Geothermal Flow Rate and Liquid/Vapor Fraction Measurement System

The emission of carbon dioxide (CO2) gases from fossil fuel power plants can be harmful to the environment and contribute to global warming. Clean energy technologies such as wind and solar are intermittent and require energy storage or alternative supplemental energy sources. One alternative energy source is geothermal power which has zero emissions and can run 24/7 with little down time and is therefore a beneficial energy source for maintaining base load in a net zero carbon emission future. To maximize the output and lifespan of a geothermal well, it is beneficial to monitor several parameters, including mass flow rate and vapor/liquid fraction of the fluid in real time for the purpose of monitoring the total enthalpy from each well. Current methods are not sufficiently accurate, cannot be done in real time, or are cost-prohibitve to use for each well individually. This project proposes to develop a real time mass flow and liquid/vapor fraction measurement system for geothermal wells. This will be accomplished with a two-phase flow meter consisting of a differential pressure device paired with an electrical resistance measurement of the void fraction. A model will be developed to correlate the measured pressures and void fraction with the mass flow rate and liquid/vapor fraction. The hardware used for these measurements will be able to operate at elevated temperatures in excess of 390 ºF. The success of this project will provide a new and unique real time flow meter for geothermal systems with two-phase flow. The flow meter will provide improved accuracy of mass flow and liquid/vapor fraction measurements for the purpose of tracking enthalpy from individual wells in real time, which will provide greater insight on the evolution of geothermal reservoirs over time to maximize efficiency and production potential. The public benefits of this flow meter will be greater production capacity from geothermal plants, which will decrease cost per kilowatt-hour produced and help clean geothermal energy to become a larger portion of total electricity production so that fossil fuel usage can be reduced. In the long term this will lead to a reduction in the environmental impact of electricity production.