The goal of the Asian Development Bank project ‘Renewable Energy for Climate Resilience’ in Bhutan is to diversify Bhutan’s energy portfolio. Bhutan’s power sector almost exclusively relies on hydropower generation. Hydropower, however, is vulnerable to climate change and natural disasters caused by climate change. The first deployment of non-hydro renewables at utility scale in Bhutan will be the first step to diversify the power generation portfolio, increase the resilience against severe weather events such as droughts, and complement the hydropower generation profile during the dry season. Other renewable energy resources such as solar photovoltaic (PV) and wind can complement hydropower in forming a more diversified electricity generation portfolio, which is, in healthy mix, resilient to changes in seasonal weather patterns and weather extremes that can adversely affect power supply.

Within this project ADB develops two solar and one wind plant. FutureWater has undertaken a Climate Risk and Adaptation assessment (CRA) for these power plants, with a two-fold objective:

  1. Validate the underlying rationale for diversification of Bhutan’s energy generation portfolio. The rationale is that more unreliable flows under climate change adversely affect the hydropower generation, in particular in the low flow season outside the monsoon season. This are the seasons with high potential for solar and wind energy, under the current climate conditions. The diversification of Bhutan’s energy generation portfolio is considered as type 2 adaptation, related to system change and resilience building in the climate change context.
  2. Assess the vulnerability of the project components to future climate change and recommend adaptation options for climate-proofing of the design. This is considered as type 1 adaptation, related to climate proofing.

The rationale for diversification is related to the expectation that climate change impacts on the cryosphere and hydrology in Bhutan will lead to less reliable flows, in particular outside the monsoon season. This will make hydropower a less reliable source of energy, which may not be sufficient during the dry season. During these periods outside the monsoon season, the climate in Bhutan is characterized by clear skies and daily patterns of wind. This intuitively makes solar and wind suitable energy sources to complement hydropower.

The CRA concludes that this rationale holds when validated with future scenarios of climate change and hydrological changes. These project more erratic flows, meaning on one hand more extremes on the high end (floods), in itself posing risks for hydropower infrastructure, but also through increasing sediment loads and risks of exposure to landslides and glacier lake outburst floods. On the other hand, a small increase in frequency and length of hydrological droughts is projected. Furthermore, projections of wind speed and incoming solar radiation indicate more or less stable conditions compared to the present day climate, further substantiating the rationale for portfolio diversification.

For adaptation and climate proofing the main recommendation is to verify that the proposed drainage systems at the sites are sized for extreme flows that are 20-30% larger in magnitude than current extremes. This is valid across return periods. The second high priority recommendation is to design foundations of solar, wind, and transmission infrastructure to withstand increased erosion rates and substantially increased risk of landslides in landslide prone areas. A third recommendation is to take into account lower production for solar panels at increased frequency of heat stress, as well as in the sizing of capacity of transmission infrastructure, which may have reduced capacity during periods of high heat stress.

Warming of the climate system is unequivocal. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased. The Himalayan region (after Antarctica and the Arctic) has the third largest amount of ice and snow in the world, and is exceptionally vulnerable. The various Global Climate Models (GCM) predict very similar future temperature trends for the region, but projections of future precipitation patterns differ widely. As a consequence, the need for increased knowledge about future climate change remains high. The main focus of GCMs thus far was on temperature increases and potential changes to the hydrological cycle. The overall tendency that has emerged is that wetter regions are likely to become wetter and drier regions drier. Increased scientific knowledge, coupled with recent weather events, show that changes in hydrological extreme events can be substantial and the geographical and temporal resolution of predicted changes remains low in many areas.

For Statkraft, as the largest generator of renewable energy in Europe and a leading company in hydropower internationally, an understanding of future changes to the hydrological cycle and its uncertainty is crucial for effective business planning. Investment decisions regarding the business strategy for the next 50 years depend on accurate predictions of climate change impacts on inflow over that period.  In addition, changing probabilities and magnitudes of extreme events can put additional risk on infrastructure (dams and hydropower plants) or on other crucial infrastructure (roads and transmission lines).  Statkraft’s intention to grow in the region makes it necessary to assess short, medium and long-term impacts, risks and opportunities resulting from climate change, to ensure sustainable management of the water resources for all stakeholders. Currently, Statkraft’s main business focus lies with northern India (mainly the state of Himachal Pradesh) and Nepal, while Bhutan and Myanmar might be areas of future business development as well.

Kaligandaki Hydro power located in Nepal.

Through the International Centre for Integrated Mountain Development (ICIMOD), the inter-governmental learning and knowledge sharing Centre serving the eight regional member countries of the Hindu Kush Himalayas (HKH), FutureWater provided a comprehensive review study on climate change and the impacts on cryosphere, hydrological regimes and glacier lakes in the Indus, Ganges, and Brahmaputra river basins. This review study was done in the context of future hydropower development in the region.

ICIMOD is the implementing agency for the Himalayan Climate Change Adaptation Programme (HICAP) that runs from January 2011 to December 2015. HICAP addresses climate change adaptation challenges across different related disciplines such as water resources, ecosystem services, food security, vulnerability and gender. Part of the project is related to the generation of water availability scenarios from upstream river basins that are primarily characterized by snow and glacial melt. ICIMOD has contracted FutureWater to generate these scenarios based on a high resolution hydrological model that FutureWater has developed. The project runs from January 2012 until June 2013. FutureWater will generate climate change and water availability scenarios for the upstream parts of the Indus, Ganges and Brahmaputra river basins.

With the overall goal to improve our knowledgebase on climate change impact on water availability and demand in the upper parts of the Indus, Ganges and Brahmaputra basins, the specific objectives of the proposed study are to:

  • Assess climate change scenarios and develop water availability scenarios corresponding to base and future climate scenarios at sub-basin and catchment scales in the three basins
  • Improve our understanding of the partitioning of runoff contribution from different natural sources (snow, glacier, rainfall and base flow)
  • Detailed analysis of uncertainty of water availability scenarios and assessment of hydropower potential for five pilot catchments