NZ pavilion (emerge)IMG_6719In the Net Zero Zone at Greenbuild 2014, exhibitors will demonstrate a solar-powered microgrid by disconnecting from the energy utility.

Photo of Greenbuild
Solar modules on the balcony of the convention center power the Net Zero Zone at Greenbuild 2014

“Two years ago at Greenbuild I predicted that in a few years you’ll come to this conference and the booths will be powered by renewable energy generated at the show,” says Brian Patterson, president of the nonprofit EMerge Alliance. “When I walked away from that conversation, I decided that was my goal.”

Mr. Patterson will finally see that goal become reality in the Big Easy this morning at the 2014 Greenbuild International Conference and Expo. The “Greenbuild Unplugged” opening ceremony will introduce the world’s first net-zero-energy exhibit pavilion.

Greenbuild photo
The Net Zero Pavilion in the expo hall of Greenbuild 2014 during setup on Tuesday

The Net Zero Zone will showcase how 11 exhibits in the Greenbuild expo hall can unplug from the utility grid and operate on power generated by solar panels on the balcony of the Morial Convention Center.

What if it’s a cloudy day? Not likely this week in New Orleans. But if the solar power were to be interrupted, a battery bank and utility power would continue supplying electricity to the exhibits. A lithium iron phosphate (LiFePO4) battery bank stores power to be used when demand exceeds solar energy supply. The batteries can also recharge using grid power.

The exhibits are connected using a microgrid. The term is broadly used to describe an electricity generation, distribution and storage network designed to operate either in combination with or in isolation from the main power grid. There are varieties of microgrids.

“When utilities talk about microgrids they’re talking about multiple buildings,” Mr. Patterson explains. The Net Zero Zone’s microgrid is different. It’s a direct-current (DC) network connecting electric loads within one building.

Of the 11 exhibits in the pavilion, only EMerge Alliance and two others run exclusively on DC power. Most of the exhibits are using conventional alternating current (AC) for lighting and other loads. For those vendors, DC power is inverted to AC at their exhibits.


Net Zero Energy Pavilion photo
Lithium iron phosphate batteries store energy for a rainy day, or any time solar isn’t keeping up

CONSIDERABLE WORK remains to be done before we’ll see entire buildings running on DC power. It’s among the more ambitious market transformation efforts in the energy efficiency sector. There are standards to define, equipment to redesign, and building industry people who need to get comfortable with the idea.

The EMerge Alliance has published standards for occupied interiors, data centers and telco central office facilities. The Alliance will have another standard coming out in 2015 for microgrids that connect whole buildings and campuses. A residential standard is also in the works.

Turning buildings into their own generating stations appeals to owners and tenants, but not so much to the utilities that are required to serve them when solar power doesn’t keep up with demand.

“If we can isolate buildings and operate them as if they’re mini power stations, we can manage demand response and load balancing, and we think we could even give VAR assistance and phasing help to utilities,” Mr. Patterson says. That might make utilities a little less squeamish about microgrids.


SOLAR POWER isn’t an option for every building. In that case, “you can run your own generators on biofuels, or you might use wind power or a fuel cell, which is extremely clean,” Mr. Patterson says. Then there are the less obvious energy sources.

“In my opinion there is enough waste power around that even today we’d have a squanderable supply of electrons if we would harvest everything we can.” Mr. Patterson is talking about energy from building vibration, flipping light switches, micro hydro from lavatories, even employees on exercise bikes.

Some energy is consumed in converting those sources to AC power to make it compatible with conventional building equipment. To harvest it without that drain would require equipment that runs on DC power. The Alliance’s 90 member companies are manufacturing that equipment.


Energy dashboard at Greenbuild 2014
Dashboards on the Greenbuild expo floor and in the Net Zero Networking Lounge will display the pavilion’s performance

A HUGE HURDLE for DC microgrids is a lack of awareness among the architecture and engineering community.

“Most architecture, engineering and construction people haven’t been exposed to this idea,” Mr. Patterson says. “So far we have mostly pioneers, the few brave people who have embarked on it.”

Thus the fanfare at Greenbuild, to reach that audience. The “unplugging” ceremony will take place at 10:30 a.m. Wednesday, October 22, 2014, in the Net Zero Networking Lounge in Hall X on level 2 of the Morial Convention Center in New Orleans, LA. Participants will include representatives from the U.S. Green Building Council, Hanley Wood, the EMerge Alliance and local officials. Greenbuild attendees are welcome to join in.

The exhibits in the Net Zero Zone are centered around the EMerge Alliance booth number 2069. The expo hall opens at 9:00 a.m.

Dashboards on the expo floor and up in the networking lounge will display the pavilion’s performance in real time. Mr. Patterson is expecting a larger pavilion at Greenbuild 2015, and perhaps an online dashboard so the world can watch the Net Zero Zone produce its own power.

Microgrids have been a hot topic since hurricanes Rita and Katrina caused widespread utility interruptions here in 2005. Resiliency against natural disasters is a subtheme at Greenbuild 2014.

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Denis Du Bois has been attending Greenbuilds since 2005.