Customer application 16 March 2018
Balancing Energy from the Refinery

In its virtual power plant, the VERBUND Power Pool, Viennese energy supplier VERBUND Solutions GmbH combines decentralized electricity producers and loads for marketing to the balancing energy market. One of these decentralized producers is OMV, an integrated oil and gas company. The process data is exchanged via telecontrol technology from WAGO.

Providing electricity is a complex business that presents technical and logistical challenges to power supply companies, because the balance between production and consumption needs to be maintained at all times to keep the power system from collapsing. Therefore, electric companies have to ensure that sufficient electricity is always available in the system and the grid remains stable, despite unpredictable, fluctuating consumption levels.

Frequencies in the power grid can fluctuate in the event of supply peaks or power plants outages, so national balancing energy markets exist to guarantee a constant frequency of 50 Hz. Balancing energy is a type of energy reserve that can be physically tapped on short notice to prevent an electrical grid collapse by re-stabilizing the frequency at 50 Hz. Austria defines primary, secondary and tertiary balancing reserves according to whether the producer supplies the required energy within a few seconds within five minutes or within ten minutes.

Integrating Decentralized Suppliers – Here’s How WAGO Supports You:

Pre-assembled control boxes link producers, consumers and sellers.
The heart of this solution is the WAGO PFC200 Controller, which features the latest safety technologies.
An integrated GSM modem also makes allows remote systems to be connected to a virtual power plant.

The Pan-European Balancing Energy Market

In addition to conventional electricity producers, the balancing energy market makes it possible for loads and consumers in industrial environments to keep the electrical system stable through reductions/increases in electrical generation and activation/deactivation of loads, following successful prequalification. In Austria, the oil and gas company OMV took advantage of this opportunity and prequalified as a supplier of tertiary balancing energy three years ago.

“We operate two combined heat and power plants at our refinery in Schwechat, near Vienna. Thesse power the entire petrochemical facility. We burn unusable residues from gasoline and diesel production, as well as natural gas, residual gas and mixed gas,” explains Alexander Radauer, Head of Fuel Procurement for the OMV refinery in Schwechat, and adds: “The capacity of our CHPs essentially meets our in-house demand. However, the production residues we convert to electricity don’t arise in a predictable way and can’t be stored in all cases. When the balancing energy market opened up for industrial systems, that offered us the option of selling our excess electricity.”

When the balancing energy market opened up for industrial systems, that offered us the option of selling our excess electricity.

Alexander Radauer, Head of Procurement at OMV

After a year of collaboration with Slovenian energy supplier GEN-I, OMV now cooperates with VERBUND Solutions GmbH on the VERBUND Power Pool. When excess capacity exists, this e oil and gas company can activate up to 15 megawatts for the short-term balancing reserve. A Radauer explains: “We only provide the asset. The Power Pool select sells the energy to the balancing energy market.”

OMV’s asset is one of many that feed current into the power grid during frequency fluctuations or draw power in the event of a surplus. To simplify handling of both the decentralized electrical producers and the loads, VERBUND Solutions combines the decentralized energy systems and loads into so-called virtual power plants. “As a supplier of balancing reserve energy, this has many advantages for us: We can combine decentralized producers and consumers into one large aggregate in a virtual power plant. Then we can sell the bundled individual participants to the balancing energy market,” explains Bertram Weiss, Product Manager at VERBUND Solutions GmbH.

The Control Box as the Heart of the System

A control box located in the corresponding power plant functions as a communication interface between the producers, consumers and sellers. At its core is a WAGO PFC200 Controller. “Upon request of the virtual power plant, the WAGO controller collects the requested power plant data, such as supply capacity status and available output information, and returns it in bundled form. In the reverse direction, the PFC200 accepts requests to provide power and transmits them to the control center of the CHP. “Power-plant-specific interfaces originally consisted of several digital and analog signals. Since the conversion, this information is now transmitted with serial two-wire bus systems, Modbus RTU,” explains Martin Kluchert from WAGO.

The communication between the virtual power plant and the WAGO controller goes over landlines and is encrypted via a VPN tunnel. In the OMV/VERBUND cooperation, the oil and gas company transmits around 25 data points to the grid operator, which sends around ten data points to its decentralized electrical suppliers. The WAGO controller converts commands and information to Modbus RTU in order to communicate with the process command system at OMV.

“The process command system notifies the power plant operator of the request, both on a user interface and with an acoustic signal, at which point the operator supplies excess capacity to the grid by manually spinning up the turbines. As a supplier of tertiary balancing energy, OMV is required to reach the setpoint within ten minutes,” explains Bernhard Voge, who is in charge of maintenance of the CHP control technology at the OMV refinery in Schwechat. Direct automated access to the power plant controller via the control box is not required, due to the long run-up time; however, such access is planned for the future when the company begins providing primary balancing reserves, for which the run-up time is a few seconds.

As a supplier of tertiary balancing energy, OMV is required to reach the setpoint within ten minutes.

Bernhard Vogel, Head of Maintenance at OMV

“Their high level of operational reliability, ease of operation and expandability, as well as the large number of supported interfaces, are all points in favor of WAGO controllers,” says Jakob Fölser, the contact person for technical connection of virtual power plants at VERBUND Solutions, adding: “The pre-assembled control boxes allow us to add a decentralized energy supplier to a virtual power plant at any time and, what’s most important, without any programming. This helps save time and money.”

Controller Communication Interface

“Small, decentralized power plants often lack a uniform interface and instead have hardware inputs and outputs. For example, digital outputs report operating states, like faults, maintenance or availability, and analog signals are used to exchange information on the capacity current available or requested. Bus systems like MODBUS are PROFIBUS are also common,” says Martin Kluchert from WAGO. The WAGO controller provides the communication interface between power-plant-specific interfaces and the control system of the virtual power plant. The connection to the network operator out uses various standardized telecontrol protocols. In Europe, this is usually IEC 60870 or IEC 61850, depending on the system type.

And the WAGO controllers also implement additional specifications like VHPready. This new industry standard, introduced by WAGO, defines operating conditions, operating properties and data points so precisely that any system can be integrated into a VHPready network without additional software programming. “Security technology, from firewalls to VPN clients, is integrated into the controllers to help protect critical infrastructures. And linking small, remote power plants together into one virtual power plant is quite simple using the integrated GSM modem,” adds Kluchert.

The pre-assembled control boxes allow us to add a decentralized energy supplier to a virtual power plant at any time and without any programming.

Jakob Fölser, Contact Person for Technical Connection at VERBUND Solutions GmbH

VERBUND Solutions already employs the VHPready standard in additional control boxes, using it to connect several small power plants to its virtual power plant. For this purpose WAGO, offers an application that is read-made but still expandable. It enables VERBUND Solutions to link power plants quickly and flexibly with a graphical configuration interface, taking individual request into account in the process. The modular WAGO I/O SYSTEM, which is provided in pre-wired boxes, supports this process and ensures long-term system availability thanks to its extreme durability.

Text: Martin Kluchert | WAGO

Photo: OMV

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Customer application 16 March 2018 Balancing Energy from the Refinery