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Stock Comparison

CLNE vs OPAL vs GPRE vs AMTX

Revenue, margins, valuation, and 5-year total return — side by side.

Live fundamentals10-year financials5-year price chart
CLNE
Clean Energy Fuels Corp.

Oil & Gas Refining & Marketing

EnergyNASDAQ • US
Market Cap$507M
5Y Perf.-70.8%
OPAL
OPAL Fuels Inc.

Regulated Gas

UtilitiesNASDAQ • US
Market Cap$54M
5Y Perf.-76.0%
GPRE
Green Plains Inc.

Chemicals - Specialty

Basic MaterialsNASDAQ • US
Market Cap$1.15B
5Y Perf.-48.4%
AMTX
Aemetis, Inc.

Oil & Gas Refining & Marketing

EnergyNASDAQ • US
Market Cap$213M
5Y Perf.-77.0%

CLNE vs OPAL vs GPRE vs AMTX — Key Financials

Market cap, revenue, margins, and valuation side-by-side.

Company Snapshot
CLNE logoCLNE
OPAL logoOPAL
GPRE logoGPRE
AMTX logoAMTX
IndustryOil & Gas Refining & MarketingRegulated GasChemicals - SpecialtyOil & Gas Refining & Marketing
Market Cap$507M$54M$1.15B$213M
Revenue (TTM)$439M$349M$1.94B$209M
Net Income (TTM)$-99M$15M$-15M$-74M
Gross Margin11.7%28.1%1.8%3.4%
Operating Margin7.4%1.4%1.2%-13.4%
Forward P/E15.6x46.6x
Total Debt$99M$365M$508M$318M
Cash & Equiv.$158M$24M$182M$5M

CLNE vs OPAL vs GPRE vs AMTXLong-Term Stock Performance

Price return indexed to 100 at period start. Dividends excluded.

CLNE
OPAL
GPRE
AMTX
StockMay 21May 26Return
Clean Energy Fuels … (CLNE)10029.2-70.8%
OPAL Fuels Inc. (OPAL)10024.0-76.0%
Green Plains Inc. (GPRE)10051.6-48.4%
Aemetis, Inc. (AMTX)10023.0-77.0%

Price return only. Dividends and distributions are not included.

Quick Verdict: CLNE vs OPAL vs GPRE vs AMTX

Each card shows where this stock fits in a portfolio — not just who wins on paper.

Bottom line: OPAL leads in 5 of 7 categories, making it the strongest pick for growth and revenue expansion and valuation and capital efficiency. Clean Energy Fuels Corp. is the stronger pick specifically for capital preservation and lower volatility. GPRE also leads in specific categories worth noting. This set spans 3 sectors — these stocks serve different portfolio roles, not just different price points.
CLNE
Clean Energy Fuels Corp.
The Defensive Pick

CLNE is the #2 pick in this set and the best alternative if sleep-well-at-night and defensive is your priority.

  • Lower volatility, beta 1.19, Low D/E 17.5%, current ratio 2.32x
  • Beta 1.19, current ratio 2.32x
  • Beta 1.19 vs OPAL's 1.58, lower leverage
Best for: sleep-well-at-night and defensive
OPAL
OPAL Fuels Inc.
The Income Pick

OPAL carries the broadest edge in this set and is the clearest fit for income & stability and growth exposure.

  • Dividend streak 0 yrs, beta 1.58, yield 15.3%
  • Rev growth 16.3%, EPS growth 6.4%, 3Y rev CAGR 14.0%
  • 16.3% revenue growth vs AMTX's -22.3%
  • Better valuation composite
Best for: income & stability and growth exposure
GPRE
Green Plains Inc.
The Long-Run Compounder

GPRE is the clearest fit if your priority is long-term compounding.

  • 21.3% 10Y total return vs AMTX's 31.1%
  • +336.6% vs OPAL's -0.4%
Best for: long-term compounding
AMTX
Aemetis, Inc.
The Secondary Option

AMTX lags the leaders in this set but could rank higher in a more targeted comparison.

Best for: energy exposure
See the full category breakdown
CategoryWinnerWhy
GrowthOPAL logoOPAL16.3% revenue growth vs AMTX's -22.3%
ValueOPAL logoOPALBetter valuation composite
Quality / MarginsOPAL logoOPAL4.2% margin vs AMTX's -35.4%
Stability / SafetyCLNE logoCLNEBeta 1.19 vs OPAL's 1.58, lower leverage
DividendsOPAL logoOPAL15.3% yield; the other 3 pay no meaningful dividend
Momentum (1Y)GPRE logoGPRE+336.6% vs OPAL's -0.4%
Efficiency (ROA)OPAL logoOPAL1.6% ROA vs AMTX's -29.3%, ROIC 0.5% vs -70.3%

