Research at the University of Arizona's Biosphere 2 campus is finding ways for cities to more effectively monitor – and manage – water and energy use.
"We look now at the entire 30-acre campus of Biosphere 2 as a model city," said Nate Allen, sustainability coordinator at the facility near Oracle. "It's not a real city, but it has enough qualities of a real city with a level of control and flexibility to manipulate it that you don't have in a real city that we can learn things from that."
The Biosphere 2 campus contains scaled down versions of the water and power use elements that make up a large community: residential, office and commercial/manufacturing, Allen said.
On Biosphere 2's microgrid, 30 casitas, where researchers working at the facility or people attending conferences can stay, represents a residential neighborhood scale of energy and water use, he said. A section of campus made up of administrative offices and conference facilities is comparable in energy and water use to an office building. And the 3.15 acre enclosed Biosphere 2 structure itself is comparable to a commercial or manufacturing site in terms of water and energy use, he said.
"Both the scale of the Biosphere 2 campus, where it's got these different levels of energy and water demand, and the level of control we have over it, allows us to run simulations that can teach us lessons we can apply to the greater utility grid both in southern Arizona and across the nation," he said.
"What were working to do in our own small microgrid here is instrument our grid to the level where we have a high accuracy of monitoring where all the energy and water is going, at what times of day, in what amounts, and being able to control that more effectively in real time," Allen said. "So we can say, there is a cloud coming over, and the solar panel power is gong to drop, so we can turn off these non-essential pieces of equipment so that the essential pieces of equipment can continue to run on solar power until the sun comes back out and we can turn everything else back on."
Each of the guest casitas features a power cost monitor that shows in real time how much energy is being used at that moment, the cost of that energy, energy cost per day, a record of energy use in the past day and week, along with a prediction of that the monthly energy bill will be, Allen said.
A supervisory control and data acquisition system monitoring the entire Biosphere 2 campus offers a detailed look at what is going on to keep the operation running.
The system offers data on temperature, humidity and CO2 levels throughout Biosphere 2 as well as monitoring energy and water use at the facility.
By studying use patterns, researchers can predict when energy demand will wax and wane, and plan so that non-essential devices can be used in non-peak use times.
Biosphere 2 researchers are working to find ways to make water and energy work together for sustainability.
"We think our existing water system is well suited to do pump hydroelectric storage," he said. "From the well to the top tank it's about 1,000 feet grade difference so we can pump about 300,000 gallons of water back and forth between those storage tanks. We're pursing funds to do multi-directional turbines."
Water would be pumped uphill during the day using power from solar panels. The water would run downhill powering turbines to produce electricity at other times, he said.
Water and energy combine to play key role in sustainability, he said.
"Water and energy, we seem to always separate when we talk about them. In reality, they are very difficult to separate. Most municipalities average about 70 percent of their total electric bill moving and treating water. A vast amount of water is used in the process of making the electricity we then use to move the water around," he said. "The Biosphere 2 campus is a great place where we both use energy and water from the grid and we have energy and water sources that are our own."
Biosphere 2's efforts to conserve have proven effective.
"Since the University of Arizona has come to Biosphere 2, our energy consumption has dropped by nearly 70 percent," Allen said. "In 2003, the Biosphere was typically operating at about 13 million kilowatt hours (per year). This last year, 2009, we used about 4.5 million kilowatt-hours. And in large part that is because we have gotten creative about how we maintain conditions inside the Biosphere 2."