Viability of a Hybrid Power System at the Oroville Dam
Mike Ryan, Social Sciences-Law and Society, Michigan Technological University
Summary
What is the viability of changing the power generation system of Oroville Dam from hydroelectric power to a hybrid power system?
In February 2017, the Oroville Dam, located near the town of Oroville in the greater Sacramento Area, experienced massive damage to its main spillway due to flooding. Lake Oroville, California’s second largest man-made lake, flooded in early 2017. This flooding caused the water level near the Dam to rise to critical levels. The Dam’s main spillway is designed to control the lake level, but it had experienced damage in early February. As it was the only means for water level control, the main spillway was still used despite its damage. When the main spillway became too damaged for continued use, the lake level rose over the concrete weir (barrier to control flow) of the emergency spillway, causing further erosion damage. Hundreds of thousands of people who live downstream from the Feather River, which Lake Oroville feeds into, were evacuated as a precaution.
The Oroville Dam is the United States’ tallest earth-fill dam, and provides many citizens in the Sacramento Area with electricity and drinking water. Due to the damage to the Dam’s spillways, many are questioning the Dam’s integrity. If erosion continues, the entire Dam could fail, displacing, injuring, or killing millions downstream. One way to solve this potential danger is to reduce the water level of Lake Oroville and transfer the energy production to another system. Policy makers in California need to seriously consider the possibility of alternatives to the Dam in terms of hydroelectric power.
Recommendations
The Oroville Dam was installed with a capacity for generation of 815 Megawatts (MW). This large capacity makes the Dam one of the largest hydroelectric dams for generation in the U.S. However, it is possible to generate that amount of electricity from another system. The recommendation that policy makers should consider is to replace the Oroville Dam’s power generation with a Hybrid Power System (HPS). HPSs use a combination of wind turbines and solar panels to produce electricity, as well as fuel cells to store energy. A HPS would allow for distributed generation for the Sacramento Area residents who receive their power from the Oroville Dam, as well as strengthen power continuity. The specific recommendation that this policy brief makes is to install one (or multiple) micro-grid system(s), which alter a standard HPS to include backup diesel generators to assure continuous power.
Introduction
The Oroville Dam was part of the California State Water Project (SWP). Construction began in 1961 and the Dam officially came online in 1968. Located along the Feather River, the Dam is used for hydroelectric power generation and flood control, and water is diverted into the California Aqueduct for consumptive use. It is the tallest dam in the U.S. at 770 feet and provides electricity and water for hundreds of thousands in the Sacramento Area in California’s Central Valley.
In early February 2017, the Dam’s main and emergency spillways were severely damaged after Lake Oroville’s water level reached critical mass. Hundreds of thousands downstream from the Dam were evacuated to prevent further disaster. Due to the damage at the Dam, its viability has come into question.
The Oroville Dam has an installed generation capacity of roughly 800 MW. This means that many in the Sacramento Area depend on the Dam for their electricity. This does not mean, however, that hydroelectric power is the only option for those residents. There are various alternative renewable sources for energy that can provide power at a similar cost and efficiency.
Background
California has had a long history of water management. The United States Bureau of Reclamation (USBR) authorized the Central Valley Project (CVP) in 1933, a project designed to reroute water for irrigation in the San Joaquin Valley. The CVP system has a hydroelectric capacity of 2,000 Megawatts. The California State Water Project (usually known as the State Water Project, SWP) was authorized in 1959 by the Burns-Porter Act and began in 1960. The SWP has a hydroelectric capacity of almost 3,000 MW. The Oroville Dam was the main proponent of the SWP, as well as the construction of the California Aqueduct and various other dams, canals, and channels throughout the state.
The Oroville Dam officially came online in 1968, and began producing electricity shortly after. The Dam was operational from 1968 to 2005 without issue. In 2005, several groups filed motions with the Federal Energy Regulatory Commission (FERC) claiming that the earthen emergency spillway did not meet modern safety standards. Concerns with the cost of making modifications to the structure, FERC dismissed the concerns, saying that erosion in the event of flooding was acceptable. In 2013, the DWR found cracks in the main spillway, and in 2015 the Division of Safety of Dams inspected the spillway, but found no problems. In February 2017, the main and emergency spillways experienced massive damage after flooding. The damage has yet to be fully assessed by the DWR or any other agency. Early cost estimates for repair range from $200–300 Million.
Context
When the California Department of Water Resources (DWP) began the Oroville Dam project in 1960, hydroelectric power was the only truly competitive source of renewable energy compared to coal and natural gas. With an installed capacity of just over 800 MW, the Dam produces a massive amount of energy. Granted, the Dam itself uses a good portion of that energy to operate. It is a favorable alternative to coal or natural gas power, but it is not without its limitations.
The Oroville Dam produces electricity through the Hyatt Powerplant, located within the Dam. As mentioned, the Plant was installed with a capacity of around 800 MW. When needed, water is pumped from the reservoir through the Dam, which turns a turbine that converts the mechanical energy of the flow of water to electrical energy that is transported through powerlines. The upside to having a hydroelectric plant is that, so long as there is water in the reservoir, water can be pumped at any time to generate electricity. It gets complicated, however, when that water also needs to be used for irrigation and consumptive use, and the Dam’s additional purpose is flood control.
