Competition > Net Metering
In an effort to reflect how most residential solar systems operate when connected to the power grid, the 2009 Solar Decathlon features a new Net Metering contest. Each team house will be equipped with a utility meter that moves in two directions. This will enable competition organizers to measure how much net energy the house produced or consumed over the course of the competition. Teams score points for producing as much or more energy than they need. When the solar system produces excess electricity, it forces the electric meter to turn backward, enabling surplus electricity to be measured.
The Net Metering contest comprises two parts:
Energy Balance — Teams receive 100 points for producing at least as much energy as the house needs, thus achieving a net energy consumption of zero during contest week. This is accomplished by balancing production and consumption. At the end of competition week, when competition officials read the house electrical meter, it must be zero or less for the team to receive 100 points.
Energy Surplus — Unlike consumers, who in most cases do not benefit from producing more energy than consumed, Solar Decathlon teams can receive up to 50 additional points for producing surplus energy over and above what they use during the contest week. When a team generates surplus energy, the house electrical meter turns backward past the net zero point to indicate a negative reading.