Skip to content
Contact us
  • There are no suggestions because the search field is empty.

Track Round-Trip Efficiency (RTE) on system level

Learn how TWAICE calculates system-level round-trip efficiency, which components it includes and how power level affects the result.

On this page

TWAICE has a new system-level key performance indicator, Roundtrip Efficiency (RTE). It is calculated based on the battery, inverters and transformers efficiencies, helping asset owners & operators take performance optimization and warranty management to the next level.

This is the first KPI in Energy Storage Analytics that uses additional system-level data, combining battery data with data from transformers and inverters.

Introduction

Roundtrip Efficiency represents the ratio of energy output to energy input during a complete charge-discharge cycle, expressed as a percentage. Some energy is always lost to factors such as internal resistance or heat generation, meaning RTE is always less than 100%.

RTE directly affects cost savings and performance of energy storage systems. A high RTE means lower energy losses and better economic returns, whilst a low RTE indicates inefficiencies that might require technical or operational improvements.

Roundtrip efficiency is important for a variety of use cases, from enforcing battery performance guarantees to maximizing profits in wholesale markets.

How TWAICE's RTE is calculated

Components considered

To provide an accurate RTE, TWAICE continuously monitors and analyzes performance across the battery components, inverters and transformers, aggregating data to the system-level.

Figure 1: RTE calculation

Power dependency

RTE is strongly dependent on the applied power. Therefore it is important to consider the operation to provide RTE which aligns with contractual defined RTE targets. To enable this, TWAICE defines a minimal power threshold for the calculation of the RTE. As a standard threshold, 50% of max power regarding installed components is applied.

This KPI is available in the Warranty Tracker and Data Explorer and will gradually be incorporated into additional modules and features in Energy Storage Analytics.

Figure 2: RTE in Warranty Tracker

Additional data required

The RTE calculation uses data from inverters and transformers. Therefore, we will need additional data in order to calculate this for your system.

  • Inverter Level Active Power

  • Either

    • Inverter Level DC Power OR

    • Inverter Level DC Current and Voltage

  • System Level Active Power

Key Benefits & conclusion

  • Continuously access your systems’ RTE, ensuring they meet contractual obligations and optimize BESS performance.

  • Detect and resolve inefficiencies before capacity tests, reducing costly retests and downtime.

  • Gain accurate insights into system efficiencies for trading algorithms.

  • Ensure systems meet contractual guarantees, reducing warranty disputes and service penalties.

Accessing RTE continuously can assist owners and operators significantly improve BESS management and operations. Furthermore, this is the first KPI in TWAICE Energy Storage Analytics that uses system-level data, combining battery data with additional components, in this case inverters and transformers. Stay tuned for more system-level KPIs!