Integrated Hydrogen Energy Storage System (IHESS) for Power Generation (Final Report)

Abstract

GTI Energy partnered with Praxair Inc., a subsidiary of Linde PLC (Praxair), the Center for Electromechanics at the University of Texas at Austin (CEM), Entergy Corporation (Entergy), Quanta Services (Quanta) and Mitsubishi Heavy Industries (MHI) to perform a feasibility study that determines the economic and technical feasibility of low-carbon hydrogen energy storage integrated with a site-specific fossil fuel asset to decarbonize electricity production using the Integrated Hydrogen Energy Storage System (IHESS). IHESS consists of the following components: Praxair’s hydrogen production assets, hydrogen transportation via Praxair’s hydrogen pipeline delivery infrastructure, hydrogen storage from Praxair’s existing geologic storage formation and pipeline “line pack”, existing natural gas supply networks, a gas fired power generation facility with blended hydrogen/natural gas compatible turbines. The proposed IHESS concept is novel, as it sought to leverage the existing natural gas infrastructure, hydrogen production and pipelines, existing underground hydrogen storage system and power plants in the Gulf Coast region to reduce carbon emissions and generate low-carbon electricity. The gulf coast region is home to one of the largest hydrogen hubs in the nation. Within this region, Texas alone consumes about 9 million kg of hydrogen per day, or about 1/3 of the total US consumption4. Currently, most of this hydrogen is used as feedstocks for the chemicals and oil and gas industries and is produced via steam methane reforming (SMR) process. The Texas Gulf Coast also has the most extensive hydrogen pipeline network in the country, roughly 1600 miles of dedicated hydrogen pipelines move hydrogen throughout this region including Louisiana. There are roughly 556 GW of natural gas fired power plants in the US and about 14% (79 GW)1 of those power plants are in Texas and many are located along the Texas Gulf Coast region. The findings from this study suggest, to support 10 MWh of energy, it requires roughly 273 kg of hydrogen. Even though his can be easily achieved by using gaseous tube trailers typically used for delivering compressed hydrogen via trucks up to 300 kg per trailer this project study was focused on leveraging the underground storage facilities. To provide a buffer of a one-day supply of hydrogen to the power plant at a 30% blend, 7 tonnes of hydrogen storage is required and if hydrogen production is offline then 170 tonnes of storage for a 24-hour power generation resiliency. This can we easily achieved by the use of a nearby underground storage cavern with a 7 million kg of hydrogen storage capacity, providing over 30 days of resiliency. Another key finding from this study suggests, 4.8-11% carbon (CO2) emissions reduction is possible using up to 30% hydrogen in its natural gas turbine fuel stream. To achieve at least 20% CO2 emissions reduction, the natural gas turbines at the power plant must be capable of blending at least 45% hydrogen by volume (or the plant may include additional carbon capture and storage technologies). Finally, the study indicates that blending hydrogen into a power plant’s fuel stream is currently more expensive than using 100% natural gas. A 30% hydrogen natural gas blended fuel stream increases the power plant’s cost by 6.89-11.62 $/MWh (study assumes a price of 3.50 $/MMBTU for natural gas and varying prices for hydrogen depending on production technology), depending on if the hydrogen is sourced from electrolysis or other production technologies. This study has shown that IHESS has a promising commercial outlook as the concept leverages existing natural gas infrastructure assets and hydrogen production and storage that are unique to the Texas gulf coast region. A key hurdle with hydrogen supply and transportation has been capital investment. By storing hydrogen in underground storage and delivering it as a fuel source during peak demand using the existing infrastructure minimizes the capital investment. Regional petrochemical producers who are actively seeking opportunities to reduce costs and lower emissions should find the IHESS concept very appealing.