inputs, including device status, weather, grid measurements, and market data.
Machine learning algorithms monitor these changing market conditions set by local operators as another set of inputs. One valuable example of this is frequency regulation The hardware/software convergence on the grid. High power demand or down-ramp supply Hardware is an important element to support software from renewable energy can cause the shortage of electrical operations because the strength and integrity of the energy power supply on the grid, causing its frequency to decrease. storage battery can help the system last longer and handle Conversely, the opposite effects can cause the frequency to complicated and fast-changing priorities. Batteries working increase. Frequency volatilities can damage machinery, create alongside renewable energy plants or supporting the grid are challenges for getting energy to the load centres, and cause endlessly switching between collecting, storing, and delivering brownouts or blackouts. Grid operators rely on a tool called power as the needs of the grid and asset owner fluctuate. frequency regulation that enables energy storage to provide This process of fully charging and discharging a battery is the extra power and inertia needed to get the grid’s frequency referred to as battery cycling and is a delicate dance. Different back to a normal level. Energy storage systems are able to battery chemistries and devices have different operating monitor the electrical quality of the grid and detect frequency limits before they begin to degrade, including the number of anomalies in real-time, as well as respond to any deviations charge cycles a battery can handle in its lifetime, the number with fast powers in both directions to quickly bring the grid it can handle in a day, and the depth of discharge. Pushing the back into balance. battery beyond these limits can shorten the battery’s lifespan. A 22 MW energy storage project connected to wind While commissioning a project, system operators perform farms in Cremzow, Germany, helps balance the German grid endurance testing to ensure that the system can handle the network by providing frequency regulation services through changing priorities and workflows it is designed to undertake. applications including primary control reserve (PCR) and This complements the battery manufacturer’s own endurance reactive power. The Primärregelleistung (PRL) market in testing. Machine learning-enabled software factors these Germany offers the grid fast-acting energy reserves. Whenever nuanced battery limitations into its computations as a first Wärtsilä’s GEMS software platform detects a critical frequency input. anomaly or system imbalance at the Cremzow site, the Once up and running, the software begins to optimise the software automatically triggers the battery system to dispatch system based on the device’s status and capacity. This also energy, delivering it within seconds. The main purpose of PCRs includes understanding the battery’s forecasted capacity. is to ensure the security of supply, and they are particularly For energy storage systems connected to renewable energy helpful in situations such as a power plant outage. Energy projects, the device’s capacity is largely a factor of weather, sources that participate in the PRL market must go through a since future sun and wind resources determine when the stringent qualification process and prove that they can provide battery will charge again. Once the algorithm understands the energy capacity in cases where other sources, such as variable amount of energy it is able to dispatch and when, the system renewable energy, need back-up. While PCRs act as back-up, can then consider other factors such as market signals. reactive power provides more local voltage support. Both applications require the battery to manage a state of charge An ear to the market in order to have capacity to offer. For example, software Grid operators are aware that they must implement measures can enable a contextual override to the batteries’ regular to keep the electrical grid sound if they are going to let more operations to ensure the system maintains the level of reserves renewable energy onto the network. Regions across the world it committed to in the PRL market. are developing many different types of incentives to activate A collaboration with Enel Green Power, ENERTRAG AG, energy storage and flexible energy generations for security Leclanché, and Wärtsilä, the Cremzow project and software and reliability in energy markets. These incentives and power platform also buys and sells energy on the 15 min. market, needs were once static and simple but are now becoming performing energy arbitrage. Energy arbitrage takes increasingly dynamic and subject to near-real-time changes. advantage of differing energy prices by storing energy until later when it is more valuable. It also helps avoid the issue of renewables curtailment, when wind or solar project operators are asked to scale back their output as renewables flood the system at the same time. Energy storage systems are undertaking smarter things Figure 2. Wärtsilä’s energy storage technology integrates with GEMS software to deliver powerful and reliable generation performance. under the umbrella
64 ENERGY GLOBAL SUMMER 2020
