Geothermal Energy At The Salton Sea


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This report focuses on geothermal technology and the CalEnergy operations at the Salton Sea, situated near Brawley, California.

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Geothermal Energy At The Salton Sea

  1. 1. Geothermal Energy at the Salton Sea<br />By Jesse Rogers<br />SDSU, Intro to Renewable Energy<br />November, 2009<br />Intro<br />This report focuses on geothermal technology and the CalEnergy operations at the Salton Sea, situated near Brawley, California. CalEnergy generates energy and started geothermal energy generation in 1982. The company is 50% owned by MidAmerican Energy Holdings Company and employs 220 people for 10 generating plants. An attempt to contact CalEnergy’s corporate office in Des Moines, Iowa was made to organize a tour at the Imperial Valley operations. They referred me to Mr. Mark T. Gran, Vice President of Real Estate Assets and Community Relations. Mr. Gran’s previous background in real estate and as a long time member of the Imperial Valley Chamber of Commerce led him to his current position, which he has held for over a year and a half. Coincidentally, a fellow student of SDSU, Jeanie Anderson also contacted Mr. Gran and we decided to carpool out to the desert along with a colleague, Karen Harrington, to see what geothermal energy was all about. We arrived to Mr. Gran’s office on the morning of October 30th located in beautiful downtown Brawley, where he gave us several presentations about the history, technology, and key issues surrounding the plants, in addition to his profound knowledge of the trends of the area. We then drove to the Hoch plant at the rim of the Salton Sea and got a first-hand look at the plant in operation and were able to ask several of the workers questions about their responsibilities and challenges they face daily. The trip was long, but well worth our time and effort. The following sections will reveal the information gained from our tour so that the reader will better understand not only the technology, but also the obstacles that the plants confront to generate energy, as well as other interesting information from our tour at CalEnergy. <br />Geothermal Technology Basics<br />Geothermal energy was first exploited in Larderello, Italy in 1904 and that same plant is still generating energy today. The technology uses thermal energy from reservoirs deep below the earth’s surface. To access these reservoirs, wells must be drilled as far as two miles down. At this depth, a geothermal reservoir is heated by magma or hot molten rock to temperatures that reach up to 700°F. Other visible forms of geothermal energy are hot springs, geysers, fumaroles and volcanoes. Like an artesian well, the hot water and/or steam raises to the surface naturally. While the hot water reaches the surface some of the water changes into steam, which is called a flash. Energy plants where flashing occurs are called flash steam plants and is part of the process at the CalEnergy geothermal operations at the Salton Sea. Other techniques include the dry steam plants that use only steam from the geothermal reservoir. The binary plants are another variety and use geothermal water at temperatures much lower than other techniques. To create a flash a binary plant uses a second liquid with a lower boiling point. Sulfuric acid is used to suspend the particles and brine as they come up with the steam and water to the surface. If these particles are not suspended they can corrode or clog the pipes that channel the steam through the in-take process. The natural pressure of the steam is then forced against a turbine which spins to generate electricity. The steam is in turn, condensed back into water and injected back to the geothermal reservoir, where the water gets reheated again and can be reused. An average of 25% of the water is lost through the process at the CalEnergy plants at the Salton Sea. Each of the CalEnergy plants operates with a staff of 25-30 personnel and additional administrative staff. “The combined capacity of the Imperial Valley plants is approximately 340 net Megawatts – equivalent to the electrical demands of more than 330,000 homes (CalEnergy p.1)”.<br />Capital Investment<br />According to Vince Signorotti, who worked for CalEnergy for over 25 years, “The single greatest obstacle to developing geothermal resources is the extremely high capital cost. When you develop a geothermal power plant, you are going to develop a 30 year supply of fuel by drilling all of your production wells, drilling all of your injection wells connecting those wells to a plant and building the plant, before you generate a single dollar of revenue (Heald p.5).” The Geothermal Energy Association estimates the cost of building a 50-megawatt geothermal power plant at $2,800 per kilowatt, or about $140 million. Mr. Signorotti believes that figure is low and is probably closer to $215 million. Nevertheless, once the plant is up and running the heat from the ground is free and constant.