Carbon intensity of hydropower: a key driver of power capacity expansion under climate policy in the African continent
Abstract
Hydropower is commonly considered a low-carbon electricity source and thus figures prominently in many scenarios for transitioning to a net-zero electricity system. While there is increasing evidence that greenhouse gas emissions from dammed reservoirs can increase hydropower's carbon intensity to values on-par with gas and coal power plants, these emissions are not commonly considered when planning renewable energy systems in compliance with global emissions targets. Accounting for the actual carbon footprint of hydropower in energy systems planning could significantly change the electricity mix and associated costs and impacts of future energy systems, particularly in developing countries with a major untapped hydropower potential.
Here, we explore the sensitivity of electricity expansion scenarios to greenhouse gas emissions from hydropower reservoirs under different emission constraints using the OSeMOSYS-TEMBA energy system model for the African continent. Africa is a particularly relevant case study with more than 300 new hydropower projects that could provide 100 GW of additional installed capacity and massive needs to expand clean energy generation. We find that the modeled deployment of hydropower and overall power capacity expansion strongly depend on hydropower's carbon intensity. Global studies indicate that current and future African reservoirs can have lifecycle emissions similar to gas (around 400 gCO2eq/KWh) and coal (around 1000 gCO2eq/KWh). If the carbon intensity is comparable with gas, less than 40% of the proposed hydropower capacity should be installed, and only 10 % if carbon intensity is comparable with coal. The missing hydropower capacity can be replaced with solar, but also wind and nuclear provide additional contributions. Yet, electricity prices tend to increase up to +13% with respect to expansion scenarios where carbon emissions from reservoirs are not accounted for. Our results thus indicate that accounting for hydropower's true carbon footprint can have significant impacts on the design and costs of transitioning to low-carbon electricity systems that need to be considered in regional and global energy analysis.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFMGC26F..04C