Nepal explores tapping flood-risk glacial lakes for clean power

Nepal explores tapping flood-risk glacial lakes for clean power

Subject: Geography

Section: Climatology

Context:

• In an effort to turn a risk into a gain, Nepal aims to drain burgeoning glacial lakes and produce hydropower from the flow.

Details:

• In Langtang, Nepal, two villages near the Tibet border are utilizing a glacial lake as an innovative power source.
• Due to climate change, the melting of mountain ice is accelerating, creating a threat of catastrophic flooding from rapidly filling glacial lakes. However, this situation presents an opportunity for clean energy production.
• By draining excess water from these lakes to reduce disaster risk, small hydropower generators have been installed in the drainage channels.
• Since 2017, 175 households in Langtang and Kyanjin have gained access to clean hydropower for cooking, lighting, and other energy needs, significantly reducing their reliance on firewood.
• The Kadoorie Charitable Foundation funded the $448,000 hydropower project. Despite its success, expanding such solutions in Nepal is challenging due to limited funding and the difficulties of working in high-mountain environments.

Power from risk:

• In the Himalayas and other high mountain regions, communities face increasing risks from glacial lakes that are filling rapidly and can burst, causing devastating flash floods. For example the bursting of Lhonak Lake in Sikkim.
• Nepal has taken steps to mitigate such risks by channelling water from high-risk lakes like Tsho Rolpa and Imja.
• Thulagi Lake(Nepal) holds a massive volume of water. By channelling water from Thulagi to hydropower equipment, it’s possible to generate 50 megawatts of electricity consistently and reduce the lake’s water level, significantly lowering the risk of a catastrophic burst.

Funding dilemma:

• Nepal, in collaboration with the UNDP, is seeking $50 million from the Green Climate Fund, with additional support from the government, UNDP, and the private sector, to reduce the risk of floods from the Thulagi, Lower Barun, Lumding Tsho, and Hongu-2 lakes.
• However, this proposal does not include hydropower generation plans.

What are glacial lakes?

A glacial lake is a body of water that originates from a glacier. It typically forms at the foot of a glacier, but may form on, in, or under it. As Earth’s climate warms, the world’s glaciers are shrinking, increasing freshwater outputs to all kinds of glacial lakes. Some communities depend on glacial meltwater for seasonal irrigation or domestic use, but as the balance shifts toward more melt, this water source may not be reliable in the long term and comes with new risks

How glacial lakes form?

As glaciers move, they erode the terrain under them, leaving depressions and grooves on the land. When they churn up rock and soil, they etch ridges of debris known as moraines. Most glacial lakes form when a glacier retreats and meltwater fills the hole left behind. However, natural dams, formed out of ice and terminal moraines, can also form glacial lakes. An ice dam forms when a surging glacier, which can move up to 100 times faster than an average glacier, may dam up meltwater as it closes off a valley or fjord and prevents it from draining. Dams formed by moraines can be dense and stable, holding sizable lakes behind them for years. They can also be leaky, allowing the lake to drain slowly into nearby rivers. However, prolonged melting or abrupt bursts of intense melting can wreak havoc. Too much meltwater in a short period of time might overflow a lake or burst through natural barriers, flooding lands downstream, washing away communities, and damaging roads and infrastructure. Lakes held back by moraines pose a serious threat because the porous moraine walls can destabilize easily. A rise in the amount of meltwater from glaciers increases the water pressure on the moraine barriers, which can quickly give way and threaten inundation.