CLNE vs OPAL vs GPRE vs AMTX — Revenue Breakdown by Segment

How each company's revenue is distributed across its business units

CLNEClean Energy Fuels Corp.
FY 2025
Product
77.0%$365M
Service
12.5%$59M
Station construction sales
7.2%$34M
LCFS Credits
2.7%$13M
Other services
0.6%$3M
Federal Alternative Fuels Tax Credit
0.0%$198,000
OPALOPAL Fuels Inc.
FY 2024
Environmental Credits
86.8%$176M
Service
10.8%$22M
Parts
1.9%$4M
Product and Service, Other
0.6%$1M
GPREGreen Plains Inc.
FY 2025
Products And Services Other
101.2%$94M
Intersegment Revenues
-1.2%$-1,119,000
AMTXAemetis, Inc.
FY 2025
Ethanol Sales
79.4%$116M
Wet Distiller's Grains Sales
20.6%$30M

CLNE vs OPAL vs GPRE vs AMTX — Financial Metrics

Side-by-side numbers across 4 stocks — who leads on profitability, valuation, growth, and risk.

BEST OVERALLOPALLAGGINGGPRE

Income & Cash Flow (Last 12 Months)

OPAL leads this category, winning 3 of 6 comparable metrics.

GPRE is the larger business by revenue, generating $1.9B annually — 9.2x AMTX's $209M. OPAL is the more profitable business, keeping 4.2% of every revenue dollar as net income compared to AMTX's -35.4%. On growth, AMTX holds the edge at +27.4% YoY revenue growth, suggesting stronger near-term business momentum.

MetricCLNE logoCLNEClean Energy Fuel…OPAL logoOPALOPAL Fuels Inc.GPRE logoGPREGreen Plains Inc.AMTX logoAMTXAemetis, Inc.
RevenueTrailing 12 months$439M$349M$1.9B$209M
EBITDAEarnings before interest/tax$62M$28M$122M-$21M
Net IncomeAfter-tax profit-$99M$15M-$15M-$74M
Free Cash FlowCash after capex$19M-$34M$90M-$38M
Gross MarginGross profit ÷ Revenue+11.7%+28.1%+1.8%+3.4%
Operating MarginEBIT ÷ Revenue+7.4%+1.4%+1.2%-13.4%
Net MarginNet income ÷ Revenue-22.7%+4.2%-0.8%-35.4%
FCF MarginFCF ÷ Revenue+4.3%-9.8%+4.7%-18.2%
Rev. Growth (YoY)Latest quarter vs prior year+13.3%+24.7%-25.9%+27.4%
EPS Growth (YoY)Latest quarter vs prior year+90.0%+2.7%+134.2%+29.8%
OPAL leads this category, winning 3 of 6 comparable metrics.

Valuation Metrics

OPAL leads this category, winning 3 of 5 comparable metrics.

On an enterprise value basis, OPAL's 14.0x EV/EBITDA is more attractive than GPRE's 103.8x.

MetricCLNE logoCLNEClean Energy Fuel…OPAL logoOPALOPAL Fuels Inc.GPRE logoGPREGreen Plains Inc.AMTX logoAMTXAemetis, Inc.
Market CapShares × price$507M$54M$1.1B$213M
Enterprise ValueMkt cap + debt − cash$448M$395M$1.5B$526M
Trailing P/EPrice ÷ TTM EPS-2.29x15.60x-9.14x-2.44x
Forward P/EPrice ÷ next-FY EPS est.46.62x
PEG RatioP/E ÷ EPS growth rate
EV / EBITDAEnterprise value multiple94.64x14.03x103.82x
Price / SalesMarket cap ÷ Revenue1.19x0.15x0.55x1.02x
Price / BookPrice ÷ Book value/share0.90x0.14x1.44x
Price / FCFMarket cap ÷ FCF8.47x17.84x
OPAL leads this category, winning 3 of 5 comparable metrics.

Profitability & Efficiency

OPAL leads this category, winning 6 of 9 comparable metrics.

OPAL delivers a 3.1% return on equity — every $100 of shareholder capital generates $3 in annual profit, vs $-17 for CLNE. CLNE carries lower financial leverage with a 0.18x debt-to-equity ratio, signaling a more conservative balance sheet compared to OPAL's 0.73x. On the Piotroski fundamental quality scale (0–9), CLNE scores 5/9 vs AMTX's 4/9, reflecting solid financial health.

