Climate risk to hydropower investment


In a normal winter, northern India and Nepal get 3-4 westerly disturbances. This year there were 12 frontal systems dumping snow and rain across the country.

Kathmandu Valley and surrounding mountains had snowfall twice within a month and received 90mm of rain on the night of 26 February alone -- the heaviest ever recorded, and almost five times higher than the monthly average. Rains in other parts of the country were three times higher than the winter average. Earlier lighter snowfalls in Kathmandu were in 1946 and 2007.

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Was this precipitation a natural anomaly, or was it spawned by changes in the global climate? Attributing one unusual weather event to climate change is challenging in countries like Nepal which still have significant data gaps and lack climate modeling expertise.

However, if this is a new trend, it is a cause for serious concern. Warming caused by a greater concentration of atmospheric carbon is already changing the jet stream and weather patterns that influence climate in different ways, creating a new weather normal.

Madan Lal Shrestha is Nepal’s leading climate scientist and says the trend is worrying: “The westerly systems seem to be shifting southward and bringing these anomalies.”

The scenario for new snow dynamics projected by Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD) in its 2019 assessment and the Inter-governmental Panel on Climate Change (IPCC) SR 1.5 are equally disturbing. The ICIMOD study suggests that even if global warming is limited to 1.5°C by the end of the century, the Himalayan region will warm by around 1.8°C.

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Under a 1.5°C scenario, the study says glacier volumes in the Himalaya will decline by 36% by 2100 and under business as usual emissions, by a whopping 64%. The IPCC SR 1.5 suggests temperature rise be limited to within 1.5oC by 2030, to avoid a disastrous climate future. But this looks unlikely and the above scenario may become a reality earlier than projected. These change dynamics could already be depleting base flow of many of our snow- and rain-fed rivers. Existing and planned hydropower plants in both river types face higher risks.

Nepal has a total installed hydropower capacity of about 1,000MW and in 2018 the plants supplied 4,475GWh of hydroelectricity into the Integrated Nepal Power System. New plants under construction will add 3,370MW, and new planned projects will generate an additional 4,562W. These do not include smaller community plants, export projects like Arun II, or storage projects like Budi Gandaki and West Seti.

When these are completed, Nepal will have 300 power plants with an installed capacity of 8,932MW. If we assume that each 1MW needs $200,000 worth of investment, these projects will be valued at $18 billion, and could produce about 40,000 GWh of electricity provided the hydrology of rivers, particularly their base flow, does not change.

Already, hydropower plants in fragile basins like the Bhote Kosi face floods, landslides like the one in Jure in 2014, the earthquakes four years ago, and glacial lake outbursts. As the snow and glaciers melt, energy stored in expanding glacial lakes (like this one on the Barun Glacier, above) could theoretically be harnessed in the future, but these will be technologically complex, the upfront cost prohibitive, and impose high risks to fragile mountain ecosystems.

Today, while 86% of Nepalis have access to electricity, its use in productive sectors of the economy and in creating new jobs is limited. The bulk of the country’s cooking energy still comes from biomass, and the cost of petroleum imports show no signs of slowing.

In addition, regulatory oversight is inadequate, and so is compliance to environmental and social safeguards in the development and operation of hydropower plants. Hydropower design use historical rainfall and river flow data, but climate change makes them unreliable to calculate energy performance of power plants. Agencies in Nepal involved in hydropower development must assess climate change risks, identify mitigation measures and ensure that projects deliver energy they are designed for.

Data sets generated by existing plants in Nepal’s snow-fed and rain-fed rivers can alert us to changes in flow, and in assessing related risks to their energy performance. Generation-mix for a cleaner energy future can offset potential risks of total reliance on water-based energy system vulnerable to climate change. Such a strategy must minimise import of petroleum products by using indigenous hydro and other clean sources, address persistent energy poverty, elevate use of electricity in the economy.

In 2006, Economist Nicholas Stern’s Report on the Economics of Climate Change had warned that the cost of inaction would be far greater for future generations than the costs of action taken today. A decade later he said, “I should have been much stronger in what I said in the report about the costs of inaction. I underplayed the dangers.”

Crossing the 1.50 C threshold would take us to the danger zone. To remain within that limit, we need to improve governance and institutional accountability with in-built systemic checks and balances to ensure that new climate risks are accounted for and minimised.

Ajaya Dixit is Executive Director of Kathmandu based ISET-Nepal. His monthly column Climate for Change in Nepali Times deals with the impact of global warming in Nepal.

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