The house of the future

• UC Irvine students travelled to a SoCalGas demonstration home and microgrid 30 miles from campus to learn about sustainable energy technologies.
• Similar equipment will potentially be used to demonstrate the viability of blending hydrogen with natural gas in a confined area on campus.
• The students enjoyed a lunch of tacos cooked on a hydrogen-powered stovetop.

A small group of UC Irvine students recently toured one of the most normal things ever - a suburban house. But this home is anything but. It has some special characteristics, including the highly sustainable way in which it was built and that it is powered almost entirely by renewable energy.

The structure sits at the SoCalGas Energy Resource Center in Downey, Calif. The students visited the site to gain more knowledge about the practical applications of blending hydrogen with natural gas to power home appliances such as stoves, fireplaces, clothes dryers, barbeques and heating systems.

SoCalGas and UC Irvine are working on a proposed project currently being evaluated by the California Public Utilities Commission to blend hydrogen with natural gas in a closed-loop system serving the Anteater Recreation Center on campus. The blended gas will be used in the facility's heating and cooling system and to heat water in its pools and locker rooms. The ARC's instructional kitchen also will be served with the blended gas should the plan gain approval.

Jennifer Medina, SoCalGas engineering development and technology principal engineer, tells UC Irvine tour group participants about the features of a microgrid that delivers energy to the sustainable model home in the background. Steve Zylius / UC Irvine

photo: Steve Zylius/UC Irvine

The demonstration project's goal is to establish standards by which hydrogen can be blended with natural gas and distributed throughout pipeline networks managed by big utilities like SoCalGas. Replacing even a fraction of the methane in the system with hydrogen - which can be sustainably produced by splitting water molecules with electricity generated by wind and solar power - will reduce the combustion of fossil fuels and help California reach its goal of minimizing carbon dioxide emissions.

The proposed blending project has generated much discussion among students, faculty and staff on campus in recent years. Advisory committees have been formed to evaluate the initiative, and student government has held numerous meetings on the subject. Some who prefer direct electrification options have opposed such projects.

Among those who are in favor of the demonstration project are Jack Brouwer, professor of mechanical and aerospace engineering and director of the UC Irvine Clean Energy Institute. Brouwer says he supports the greatest extent of electrification that is possible, but he argues that hydrogen is required, in addition, to produce a redesigned energy delivery system that is mostly renewable and clean. Features of hydrogen are required to enable a reliable and resilient electric grid and to decarbonize and depollute sectors such as heavy industry, shipping, aviation and freight transport.

Brouwer says that any attempt to create an energy system with low emissions needs a diversity of features. "It's not going to be possible with wind and solar alone. We're going to need long-duration storage and underground fuel delivery to power plants to make up for times when the sun isn't shining, and the wind isn't blowing," he says. "Getting to a reliable and resilient grid that uses mostly renewable resources is going to be impossible unless we incorporate multiple technological features that renewable hydrogen can deliver."

A bus ride and a walkabout

The tour began when students, staff and Clarissa Serpas, SoCalGas senior public affairs specialist, boarded a chartered shuttle bus at the flag circle on the UC Irvine campus for the ride to Downey. Upon arriving at the Energy Resource Center, they were greeted by SoCalGas engineer Blaine Waymire, who provided an update on the prospective blending project as it wends its way through the multi-year CPUC evaluation and approval process. Then, the group headed off to the model home and an array of microgrid equipment.

Leading their tour was Jennifer Medina, SoCalGas engineering development and technology principal engineer, who oversaw the design and construction of the home and microgrid. She walked the students through a process that starts when solar panels absorb sunlight. This energy then feeds a lithium-ion battery bank with enough capacity to power the microgrid. Any excess power goes to fuel the ERC building.

In addition to learning about sustainable energy technologies during a tour of a SoCalGas model home, UC Irvine students enjoyed a lunch prepared with appliances that operate on renewable electricity or a blend of hydrogen and natural gas. Steve Zylius / UC Irvine

photo: Steve Zylius/UC Irvine

A portion of the renewable electricity goes to an electrolyzer, a machine that splits water molecules into pure hydrogen and oxygen. The oxygen is vented out to the atmosphere, although it could be bottled for other uses, of which there are many. The hydrogen, which is produced at a rate of one kilogram per hour (roughly equivalent in power to one gallon of gasoline), goes to a 10-kilogram storage tank. The microgrid also includes a hydrogen fuel cell which converts hydrogen back into electricity to power the home.

