Southern California Gas (SoCalGas) is the largest gas provider in the United States, with 22 million customers. “We transport and store about a trillion cubic feet of natural gas annually, and we cover about 20,000 square miles of service territories,” explained Jennifer Medina, hydrogen engineering team lead at SoCalGas, who presented the Hydrogen Home Project this week at Emerson Exchange. The project is a completely unmanned facility using 20%-hydrogen blended gas that can be scaled to a 200-home community, using DeltaV controls.
SoCalGas's mission is to become the cleanest, safest and most innovative energy company in America; its goal was to build a state-of-the-art demonstration project. The Hydrogen Home project highlighted the role hydrogen could play in achieving carbon neutrality. SoCalGas worked together with Caltrol, its local Emerson Impact Partner, which provided a SpartanPRO H2 Blending Solution skid, developed in partnership with Spartan Controls, and an overall H2 Home Control utilizing Emerson solutions for the first-of-its-kind home in the United States. It includes solar panels, battery storage, an electrolyzer to convert solar energy to green hydrogen, a fuel cell to convert that hydrogen back to electricity, plus hydrogen blended with natural gas for use in the home.
The first project that Medina’s group sank its teeth into was the Hydrogen Home, also referred to as the Hydrogen Innovation Experience Project. Located at SoCalGas’ Energy Resource Center in Downey, California, the 2,000-square-foot, LEED-certified Hydrogen Home was reconstructed in eight hours, after first being built off-site.
Solar panels were used to create a microgrid, ensuring the home could operate independently. The site is fully powered by 6 kWh of solar. Green hydrogen is generated on-site through electrolysis. “Our control system is DeltaV for the power controller, blending skid, fuel cell and electrolyzer,” said Medina.
Because industry standards for blended hydrogen start at 29%, SoCalGas is testing a mixture that is 20% hydrogen blended with natural gas to produce the fuel blend. “For blends up to 20%, no modifications are required by appliances, and there’s no reduction of appliance functionality,” explained Medina. Standard consumer gas appliances were used. “They tested to failure, and some of the appliances worked up to 40% blend,” said Medina, who’s also part of a group working on a blended-gas standard for the state of California. “This was the first step to learning what we can do,” she said.
“Our battery system stores 300 kW of the solar,” said Medina. “Our electrolyzer is the smallest you can get. It outputs about 1 kg/hour of hydrogen.” The blended gas is used for a tankless water heater, clothes dryer, gas stove, gas barbecue, indoor fireplace and outdoor fireplace. Carbon monoxide detectors are used in the home to detect leaks.
The challenges of hydrogen blending included the accuracy of the hydrogen concentration measurement and control, wide flow turndown requirements and gas composition changes. “The required turndown for this hydrogen flow is 1,600:1—not an overwhelming application, but we had to look at the variables,” said Brian Burkowsky, general manager, advanced solutions, at Caltrol, who was part of the solution team, along with Luis Martin Del Campo, Caltrol account manager.
The Hydrogen Home’s SpartanPRO blending skid uses a Coriolis flowmeter and thermal gas measurements for ratio control, explained Burkowsky. “Control valves are used for precise control; dual run is available for additional turndown. Tight shutoff valves isolate the process. And there’s online analysis to confirm blend ratio is on spec.”
The skid includes a static mixer to mix the hydrogen and natural gas by creating turbulence to alleviate possible stratification, one Coriolis flowmeter and three thermal mass flowmeters. “Instead of PID control, we’re using parallel ratio control for trim ratio,” explained Burkowsky. “The overall home project control was completed by DeltaV, including advanced process control (APC), CHARMs I/O, safety instrument system (SIS), connections to all assets at the home location and connections for digitalization to help meet SoCalGas’ Aspire 2045 goals.