Axpo has been pursuing the development and use of battery energy storage systems (BESS) for several years. Recognising their growing importance in the supply of energy, we have created a competence centre which provides specialist knowledge, expertise and resources to our colleagues and customers. In an increasingly volatile and decentralised energy supply system, Axpo’s experience shows that the intelligent use of battery storage systems can generate real added value. Based on solutions developed for our customers, we can provide you with expert support in their planning, commissioning and management.
Axpo plans and implements turnkey battery storage systems. One example is the real- isation of a decentralised battery storage system for the EWJR.
with 181 kWh each
The project was developed between 2018 and 2019. Our services included:
From procurement and factory acceptance testing to transportation of the system to the customer's site and its installation, our experience ensured that the project ran smoothly. Following installation, we then supported our customer during pre-qualification of the system by Swissgrid, the Swiss transmission system operator. We are also providing maintenance and support services for the system through its entire service life of at least 10 years.
Battery storage systems are playing an increasingly important role in the energy supply and can be used in a variety of ways. In Switzerland and Germany, they are currently used most frequently in the energy management market including so-called peak shaving, the proactive management of overall demand to eliminate short-term spikes.
Special applications for grid operators
Building a battery energy storage system takes about 12 months and, as a rule, the system can be operated for 20 years. The environmental impact of its construction is minimal and the system’s operation is environmentally friendly.
The majority of battery cells are produced in Asia. The most critical component of lithium ferro phosphate (LFP) batteries is lithium, most of which is mined in South America, Australia and China.
Batteries contain critical raw materials, which are difficult to mine in Europe. Once the battery has reached the end of its service life, the raw materials can be extracted and recycled.
The investment costs for battery systems are expected to decrease over the long term as the efficiency of implemented projects increases and more economies of scale are achieved. However, lithium shortages could result in a temporary price increase, as was seen at the beginning of 2022.
Regulatory framework conditions
Battery storage systems are used in many markets and both consume and generate energy. So it is vital that regulatory authorities establish a clear framework for the construction and operation of such systems.
Historically, transmission and distribution grids in most countries were designed with centralised production in mind. The battery capacity that can be installed is therefore dependent on the feed-in point and network topology at any specific location.
Battery storage capacity indicates the energy volume that can be stored and is measured in megawatt-hours (MWh).
Output indicates the energy per time unit that can be charged or discharged (also measured in MWh).
The C-Rate indicates how quickly a battery can be charged or discharged. C-Rate = output divided by storage capacity.
State-of-health (SoH) describes the relationship between the storage capacity of a used battery and a new battery: initially, the SoH is 100%.
State-of-charge (SoC) indicates the charging state of a battery: at 0% the battery is empty and at 100% SoC it is fully charged.
The number of cycles indicates how many equal, full charging and discharging cycles a battery carries out over a specific period of time. As a rule, batteries carry out one to two equivalent full load cycles per day.
Round-trip efficiency measures the energy that can be recovered in comparison to the energy stored (output divided by input). Round-trip efficiency is normally 85% or higher.
Battery service life depends on its operation. Frequent charging and discharging, as well as extreme charging states, decreases the service life of a battery.