Southwest Research Institute is expanding its flowmeter research in collaboration with NYSEARCH, a nonprofit research and development organization for the gas industry, to address the impact of introducing H₂ and natural gas blends into the residential and commercial energy mix. In the second phase of the program, SwRI will expand its research in measuring the energy content of blended gas to determine the accuracy of current flowmeter technology for monitoring usage in homes.

Natural gas is widely used to power appliances and heat homes. Introducing H₂ into these flow streams can reduce the carbon footprint of energy delivery using existing natural gas infrastructure. In the next decade, some gas companies are planning to blend H₂ gas with natural gas to curb carbon emissions. Because the density of the resulting blends would be significantly different than natural gas, flowmeters calibrated to measure the flow of natural gas will have some error when trying to measure blended gases.

“We are working to assess the accuracy of the flow meters attached to homes and businesses,” said Angel Wileman, manager of SwRI’s Thermofluids Section. “Those flow meters measure the amount of gas flowing into the home, which determines how much the utility charges for energy use. Currently, industry does not know the impact of using existing flow meters to measure a blended gas.”

The ability of a natural gas flowmeter to accurately measure how much energy a building consumes depends on three things. First is the energy content of the gas. While the energy content of natural gas is well known, SwRI must determine the energy content of blended gas. Second, they will verify that flowmeters are accurately reading volumetric flowrate. Third, they will measure the density of the blended gas to calculate the mass flowrate.

In the project’s first phase, SwRI verified the density of blended gas at multiple concentrations and verified the accuracy of common flow meters with blended gas. The second phase, which will be completed by the end of 2023, will expand on this work by investigating more meters and at lower temperatures and pressures. The team will verify the energy content of multiple H₂ and natural gas blends to calculate the energy transferred to a customer based on the volumetric flow rate measured by flow meters and the density of the gas. Additionally, the SwRI researchers will investigate these same gas properties for renewable natural gas blends from non-fossil fuel sources such as landfills and dairy farms. The team will characterize the accuracy of three flow meter technologies in a blended gas environment and experimentally gather density data for H₂ and natural gas blends for residential applications.

“We need to address many questions about blended gas and how it affects equipment,” Wileman said. “When it comes down to it, it will affect people’s pocketbooks. The flowmeter determines how much gas a distribution company delivers to a consumer. Making sure that people are charged accurately is vital as we move closer to utilizing blended gas.”