MetricCLNE logoCLNEClean Energy Fuel…OPAL logoOPALOPAL Fuels Inc.GPRE logoGPREGreen Plains Inc.AMTX logoAMTXAemetis, Inc.
ROE (TTM)Return on equity-17.2%+3.1%-2.0%
ROA (TTM)Return on assets-9.2%+1.6%-1.0%-29.3%
ROICReturn on invested capital-9.4%+0.5%-5.2%-70.3%
ROCEReturn on capital employed-9.4%+0.6%-6.2%-19.0%
Piotroski ScoreFundamental quality 0–95544
Debt / EquityFinancial leverage0.18x0.73x0.66x
Net DebtTotal debt minus cash-$59M$341M$326M$313M
Cash & Equiv.Liquid assets$158M$24M$182M$5M
Total DebtShort + long-term debt$99M$365M$508M$318M
Interest CoverageEBIT ÷ Interest expense-1.07x0.18x-0.08x-0.27x
OPAL leads this category, winning 6 of 9 comparable metrics.

Total Returns (Dividends Reinvested)

AMTX leads this category, winning 4 of 6 comparable metrics.

A $10,000 investment in GPRE five years ago would be worth $5,149 today (with dividends reinvested), compared to $2,387 for AMTX. Over the past 12 months, GPRE leads with a +336.6% total return vs OPAL's -0.4%. The 3-year compound annual growth rate (CAGR) favors AMTX at 11.2% vs OPAL's -29.2% — a key indicator of consistent wealth creation.

MetricCLNE logoCLNEClean Energy Fuel…OPAL logoOPALOPAL Fuels Inc.GPRE logoGPREGreen Plains Inc.AMTX logoAMTXAemetis, Inc.
YTD ReturnYear-to-date+6.9%-1.7%+60.1%+96.2%
1-Year ReturnPast 12 months+44.4%-0.4%+336.6%+140.0%
3-Year ReturnCumulative with dividends-46.3%-64.5%-46.8%+37.4%
5-Year ReturnCumulative with dividends-73.8%-76.1%-48.5%-76.1%
10-Year ReturnCumulative with dividends-26.9%-76.1%+21.3%+31.1%
CAGR (3Y)Annualised 3-year return-18.7%-29.2%-19.0%+11.2%
AMTX leads this category, winning 4 of 6 comparable metrics.

Risk & Volatility

Evenly matched — CLNE and GPRE each lead in 1 of 2 comparable metrics.

CLNE is the less volatile stock with a 1.19 beta — it tends to amplify market swings less than OPAL's 1.58 beta. A beta below 1.0 means the stock typically moves less than the S&P 500. GPRE currently trades 86.9% from its 52-week high vs OPAL's 57.4% drawdown — a narrower gap to the peak suggests stronger recent price momentum.

MetricCLNE logoCLNEClean Energy Fuel…OPAL logoOPALOPAL Fuels Inc.GPRE logoGPREGreen Plains Inc.AMTX logoAMTXAemetis, Inc.
Beta (5Y)Sensitivity to S&P 5001.19x1.58x1.22x1.46x
52-Week HighHighest price in past year$3.11$4.08$18.94$3.80
52-Week LowLowest price in past year$1.56$1.65$3.39$1.22
% of 52W HighCurrent price vs 52-week peak+74.3%+57.4%+86.9%+82.1%
RSI (14)Momentum oscillator 0–10044.648.054.358.2
Avg Volume (50D)Average daily shares traded1.3M198K1.5M1.8M
Evenly matched — CLNE and GPRE each lead in 1 of 2 comparable metrics.

Analyst Outlook

Insufficient data to determine a leader in this category.

Analyst consensus: CLNE as "Buy", GPRE as "Buy", AMTX as "Buy". Consensus price targets imply 51.5% upside for CLNE (target: $4) vs -43.9% for AMTX (target: $2). OPAL is the only dividend payer here at 15.29% yield — a key consideration for income-focused portfolios.

MetricCLNE logoCLNEClean Energy Fuel…OPAL logoOPALOPAL Fuels Inc.GPRE logoGPREGreen Plains Inc.AMTX logoAMTXAemetis, Inc.
Analyst RatingConsensus buy/hold/sellBuyBuyBuy
Price TargetConsensus 12-month target$3.50$13.80$1.75
# AnalystsCovering analysts22207
Dividend YieldAnnual dividend ÷ price+15.3%
Dividend StreakConsecutive years of raises00
Dividend / ShareAnnual DPS$0.36
Buyback YieldShare repurchases ÷ mkt cap+1.6%0.0%+2.6%0.0%
Insufficient data to determine a leader in this category.
Key Takeaway

OPAL leads in 3 of 6 categories (Income & Cash Flow, Valuation Metrics). AMTX leads in 1 (Total Returns). 1 tied.

Best OverallOPAL Fuels Inc. (OPAL)Leads 3 of 6 categories
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CLNE vs OPAL vs GPRE vs AMTX: Key Questions Answered

9 questions · data-driven answers · updated daily

01

Is CLNE or OPAL or GPRE or AMTX a better buy right now?

For growth investors, OPAL Fuels Inc.

