[ExI] Trash to Fuel

[Keith Henson]

Latest on this topic.  Will post on asteroid mining next.

A. Two-Page Technical White Paper

(Utility-focused, suitable for internal circulation)

Solar-Driven Waste Gasification for Dispatchable Power and Energy Storage

Abstract

This paper describes a system that uses intermittent solar electricity
to gasify municipal solid waste (MSW) in steam, producing storable
syngas that can be converted into dispatchable electricity using
conventional combined-cycle (CC) turbines. The approach integrates
waste management with grid-scale energy storage, addresses solar
curtailment, and reduces landfill methane emissions. At city scale,
the system can operate at multi-gigawatt levels while providing
short-duration to seasonal energy storage.

________________________________

1. Background and Motivation

Electric grids with high solar penetration increasingly face
overgeneration during daylight hours, curtailment, and insufficient
firm capacity after sunset. Separately, municipal waste disposal
remains a persistent environmental and political challenge,
particularly due to landfill methane emissions.

This proposal connects these two issues by adapting historical
town-gas gasification methods using modern equipment, controls, and
electric heating. Instead of burning part of the feedstock for process
heat, externally supplied solar electricity provides the required
endothermic heat.

________________________________

2. Process Description

Municipal waste is gasified in steam using resistive or induction
heating powered by intermittent solar electricity. The process
produces syngas (primarily CO and H₂), along with vitrified slag and
recoverable metals.

Key features:

No on-site combustion required for process heat

Rapid thermal response compatible with intermittent power input

Chemical energy stored in syngas decouples generation from use

________________________________

3. Energy Accounting (Per Ton of Carbon in Waste)

Electric heat input: ~4 MWh

Syngas produced: >10 MWh (LHV equivalent)

Electrical output via CC turbines (~60% efficiency): ~6 MWh

The net electrical output exceeds the electrical input because the
system converts the chemical energy of waste carbon into electricity.
This is not a round-trip efficiency claim; it is energy recovery from
waste enabled by electric heating.

________________________________

4. Dispatch and Storage

Syngas production and power generation are temporally decoupled. For example:

8 hours of solar-powered gasification at ~4 MW electric input

Produces sufficient syngas to support ~8 hours of dispatch at ~6 MW

Storage options range from near-term tank storage to longer-duration
storage in suitable geological formations, enabling both diurnal and
seasonal dispatch.

________________________________

5. Scale and Grid Relevance

Los Angeles generates approximately 100,000 tons of waste per day.
Processing this stream corresponds to:

~6.4 GW continuous operation, or

~20 GW if operated only during solar availability

This scale is directly relevant to grid-level capacity planning, solar
curtailment mitigation, and firm resource replacement.

________________________________

6. Environmental and Byproducts

Substantial landfill diversion and methane avoidance

Products include syngas, vitrified slag suitable for construction
aggregate, and recoverable metals

Integrates waste handling and power generation into a single system

________________________________

7. Engineering Note

An induction-heated gasifier enables fast thermal ramping and
compatibility with variable power input. The design is central to
coupling intermittent renewables with continuous chemical processing.

________________________________

8. Conclusion

Solar-driven waste gasification offers a pathway to dispatchable
renewable power, grid-scale storage, and waste reduction using proven
components arranged in a novel configuration. The concept aligns with
long-term decarbonization and grid-reliability goals while addressing
public concerns around waste disposal.

________________________________

B. One-Slide Schematic Narrative

(For an initial technical briefing slide)

Title:
Solar-Powered Waste-to-Syngas for Dispatchable Grid Power

Problem:

Solar overgeneration and curtailment

Lack of firm, dispatchable renewable capacity

Landfill methane emissions

Concept:

Intermittent solar electricity supplies heat (via induction/resistive heating)

Municipal waste is gasified in steam → syngas

Syngas is stored (tanks or geological storage)

Stored gas fuels combined-cycle turbines on demand

Energy Flows (per ton of waste carbon):

~4 MWh electric input (solar)

10 MWh syngas produced (LHV)

~6 MWh dispatchable electricity output

Grid Value:

Converts curtailed solar into firm capacity

Provides diurnal to seasonal storage

Dispatchable after sunset

Environmental Value:

Landfill diversion

Methane avoidance

Useful byproducts (slag, metals)

Scale (Los Angeles):

~100,000 tons/day waste

~6.4 GW continuous or ~20 GW solar-only operation

Status:
Conceptual system using proven components; induction-heated gasifier
design available for technical review.



