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Denver, Colorado
October 5-15, 2017

Solar Decathlon Blog - Energy Balance

Below you will find Solar Decathlon news from the Energy Balance archive, sorted by date.

Balance of Power: Solar Decathlon Contest Requires Energy Efficiency and Power Production

Thursday, July 17, 2014

By Carol Laurie

Not consuming energy is better than buying or producing it—even when that energy is generated by clean, renewable solar. That’s the message the U.S. Department of Energy Solar Decathlon 2015 is sending to decathletes through the Energy Balance Contest, which measures the energy each team house produces and consumes over the course of the competition.

The contest is divided into two subcontests: energy production and energy consumption. To earn full points in the energy production subcontest, teams must produce at least as much energy as they consume, achieving a net electrical energy balance of at least 0 kWh. Reduced points are earned for a net electrical energy balance between -50 kWh and 0 kWh. For the energy consumption subcontest, teams must limit their electrical energy consumption to 175 kWh over the course of the contest. This consumption level is significantly less than that of a comparably sized, newly constructed, code-compliant U.S. house.

Photo of a young man wearing an oven mitt and holding a pan of food above a stove.

Michael Kinard, a member of the University of North Carolina at Charlotte Solar Decathlon 2013 team, prepares traditional southern cuisine for dinner guests from other university teams. To achieve high scores in the Solar Decathlon 2015 Energy Balance Contest, teams will have to use energy strategically when completing competition tasks such as cooking and hosting dinner parties. Credit: Eric Grigorian/U.S. Department of Energy Solar Decathlon

“Teams will have to think carefully about energy use to score well in the Energy Balance Contest,” said Joe Simon, U.S. Department of Energy Solar Decathlon competition manager. “They will have to design houses that are extremely energy-efficient and will have to operate them intelligently.”

According to Simon, the Energy Balance Contest will require teams to complete all competition tasks—such as doing laundry, running the dishwasher, and hosting dinner parties—using approximately 60% of the energy consumed by the average house built today.

“Challenges presented by the Solar Decathlon through contests like Energy Balance require teams to establish strategic and sometimes creative strategies to win,” he said. “By encouraging innovation like this, the Solar Decathlon provides students with a unique and effective way of learning science, technology, engineering, and mathematics that prepares them for careers in clean energy.”

Carol Laurie is the communications manager of the U.S. Department of Energy Solar Decathlon.

Solar Decathlon Village Powered by Microgrid and Sponsor Support

Wednesday, June 25, 2014

By Carol Laurie

Since the U.S. Department of Energy Solar Decathlon 2009, a temporary, ground-laid electrical grid (or “microgrid”) has connected Solar Decathlon houses with one another and the local utility. The village microgrid allows excess power generated by the houses’ solar electric systems to be sent back to the larger city utility grid and its customers. The microgrid also enables the competition houses to draw energy from the utility when consumption exceeds production.

In Solar Decathlon 2002, 2005, and 2007, Solar Decathlon houses were grid-independent and ran off batteries that stored the electricity generated by their solar photovoltaic systems. In 2009, competition organizers decided to connect the houses to the electrical grid to better reflect the typical residential configuration found today. By connecting each house to the local electric utility grid, the microgrid enables houses in the Solar Decathlon village to function the same way solar households throughout the United States operate.


Photo of a group of people talking next to an electrical box.

Byron Stafford (second from left), who served as the Solar Decathlon site operations manager from 2002 until 2013, consults with a team member from the City College of New York (right) about interconnecting the team’s house with the 2011 village microgrid. Stafford and his team of engineers transitioned the solar village from battery storage to grid power by installing the first Solar Decathlon village microgrid in 2009. (Credit: Carol Anna/U.S. Department of Energy Solar Decathlon)

Energy Balance Contest

The microgrid also changed the Energy Balance Contest, for which teams earn points based on their energy production and energy consumption. Before the microgrid, organizers measured the flow of energy in and out of battery storage during the competition. Now, the energy each house produces and consumes over the course of the competition is measured with a bidirectional utility meter.

When the sun shines, the solar system produces electricity that is used to power appliances, lights, mechanical systems, and even an electric car. If the system produces more electricity than the house needs, excess electricity flows from the house back into the microgrid and the larger utility grid. At night, or when the demand for energy exceeds the amount of energy being produced, the house consumes electricity from the grid.

In this way, the microgrid provides two-way power flow and enables the Solar Decathlon village to operate continuously regardless of available sunlight or household electricity requirements.

Powered by Sponsors

The Solar Decathlon depends on sponsors to provide the supplemental expertise and equipment needed to design, build, and operate the village microgrid.

For the 2009, 2011, and 2013 competitions, Solar Decathlon sponsor Schneider Electric provided microgrid design and engineering services as well as electrical distribution equipment required to safely and reliably connect the Solar Decathlon village to the local utility. In 2011 and 2013, Schneider Electric also provided a proprietary metering and data system that enabled online and onsite demonstrations of real-time electricity generation and consumption in the village.

The microgrid also depends on local utilities to enable interconnection of the main utility grid with the Solar Decathlon microgrid. Edison International (the parent company of Southern California Edison) provided this crucial sponsorship in 2013, and Pepco stepped up to the plate for Washington, D.C., events in 2009 and 2011.

Other microgrid sponsors include MicroPlanet, which sponsored voltage regulation equipment in 2013, and M.C. Dean, which installed the microgrid in 2011.

All of these sponsors worked together to provide a valuable addition to the competition.

Carol Laurie is the communications manager of the U.S. Department of Energy Solar Decathlon.

