CLNE vs RNG: Which Is the Better Buy in 2026?

Same yardstick, side by side (as of August 2026). Valuation lined up like this is most meaningful for two names in the same corner of the market, which these are. Figures are approximate; verify before investing.

Reading it: RNG is the cheaper of the two on forward earnings, but cheaper is not the same as better. Pair the valuation with growth (how far the forward P/E sits below the trailing P/E) and risk (beta) before you decide.

The metrics above tell you which is the marginally better business. The bigger risk for most people is not picking the slightly worse stock, it is over-concentrating. CLNE and RNG share themes, so owning both, or adding either to what you already hold, can quietly push a large share of your portfolio into one bet.

This is the part a generic comparison page cannot answer, because it depends on what you own. Connect your brokerage and Walnut shows your real, combined CLNE and RNG exposure, flags overlap with your existing positions, and tells you if adding one would tip you past a concentration you are comfortable with, read-only by default, with your login staying at your broker. Walnut is not an investment adviser.

Clean Energy Fuels Corp. is a provider of natural gas and renewable natural gas (RNG) as a fuel for transportation, focused on heavy-duty fleets such as trucking, transit buses, refuse trucks, and airport and municipal vehicles. It owns and operates a large network of fueling stations across the United States and Canada, sells compressed and liquefied natural gas, and is expanding into upstream RNG production, including dairy projects that capture methane from manure and process it into low- or negative-carbon fuel. RNG is the strategic centerpiece because it can carry environmental credits and lower lifecycle emissions, which supports both pricing and the sustainability case fleets use to switch.

Full CLNE guide

RingCentral, Inc. (NYSE: RNG) sells cloud-based business communications, known in the industry as Unified Communications as a Service (UCaaS). Its core product bundles a business phone system, team messaging, video meetings, and, increasingly, an AI-enabled contact center (RingCX) and AI assistants like its AI Receptionist. Customers are mostly businesses that replace legacy on-premise phone hardware with RingCentral's subscription software, which is why roughly 97% of revenue is recurring subscription revenue. The company has historically grown through direct sales plus channel partnerships (including a long-running relationship with Avaya) and serves small businesses up through large enterprises.

Full RNG guide

Both fit overlapping themes, but they are not interchangeable. The useful comparison is which set of drivers and risks you want exposure to.

• CLNE drivers: Renewable natural gas volume growth; The Cummins X15N engine and fleet adoption.
• RNG drivers: Margin expansion and free cash flow; AI and contact center (RingCX / RingSense).

A faster-growing, richer-valued name usually swings harder, so it suits a longer horizon and a higher tolerance for volatility; a steadier, more cash-generative business suits a more conservative or income-minded investor. The honest test is which set of risks you could hold through a drawdown: The dominant risk is that Clean Energy has a long track record of GAAP losses and depends on RNG volumes, fuel economics, and environmental credits that can be volatile and policy-dependent. For RNG, the dominant risk is competition from Microsoft Teams Phone and Zoom Phone, which can bundle business calling into platforms enterprises already buy, pressuring both pricing and win rates.

Growth-minded investors who believe the theme has years to run tend to accept the richer multiple for more upside; value-minded investors lean toward the cheaper forward earnings and steadier profile. Pick CLNE if you believe its drivers more; RNG if you believe its. Many investors hold both, but since they share themes, that is a concentrated bet, not diversification. Decide deliberately and check overlap. For the full detail, see the CLNE and RNG guides.

CLNE. Figures are approximate and tied to the asOf date; verify live numbers before acting. Because Clean Energy is not consistently profitable on a GAAP basis, traditional earnings multiples are not the main lens; investors focus on RNG volume growth, adjusted EBITDA, and whether natural gas engine adoption expands demand. Environmental credits and policy support are a large and variable part of RNG economics, so results can swing with regulation as much as with fuel sold. Treat this as a speculative energy-transition holding.

RNG. As of July 2026 the stock traded near $39 (a 52-week range of roughly $24 to $50), putting the market cap around $3.3 to $3.5 billion against about $2.51 billion of trailing revenue, so roughly 1.3 to 1.4 times sales. Reported P/E figures around 39 to 45 reflect thin GAAP earnings, while the company is more profitable on a non-GAAP and free-cash-flow basis (FY2026 non-GAAP EPS guidance of roughly $4.85 to $5.01). The valuation gap between GAAP and cash metrics is central to how investors frame the stock.

Headline figures (approximate, Jul 2026): CLNE shows revenue (q1 2026) ~$117.6 million, up from roughly $103.8 million a year earlier, rng volume (q1 2026) ~67.4 million gallons, up from about 50.6 million a year earlier, net loss (q1 2026) ~$12.4 million, or roughly $0.06 per share, a much smaller loss than the prior year, adjusted ebitda (q1 2026) roughly $16.6 million, broadly in line with the prior-year quarter; RNG shows revenue (ttm) ~$2.51 billion, revenue growth (yoy, q1 2026) ~5%, fy2026 revenue guidance ~$2.62 to $2.64 billion, free cash flow (fy2026 outlook) ~$600 million.

CLNE and RNG are related but distinct: same themes, different businesses and risks. Neither wins in the abstract; the right pick is whichever thesis you actually believe, sized so you are not over-concentrated in one theme. Walnut can show your combined CLNE and RNG exposure against your real portfolio. It is not an investment adviser.