Assertion Supported AI assessment confidence: 95% certainty 3/5 debate potential 2/5

Schroeder: Flow batteries typically have around 65% AC round-trip efficiency

Dave Schroeder · When will batteries take over the world? · Mar 17, 2022 · at 42:30

Volta Energy Technologies CTO Dave Schroeder explains technical performance benchmarks for flow batteries used in grid energy storage.

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“Generally, they have round trip AC to AC efficiency in the 65% range, which I don't know if that sounds good or bad to you.”

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The claim, plainly

Flow batteries generally have an AC-to-AC round-trip efficiency in the 65% range.

a quote alone can be ambiguous, so this restates it with the references and context of the conversation around it resolved. AI-written; the tape below the player is the source.

Assessment

Technical benchmarks and reports from leading national laboratories and industry research organizations consistently substantiate that commercial- and utility-scale flow batteries (principally vanadium redox flow batteries) have an AC-to-AC round-trip efficiency (RTE) centered in the 60% to 70% range. While DC-to-DC cell-stack efficiency is typically 70% to 80%, bidirectional power conversion system (PCS) losses and parasitic auxiliary loads (such as electrolyte circulation pumps and thermal management) reduce overall AC-to-AC RTE to approximately 65%. For example, the PNNL/DOE 2022 Grid Energy Storage Technology Cost and Performance Assessment established a baseline AC-to-AC RTE of 65% for utility-scale VRFBs, aligning directly with the statement.

PNNL/DOE 2022 Grid Energy Storage Technology Cost and Performance Assessment (PNNL-33283) established a baseline AC-to-AC round-trip efficiency of 65% for utility-scale vanadium redox flow battery systems.
PNNL/DOE 2020 Grid Energy Storage Technology Cost and Performance Assessment benchmarked redox flow battery system-level AC round-trip efficiency at 65% to 70% once parasitic pump loads and power conversion losses were included.
EPRI technical reports and commercial field demonstration studies (e.g., IMDEA Energy/E22) document AC-to-AC system RTE clustering between 60% and 70% due to PCS conversion losses and pump auxiliary consumption.

Checked against

[1] stanford.edu [2] mdpi.com [3] stanford.edu [4] pnnl.gov [5] undecided.tech [6] pnnl.gov [7] escholarship.org [8] scribd.com

flow battery AC AC round trip efficiency RTE NREL PNNL "2022 Grid Energy Storage Technology Cost and Performance Assessment" "vanadium redox" "round trip efficiency" OR "RTE" "2022 Grid Energy Storage Technology Cost and Performance Assessment" "Redox Flow" "Round-Trip Efficiency" OR "RTE" "Grid Energy Storage Technology Cost and Performance Assessment" "vanadium" "round-trip" OR "RTE" "65%" OR "70%" OR "65" OR "67" OR "68" PNNL Energy Storage Technology Cost and Performance Assessment flow battery round trip efficiency AC "2020 Grid Energy Storage Technology Cost and Performance Assessment" "Redox Flow" "Round-Trip Efficiency" OR "RTE" EPRI vanadium redox flow battery AC to AC round trip efficiency NREL flow battery AC round trip efficiency 65

assessed as of 2026-09-03

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