Medina told the students that there are advantages to storing energy in gas form. It allows a home to keep it for much longer in a significantly smaller space.

"There's nothing wrong with batteries, batteries are great and we need them, even here in our microgrid," says Medina. "But a megawatt of power in batteries takes up a huge amount of space. Power leaks out of batteries over time. As long as there is not leak on the hydrogen take, which we monitor for, your energy is going to be available to you for as long as you need it. It can sit there for days, weeks, month, years; there's no degradation. You can generate a bunch of hydrogen with renewables - wind and solar - and when the renewables aren't providing, you can use the hydrogen."

Other features of the microgrid include its water purification system, fire detectors and leak-prevention technologies. Every 10 seconds, the autonomously controlled microgrid monitors the hydrogen concentration in blended gas; if it differs from the intended level, the system shuts down automatically. The proposed blending project on the UC Irvine campus will have much of the same equipment, minus the fuel cell and battery bank.

The model home at SoCalGas' Energy Resource Center in Downey features an outdoor fireplace and barbeque grill using a blend of renewable hydrogen and natural gas. Steve Zylius / UC Irvine

Lunch and learn

Following the microgrid tutorial, the students inspected the home. It's a 1920-square-foot structure constructed of six containerized modules, three downstairs and three upstairs. The Leed Platinum-certified house took three weeks to assemble and features sustainably sourced cabinets, fixtures and furnishings. The home has a grey water system to hydrate the landscaping. The appliances include a dryer, indoor and outdoor fireplaces, a barbeque grill, and a kitchen stove. All are all powered by a blend of 20 percent hydrogen and 80 percent natural gas. Students observed that there is no pilot flame when the stove burner is in the off position.

Lunch was tacos with rice cooked on the stove inside and meats grilled on the blended gas-powered barbeque on the patio. Beverages, guacamole and other accompaniments were kept cool in the renewable energy-powered refrigerator.

Earth system science student Anya Shram, co-president of the Sustainable & Just Future environmental group at UC Irvine, asked how the proposed demonstration project will contribute to SoCalGas' goal of blending up to 20 percent hydrogen with natural gas. Waymire used an example of rolling out fiber-optic cable service in a community; it must start on a smaller scale so that state regulators, residents and utility employees can do it successfully. Interconnecting hydrogen into existing infrastructure won't happen overnight.

Serpas said at its heart, the proposed project was being carried out, at the request of the CPUC, to support California's clean energy transition.

The cooktop on the stove inside the SoCalGas model home burns a blend of hydrogen and natural gas. By using a fraction of hydrogen, normal gas appliances can operate while burning smaller amounts of fossil fuels and emitting less carbon dioxide to the atmosphere. Steve Zylius / UC Irvine

Tina Javid, SoCalGas regional public affairs manager, says her organization and UC Irvine have been cooperating on such a project for more than 30 years. "Who better to partner with than UC Irvine, and why wouldn't you want to do it here in California? We are proud to have projects like this," she said.

"This tour really helped me understand the generation process and the safety measures and monitoring measures. It was nice to get a clear and concise overview of the benefits, not only environmentally but to the UC Irvine community of the project," says Sophia Koelsch, an undergraduate student in environmental engineering and Earth system science and president of Engineers for a Sustainable World.

"To put it bluntly, the tour was really cool. From an engineering perspective, it's fascinating. And for someone interested in the environment, it's interesting to see how normal this kind of technology can look, because it sounds so strange and outlandish. If you go inside the home, it looks just like a normal home," says Koelsch. "It's nice to see that these complex ideas, or ideas that look complex to the typical person and still look like something super familiar."

Project managers expect to see if the CPUC accepts the demonstration project on the UC Irvine campus by the third or fourth quarter of this year.