The Asian Development Bank (ADB) identified the need for a detailed Climate Risk and Adaptation (CRA) assessment for the DKSHEP to understand the risk posed by the changing climate on hydropower and the environment. Therefore, the objective of this Climate Risk and Adaptation Assessment (CRA) is to assess the vulnerability of the project components to future climate change and recommend adaptation options for climate-proofing of the design. Therefore, this CRA covers both type 2 adaptation, related to system change and resilience building, as well as type 1 adaptation related to climate-proofing This CRA assesses historic trends in relevant climate-related variables and analyses climate projections for the DKSHEP. Based on these projections, an assessment of the current and future climate risks and vulnerabilities relating to the proposed project activities will be outlined. Finally, recommendations will be presented for climate adaptation measures.
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:
- 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.
- 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.
“Gabon is a rapidly developing country that contains substantial amount of intact natural areas and biodiversity, and large untapped natural resource stocks, placing the country at the forefront of a green economic development opportunities. TNC supports the government in preserving Hydrologic Ecosystem Services which are essential to include into development projects as for example hydropower.
This study will assess these services for the Komo basin where certain pressure already exists due to forestry operations and planned hydropower. It will evaluate various management scenarios which may improve and sustain hydrological flow conditions and hydropower options. The analysis will help the government in implementing an integrated water resources management (IWRM) approach in this basin.
FutureWater will deliver this study through hydrological modeling and scenario analysis to assess how hydrological ecosystem services provision in the Komo basin can be improved by a series of potential alternative scenarios based.”
This glacio-hydrological assessment delivered river flow estimates for three intake locations of hydropower plants in Nakra, Georgia. The assessment included the calibration of a hydrological model, daily river discharge simulation for an extended period of record (1980-2015), and the derived flow duration curves and statistics to evaluate the flow operation of hydropower turbines. The daily flow calculations for the three sites (HPP1, HPP2 and HPP3) can be used in the hydropower calculations, and to assess the overall profitability of the planned investment, considering energy prices, demand, etc.
In the Nakra basin, glacier and snow model parameters were tuned to obtain accurate river flow predictions. Also, the latest technology of remote sensing data on precipitation and temperature (product ERA5) was used to reduce potential errors in flow estimates. Even though these flow estimates are useful for short-medium term evaluations on profitability of the planned investment, climate change pose a challenge for long-term evaluations. Glacier-fed and snow-fed systems, such as the Nakra basin, are driven by a complex combination of temperature and precipitation. Due to future increasing temperature, and changing rainfall patterns, glacier and snow cover dynamics change under climate warming. This can lead to shifts in the flows, like a reduction in lowest flows, and higher discharge peaks when the hydrological system shifts towards a more rainfall-runoff influenced system (Lutz et al. 2016). This can jeopardize the sustainability of the project on the long-term. To provide a better understanding of future river flows, it is recommended to develop a climate change impact assessment.
This hydrological assessment delivered river flow estimates for an intake location of a potential hydropower plant in the Lukhra river, Georgia. The assessment included a tuning of a hydrological model based on knowledge of neighboring basins, daily river discharge simulation for an extended period of record (1989-2019), and the derived flow duration curves and statistics to evaluate the flow operation of hydropower turbines. The daily flow calculations for the site can be used in the hydropower calculations, and to assess the overall profitability of the planned investment, considering energy prices, demand, etc.
In the Lukhra basin, snow model parameters were tuned to obtain accurate river flow predictions. Also, the latest technology of remote sensing data on precipitation and temperature (product ERA5-Land) was used to reduce potential errors in flow estimates. Even though these flow estimates are useful for short-medium term evaluations on profitability of the planned investment, climate change pose a challenge for long-term evaluations. Snow-fed systems, such as the Lukhra basin, are driven by a complex combination of temperature and precipitation. Due to future increasing temperature, and changing rainfall patterns, snow cover dynamics change under climate warming. This can lead to shifts in the flows, like a reduction in lowest flows, and higher discharge peaks when the hydrological system shifts towards a more rainfall-runoff influenced system (Lutz et al. 2016). This can jeopardize the sustainability of the project on the long-term. To provide a better understanding of future river flows, it is recommended to develop a climate change impact assessment.
Hydropower is essential to fulfill future energy demands. Water scarcity is likely to increase due to climate change and aase in water demand. Therefore, Climate Risk Assessments are required before large investments in new and large hydropower stations (>100 MW) are made. Small hydropower (1 – 20 MW) does not require these Climate Risk Assessments yet, but this will eventually happen in the future. Investors are highly interested in the profitability of these small hydropower stations, especially because of the uncertainty caused by future climate change. Current methods for Climate Risk Assessments (CRA) are however still too costly for these small-hydro projects because they are very labor intensive and require specific knowledge.
FutureWater has carried out a feasibility study to assess the possibilities for the development of a “Small-Hydro Climate Risk Assessment tool” (SH-CRA) that can make CRA’s for small-hydro projects cost effective. The starting point of this project to develop the SH-CRA is the recent change in the approach to CRA’s: until a few years ago, these were based purely on climate models, also known as the “Top-down” approach. Nowadays however, investors require a more pragmatic approach in which climate risks are balanced against other risks and presented in a clear way. This new “Bottom-up” approach makes it possible for small-hydro projects to include climate risks in the investment decision.
This feasibility project has therefore investigated whether the “bottom-up” climate risk analysis approach can make it possible to develop such a SH-CRA solution, based on a combination of literature research, an inventory of available technology and potential partners, and competition analysis.
