Virtual reality

ABB’s central control and optimization system enables cost-effective virtual power plant operation

SLEMAN SALIBA – A virtual power plant (VPP) is a collection of power balancing. Hence, the penetration of and the revenues power generator units, power storage devices and flexible from renewables can be increased significantly. ABB’s central power consumption units that is directed by a central control VPP control and optimization system not only allows opera- system. A VPP can enable the participation of small- and tors to run their VPPs in real time, but it also enables them to medium-sized renewable power generation units in the operate their plants in a cost-optimized manner according to or in the provision of grid services such as their own particular needs.

­24 ABB review 4|15 1 ABB’s central VPP control and optimization system simplifies VPP operations.

Gas turbine power plant Industrial side Hydropower plant

+ - Storage plant

Wind farm Control center

Power grid

Demand Production Power price forecast forecast forecast

+ - Storage Industrial side Gas turbine Technical units / microgrids

Energy trading takes place in three dif- Typically, VPPs will ferent markets: the balancing market, the spot market and the derivatives pool production market. Additionally, there are over-the- otential VPP power generation counter (OTC) trades in which partners assets encompass almost the from hundreds of trade energy bilaterally. This article entire spectrum of power-pro- small- and medi- deals with the opportunities that arise P ducing technology: , bio- for VPPs in the liberalized energy mar- mass, combined heat and power (CHP), um-sized renew- ket and uses the German microCHP, wind, solar, hydro, power-­to- and the European Energy Exchange as heat, diesel engines and fossil-fuel. Typi- able energy plants references. The concepts, however, apply cally, VPPs will pool production from hun- into a large-scale to most international power grids and dreds of small- and medium-sized energy markets. plants into a large-scale VPP that has the VPP that has the size and flexibility to par- The balancing power market ticipate in the electricity market – espe- size and flexibility The prerequisite for stable operation of cially in lucrative ancillary grid services. to participate in the the power grid is a balance between pow- er generation and power consumption. In addition, a VPP can make use of many electricity market. So-called balancing power is injected if kinds of solutions – like any difference between the two should batteries, thermal storage, compressed arise. The goals of balancing power are to air or pumped storage. Finally, some Markets ensure that the frequency stays, within a consumers can also become a part of One of the main challenges involved in defined tolerance, at 50 Hz and to com- the VPP topology – by, for example, operating a VPP is to place available pensate for regional differences in power varying their processes to suit prevailing power on the different energy markets to generation and power consumption. power economics or by timeshifting maximize returns. ­production loading ➔ 1. To achieve these goals, three types of The first step in accomplishing this is to balancing power interact dynamically: Broadly stated, the goals of a VPP are establish the available power capacities primary balancing power, secondary bal- threefold: to attain better prices for pro- in the VPP, the renewable production ancing power and minute reserve. duced energy on the spot and deriva- forecast, the foreseen load demand and tives markets, to participate in the power the long-term obligations. These are Balancing power is obtained from ancil- balancing market and to optimize inter- then passed to a market optimization lary grid service providers responding to nal production and consumption. system that distributes available power offers to tender issued by the transmission generation capacities from the VPP to system operators (TSOs). Before the VPP the different energy markets. operator can bid on this balancing power Title picture How do virtual power plants enable the integration market, each of his power generation units of renewable and distributed power? has to undergo TSO prequalification.

Virtual reality 25­ 2 Integration of the central control and optimization system into the IT landscape

Trader cockpit

EEX Forecasts Plant schedules Accounting EPEX Delivery commitments Plant data Reporting OTC Auction results Availabilities Diagnosis

Interfaces Grid operator Web service File transfer/xml/csv SQL minute reserve OPTIMAX® PowerFit

Real-time interfaces IEC 60870-5-101/104 Modbus/TCP OPC Grid operator secondary control