New Contest Data Displays Provide Insight into Competition Scoring

Saturday, October 5, 2013

By Solar Decathlon

New contest data displays are now available on the U.S. Department of Energy Solar Decathlon website. If you are interested in the real-time performance of each house and want to keep a close eye on the competition, check out the Contests section pages.

In the Contests section, the pages for the measured contests (Comfort Zone, Hot Water, Appliances, Home Entertainment, and Energy Balance) explain the contest requirements and provide real-time graphical displays of the accumulated measurements/scores for each team. Roll your cursor over the graphics to see more detailed information about each contest. For example, in the Appliances Contest graphic, the scores for running the refrigerator, freezer, clothes washer, dryer, and dishwasher are displayed. The measurements for the Refrigerator and Freezer subcontests are shown in graphs below.

The Energy Balance display is also insightful. In the Energy Balance Contest, teams receive full points (100) for producing at least as much energy as their house uses. The graph shows the net energy production/consumption of each house in kilowatt-hours (kWh). If the value for net energy is a positive number, the houses have produced more energy than they have used during the competition. Hover your cursor over a line to display the team name. Or toggle team lines off and on by clicking on the teams names in the legend on the right.

Contests one through five are juried contests. Check back on Thursday for Affordability and Market Appeal contest results, Friday for Communications and Architecture contest results, and Saturday for Engineering Contest and overall winner announcements. In the meantime, follow the scoring for the performance-based contests like never before!

University of Wollongong Wins SD China!

Sunday, August 11, 2013

By Richard King

I am proud to be an American—and prouder yet to be an employee of the U.S. Department of Energy. We brought an inspiring and beneficial competition to the People’s Republic of China! By the end of the event, a quarter-million people will visit the competition houses displayed at Solar Decathlon China. The event has made a real impression on the government and people of Datong. I hope it leads to positive change.

Photo of a group of students cheering on a stage. They hold a banner that says “University of Wollongong: Australia.”

Team UOW from Australia rejoices after being announced as the winners of Solar Decathlon China.

Team UOW from the University of Wollongong in Australia held the winning trophy high this morning and rejoiced in a remarkable victory. Its entry was the first retrofitted house entered in a decathlon. Instead of designing and building a new house from the ground up, they took an old house and refurbished it. They added new insulation to the walls and attic, installed new windows, and changed some of the interior rooms for more functionality. The end result was a modern, very energy-efficient house that won the praise of everyone—especially the jurors—who went inside for a tour. This morning, the team was awarded first place in Architecture and Solar Application! I will remember them as the team from Down Under who always greeted you with a friendly “G’day, mate!”  

Photo of a group of students cheering a raising a small trophy in the air.

Team SCUT, the second-place winner from South China University of Technology and Huazhong University of Science and Technology celebrates.

Team SCUT from South China University of Technology and Huazhong University of Science and Technology took second place. It moved ahead of Sweden with its near-perfect performance. Team SCUT received the highest score in four of the performance-based competitions: Hot Water, Appliances, Home Entertainment, and Energy Balance. It also won third in the Architecture Contest. The team was overjoyed and so happy to take a top honor. I am sure people throughout China are proud of this team.

Team Sweden from Chalmers University of Technology won third place. The team was in the top of the standings throughout the competition and finished with a strong performance. I loved that you had to put your shoes in a basket by the door before entering their house. Then, after touring the house in your socks, you would look for your shoes in a basket by the back door. The house, designed for college students to live in, was enjoyed by all.

As a proud employee of the U.S. Department of Energy, I couldn’t be happier. We nurtured this event in America, watched it grow in Europe, and witnessed it reach new heights here in China. I am so glad to see our good work spread around the world.

There are so many people to thank for making the first Solar Decathlon China a success: The National Energy Administration, the City of Datong, sponsors, students, faculty, and the hundreds of volunteers who worked tirelessly. They deserve our deepest thanks and appreciation.

And the student decathletes, especially. They bring us so much hope for a better future.

Richard King is the director of the U.S. Department of Energy Solar Decathlon.

Solar Decathlon Data Demystification

Thursday, September 29, 2011

By Alexis Powers

How do you identify the measured contest captain on each U.S. Department of Energy Solar Decathlon team? Listen for words such as datalogger, monitored performance subcontest, and database-driven scoring application.

These students focus on maximizing the points their teams earn in the five measured contests:

  • Comfort Zone
  • Hot Water
  • Appliances
  • Home Entertainment
  • Energy Balance.

To be successful in measured contests, the decathletes must strategize. For some measured contests, they must complete tasks such as washing a load of towels and operating a home entertainment system for a set time. A group of observers keeps detailed logs on their task performance that are later translated into scores. For other measured contests, the competition houses are equipped with sensors that measure factors such as humidity and temperature. An instrument called a datalogger keeps track of the data points and sends this information to a central database every 15 minutes.

Photo of a circuit panel section labeled “datalogger.”

The datalogger in Team New Zealand’s house is competition-ready. (Credit: Alexis Powers/U.S. Department of Energy Solar Decathlon)

“The equations in the rules define how we take information from the dataloggers and observer logs and calculate a score,” says Mike Wassmer, the scorekeeper and assistant competition manager of Solar Decathlon 2011. These algorithms translate a sea of data into a final score for each measured contest.

To follow your favorite team’s progress in the measured contests, visit the scoring pages on the Solar Decathlon website. Then tell all friends about it—and make sure to spice up your conversation with words such as observer logs and central scoring database.

Alexis Powers is a member of the Solar Decathlon communications team.



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