The United States has committed to combat climate change by reducing greenhouse gas emissions. The transportation sector generates the largest share of greenhouse gas emissions. Greenhouse gas emissions from transportation comes mainly from burning fossil fuel in cars, trucks, ships, trains, and planes. As a result, there is an urgent need to transition to cleaner and more sustainable energy sources and while significant progress has been made in reducing emissions from light-load vehicles with short travel distances, the heavy-duty transportation sector still poses unique challenges. The recent U.S. Infrastructure Investment and Jobs Act offers hope for addressing these challenges because it includes provisions for the development of clean hydrogen hubs, signaling a promising path towards green transportation technologies.
Hydrogen, particularly green hydrogen produced using renewable energy sources, has gained traction as a potential solution to decarbonize various sectors, including transportation. In a new study led by Professor Terry Alford from the School for Engineering of Matter, Transport, and Energy at Arizona State University, in collaboration with Selisa Andrus and Rob Diffely from the Bonneville Power Administration, published in the International Journal of Hydrogen Energy, explored the potential of utilizing excess hydropower for hydrogen production in the Pacific Northwest and its implications for grid reliability, environmental impact, and economic benefits.
The Pacific Northwest has over 370 hydropower dams within the Columbia River Basin. Among these dams, 31 are federally owned and operated and comprise the Federal Columbia River Power System (FCRPS). A subset of the FCRPS projects, known as the Columbia River System (CRS), have many objectives, including flood risk management, navigation, hydropower production, irrigation, fish and wildlife conservation, recreation, municipal and industrial water supply, and water quality maintenance. Hydropower generation in the CRS includes both storage and run-of-river facilities. Storage projects use dams to store river water in reservoirs, allowing for controlled energy release to meet fluctuating electricity demand. In contrast, run-of-river facilities channel a portion of a river through a penstock to produce energy without the need for reservoirs. These hydropower projects are essential for providing a stable and reliable electricity supply in the region.
The authors discussed the Pacific Northwest experiences seasonal variations in hydropower generation due to spring and summer peak flows from snowmelt and annual precipitation patterns. During these periods, hydropower surpluses can occur when the generation capacity exceeds the region’s electricity demand. While these surpluses offer opportunities to displace fossil-fueled power generation, they also pose challenges, such as grid balancing and potential energy curtailment.
To assess the potential for hydrogen production from overgeneration spill at hydropower projects in the CRS, the authors utilized results from a hydroregulation model known as HYDSIM. This model simulates reservoir, powerhouse, and dam operations over an extended period, allowing for a detailed analysis of hydropower operations and the calculation of overgeneration spill. Overgeneration spill occurs when excess energy cannot be absorbed by the grid, presenting an opportunity to repurpose this surplus energy for hydrogen production. The authors’ findings indicated significant potential for hydrogen production from overgeneration spill in the Pacific Northwest. They estimated 1.98 million kilograms of hydrogen per year could be produced from 11 hydroelectric projects in the region. This hydrogen production could be a game-changer for reducing carbon emissions and promoting sustainable transportation.
According to the authors, the environmental benefits of using hydrogen as an alternative fuel source for heavy-duty vehicles are substantial. Heavy-duty vehicles, such as trucks and buses, are responsible for a significant portion of CO2 emissions in the transportation sector. By replacing diesel with hydrogen, the Pacific Northwest region could reduce emissions equivalent to $1.4 B – $3.5B in CO2 capture costs. Additionally, the authors estimated the cost of producing hydrogen from surplus hydropower energy is economically viable, with production costs ranging from US$ 2.60 to US$ 12.30 per kilogram of hydrogen. This benefit of cost-effectiveness, combined with the potential savings from avoided CO2 capture costs, makes hydrogen production from hydropower a promising avenue for investment.
The growing integration of variable renewable energy sources, such as wind and solar, into the grid necessitates increased operational flexibility for hydropower facilities. Excess hydropower energy can provide grid stability during periods of low demand for electricity from other sources. Furthermore, the use of surplus hydropower for hydrogen production can reduce wear-and-tear on hydropower facilities caused by frequent starts and stops.
While the new study demonstrated the substantial potential of utilizing excess hydropower for hydrogen production in the Pacific Northwest, future research should explore several important avenues. First, the study acknowledges the need for a more granular daily model analysis to capture the nuances of energy flow and potential hydrogen production. Additionally, assessing the impact of climate change on hydropower generation in the region using more extended streamflow forecast models is crucial for long-term planning.
In conclusion, the new study led by Professor Terry Alford and collaborators from the Bonneville Power Administration underscores the immense potential of repurposing excess hydropower for hydrogen production in the Pacific Northwest. Moreover, it offers a sustainable and economically viable path towards reducing carbon emissions in the transportation sector, enhancing grid reliability, and realizing substantial economic benefits.
Selisa R. Andrus, Rob J. Diffely, Terry L. Alford, Theoretical analysis of green hydrogen from hydropower: A case study of the Northwest Columbia River system, International Journal of Hydrogen Energy, Volume 48, Issue 22, 2023, Pages 7993-8001.