Alternative renewable energies such as wind and solar power have developed rapidly since 1960. Each technology has had its own respective innovations to make it more competitive and viable as an energy source. Wind turbines have grown bigger, quieter, and more efficient, with large wind farms popping up over much of the Central and Western United States. Solar Photovoltaic (PV) Panels have become standardized for solar energy production, and can be found in both residential and commercial use. However, each energy is not without its own limitations as well. Solar panels cannot work if the sun does not have direct contact with the solar cells within the panel. In places where the angle of the sun is low, or sunlight is limited throughout the day, solar panels are less effective. Comparatively, wind turbines can only operate within a range of wind speeds. If there is too little or too much wind, power will not be generated.
California has seen a proliferation of solar and wind power since Oroville Dam’s installation. According to estimates by the California Energy Commission (CEC), in 2016 Solar PV and Wind accounted for 23% and 39% (62% total), respectively, of generation from renewable facilities in California. Hydro power only accounted for 4%. In addition, the CEC estimated a capacity for Solar PV of 13,000 MW and 6,000 MW for Wind. For comparison, hydro power was estimated at only 1,800 MW.
Alternative Hypotheses
The Oroville Dam is immense, and was one of the USBR’s most ambitious projects. With that ambition comes potential drawbacks. The Dam operated without fault from 1968 to 2017. That’s almost 50 years of controlling floods and providing electricity. Unfortunately, with a project as big as Oroville, when something does go wrong, it’s bound to be big. It was simply a matter of time before something like the spillway disaster happened. Some would say that it is now just a matter of picking up the pieces; it is not time to let this Dam be forgotten or substituted for the next-best-alternative.
Cleanup and repair of the Dam is currently estimated at between $200–300 million. This number is high, of course, but not as high as the initial costs to build the dam, some part of the $1.75 billion initially allocated in the Burns-Porter Act for the SWP. The high cost of repair would not include improvements to the dam’s structure, but no official plan for repair has been released. Some would say, however, that it is necessary to repair the dam back to full capacity in order to maintain the integrity of California’s water management system.
Policy Alternatives
While the Dam cannot remain in the current state of disrepair it is in, it also cannot continue to operate prior to the spillway failure. With the threat of floods continuing, the Dam cannot be allowed to reach max capacity again. There are multiple possibilities for policy makers to consider, and none of them should be taken lightly. This is a situation that needs a definitive and concrete answer to prevent further disaster in the future. This brief offers three solutions to this problem, each of which have their own pros and cons.
First, repair the dam, raise the embankment on the dam itself, and raise the concrete wall on the weir of the emergency spillway. This would be expensive, as discussed before, but would prevent the possibility of further disaster when finished. Raising the embankment and weir would allow the dam to continue to operate at capacity, but the danger of another spillway failure would be lessened. This solution would not, however, prevent from further disaster should the lake level rise to the top of the modified levels, but it would be the easiest.
Second, replace the power generation of the Hyatt Powerplant with either a solar PV array or wind farm. These two types of technologies are proven in efficiency, and the cost estimates are becoming more reasonable as the cost of materials and installation fall. In 2013, the Levelized Cost of Energy (LCOE) — which is calculated as dollars per Megawatt hour — for wind and solar were $32–77 and $43–60, respectively. For comparison, Coal was between $65 and $150. Again, however, wind and solar are both limited by how windy or sunny it is in the locations that you place them. Intermittent power is a possibility with both of these systems.
Third, repair the Dam enough to reduce the capacity by 50% and mitigate the power loss with a Hybrid Power System (HPS). A HPS is a system that combines solar and wind power to generate electricity continuously. In some cases, a HPS can also combine fuel cells with solar and wind to allow power storage when electricity isn’t being generated. This is a relatively new concept, and implementation of HPSs have not been widespread. The preliminary research is promising, however, and a HPS could prove to be just what the Oroville Dam situation needs.
Policy Recommendations
The recommendation of this brief is for California Policy makers to implement several micro-grid Hybrid Power Systems. This would reduce the load on the Oroville Dam and prevent future disaster. A micro-grid HPS is similar to a standard HPS, using a combination of solar and wind, but also uses hydrogen fuel cells and a backup diesel generator to assure continuous distributed generation. As mentioned in the CEC report, it is Governor Brown Jr.’s vision to see 12,000 MW of renewable distributed generation by 2020. The CEC defines distributed generation as a facility producing less than 20 MW for the market. Micro-grids would be a perfect solution to both the Oroville Dam problem and the renewable energy initiative.
With the costs of construction and implementation of a micro-grid system to substitute energy production at Oroville Dam taken into consideration, this project would be ambitious, to say the least. But action is needed to solve this problem. Total disaster was avoided with the February 2017 spillway damage, but the next time might be more costly. Many people may get hurt or die. Policy makers need to realize that hydroelectric is not making a comeback, but other alternatives exist. An HPS is affordable and ecologically more sound than hydroelectric or fossil fuels. Of course, the cost of implementation would be expensive, but compared to the multi-billion dollar projects of the 1950s and 1960s, it would be a small price to pay for a safer, greener future.
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