontrolled oil release at one of our hydroelectric plants. Ice sliding down the face of the dam impinged on a transformer, causing some insulating oil to leak into a nearby waterway.
Any utility that has experienced such an unforeseen incident knows that the aftermath - whether it’s the actual cleanup process or the stakeholder communication - is a difficult period. First and foremost, the environmental impact considerations are paramount. Containing the spill and cleaning up the waterway is the first priority. Equally important, though, is the responsibility to communicate with stakeholders in an honest and open way, to explain how the incident happened and the steps you have taken to remediate it and to avoid such an event from happening again in the future. Overall, the response from an oil leak requires many hours, external response teams, and interactions with agency personnel to resolve.
For more than 125 years, our company has been committed to protecting the environment, so when the 2009 incident occurred we took swift action to report the leak to the responsible agencies, clean up the spill, repair the damaged transformer and enhance our spill containment defenses to prevent such a leak from happening again.
|Biodegradability testing of the bio-hydraulic fluid being developed took place at WSU’s Applied Sciences Laboratory.|
After the cleanup was completed, the Avista engineers involved in the response, including myself, began discussing whether anything could be done to make the oil itself less toxic. “What if we switched to an oil that was nontoxic to native species and people? What if we switched to an oil that was biodegradable, so that even in the unfortunate event of a spill, it would pose no harm to the environment or people?”
Even if it could be done, we knew that finding or developing an oil that fit these requirements would in no way absolve us from our responsibility to devote every effort to prevent leaks from happening in the first place. Avista always strives to go above and beyond the environmental laws and regulations and to conduct business in a way that honors the integrity of the natural resources in the areas we serve. Our goal was to significantly reduce the potential environmental consequences from any future oil spill. Use of an environmentally-friendly oil would not alter Avista’s processes and protocols for responding to a leak, but it could greatly change the impact a leak could have on the waterway and surrounding areas.
We considered transformer oil and realized that the special dielectric properties would present some challenges. It was at this time that we discovered an opportunity to replace petroleum-based oil in our hydro plants: the governor systems.
Investigating the opportunity
Low-pressure hydraulic governor systems - as well as other hydraulic systems in hydropower plants - require a significant quantity of oil: thousands of gallons, in some cases. In this application, the oil is primarily used for hydraulic power transmission and lubrication, not for heat transfer or electrical insulation. The idea of replacing hundreds or even thousands of gallons of petroleum-based oil with biodegradable oil, with no loss in plant performance or durability, had merit to our engineers.
As we began this work, we knew Avista did not have adequate research and development personnel or facilities to move forward on our own. We would need help. So we enlisted the aid of Washington State University’s Applied Sciences Laboratory (WSU ASL) in Spokane to research alternative hydraulic fluids that would reduce the risk to the environment, should an unplanned release of hydraulic fluid occur in one of our hydroelectric stations.
Avista has long worked collaboratively with partners to bring innovative thinking and new solutions to the industry, so partnership with WSU’s ASL was a natural fit. Likewise, WSU’s ASL was built with the goal of collaborating with industry partners to develop solutions to real-world problems. Thus, it was a win-win for our two organizations to pair up.
Scientists with WSU’s ASL provided the project with the needed institutional expertise and focus, as well as the laboratory setting to conduct small-scale testing to refine and adjust the fluid mixture.
Avista and WSU’s ASL initiated the project with three main criteria:
- The fluid properties (viscosity, lubricity, etc.) needed to be highly stable across a wide temperature range.
- The lubricant had to have a long lifespan.
- The fluid had to be inherently biodegradable. Meaning, in the presence of water it begins dissolving and rapidly breaks down into benign components.
Associate Director and Senior Scientist Hergen Eilers at WSU’s ASL put it best when saying, “Making a bio-hydraulic fluid is a difficult thing to do. We are developing a fluid that, when in the equipment, is stable, high-performing, and long-lasting, but if it escapes into water, should break down immediately. These are two very contradictory requirements.”
Even with that challenge, the team marched forward and developed a nontoxic, biodegradable vegetable-oil-based alternative fluid that addresses the deficiencies of the current varieties of vegetable-based products on the market today. These include limited lifetime and reliability due to performance issues in cold weather and breakdown due to heat.
An initial proof test was conducted from early 2014 through the fall of 2016 in a non-critical trashrake system at Avista’s 10-MW Upper Falls hydroelectric project. The plant, which was built in 1922, was chosen as the site for this test because it was conveniently located in downtown Spokane on the Spokane River. WSU’s ASL researchers monitored the trial and tested the new fluid frequently, incorporating additional nontoxic ingredients to address shortcomings that had been an issue for earlier vegetable-based hydraulic fluids. The test results looked promising.
