Climate change impacts, such as sea level rise, flooding, and drought, threaten renewable energy generation, particularly hydropower due to the necessary proximity of power stations to water sources. As a result, energy security and the ability of countries to meet their greenhouse gas reduction targets may be compromised. Through an approach called Integrated Resource and Resilience Planning (IRRP) power providers are able to assess the performance trade-offs of different potential investment plans using multiple criteria—such as cost, reliability, and greenhouse gas emissions—under different future scenarios. Following this process allows planners to determine a “least regrets” plan that is more resilient than a least-cost plan.
A new paper in the Resources to Advance LEDS Implementation (RALI) Series describes how IRRP was applied in Tanzania to assess the impact of drought on alternative power sector investment pathways.
Considering Power Systems Investments under Drought Conditions
Hydropower generation is a key component of low emission development strategies, providing two-thirds of global renewable electricity generation. Tanzania depends on hydropower for one-third of its total generation capacity. However, Tanzania is prone to drought, which reduces the reliability of electricity generation from hydropower. During past droughts, Tanzania was substituting higher greenhouse gas-emitting and more costly alternatives to hydropower, such as coal and natural gas. Due in part to hydropower variability, Tanzania has diversified its electricity supply over time, reducing dependence on hydropower from 96% in 2003 to 34% in 2015. Recently, USAID supported the national utility, TANESCO, in applying the IRRP method to assess the performance of different potential investment portfolios under a range of future scenarios, including drought.
The analysis shows that in Tanzania, drought increases greenhouse gas emissions because reductions in hydropower generation are compensated for through increased use of fossil fuel-based sources. In fact, the impact of drought and increased temperatures could be even greater if their effects on power generation by other renewable energy resources (e.g., biomass or solar) are also taken into consideration.
Power utilities and planners looking to meet greenhouse gas emissions objectives should be mindful of back-up generation methods, as replacement generation may be just as important as primary electricity sources. In Tanzania, that may involve considering trade-offs between coal (cheaper but higher emitting) and natural gas (more expensive but lower emitting) or other alternatives.
The purpose of the IRRP in Tanzania was to identify the least regrets investment plan, which informed the development of the integrated power systems master plan. However, the IRRP framework can be used to test the implications of other climate sensitivities (e.g., increased rainfall intensity and flooding, higher temperatures) on power system investments.
Molly Hellmuth is the Climate Resiliency Senior Advisor for USAID’s Integrated Resource and Resilience Planning projects in Ghana and Tanzania. She is an international expert in water resources, climate risk management, and resilient development. She has over 20 years of international experience, and has developed climate risk management strategies, tools, models, and guidelines for various clients, including for USAID, the African Development Bank, the World Bank, the ASEAN Centre for Energy, the US Millennium Challenge Corporation (MCC), the Western Electric Coordinating Council (WECC), and the U.S. Departments of Defense and Energy (DOD, DOE), among others. She has provided guidance on building climate resilience in the power sector for the U.S. MCC and WECC, and has developed specific guidance on climate risk and resilience of hydropower plants for USAID, and DOE. She holds a PhD and M.S. in Civil and Environmental Engineering from the University of Colorado-Boulder, a B.S. in Environmental Studies, and a B.A. in French.