Talk:Roundtrip efficiency

AI prompts

This article was created with the assistance of Google Gemini Pro 2.5. The prompts were:

• fetch data from figure 9 of last work [cannot find it]
• [figure 9 uploaded as image] here is the figure 9
• you are an english wikipedia editor. based only these sources, create wikitext for an article "Roundtrip efficiency". Use sfn for references

Extensive manual rework followed. Викидим (talk) 04:57, 17 October 2025 (UTC)

Verification report

This table verifies claims made in the article against the cited sources. See the AI info at the bottom.

Claim Verification Table

#	Claim in Article	Cited Source	Verification Status	Notes
1	"Roundtrip efficiency ... evaluates the energy losses incurred during a complete charging and discharging cycle."		Supported	p290.txt states: "Roundtrip efficiency specifically evaluates the energy losses incurred during the complete charging and discharging cycle of the ESS."
2	"It is defined as the ratio of the energy output from the system during discharge to the energy input supplied during charging."		Supported	p290.txt states: "It measures the ratio of energy output during discharge to the energy input during charging, accounting for losses due to conversion inefficiencies, heat dissipation, and other factors."
3	"A higher round-trip efficiency indicates lower energy losses and operational costs."		Supported	p290.txt states: "High efficiency minimizes energy losses and maximizes the usable energy stored in the system, improving overall performance and reducing operational costs."
4	"Round-trip efficiency greatly affects the economics of energy storage systems, particularly for applications in grid stability, renewable energy integration, and peak demand management."		Supported	p290.txt states: "Maximizing efficiency and roundtrip efficiency is essential for enhancing the economic viability and sustainability of ESS, particularly in applications where energy storage plays a critical role in grid stability, renewable energy integration, and peak demand management."
5	Factors affecting efficiency include "Conversion inefficiencies" and "Heat dissipation"		Supported	p290.txt states roundtrip efficiency accounts for "losses due to conversion inefficiencies, heat dissipation, and other factors."
6	"The hydrogen production energy linearly depends on the required voltage (that in turn depends on the catalyst used in anode and cathode)"		Supported with caveat	Kojima Eq. (2): E_rH2 = nFV/1000 confirms linear dependence on voltage. Catalyst dependence is implied by Table 1 listing different electrocatalyst voltages. However, the parenthetical about "anode and cathode" is editorial synthesis — the source discusses catalysts broadly, not in that exact framing.
7	"the energy required for ammonia synthesis is relatively small"		Supported	Kojima p.2 states: "The reaction for synthesizing ammonia from nitrogen and hydrogen (nitrogen fixation method) is an exothermic reaction, and the energy required for ammonia synthesis is small." Also: hydrogen production energy is "16 times the sum of nitrogen production and Haber-Bosch process."
8	"combined cycle gas turbine provides the highest efficiency of 64% assumed for high-end estimates"		Supported	Kojima p.2 states: "the thermal efficiency of green ammonia e_t was assumed to be 64.0% of LHV." GTCC is the highest-efficiency power generation option in the paper (vs. 43% for steam turbine).
9	"Different energy storage technologies exhibit a wide range of round-trip efficiencies."		Supported	Ma et al. Figure 9 (p.9) shows a bar chart comparing efficiencies across multiple storage technologies with widely varying ranges.
10	Lead-acid battery: median ~75%, range ~68%–82%		Plausible but imprecise	Figure 9 shows Pb-Acid battery efficiency as a box-and-whisker range. Exact values are read from a chart and are approximate. The range appears broadly consistent with the figure but precise numbers cannot be confirmed from the image alone.
11	Li-ion battery: median ~85%, range ~75%–95%		Plausible but imprecise	Figure 9 shows Li-ion with a high efficiency range. Kojima p.5 separately states Li-ion efficiency as 85–95%, partially corroborating the upper range. However, 75% as the low end may be a generous reading of the chart.
12	NaS battery: median ~65%, range ~62%–70%		Plausible but imprecise	Figure 9 shows NaS battery with a mid-range efficiency. Values are approximate chart readings.
13	Flywheel: median ~93%, range ~90%–95%		Questionable	Figure 9 shows Flywheel efficiency appearing to be approximately in the ~60%–70% range based on visual inspection. A 90–95% range seems significantly higher than what the figure depicts. Most literature reports flywheel round-trip efficiency at 80–90%, not 90–95%. This may be a misreading of the chart or confusion with another technology.
14	SMES (Superconductive): median ~90%, range ~85%–95%		Plausible	Figure 9 shows SMES with a relatively high efficiency. The cited range appears broadly consistent with the chart.
15	Compressed air: median ~52%, range ~42%–72%		Supported	Ma et al. p.5 discusses CAES efficiency: "the net energy efficiency of CAES can be in the range of 40%-50%" without heat recovery, and "the roundtrip efficiency for CAES can be claimed to be as high as 70%" with favorable assumptions. The article range of 42–72% is consistent.
16	Thermal energy storage (conversion to electricity): median ~40%, range ~30%–50%		Supported	Ma et al. p.4 states: "The roundtrip efficiency can range from 30% to 50%, depending on the operating conditions." This matches exactly.
17	Pumped hydro: median ~75%, range ~65%–82%		Plausible	Figure 9 shows PHS with a high efficiency range. Ma et al. p.5 describes PHS as "the most efficient long-term, large-scale energy storage method." The cited range is plausible from the chart. Kojima p.5 gives PHS as 70–85%, which is close but not identical.
18	Green hydrogen median ~40%		Supported	Headley & Schoenung p.3 states: "The roundtrip efficiency of hydrogen storage based on electrolysis and fuel cell systems is generally around 40%."
19	Green hydrogen range 28–52%		Supported	Kojima abstract states: "The round-trip efficiencies were 28–52%." Kojima p.4 confirms: "steam turbines 28% < PEMFC 38% < GTCC 41%" for conventional, up to 52% at thermoneutral voltage for GTCC.
20	Green ammonia range 23–42%		Supported	Kojima abstract states: "The round-trip efficiencies were 23–42% depending on the voltage reduction from 1.84 to 1.48 V and power generation systems." Kojima p.4 confirms: "steam turbine 23% < PEMFC 26% < GTCC 34%" for conventional, up to 42% at thermoneutral voltage.
21	The formula: Roundtrip Efficiency (%) = (Energy Out / Energy In) x 100	(no specific citation)	Standard definition, uncited	This is a standard textbook formula consistent with the Penthia source definition but not explicitly given in formula form in p290.txt. The formula is uncontroversial. Ma et al. p.2 describes eta_EES as "the net electricity delivered from the storage system relative to the amount of electricity put into the storage system," which is equivalent.
22	Table caption: "Comparison of Round-trip Efficiency for Energy Storage Methods" attributed to Figure 9 of Ma et al.		Partly supported	Figure 9 is the source for most rows. However, the green hydrogen and green ammonia rows cite different sources (Headley/Schoenung and Kojima), so the table caption attribution to Ma et al. alone is slightly misleading — the table is a composite from multiple sources.
23	Headley & Schoenung cited as year "2015"	Headley & Schoenung chapter	Date uncertain	The chapter PDF header says "Chapter 11 Hydrogen Energy Storage" from the "U.S. DOE Energy Storage Handbook" with Sandia report number SAND2015-1002. However, the references section in the chapter cites sources from 2019 and 2020, suggesting the chapter was written circa 2020 or later. The "2015" in the SAND number may refer to the original handbook series, not this specific chapter's publication date.

