Of course EcoGrid is still just a demonstration and research project. The control units are only being used for the electric heating systems, boilers, and heat pumps. Dishwashers and washing machines, for example, cannot be easily integrated into the system, because they don’t speak the same digital language. The devices that are suited to the project are mainly those whose operation is flexible. That includes heating systems, because the exact time when heating is on is less important than a constant pleasant temperature. In the future, solar cells and electric vehicles will be integrated into the system, but even the success achieved to date is impressive. “If we use the data we have already accumulated from the Siemens houses to calculate how much energy was used during periods of peak supply,” says Per Lund, the Chief Engineer at Energinet.dk, “we can already conclude this technology can help the Danish power system to integrate renewable energy sources and to operate in balance.”
The interim results also clearly show that automation is the best solution. That has been demonstrated by the behavior of the group of households that manually switched appliances on or off based on electricity prices provided over the Internet. Those households hardly reduced their electric bills at all. “At first it was fun to follow our power use on the Internet,” says Group 2 participant Niels Erik Rasmussen. “But in the long run it was just too much effort.”
Rasmussen’s opinion reflects experience in other energy markets, such as the U.S. For example, in 2008 researchers from the Xerox Research Center provided labels for appliances in Californian test households to inform owners about the cost of electricity at various times of th day. But people continued to use their appliances whenever they needed them, rather than at the times when power was cheapest. “If we want to stabilize the electric grid, energy demand will have to be adjusted automatically,” says Professor Jacob Østergaard from DTU Technical University. “The electric bill will then shrink by itself. Customers will only need to enter their preference settings.”
Østergaard has built a replica of the control room of the Østkraft electric company at his university. “In theory, we could intervene in the power grid,” he says. “However, we’ve deactivated these functions; we only want to collect measurements.” His projects include not only EcoGrid, but also a network of about 50 refrigerators in supermarkets. When the frequency in the grid decreases, the cooling units are automatically switched off. After the frequency stabilizes, the cooling units are switched on again. Either some or all of the units can react together, depending on the degree of fluctuation in the grid.