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Technology & EvidenceWhat supports the proposition?
Oxy-fuel combustion is the component that makes a high-purity CO₂ stream available without a conventional capture plant. This page explains how it works, where the system boundary sits, what has been demonstrated by the technology owner, what remains to be integrated at a specific site — and how to read every number Valverde publishes.
Combustion in oxygen instead of air
Conventional gas-fired generation burns fuel in air. Air is 78% nitrogen, so the exhaust is a dilute mixture of nitrogen and about 4–8% CO₂ that is costly to separate. The oxy-fuel process removes the nitrogen before combustion rather than the CO₂ after it.
Text description of the diagram
- Inputs: fuel gas (pipeline gas, low-BTU or CO₂-rich streams) and oxygen from an air separation unit sized to the site.
- Generation: the oxy-fuel generator combusts the fuel in oxygen (no nitrogen, low NOx) and produces a steam-and-CO₂ stream that drives a turbine generator.
- Power delivery: electricity supplies facility loads (electrified compression, generators, plant) and, where interconnected, grid export.
- Carbon management: the exhaust is condensed; water is recovered and the high-purity CO₂ stream is compressed for storage or enhanced oil recovery.
Oxygen supply
An air separation unit (ASU) on site, or an over-the-fence supplier, provides oxygen. Sizing the ASU and its power draw is one of the main economic variables of the project.
Oxy-fuel generator
Fuel gas is combusted in oxygen inside the CES Direct Steam Gas Generator — a design derived from rocket-engine combustion technology — with water injection to control temperature. The products are steam and CO₂ with very low NOx.
Turbine generator
The steam and CO₂ stream drives a turbine generator (CES’s OFT-900 class turbine in the reference design) to produce electricity for the facility and, where connected, the grid.
Condensing
The exhaust is condensed. Water is recovered — the process is a net producer of distilled water — and the remaining stream is CO₂ at high purity.
CO₂ compression
The CO₂ is compressed to pipeline or injection pressure. Compression power is an internal load that reduces net export and must be counted in any net-output statement.
Storage or use
Geological storage, delivery to a CO₂ pipeline or hub, or injection for enhanced oil recovery. These are different categories with different permanence, accounting and incentive treatment; we do not use them interchangeably.
“It’s not rocket science. Well, actually… it is.”
Valverde’s original tagline is literally true. The CES combustor descends from rocket-engine technology: fuel and oxygen burned at pressure, with water injected to control temperature, in a compact chamber originally engineered for launch vehicles. On the ground, that heritage gives a small footprint, high combustion efficiency and an exhaust of nothing but steam and CO₂ — which is what makes the carbon simple to capture.
The tagline is kept here as the technology’s origin story. The commercial proposition on this site is the integrated project, not the novelty of the burner.
Benefits as stated by Valverde and CES
Company statements reproduced from valverdepowersolutions.com, each with its evidence status.C17
- Combusts methane or any hydrocarbon in pure oxygen supplier
- Burns contaminated gas streams with no efficiency loss supplier · not published
- Captures all combustion CO₂, versus ~90% in post-combustion capture design basis
- Low NOx emissions design basis
- Lower capex and opex than post-combustion capture company statement
- Small footprint; scales up or down supplier
- Post-capture output is distilled water design basis
Clean Energy Systems and the master licence
Clean Energy Systems (CES) of Rancho Cordova, California, holds the patents on the oxy-fuel combustor and has developed and tested oxy-fuel generation systems over roughly 25 years, including its ZEUS zero-emission power-station concept. CES employs about 25 professional engineers and is a minority shareholder in Valverde.
On 6 October 2021, Valverde and CES announced a definitive Master License Agreement granting Valverde the right to use the CES oxy-fuel combustion technology for an initial set of identified clean-power and carbon-capture projects in the United States, Canada and Mexico.
Scope of the licence. The October 2021 announcement described rights to use the technology for an initial set of identified projects in the United States, Canada and Mexico; Valverde’s partner page describes a master licence for Canadian oil and gas applications. Territory, field of use, exclusivity and duration are governed by the agreement itself, which is not public, and are not interpreted here.C08
Equipment shown is the licensor’s reference design, not a Valverde installation. Images are reproduced from valverdepowersolutions.com.