<br />Maintenance and Brine<br />While the cost of operating an up and running plant is relatively low, schedule maintenance is carried out at least once a year, which involves shutting the entire plant down for a week to examine and/or replace faulty components. While maintenance can hinder production, brine that is carried up from the geothermal reservoir can also prove extremely problematic. The brine is made up of primarily Chloride, Sodium and Calcium, but also includes Potassium, Carbon Dioxide, Iron, Manganese, Zinc, Silica and Strontium. Ideally, this brine is kept suspended while it rises to the surface with the help of sulfuric acid. If the brine is not suspended it has the potential to severely damage the intake components. For example, plant Sinclair #1 was taken off line permanently after only two months of operating because of clogged pipes. Given that each of these plants is obligated to a contract to generate energy, an unexpected event that shuts the plant down could cut into the projected amount that the geothermal energy company agrees to supply to the utilities. <br />Water<br />Because the Imperial Valley is situated in the desert, access to water is a very important feature in the economic development of the region. In fact, the Salton Sea, which is located in the Imperial Valley, did not always exist. The history behind the creation of the Salton Sea started in 1901, when the California Development Company made an attempt to dig irrigation canals from the Colorado River to supply the Imperial Valley. To the engineer’s surprise, heavy rains caused the canal system to break and directed nearly all of the rivers flow into the valley. The breach was later repaired, but the incident had already created the present day Salton Sea. <br />The governing body that oversees the water issues in the region is the Imperial Irrigation District (IID). In reaction to the expanding agricultural farms and the potential for additional energy generation facilities, “the IID has an interim plan in place to limit the non-agricultural businesses around the Salton Sea to 3.1 acre feet of water and 2.5 acre feet for agriculture annually (Gran)”. Nevertheless, CalEnergy has not exceeded their limits of water and has not impaired productivity of any of the local farms. <br />Transmission<br />Despite the lucrative opportunities that exist for additional geothermal plants, the issue of expanding the current transmission line poses the greatest obstacle. Currently, the Imperial Valley has a number of projects in the works to develop more geothermal plants, solar thermal plants and wind farms. However, none of these can break ground until an adequate transmission infrastructure is put in place. SDG&E, our local utility company, received approval on the Sunrise Powerlink from the CPUC which would install an approximately 90-mile, 500 kV line from Imperial Valley Substation (in Imperial County, near the City of El Centro) to a new Central East Substation (in central San Diego County, south of the intersection of County Highways S22 and S2). The project has been controversial, because of the possible environmental impact, aesthetics, and also because of the cost and reliability issues. Most residents fear that the power lines will damage important local habitat and the quality of life that drew them to the area. On the other hand, Michael Shames the executive director of the Utility Consumers Action Network in San Diego has filed two lawsuits challenging the project. " We're asking the court to review whether the Public Utilities Commission followed the state law that requires them to consider alternatives, economically-feasible alternatives, to transmission lines," Shames says (Joyce, KPBS). He and other opponents claim alternatives, like rooftop solar, could provide the same electric resource without the environmental degradation they fear from the Sunrise Powerlink. Despite the approved plan, the additional transmission lines have been held up in the courts and have not been constructed. Currently, the geothermal operations are generating 537 MW and have an estimated potential of generating 2300 MW. However, no expansion can take place until the need for more transmission lines is addressed.