Costa Rica – Ecological Engineering in the Tropics

MSU / UCR – December 15-29, 2012

Day 6 & 7 – Tilaran – ICE – Alternative Energy – Wind and hydroelectric power engineering

Tilaran – ICE – Alternative Energy – Wind and hydroelectric power engineering – Dimitri

After arriving late in Tilaran, we spent the first of three nights at Guadalupe Hotel. We woke up early to a delicious Costa Rican breakfast. The group saddled up in the minibus and left for the tour of Instituto Costarricense de Electricidad (ICE – pronounced ee-say), Costa Rica Electrical Institution.

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The front of Guadalupe Hotel

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The water inlet for the hydroelectric production at ICE

ICE, built in 1978, is the main energy producer and electrical network for Costa Rica. Their mission is to produce electricity that is environmentally safe and to satisfy the needs of customers along with remaining as Costa Ricas highest producer. This company basis their service on alternative energy resources. ICE is segregated into 4 plants: Arenal, Corobici, Sandillal, Tejona. These plants are not only engineered for green energy but they have to be able to withstand natural disasters such as earthquakes, which can be felt roughly, 20 times a year.

Last year ICE produced 7,178 GWH of Costa Ricas 9,722 GHW demand. Of the energy produced by ICE the  is production of electricity is split as such: 72% hydroelectric, 15% Geothermal, 12% Combustion (only non alternative energy – used as a back up when others are not available), 1% win.

Even though ICE is a leader in alternative energy, production hydroelectric and wind energy present environmental impact. In 1949, ICE became a public business and at this time only 10% of the Costa Rican citizens had access to electricity; now, in 2012, almost 95% of citizens have access. At Arenal, we learned about ways other dam methods of hydroelectric production and with those different types the hydroelectric cycle the worst affects on the environment is during a “clean out,” removal of sediment. In this situation, the reservoir is drained to remove sediment that collects at the inlet, which is flushed down stream causing significant damage. This task happens once every two years and the community must be involved. Since the water levels are lower the community is negatively affected but a positive for the community is the abundance of fish that are unable to escape and easy to catch. On the contrary, the elimination of water causes the wildlife to depreciate . Thus, one method is to capture the fish and restocked after water level is restored. While the water is down, the sediment is flushed from the inlet to undo the restricted flow of tunnels leading to turbines. Ecological engineers constructed a less invasive procedure that eliminates the “clean out” process. Instead, at the inlet a bucket resembling an excavator’s, lowers to tunnel where the sediment settles and removes the debris without having to lower the water level. The option of a no clean out system makes production of hydroelectric energy have less environmental impact factors.

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Inlet of ICE hydroelectric plant where the sediment is removed

The hydroelectric turbine systems used by ICE are referred to as a Francis turbine, this style has a vertical axis and horizontal turbine blades. Water from the Arenal reservoir travels 12 km (about 8 miles) and drops 200 m (about 650 ft) over its duration. Embalse Arenal (artificial lake of Arenal) is the only reservoir that is not dependent on rain fall, it is still able to function during the absence of rain which occurs during the dry season. The reservoir collects rain fall throughtout year and has rivers supplying the 1990 million cubic meter of usable water. This potential energy flow down the tunnels to Arenal were it turns its first phase of turbine, then the returns to regular flow rate and to travel to Corobici and finally to Sandillal, which also has its own reservoir. Embalse Sandillal (artificial lake of Sandillal) uses the Francis turbine but the reservoir is dependent of daily rain fall, the fall back to Sandillal is during the dry season the plant cannot run constantly due to lack of supply. Sandillal is a much smaller reservoir with 5 million cubic meters and the drop of water is 50 meters (about 160 ft). The average flow of both systems is 100 cubic meters per second.

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Statistics of the Arenal Reservoir
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An ICE employee describes the method of sediment removal with the help of a model

We got off the minibus and were welcomed by a beautiful cloudy covered mountain background surrounding the Arenal reservoir. After a group photo we went inside for a lecture about ICE. Like many of the places we have visited, translation was require to communicate with the employees. Then, they showed us a model of the Arenal inlet, that demonstrated the how the water entered the tunnel to the Francis turbines, and then the actual structure. It was intriguing to learn about how green energy manufactures most of the country’s energy. We took a short trip up a mountain to Tejona, the 30 turbine wind farm. We could tell from the excessive wind that Tejona was a great place for a wind farm. Once again, we were engaged with a lecture but this one focused only on Tejona and wind power.

