So-called “smart cities” will be characterized by power grids that will be able to balance electricity supply and demand. This will start with buildings that learn occupants’ energy needs, integrate vehicle batteries into their energy forecasts, respond to changing weather conditions, and automatically alter their behavior to maximize their efficiency. Siemens is involved in all of these areas.
The world’s most advanced buildings have brains – a kind of central nervous system that balances and reconciles competing interests such as energy minimization, occupant comfort, and grid stability.
Siemens has already developed a building automation system that accomplish this. Known as Desigo CC, it’s the first management station that allows all building systems to be integrated into a single platform that can be operated intuitively. “Fire protection, heat, ventilation and climate control, lighting, video surveillance — all of a building’s systems are still usually controlled separately today,” says Naoufel Ayachi from Siemens Building Technologies. “Our management station brings all of these systems together for the first time and also displays the status of each in real time. Staff therefore only have to be trained to use one system, which is just one of the reasons why Desigo CC has already been installed in many office complexes, schools, hospitals, and shopping centers, as well as at several airports.”
Despite this success, the standard features of the new management station are just the beginning, as Desigo already forms the core element of numerous Siemens developments that make buildings “smart” — and will do the same in the future for entire urban districts as well.
When Buildings and Cars Communicate
For years, energy experts have questioned how urban power grids will be able to support large numbers of electric vehicles. Today, answers are on the horizon. Within the framework of the EU’s Artemis research project for the Internet of Energy, and with the help of the Desigo platform, Siemens researchers have demonstrated how a fleet of electric vehicles can be integrated into the management of a building. “Here, we connected electric cars to Desigo and didn’t just look at them as energy consumers but also as temporary energy storage units,” explains Randolf Mock from Siemens Corporate Technology. “In terms of building management, they can act asenergy storage units. In the morning, they arrive at an office building, for example, and are connected to charging stations — but they don’t have to be fully charged until evening, when employees go home. During the day, however, the vehicles can be used as buffers that deliver electricity to the building when it’s suddenly cloudy, for example, thereby compensating for the lower energy output of the photovoltaic systems on the roof.”
The basis for this is known as the Internet of Energy, in which vehicles communicate with charging stations. But in this case, a building management system obtains information from the stations regarding the charging requirements of the vehicles. It then uses this information, as well as data from climate-control, heating units and other consumers, to generate an energy demand forecast for the next day. “The forecast is sent to the grid operator, which then suggests a fixed price for a guaranteed amount of electricity,” Mock explains. “If the building fails to conform with its demand forecast — in other words, if it uses too much electricity or not enough, it may have to pay a penalty. In order to prevent this from happening, Desigo uses the electric vehicles at the charging stations as electricity storage or supply units, thus making it possible to keep an entire building’s electricity demand stable.”
U.S. Role Model
Desigo is not the only smart building solution that Siemens is working on. A project in the U.S. illustrates how intelligent buildings might hold the key not only to the integration of electric vehicles into the power supply system but also to achieving stable grids and a lower level of energy demand. “There are a whole range of what are known as peaker power plants in the U.S. that only produce electricity for a few hours each year in order to prevent grid overloads during peak load times,” says Thomas Grünewald from Siemens Corporate Technology in Princeton. “These plants are very expensive to operate, so there’s great demand for cheaper solutions. Our first attempt at such a solution was made a few years ago at the University of California in Berkeley.” That was where Grünewald’s team equipped a building with a “Smart Energy Box” that can lower energy demand in a targeted manner during peak load phases. This eases the strain on the overall grid and therefore also saves money. “The Smart Energy Box can shut down specific individual consumers such as lighting or air conditioning systems,” says Grünewald. “In the process, it takes into account factors such as the anticipated electricity price, the weather forecast, and standard values for a good indoor climate to keep productivity up. This conserves energy and saves money, while maintaining the proper level of comfort for building occupants. The system can also lower energy demand outside of peak load times — by as much as 30 percent in the building in Berkeley.”
Siemens researchers took things a step further in a project in Colorado Springs, as Grünewald explains: “We connected an entire building complex at the U.S. Air Force Academy there in a microgrid. As is the case with the system in Berkeley, software manages energy demand on the basis of electricity price and weather data, but this system can also distribute savings potential across several buildings. This type of microgrid, which uses a market-based approach to data and a unified energy management system is the biggest single unit in such a setup after the building itself. It’s even possible that entire urban districts could become part of such a smart grid and communicate with one another, which would enable even greater optimization potential using a collaborative energy management approach.”
These examples provide a peak at the future of smart buildings. Such buildings will be able to manage their energy demand ever more precisely and link up with other buildings to form microgrids. This will stabilize primary grids, compensate for supply fluctuations, and reduce overall energy demand.
“The smart buildings of the future will do this using many types of temporary energy storage units, such as the electric vehicles I mentioned before, thermal storage units such as water tanks, and mechanical units such as flywheels,” says Mock. “Our Desigo system offers a preview of how all of this might be managed and intelligently controlled.”
Says Ayachi: “The intelligent control of buildings will also become more and more digital; in the future we’ll see cloud solutions without any onsite infrastructure. Costs will be much lower, the systems will be maintenance-free and require hardly any personnel, and it will be possible for customers to book systems permanently or for specific periods of time. Customers will also be able to easily enter settings via a smartphone.”
Grünewald takes a similar view. “Users will communicate more extensively with buildings in the future using smartphones or other devices and will also be able to define their own personal comfort profiles, for example. Building management systems could then use digital appointment calendars to arrange users’ workstations in line with their preferences before they arrive, and save energy when a user is not in the office.” Add it all up and it appears that buildings will increasingly have the ability to listen to and accommodate the wishes of their occupants.