There is great potential for hydropower in Georgia, and this natural resource is likely to be increasingly utilised for power generation in the future. With the escalating demand for energy, government authorities are keen to harness renewable energy from the country’s main rivers. Often these projects aim at remote communities for which connecting to the national power grid is expensive. Hence, local hydropower production is an attractive and sometimes viable option. Critical is to conduct accurate feasibility assessments for hydropower generation at the different potential sites of interest considering climate change impacts. This work is a glacio-hydrological assessment of the expected river discharge at the planned hydropower sites in the Mestiachala river, Georgia.
Based on the requirements of the project, the Spatial Processes in Hydrology (SPHY) cryospheric-hydrological model was selected for the assignment. SPHY is a hydrological model that simulates the runoff at any location within the basin at a daily timescale. SHPY is ideal to assess glacier and snow influence in the river discharge and evaluate the impact of climate change. SPHY was used to predict the river discharge for the extended period of record and provide enhanced flow duration curves for hydropower assessment. In addition, total runoff components were quantified such as snow and glacier runoff.
This glacio-hydrological assessment delivered river discharge estimates for intake locations of two planned runoff river hydropower plants near Mestia, Georgia. The assessment included the calibration of a hydrological model, daily river discharge simulation for an extended period of record (1980-2015), climate change scenarios, and the derived flow duration curves to evaluate the flow operation of hydropower turbines. In addition, total runoff components were quantified such as snow and glacier runoff.
The daily river discharge was simulated at the two intake locations for two future periods (for the end of the concession period and for the end of century period) considering two climate change scenarios (RCP4.5 and RCP8.5). Hydrological model simulations were developed using future precipitation and temperature predictions and future glacier extent predictions. The climate change scenarios provide an evaluation of flow operation uncertainty. The daily flow calculations for the two sites can be used in the hydropower calculations, and to assess the overall profitability of the planned investment, taking into account energy prices, demand, etc.
Indonesia is endowed with a full range of both renewable and fossil resources of energy, actively exploited to feed its growing economy. Emphasis has been on fossil, hydroelectric and geothermal resources rather than wind and solar. PLN (Perusahaan Listrik Negara) is the Indonesian State Electricity Company. It is an Indonesian government-owned corporation which has a monopoly on electricity distribution in Indonesia and generates the majority of the country’s electrical power, producing about 175 TWh annually. Only a small fraction of this originates from hydropower.
Indonesia has five large hydropower plants with a capacity over 250 MW: Cirata on Java (1008 MW), Saguling on Java (701 MW), Tangga on Sumatra (317 MW), Sigura-gura on Sumatra (286 MW), and Pamona on Sulawesi (260 MW). The Indonesian government aims to develop more hydropower with quite a strong focus on small and micro hydropower plants.
Capacity of PLN staff to understand the hydrology related to hydropower electricity generation needs to be enhanced. Also, the knowledge of the potential impact of climate change on hydropower requires additional capacity of PLN’s staff. Especially their ability to understand and judge feasibility studies undertaken by external consultants requires upgrading their level of knowledge. Also staffs’ capacity to understand climate risk assessment studies, as today required by most investors, should be further developed.
FutureWater was asked to develop and provide training on those two aspects (hydrology and climate change). Given the huge area of the country and PLN staff working in large distances from each other, it was decided to provide training in a eLearning setting. Initially about 25 staff will be trained and based on lessons learnt the training package will be adjusted to staff needs and further training will be undertaken.
For the two study catchments, satellite imagery and field observations were combined to perform a land degradation assessment and to identify trends. Secondly, baseline hydrological conditions were assessed using a hydrological simulation model. Future changes in hydrology and hydropower generation were evaluated by running the biophysical model for a Business-as-Usual scenario, accounting for land degradation trends, changes in water use, and climate change.
Subsequently, the impacts of three catchment investment portfolios (low, medium, high) containing different catchment activities were quantified with respect to the BaU scenario. Benefits and costs were analysed for the hydropower developers to evaluate whether it makes sense for them to invest in improved catchment activities. For one of the catchments this is clearly the case (Kiwira, Tanzania).
The analysis shows that the impacts of climate change on revenue from hydropower are in the same order of magnitude as the other negative anthropogenic factors: increased domestic water use demand in the catchment and land degradation due to poor conservation of natural areas and poor agricultural practices.
There is interest to develop run-off river hydropower plants in a watershed in southwestern Georgia: a cascade of two projects of around 25 MW each. Before the actual development phase can start, a hydrological assessment is necessary to assess expected flows at the two locations with higher accuracy than currently available from limited flow measurements.
FutureWater was contracted by the developers to undertake an assessment of the expected daily flows at the two site locations , based on satellite data and hydrological modelling. Only very limited streamflow data were available, so the assessment was based mainly on hydrological modelling of the basin upstream of the points of interest. Principally global datasets were used for the input requirements of the hydrological modelling. Validation of the model was done using limited recent streamflow data available and satellite-based snowcover measurements. The principal output of the work are daily flows and a flow duration curve, based on model simulations. The flow duration curve includes confidence bounds based on the uncertainties that can be expected originating from data and model parameters.
From this hydrological assessment, a number of recommendations are put forward that aim at increasing the level of accuracy in the outcomes and narrow the uncertainty range for the following feasibility stage. Recommendations are done for data improvements, model improvements and field validation.Outcomes of this study will be used by the developer to analyse the hydropower potential and evaluate the economic feasibility.