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Allison and Luke at Tejona with the wind farm in the background

The Tejona wind farm is composed of 30 turbine that tower 42 meters (about 135 ft) tall. Each turbine generates roughly 660 kw per hour. When wind speeds range from below 20km/h and above 80 km/h  the blades (each 21 meters in length) have to make adjustments so they are able to still function properly. The generator of each turbine is about 3 tons. After one-quarter of their lifetime, the wind is essential free energy and the initial cost and maintenance has already been covered. Everyday an analysis is ran on each turbine to depict any possible problems. ICE’s wind farm only produces about 1% of the nation’s electricity and has few draws back, the major one being aesthetic appeal.

With lunch time approaching we were taken to La Troja for great food and a great. We spent our time eating and surveying the souvenir shop before we left for a tour and lecture of ICE hydroelectric generation plant in Arenal. The group ventured back to Guadalupe Hotel for an exercise and discussion on carbon footprints. This exercise opened has caused me to slightly alter my normal habits to limit my personal carbon footprint.  For dinner we ate a bar in Tilaran, with some legit American 80’s music. After ordering our meals we had time to burn, so random chatting turned into chanting as an arm wrestling competition took place at the tables (Luke Desmet was crowned champion). While waiting for everyone to pay for their mean, Robbie decide to walk on his hands on the side and this caught the attention of some native teen parkour. We followed them to the nearby park and enjoyed the entertainment. We returned to the hotel for some group bonding and arose early for a trip to beautiful waterfall in La Fortuna. The walk down the stairs was peaceful and when we got to the bottom of the falls we the realization of the waterfall’s majestic beauty and power set in. These moments are encouraging to want to help preserve the ecosystems we live in. Many of the members in group took a nice swim at the bottom of the falls and fought against its current.  The ascent back to the minibus was not as pleasurable as it felt there were ten of thousands of stairs. After the falls, we headed in the town of La Fortuna for some shopping and food. On our way back to the hotel, a small group of people were congregate on the side of the road, as we passed we sawthey were clustered around a sloth (Bradypus pygmaeus). We decided to go back and see the unique animal. The long day ended with another dinner at the same bar as the night before and some more group bonding. I really enjoyed the day and I am glad we made the decision to visit the water. This trip has been an amazing learning experience.

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Matias and me (Dimitri) at La Troja restaurant

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Turbine for Francis System at Arenal Hydroelectric

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Katie and Robbie at the outlet of the Arenal Hydroelectric plant

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Luke and Matias arm wrestling with many people cheering them on

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Waterfall at La Fortuna

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Making our way down to the waterfall

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The sloth (Bradypus pygmaeus) we saw on the side of the road

As we traveled through Costa Rica I did notice a few different wind turbine farms. With much of Costa Rica  having mountain,  I would think wind could be a larger supplier of electricity. From the information presented to the group, wind energy seems as the best ecologically friendly and with a five year payback period it seems to be efficient.

 

Additional Links

References

The information used in this blog was presented to the study abroad group by employees of ICE.

5 thoughts on “Day 6 & 7 – Tilaran – ICE – Alternative Energy – Wind and hydroelectric power engineering

  1. Dmitri, thank you for a great description of this day. Admittedly, I got lost in the technical aspects but am so heartened that you guys understand it!! I loved hearing about the waterfall experience, the arm wrestling and Robbie’s spontaneous hand-walking!!

  2. Thank you for the trudging through the technical aspects, they can be pretty dry. It was fun recapturing our day. Our whole trip has been a wonderful experience and I am so glad I’ve gotten to know you son.

  3. Hey dmitri, awesome blog post. I was just curious as to what you think has the most potential as an energy source for costa rica, wind or hydro power? Hydro is bbeing used the most as of now, but has terrible environmental impacts. What do you think about this?

  4. Even though hydroelectric energy has drastic environmental impacts, it has more potential to as being Costa Rica’s primary source of energy. If the dams were constructed like the one in Arenal than there would be less ecological impact.

  5. Great blog post Dimitri, also about the subject of Wind vs Water remmenber that is dificult to find place with enough wind power to sart the generator.

    This a intereting subject because the ICE has a battle of to asure energy to all the houses of Costa Rica and to protect or lower the impact of all the sources of energy.

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