<br />Environmental impact<br />According to CalEnergy, the impact that their plants have on the natural environment are minimal. As opposed to Coal, Oil and Natural Gas, Geothermal energy generation emits very low levels of Nitrogen Oxides, Carbon Dioxide and Sulfur Dioxide. <br />The plants have had a clean record and have a protocol in place to guarantee that the surrounding areas are protected. The main hazards come from the presence of sulfuric acid at the plant. In the event of an accidental dumping of sulfuric acid the company would extract all affected soil to prevent any toxins from entering the agricultural activities or watershed. <br />Occasionally, large groups of dead fish can be found around the Salton Sea, but this phenomenon is not link to the geothermal activity in the area. Normally, the number of dead fish can reach up to tens of thousands and several times there have been as many as hundreds of thousands of dead fish. The scientific explanation of summer fish die-offs involves the oxygen-depleting from a combination of sun and salt. Salt water carries less oxygen than fresh water; hot water carries less oxygen than cool water. When the Salton Sea’s briny water heats up in summer temperatures that can reach 125°F, fish begin to suffocate and when a summer wind churns up the nutrients, causing algae blooms, sometimes turning an entire end of the lake green within a day. The decaying algae also consume more of the water's oxygen.<br />Close to the geothermal plant lies the Sonny Bono Salton Sea Wildlife Refuge that has coexisted with CalEnergy’s operations since its creation. In the past, there have been a number of dead birds found around the Salton Sea, but these deaths have no connection to the geothermal activity in the area. Some experts say that the dying birds are directly related to the dying fish. Because the Salton Sea is an important stop for migratory birds, it has been suggested that it is all bad timing and the birds have nothing to eat when they arrive. On the other hand, the near extinction of the Brown Pelican has been blamed on pesticides like DDT and dieldrin. DDT causes the pelican eggshells to be overly thin and incapable of supporting the embryo to mature. The high levels of pesticides have been blamed on the agricultural activity in the area. Furthermore, the New River, which passes through Brawley, is the single most polluted river in the United States. The high levels of contamination originate from untreated runoff from Mexico and farm runoff from the local farms in Brawley.<br />Community Relations<br />One of my personal interests prior to our tour was the community relations projects that CalEnergy has had in place. Mr. Gran explained that CalEnergy has participated in a workforce development to include the local community directly with its success. The company is currently helping develop a curriculum at Imperial College and is a regular at the Brawley Union High School Career Day. In addition, the company is a co-sponsor of the Cattle Call Rodeo and several local golf tournaments. <br />Closing<br />I believe that geothermal energy is a bona fide renewable energy. It is much cleaner compared to other traditional forms of energy generation and is 100% domestic. While wind and solar can boast the benefits of distributed energy, geothermal has an annual availability around the clock. Furthermore, due to a high up front capital investment geothermal energy has a high impact on economic development. <br />I have to admit that prior to this class, I did not know a lot about neither geothermal technology nor the extensive development of geothermal energy in close proximity to San Diego. In fact, not many of my friends or family knew about it either. Given their absence in San Diego and Los Angeles, I would hope to see more outreach programs from CalEnergy and other companies waiting to exploit renewable energy around the Salton Sea to inform people about the immense potential to create jobs and cut down on carbon emissions using these resources. With more awareness there could be more public support for not only projects like the Sunrise Powerlink, but also future renewable energy generation in the area. More documentation was request from CalEnergy after our visit to provide details in this report, but that information was never received. <br />Thanks for taking the time to read my project. I really enjoyed this class. Furthermore, I feel fortunate to have learned from your expertise that all of you brought to the discussion board. There are some really intelligent people in this class and I hope that one day we can all be putting our ideas and talent to use in the field of renewable energy.<br />Bibliography<br /><ul><li>CalEnergy, “Just the Facts, Imperial Valley Geothermal Units”, CalEnergy, April. 2009, p.1.
  2. 2. Heald, Patrick, “Geothermal benefits are real, but long range”, Imperial Valley Living, 10 December. 2008, p.5.
  3. 3. Gran, Mark, T., Personal Interview. 30 October. 2009.
  4. 4. Joyce, Ed, “Opponents Of Project Say Approval Battle Far From Over, Sunrise Powerlink Project Faces Legal Challenges”, KPBS news, 13 October. 2009. Web.