Taking on an industry partner
For the next step, Avista and WSU’s ASL embarked on full-scale testing in a hydraulic governor. We approached American Governor Company (AGC) with a goal of leveraging AGC’s vast governor experience and expertise to help make this project a success. Since 2000, AGC has worked with more than 1,500 hydroelectric plants in over 65 countries and has an installed base of more than 600 digital governors controlling over 30 GW of hydropower capacity. AGC is the primary support company for the governors on more than 200 GW of hydropower, including huge fleets of legacy mechanical governors and large-capacity hydraulic systems, so it seemed a logical fit. The company was not only interested, they were enthusiastic about participating in the R&D process.
“We were excited to join the team and test the new fluid in one of our full-scale governor test stands. American Governor is proud to be in the hydro industry, the oldest form of renewable energy, and we are glad to help wherever we can to minimize or eliminate any environmental risks associated with operating a hydro plant,” said Scott Ginesin, vice president of business development and operations for AGC.
Together, the three partners are taking biodegradable oil testing to the next level. The new fluid, developed during the proof test, is being put through full-scale testing on a governor system powered by a refurbished Woodward 20 series pump. There are thousands of these pump and governor systems still operating at hydroelectric plants worldwide, so it is an excellent choice for a testing platform. The intent of the testing environment is to simulate years’ worth of normal pump and governor operation within a few months.
|The test simulator for the bio-hydraulic fluid is set up at American Governor Company’s facilities.|
“There are other factors to consider aside from the fluid’s basic mechanical properties when testing a governor hydraulic fluid. Seal compatibility, fluid life, and disposability must all be considered in the evaluation process,” said Daniel Berrien, P.E., vice president of engineering at AGC, who is directly involved with the full-scale testing. “Thus far with the first testing period nearing completion, we are experiencing very positive results on all fronts.”
Based on the test results, WSU’s ASL will continue to adjust the additives in the hydraulic fluid to counteract any deficiencies identified. While there is still much testing to complete, we are all happy and encouraged by the results we are seeing. After four months of testing, corresponding to about four years of actual operation, the original properties of the fluid remain within specification.
All three organizations are approaching this project as pure researchers. “Ultimately, this is about preventative measures to protect the environment,” said Ginesin. While it’s too early to say whether this new hydraulic fluid will be applicable across the board, in a wide range of temperatures and humidity environments, AGC thinks there may be great potential for it to be widely adopted by hydro facilities, based on the lack of alternative biodegradable fluids that can withstand this challenging environment.
The impact on U.S. hydropower
Within the utility industry, Avista has a long history of innovation. Since being founded on hydropower as Washington Water Power in 1889, we have been regarded as one of the greenest utilities in the nation, with a power supply mix of more than 50% renewable energy. Avista has spurred new technologies, companies, processes and ways of thinking about energy. While it may be unique for a utility to take on research of this type, for Avista it’s part of our DNA to be innovative and environmentally-conscious.
To truly understand the potential impact a breakthrough technology like this can have, it’s important to remember the breadth of hydroelectricity in the U.S. and the industry’s potential growth, along with the importance of clean water bodies across America for recreational and business use.
According to the National Hydropower Association and the Business Council for Sustainable Energy, hydropower in the U.S. provided a capacity of about 101,000 MW from conventional hydro and pumped storage facilities as of 2014. According to the Energy Information Administration, hydropower accounts for 7% of U.S. electric generation as of 2013, representing 52% of renewable generation that year. And according to the Electric Power Supply Association, that’s enough generating capacity to provide electricity to roughly 75 million to 101 million American homes.
The growth potential for hydropower is immense. NHA notes that the U.S. hydropower industry could install 60,000 MW of new capacity by 2025, all depending on policy decisions. And it’s important to note that this increase accounts for only 15% of the total untapped hydropower resource potential in the U.S., indicating hydropower can remain a growing renewable energy source for many years.
So what does it all mean? It means more hydropower could be developed and installed across the U.S. And, with more hydropower comes more risk for our waterways, unless petroleum-based oils are reduced or eliminated from hydro plant equipment. According to the Clean Water Action Plan, each year Americans take more than 1.8 billion trips to water destinations, largely for recreation and activities like boating, swimming or fishing. Owners and operators of hydroelectric facilities must be able to manage water quality - including the health of all species in all water bodies - while “keeping the lights on” for the rest of us.
If this new biodegradable oil performs as we think it will, its use will, at a minimum, help Avista continue an over one-hundred-year tradition of providing safe, reliable power for our customers while being a good steward of our natural resources.
Steve Wenke is chief generation engineer with Avista Utilities.