How to read every claim on this site
For each family of statement, this summary gives the evidence status, the source, what it applies to, and whether a figure has been published. Where the honest answer is “a design target” or “not established”, that is what it says.C17
| Claim family | What it depends on | Evidence status · source · applicability |
|---|---|---|
| Capture percentage e.g. “100% of combustion CO₂” | Denominator (combustion CO₂ only, or facility total); design vs measured; operating period; treatment of bypass, start-up and downtime | design basis · supplier (CES) · component Oxy-fuel combustion produces a CO₂/steam exhaust with no nitrogen, so the design intent is to capture all combustion CO₂. No measured figure has been published for any Valverde project. Not a lifecycle result. |
| Electricity carbon intensity e.g. “zero-emission”, “carbon-free” | Net vs gross basis; included emissions; upstream fuel assumptions; storage permanence; auxiliary power (ASU, compression) | design target · Valverde · proposed configuration Applies to stack emissions of the oxy-fuel unit. Whole-life intensity requires a separate lifecycle assessment with an explicit accounting boundary; none has been published. |
| Lower cost e.g. “lower CAPEX and OPEX” | Comparator technology; project scale; cost year and currency; operating assumptions; equipment and services included | company statement · Valverde / CES · general Stated relative to post-combustion capture; no cost figures, comparator basis or cost year have been published. Project-specific cost comparisons belong in feasibility, not marketing. |
| Fuel flexibility e.g. “burns ~20% methane streams” | Tested composition range; contaminants; pretreatment; derating; materials and permit constraints | supplier statement · CES · component CES and Valverde state the combustor handles a wide range of gas qualities including low-BTU and CO₂-rich streams (Valverde, 2022). Tested ranges and limits have not been published; site-specific composition is validated in feasibility. |
| Exclusive access e.g. “exclusive rights” | Territory; field of use; duration; exclusions; the actual rights holder | agreement · Valverde / CES · October 2021 Master License Agreement with CES announced 6 October 2021. Its terms are not public and are not interpreted on this site.C08 |
| Completed or proven project | Responsible entity; development stage; test scale; run duration; independent verification | supplier statement · CES · demonstration systems CES stated in October 2021 that all required systems had been tested at scale; test conditions and results have not been published by Valverde. Valverde has no commissioned project; see Projects for stage labels. |
| Dispatchable / dependable power | Availability, maintenance, outage plan, backup supply, gas security, grid interface | design basis · Valverde · proposed configuration Continuous generation is the design; availability guarantees are contractual matters set per project. Not established for any Valverde project. |
| Incentive eligibility 45Q, CCUS ITC, LCFS, TIER | Jurisdiction; date of law; storage vs EOR treatment; ownership and monetization route; stacking rules | not established · professional review General overviews only; eligibility is determined per project by tax and legal advisers. Rules changed in Canada and the US during 2026. |
What is stated as demonstrated, and what is integrated per site
Stated as demonstrated by the technology owner
- Oxy-fuel combustor operation on natural gas at test scale (CES statement, 2021; results not published by Valverde)
- Steam/CO₂ turbine generation in the reference design (CES)
- CO₂ pipeline transport, injection and EOR operations — decades of industry practice, including the leadership team’s Denbury experience
Integrated and validated for each project
- Oxygen supply configuration and its parasitic load
- Electrification of existing compression and generation
- Net output after ASU and CO₂ compression
- CO₂ specification at the storage or pipeline interface
- Outage, maintenance and backup-power plan
- Permitting, interconnection and incentive determinations
Valverde’s development work is the integration column. The technology column is the licensor’s.
The oxy-fuel plant in a wider energy system
Integrating several energy solutions is usually the most efficient way to deliver clean energy, and the oxy-fuel process can sit at the centre of a site’s system:
- Recovered water and electricity can feed hydrogen production by electrolysis; the oxygen from electrolysis can supplement the oxygen plant.
- The plant’s continuous output can firm intermittent renewable supply to the grid, and surplus renewable power can in turn support the ASU.
- Steam and boiler water are additional products where a host has a use for them.
These are configuration options, not features of any current Valverde project.
Plain-language terms
Oxy-fuel combustion
Burning a fuel in oxygen rather than air. Because there is no nitrogen, the exhaust is mainly steam and CO₂, which makes CO₂ separation a matter of condensing water rather than chemically scrubbing a dilute flue gas.
Direct Steam Gas Generator (DSGG)
Clean Energy Systems’ oxy-fuel combustor. Fuel and oxygen are burned at pressure with water injection, producing a high-temperature steam/CO₂ stream used to drive a turbine.
Air separation unit (ASU)
A plant that separates oxygen from air, typically by cryogenic distillation. It supplies the oxygen the combustor needs and consumes a meaningful share of the generated power.
Net vs gross output
Gross output is what the generator produces. Net output subtracts the plant’s own consumption — mainly the ASU and CO₂ compression. Only net output is available to the facility or the grid.
CCUS
Carbon capture, utilization and storage. Capture separates the CO₂; storage places it permanently in a geological formation; utilization uses it, for example in enhanced oil recovery. Each has different accounting and incentive rules.
Enhanced oil recovery (EOR)
Injecting CO₂ into an oil reservoir to recover additional oil. Some of the CO₂ remains in the formation; the accounting for that retention differs from dedicated geological storage.
Pre-FEED and FEED
Preliminary and full front-end engineering design: the study stages that define a project’s configuration, cost and schedule well enough for an investment decision. They precede detailed engineering and construction.
Dispatchable power
Generation that can run continuously or be scheduled on demand, as opposed to intermittent wind and solar output. Dispatchable design is not the same as a contractual availability guarantee.
45Q, CCUS ITC, LCFS, TIER
Section 45Q is the US federal tax credit for captured CO₂; the CCUS investment tax credit is Canada’s federal credit for eligible capture, transport and storage equipment; Low Carbon Fuel Standards are US state programmes; TIER is Alberta’s industrial emissions pricing system. All are subject to change and project-specific determination.
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