Summary

• Fully supported claims: 11 (claims 1–5, 7–9, 15–16, 18–20)
• Plausible / broadly consistent: 6 (claims 6, 10–12, 14, 17)
• Questionable: 2 (claim 13 — flywheel efficiency appears overstated; claim 23 — date of Headley source)
• Minor issues: Claim 21 (uncited formula) and Claim 22 (table caption slightly misleading)

Recommendations

1. Flywheel efficiency (Claim 13): Recheck against Figure 9. The 90–95% range appears high compared to both the chart and typical literature values (usually 80–90%). Consider revising or adding a secondary source.
2. Headley & Schoenung date (Claim 23): Verify the publication year. Internal references in the chapter cite 2019–2020 sources, suggesting the chapter is later than 2015. The SAND2015-1002 number may refer to the handbook series rather than this chapter's edition.
3. Table caption: Consider rewording to acknowledge that the table is compiled from multiple sources, not solely from Ma et al. Figure 9.
4. All chart-derived values (Claims 10–14, 17): Since these are read from a bar chart (Figure 9), exact numbers carry inherent uncertainty. Consider noting approximate values or adding corroborating sources.
5. Formula (Claim 21): Consider adding an inline citation to Penthia or Ma et al. to support the formula.

This report was obtained with the assistance of Claude Sonnet 4.6. The prompt was:

• You are an English wikipedia editor. Attached are sources used to write the wikipedia article, wikitext of the article is pasted. Verify the claims, creating a wikitext report in a table format:

Викидим (talk) 02:34, 13 March 2026 (UTC)