Firewall/router

GPRS Internet

Technical units / microgrids

Traditionally, conventional power plants The derivatives market is often used to Broadly stated, the were the only source of balancing ener- hedge against the price fluctuations on gy. Now, however, a VPP can intercon- the spot market. goals of a VPP are nect multiple smaller power generation units to reach the minimum offer size for Optimal operation of VPPs threefold: to attain placing bids in the balancing power mar- As can be inferred from the above dis- better prices for ket. Generally, the VPP operators proffer cussion, a VPP operator not only has a certain amount of balancing power and to have a clear overview and control of produced energy market agents place these bids in the his power generation assets, but also energy market. a means of managing the commercial on the spot and side of the enterprise in a cost-effective derivatives mar- The European spot market way ➔ 1. ABB’s central control and opti- The European spot market, EPEX, offers mization system provides the foundation kets, to participate two opportunities for short-term trading for the VPP to accomplish both these of energy: the Day-Ahead market and the aims. It connects the decentralized as- in the power bal- Intraday market. In the former, electricity sets and optimizes the operation, plan- ancing market and is traded for delivery the following day ning and commercial considerations ➔ 2. in hourly blocks or blocks of hours. The to optimize internal daily auction takes place at noon, seven The control system needs to have high days a week, all year round, including availability to comply with the strict re- production and statutory holidays. In the latter, electricity quirements for providing grid services consumption. is traded for delivery on the same day or and all operational optimization results on the following day in single hours, must be available in real time. 15-minute periods or in blocks of hours. VPP operators often face the challenge Power derivatives market of a rapidly growing installed base. The third market is the European Energy Therefore, it is essential that the central Exchange (EEX) power derivatives mar- control and optimization system is high- ket. In this market, the broker can finan- ly scalable so it can be grown from a cially settle power futures and options on few units to a few thousand in a short these. time. In one of ABB’s installations, the

­26 ABB review 4|15 3 VPP control and optimization system modules

Forecasting Virtual power plant Energy trading PV/wind forecasts,… Central control and optimization system

Commercial optimization Monitoring Decision support for trading Portfolio management

Invoice data export

Invoicing Aggregation/disaggregation TSO Minute reserve Day-Ahead/Intraday optimization Process Generate schedules Hourly database Battery storage management Alarms & events Data historian Plant schedule Real-time optimization Forecasts Asset control and monitoring Unit commitment Second-by-second TSO Balancing power calls Secondary reserve Disturbance compensation

TSO Real-time interface Primary reserve

Secure communication

Pool 1 Pool 2 ... n ... Pool m Unit Unit 1 Unit 2 Unit 3 Unit 4 Unit 5 Unit ... Unit ... Unit ... Unit ... Unit ... Unit ... Unit ... Unit 1 Unit 2 Unit 3 Unit 1 Unit 2

customer installed base grew from 20 to terminal units that employ VPN tunnels over 2,800 units in under three years. to transmit signals using private GSM or As all hardware and software additions encrypted Internet connections ➔ 2. were hot-swappable, ABB was able to add all the units without interrupting In the optimization on the commercial ­operations. side of the control system, the forecasts for renewable power generation require- Connections to the decentralized assets ments, the committed long-term obliga- are wireless-based. Therefore, it is cru- tions, the load demand and the available cial to meet the highest cyber security capacities of the assets are aggregated. standards for transmitting set points and In this way, the VPP operator gets an balancing power release calls from the overview of the available capacities and the marginal costs. Based on this in- ABB’s central control and formation, optimal bidding strategies optimization system gives the for the different electricity markets operator a clear overview and are proposed to control of his power genera- the trading depart- ment, which then tion assets, and a means submits offers to the energy markets. of managing the commercial Successful bids – side of the enterprise in a ie, power deliver- ies and grid ser- cost-effective way. vice commitments – are returned to control system to the units in the field. the control and optimization system, This is achieved by equipping the assets which generates the necessary sched- – or pools of local assets – with remote ules for the power-producing units, tak-

Virtual reality 27­ 4 Balancing power calls are distributed to the available units. Overall balancing power calls (lower left); and positive calls in green and negative calls in red (lower right).

ing all current restrictions and distur- As the world introduces ever more re- Connections to bances into account ➔ 3. newable energy sources, the role of the VPP in sustainable power generation the decentralized Further, instant-by-instant incoming bal- will increase in significance. The grow- ancing power calls are also incorporated ing complexity of generating power in assets are wire- into the individual schedules to provide the the most optimal way, matching it with less-based. There- optimal set points for all relevant units ➔ 4. demand and marketing it in the most cost-effective way means that ABB’s fore, it is crucial to The standardized open interfaces sup- central control and optimization system plied by ABB make it easy for the VPP will continue to be a crucial tool for the meet the highest operator to integrate the control system VPP operator. cyber security into the IT landscape and automate the information and signal flow from the field standards. level to the energy management level ➔ 2.

The ABB solution utilizes a mathematical optimization program to distribute the optimal set points in real time. Plant properties such as power limits, distur- bances or schedule deviations are mea- sured online and directly factored into the control of the assets. In this way, the optimization program ensures that the VPP is always run in the best possible configuration.

With its solution portfolio, ABB covers all aspects and requirements for the optimal operation of VPPs. In particular, the cen- tral control and optimization system runs redundantly on servers that are located in geographically dispersed data cen- ters. In this way, ABB can ensure the Sleman Saliba high availability that is an essential char- ABB Power Systems, Power Generation acteristic of a control system running in Mannheim, Germany such a high-criticality environment. [email protected]

­28 ABB review 4|15