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Siemens puts two virtual power plants into operation; integrating small renewable sources, including vehicles eventually

Siemens recently put two virtual power plants into operation. Virtual power plants are networks of several small power stations that are run as a single system. One of the new virtual power plants enables the Munich municipal utility company to run six of its cogeneration modules, five hydroelectric facilities, and one wind-power plant more efficiently and economically than if they were operated separately. The facilities have a combined output of 20 megawatts.

The second virtual power plant was set up for the utility company RWE and consists of a number of similar components to those in Munich. Although it will initially also have an output of 20 megawatts, the second virtual power plant will be expanded to 200 megawatts by 2015. The key component of each virtual power plant network is the distributed energy management system from Siemens.

When incorporated into smart grids, virtual power plants open up new possibilities for energy suppliers and operators of energy generation systems.

The electricity produced in this manner can be traded on the European Energy Exchange in Leipzig, Germany, for example, or offered to other markets. Besides offering energy suppliers an additional way of selling electricity, virtual power plants also make the utilities more flexible. In addition, they can help improve grid stability by making controlling power available in the minute reserve range.

Virtual power plants are ideally suited for renewable sources of energy, Siemens says. Since Germany’s Renewable Energy Act was amended in January 2012, the associated market subsidy system encourages operators to sell electricity from their virtual power plants directly on the energy markets.

Siemens’ distributed energy management system networks and combines the various decentralized power producers so that they can be centrally managed. To make this possible, the system processes all of the relevant information, including weather forecasts, current electricity prices, and energy demand. On the basis of this data, the system draws up an operation schedule for all of the associated facilities and monitors its implementation. The system updates its energy consumption prediction every hour, depending on the weather forecast and the type of day. The operation schedule minimizes the costs of generating electricity and operating the facilities within the virtual power plant network. In doing so, the system takes economic as well as environmental aspects into account.

To complement this effort, Siemens’ global research department Corporate Technology is also developing a decentralized communications unit that will enable operators of solar or wind power facilities to logon to a virtual power plant through the Internet with just a few mouse clicks. The operators will retain full control over their facilities and can decide how much of them they wish to integrate into the virtual power plant. A non-commercial prototype of the system was presented at the Hanover Fair 2012 by the RegModHarz project team for renewable energy in the Harz region.

At Hanover, the project team demonstrated all of a virtual power plant’s components, ranging from the powerbridge and the control center to the network surveillance system and the market platform for operators and consumers. The project’s virtual power plant already encompasses several electricity generation and storage facilities in the Harz region, including wind farms, cogeneration plants, and pumped-storage power stations, which were operated live at the trade fair.

At the heart of the control unit is the powerbridge, which can operate all of the connected power generation, storage, and load systems in a coordinated manner. A security architecture protects all of the communications activities. The powerbridge was designed in accordance with the internationally standardized protocol IEC 61850.

Germany’s Harz region is already home to hundreds of small energy generation facilities, which could be integrated into the virtual power plant. The number of facilities is increasing daily through the installation of new photovoltaic systems. Experts forecast that virtual power plants spanning entire regions will one day combine thousands of wind turbines, solar power plants, geothermal facilities, and other energy generation systems in Germany. They will be joined by buildings and electric cars, which will serve as flexible energy sources and increase the number of facilities into the millions.

This huge number of distributed energy generation systems can only be coordinated and managed if the decentralized control units are interconnected in an automatic, easy-to-use, and secure fashion, Siemens suggests.



A case where legal changes has enabled more efficient use of facilities. An example of the alternative is in California: the solar thermal power plants have inefficient gas backup for bad days so that they can individually satisfy their contracts with the utility. A virtual generator consisting of multiple solar thermal and a single efficient gas generator would be more efficient. Just need to structure the business environment so that it makes sense for potential competitors to cooperate like this.

Henry Gibson

Co-generation in homes and other buildings where natural gas is available is the least costly way of reducing CO2 quickly. With computer control already turning off air cooling loads, it can also turn on co-generation eving if some heat must be wasted with low local heat demand. Central fossil power stations waste up to 70 percent of the heat all the time. ..HG..


I was mainly thinking about existing capacity where there is no (more) capital costs to having such an agreement.

But domestic CHP provides another example - not attractive to the utility because it mainly produces electricity in cold weather. But if the CHP scheme came to an agreement with a solar thermal generator - that has the opposite problem - then the two generators spread the risk between themselves and provide something more useful for the utility.


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