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From a cutting-edge micro-grid electrical system to a 71,000-gallon basement cistern that stores rainwater for conversion to drinking water, the PAE Living Building in Portland is going to be a living laboratory of innovation.

Walsh Construction is preparing to break ground soon on a parcel at the corner of Southwest Pine Street and First Avenue in Old Town Chinatown. The five-story, 58,700-square-foot office building was designed by ZGF Architects to meet the requirements of the International Living Future Institute‘s Living Building Challenge. If successful, it will be the largest commercial Living Building in Oregon and the first of its type in Portland.

鈥淭here are not many buildings like this out there,鈥� said Marc Brune, a principal with PAE, the engineering firm responsible for designing the building’s mechanical, electrical and plumbing (MEP) systems. 鈥淎nd they’re all different.鈥�

Brune, who led the PAE design team, detailed several new technologies and processes expected to help the structure ultimately become a certified Living Building. That will require it to produce more power and potable water than it consumes.

Power is probably the easier of the two, Brune said, and will be accomplished through the combination of a 95-kilowatt rooftop photovoltaic array and a micro-grid system that uses a large lithium-ion battery to store excess power.

鈥淏ecause of the spot network and the way the grid is set up, we can’t feed as much energy as we want out to the grid,鈥� Brune said. 鈥淪o we’re getting around that with a 250-kilowatt battery. It’s a pretty big battery for a building, and a micro-grid controller paired with batteries allows the building to operate on an independent grid within the building itself.鈥�

The controller determines whether to send energy to batteries, the grid or the building itself. Use of a battery also allows for a larger photovoltaic array than otherwise.

The project is being closely watched by Portland General Electric, which already is running a pilot program for two other projects’ micro-grid systems. One of them is the Beaverton Public Safety Center being constructed by Skanska USA Building. PAE also served as the MEP engineer for that project and lessons learned are being carried over into the PAE Living Building.

Darren Murtaugh, a senior manager for energy storage at PGE, said the term micro-grid describes systems ranging from a single site up to a large section of the electric grid.

Unlike the Beaverton project, the PAE Living Building will have to contend with a much denser network.

鈥淭he challenge that we both recognize is they’re in the downtown core area network, where it’s really difficult to be able to feed energy back to the grid,鈥� Murtaugh said. 鈥淭hat’s where the engineers on both sides of the equation both get very excited; that’s part of the fun. We’re working together pretty closely these days to figure out how can we unlock this puzzle and qualify as a Living Building.鈥�

The key is energy storage technology.

鈥淚t’s the ability to time-shift the energy they produce with solar and 鈥榣evelize’ it so there’s no instance in time where the back-feed into the grid is too great,鈥� Murtaugh said.

Further, the system will automatically disconnect when power flows from one or more customers back to the grid.

鈥淭his didn’t use to be a problem,鈥� Murtaugh said. 鈥淏ut in tomorrow’s world that is a concern. Fundamentally it changes everything about what was a really high-reliability design. It doesn’t work right when you have customers who want to back-feed into the grid.鈥�

Fortunately, micro-grid systems are an emergent technology, and the price of lithium-ion battery storage has fallen in recent years. Think Tesla electric cars for a close comparison.

鈥淢ost buildings have not been designed to do net zero in places where your grid limits your ability to feed back,鈥� Brune said. 鈥淎nd other projects that consider a micro-grid controller and battery are normally critical facilities, something that needs to operate independent of the grid.鈥�

Achieving net-zero water use is a bit trickier. As designed, the PAE Living Building will use only water collected and treated on-site.

All rainwater falling on the building will be collected and sent to the basement cistern for treatment. On the flip side, a new type of vacuum-flush plumbing system will collect wastewater and feed it to a series of composters, which will convert it into nitrogen- and phosphorus-based fertilizers.

A urine separation system will even sequester and treat an anticipated 30 gallons of wastewater per day for use as fertilizer. The vacuum-flush system, meanwhile, will feed the cistern in just 0.1-gallon increments 鈥� roughly 20 percent of the average flush toilet.

The project will feature locally-sourced cross-laminated timber and not use galvanized steel products in order to avoid hexavalent chromium 鈥� a known carcinogen.

It’s the issue of power, however, that is most important to the project and future ones. That is because renewable energy systems have the most potential for wider adoption.

鈥淏atteries are a hot topic in the industry,鈥� Brune said. 鈥淎s costs come down, if everyone is net metering, then the utility becomes stressed without the storage aspect.鈥�

It’s an area of the industry where even the experts have a lot to learn, Murtaugh said.

鈥淲e’re hoping they (pilot projects) will give us real world experience in location-specific benefits,鈥� he said. 鈥淲e can answer how these resources can be leveraged to offset traditional distribution investment and how they can improve voltage management. Today, none of us are very good at quantifying what that potential value is.鈥