(OPAL) is the stronger pick with 16. 3% revenue growth year-over-year, versus -22. 3% for Aemetis, Inc. (AMTX). OPAL Fuels Inc. (OPAL) offers the better valuation at 15. 6x trailing P/E, making it the more compelling value choice. Analysts rate Clean Energy Fuels Corp. (CLNE) a "Buy" — based on 22 analyst ratings — the highest consensus in this comparison. The "better buy" depends entirely on your goals: growth investors should weight revenue trajectory, value investors should weight P/E and PEG, and income investors should weight dividend yield and streak.

02

Which is the better long-term investment — CLNE or OPAL or GPRE or AMTX?

Over the past 5 years, Green Plains Inc.

(GPRE) delivered a total return of -48. 5%, compared to -76. 1% for Aemetis, Inc. (AMTX). Over 10 years, the gap is even starker: AMTX returned +31. 1% versus OPAL's -76. 1%. Past returns do not guarantee future results, and the stock with the higher historical return may already have its best growth priced in.

03

Which is safer — CLNE or OPAL or GPRE or AMTX?

By beta (market sensitivity over 5 years), Clean Energy Fuels Corp.

(CLNE) is the lower-risk stock at 1. 19β versus OPAL Fuels Inc. 's 1. 58β — meaning OPAL is approximately 33% more volatile than CLNE relative to the S&P 500. On balance sheet safety, Clean Energy Fuels Corp. (CLNE) carries a lower debt/equity ratio of 18% versus 73% for OPAL Fuels Inc. — giving it more financial flexibility in a downturn.

04

Which is growing faster — CLNE or OPAL or GPRE or AMTX?

By revenue growth (latest reported year), OPAL Fuels Inc.

(OPAL) is pulling ahead at 16. 3% versus -22. 3% for Aemetis, Inc. (AMTX). On earnings-per-share growth, the picture is similar: OPAL Fuels Inc. grew EPS 638. 9% year-over-year, compared to -173. 0% for Clean Energy Fuels Corp.. Over a 3-year CAGR, OPAL leads at 14. 0% annualised revenue growth. Higher growth typically commands a higher valuation multiple — check whether the premium P/E or P/S is justified by the growth rate using the PEG ratio.

05

Which has better profit margins — CLNE or OPAL or GPRE or AMTX?

OPAL Fuels Inc.

(OPAL) is the more profitable company, earning 1. 2% net margin versus -52. 3% for Clean Energy Fuels Corp. — meaning it keeps 1. 2% of every revenue dollar as bottom-line profit. Operating margin tells a similar story: OPAL leads at 1. 4% versus -22. 1% for CLNE. At the gross margin level — before operating expenses — OPAL leads at 24. 0%, reflecting greater pricing power or product mix advantage. Stronger margins indicate durable pricing power, lower cost of revenue, or higher mix of software/services. They are one of the clearest signs of business quality.

06

Is CLNE or OPAL or GPRE or AMTX more undervalued right now?

Analyst consensus price targets imply the most upside for CLNE: 51.

5% to $3. 50.

07

Which pays a better dividend — CLNE or OPAL or GPRE or AMTX?

In this comparison, OPAL (15.

3% yield) pays a dividend. CLNE, GPRE, AMTX do not pay a meaningful dividend and should not be held primarily for income.

08

Is CLNE or OPAL or GPRE or AMTX better for a retirement portfolio?

For long-horizon retirement investors, OPAL Fuels Inc.

(OPAL) is the stronger choice — it scores higher on the combination of lower volatility, dividend reliability, and long-term compounding (15. 3% yield). Both have compounded well over 10 years (OPAL: -76. 1%, AMTX: +31. 1%), confirming both are viable long-term holds — but the lower-volatility option typically results in less emotional selling during corrections. Retirement portfolios generally favour predictability over maximum returns. Consult a financial advisor before making allocation decisions.

09

What are the main differences between CLNE and OPAL and GPRE and AMTX?

These companies operate in different sectors (CLNE (Energy) and OPAL (Utilities) and GPRE (Basic Materials) and AMTX (Energy)), which means they face different economic cycles, regulatory environments, and macro sensitivities — making direct comparison nuanced.

In terms of investment character: CLNE is a small-cap quality compounder stock; OPAL is a small-cap high-growth stock; GPRE is a small-cap quality compounder stock; AMTX is a small-cap quality compounder stock. OPAL pays a dividend while CLNE, GPRE, AMTX do not, making them suitable for different income and tax situations. These fundamental differences mean investors should not choose between them on a single metric — the "better stock" depends entirely on which of these characteristics aligns with your investment strategy.

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CLNE

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  • Sector: Energy
  • Market Cap > $100B
  • Revenue Growth > 6%
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  • Sector: Basic Materials
  • Market Cap > $100B
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(CLNE: 13.3% · OPAL: 24.7%)

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