Micro Hydro: Volts for a Village in Bhutan

The small Himalayan nation of Bhutan is especially vulnerable to the impact of climate change, facing glacial lake outburst floods and dramatic shifts in rainfall patterns. Bhutan is nearly unique in the world as a carbon neutral nation, due to its limited industrialization and its dependence on carbon-free hydroelectric power.

But it faces great challenges ahead, including sustainability of hydropower, which participants in this summer’s Bhutan Ride for Climate observed firsthand on their bicycle trek through the mountainous terrain. Youth from Bhutan and the United States cycled 300 kilometers across Bhutan, learning about climate change by speaking with farmers, monks, foresters, conservationists, and other citizens of Bhutan.

The ride ended last month in Thimphu, which will host the Climate Summit for a Living Himalayas in November. Students will offer recommendations to political leaders at the summit based on their experiences. Tshewang Wangchuk, who is a National Geographic/Waitt grantee from Bhutan, organized the ride, which was sponsored by UWICE and the Bhutan Foundation.

After a series of pedaling uphill and coasting downhill, Bhutan Ride for Climate bikers veer off the main highway and onto a dirt road that leads to the village of Rukubji. Thick mud stops the bus and the truck, but the bikes and bikers prevail, dodging cows, chickens, and the stares of a few surprised villagers. Finally, the bikes are piled into the yard of a large farmhouse on the right-hand side of the road. This is not where they were supposed to stay for the night, but they are counting on the well-known hospitality of the Bhutanese. The cyclists have stopped here to learn more about a micro hydropower facility that is powering the estimated eighty houses of this village.

Chhimi Dorji, an engineer with the Bhutan Department of Energy, explains how important hydropower is to Bhutan, and this small village. Hydropower currently supplies 99.5 percent of the electricity in Bhutan. There are four large, major hydropower plants; Basochhu, Chhukha, Kurichhu, and Tala, and more than 25 smaller micro hydro projects in Bhutan like Rukubji. All of these projects are designed as “run of the river,” which means the water is diverted into a channel or tunneled toward turbines and a generator, and then back into the river system. The diverted section can go for as little as a hundred yards-like Rukubji-or on for two to three miles, depending on the site and the river. Small “run of the river” systems have minimal environmental impact compared to conventional large dam projects.

Rukubji has been experiencing daily “brownout” issues- voltage dropping below acceptable limits due to overloading- in the mornings and evenings. The stress on the system has been traced to meal times, when the villagers’ start up their electric rice and curry cookers. If the villagers can spread this usage more evenly throughout the day, then the system could provide more reliable electricity to the community.

Nathan Chase, part of a team of Humboldt State University students that have come to Rukubji to address this problem, explains, “Generally a river is very constant. In the middle of the night, it’s the same flow as it is the middle of the day, as it is at 6PM. So this is the challenge that Rukubji is facing, it’s also the challenge that America is facing, it’s a challenge that Bhutan is facing on the large grid as well. When you have a micro hydro that is producing the same amount of electricity every day, you don’t have the ability to turn up the generation to meet this peak demand.” He continues, “Here in Rukubji, they can’t increase output to meet the demand, they only have one river.”

The Humboldt team is attempting to solve the brownout issue by developing a smart grid for the village by using a device called GridShare. Each house now has a LED indicator light to show “green” for the times in which they can freely use the rice cooker and other appliances, or “red” when voltage is dropping and they should avoid using energy-intensive appliances. The beauty of the system is that at all times there is enough electricity for all households to power light bulbs and other low-intensity appliances. The students have distributed posters explaining to villagers that they can work together to spread out demand by using certain appliances later in the morning or evening. The Humboldt State team’s work at Rukubji is sponsored by the U.S. Environmental Protection Agency’s People, Planet and Prosperity Award, which focuses on climate change and sustainable development. During times of low voltage called brownouts, people resort to using firewood for cooking, which is not environment- or health-friendly. The smart grid at Rukubji hopes to curb this unhealthy activity.

For now, the villagers seem happy with the electricity they have, and in typical Bhutanese fashion, the cyclists don’t hear many complaints from them on the brownouts. One villager does express how he worries his children are only interested in moving away, and he’s not sure who will continue the work on his farm.

As far as the impact of climate change on Bhutan’s reliance on hydro power, and this tiny village, Dorji says, “We do take into account that there is climate change happening and one possibility is that it might dry out our water resources.” But for that to happen, he cautions, “for it to dry out, you would first have lots of water coming downstream with all the glaciers melting. We are making every effort to make sure that even such big events such as a big flood, caused by glaciers or a moraine outburst, are taken into account for the design of our future infrastructures. Safety is a high priority to make sure to take care of those surprises in the future.”