Keith

On Mon, Nov 17, 2025 at 12:51 AM Keith Henson <hkeithhenson at gmail.com> wrote:
>
> This is likely too long for the list.
>
> Making synthetic fuel from trash and intermittent renewable energy
>
> H. Keith Henson hkhenson at gmail.com
>
> Nov 16, 2025 Engineering draft notes (please check the numbers)
>
> Abstract
>
> This paper explores making synthetic fuel from trash and coal using
> renewable energy. The key reaction, dating back to the 1850s, involves
> heating carbon in steam to produce hydrogen and carbon monoxide. This
> endothermic reaction requires heating, traditionally done by
> alternately burning coke and injecting steam. Using intermittent
> renewable electricity for heating is now feasible.
>
> A metric ton of carbon requires 3.03 MWh of heat to produce 13.1 MWh
> of syngas; a 4 to 1 energy gain. The gas can be stored, burned, or
> converted into methane, jet fuel, or diesel. The water-gas shift
> reaction can be used to increase the hydrogen at the expense of CO.
> The resultant CO2 (about half) can be sorted out of the gas stream and
> sequestered.
>
> Following the water-gas shift, the Fischer-Tropsch (FT) process
> converts syngas into hydrocarbons, with water as a byproduct.
>
> An example design uses 9,000 tons of trash daily from the Sylmar, CA
> landfill supplemented with coal, to produce syngas. The project would
> need significant power and infrastructure, including a 3-GW vaporizer
> and new high-voltage DC lines.
>
> The venture could generate over $600 million annually from the sale of
> diesel, with costs for coal and power totaling $241 million. The
> project addresses landfill overuse and methane leakage, and provides a
> renewable energy solution for synthetic fuel production, though it
> requires substantial investment and the development of a 3-GW
> gasifier.
>
> Background
>
> History
>
> In the early days of the Industrial Revolution, “gas works” made “town
> gas” by heating coke (burning it) then shutting off the air and
> blowing steam into the white-hot coke. This made CO and hydrogen. The
> proposal here is to heat any carbon source in steam with renewable
> power and then feed the syngas to a FT plant to make liquid fuels. It
> takes 3 MWh to vaporize a ton of carbon in steam. (Making the steam
> takes 0.94 MWh/ton of carbon and some of the heat can be recovered
> from the hot syngas.) This avoids burning the carbon to provide
> process heat.
>
> “Town gas is a more general term referring to manufactured gaseous
> fuels produced for sale to consumers and municipalities.
>
> “The original coal gas was produced by the coal gasification reaction,”
>
> https://en.wikipedia.org/wiki/Coal_gas
>
> about 1/3rd of the way into the article.
>
> “The problem of nitrogen dilution was overcome by the blue water gas
> (BWG) process, developed in the 1850s by Sir William Siemens. The
> incandescent fuel bed would be alternately blasted with air followed
> by steam. The air reactions during the blow cycle are exothermic,
> heating up the bed, while the steam reactions during the make cycle,
> are endothermic and cool down the bed. The products from the air cycle
> contain non-calorific nitrogen and are exhausted out the stack while
> the products of the steam cycle are kept as blue water gas. This gas
> is composed almost entirely of CO and H2, and burns with a pale blue
> flame similar to natural gas.”
>
> Chemistry
>
> The chemical reaction upon which this depends is:
>
> H2O + C → H2 + CO (ΔH = +131 kJ/mol)
>
> 18 12 2 28
>
> “The reaction is endothermic, so the fuel must be continually
> re-heated to maintain the reaction.“ (Wikipedia). Traditionally this
> was done by alternately blowing air and steam through the hot coke,
> burning a lot of the coke to drive the reaction. The idea of heating
> the coke (or other carbon source) with electricity would not have made
> economic sense at that time, even if someone had thought of it.
>
> Carbon is 12 g/mol, 83.3 mol/kg; a kg would soak up 10900 kJ. A ton of
> carbon evaporated in steam would need 10,900,000 kJ or 3.03 MW hours.
>
> This would produce 1/6th of a ton of hydrogen with a combustion energy
> content of 39.4 MWh/ton, about 6.57 MWh. The CO combustion energy is
> 10.1 MJ/kg. A ton of carbon produces 2,333 kg of CO or about 6.55 MWh.
> The reaction makes about 13.1 MWh of syngas from a ton of carbon and
> 3-4 MWh of renewable electric power, an energy gain of over 3. Most of
> the energy in the gas is from carbon sources such as trash or coal.
>
> It’s an efficient way to use intermittent power, though. From this
> point, the gas can be stored for winter, burned in combustion
> turbines, or made into methane, jet fuel, gasoline, or diesel.
>
> Making Liquid Fuels
>
> “The FT is a collection of chemical reactions that converts a mixture
> of carbon monoxide and hydrogen, known as syngas, into liquid
> hydrocarbons. These reactions occur in the presence of metal
> catalysts, typically at temperatures of 150–300 °C (302–572 °F) and
> pressures of one to several tens of atmospheres. The FT process is an
> important reaction in both coal liquefaction and gas-to-liquids
> technology for producing liquid hydrocarbons.[1]”
>
> https://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_process
>
> The FT reaction is:
>
> CO + 2H2 → (CH2)n + H2O. Half the CO in raw syngas must be converted
> to hydrogen via the water-gas shift reaction.
>
> CO + H2O → CO2 + H2. This CO2, about half, can be sorted out and stored.
>
> Sasol has an FT plant in Qatar which makes 34,000 bbl/day of synthetic
> diesel. It has been in operation since 2007.
>
> Development
>
> The only part of this proposal that does not already exist at scale is
> the electrically heated gasifier. There is no reason it would be very
> expensive per ton of capacity, certainly much less than
> platinum-containing electrolytic cells used to make hydrogen.
>
> One problem with using trash a carbon source is that we don’t make
> enough of it. Can we collect enough biomass? Possibly. It would reduce
> the cost of waste collection if biomass were collected with the trash.
>
> Producing Hydrogen
>
> Optimized for hydrogen production, a ton of carbon can make 1/3rd of a
> ton of hydrogen at an energy cost of 3-4 MWh. A ton of hydrogen would
> take 10 MWh to make. At $20/MWh, the cost would be $200/ton or 20
> cents per kg. To this must be added the capital cost of the plant and
> the disposal cost of the CO2, but even so, it should come in less than
> the $1.50/kg cost of gray hydrogen. Electrolytic hydrogen takes 50
> MWh/ton to make, 5 times as much energy, and requires expensive
> platinum.
>
> If the cost of a 9,000-ton per day plant is a billion dollars, written
> off in 5 years, the yearly production capital cost of hydrogen would
> be $1B/(3,000 t/d x 365 d/y x 5 y) or around $180/ton. That about
> doubles the cost of hydrogen to 40 cents per kg, which is still a
> bargain.
>
> A Back-of-the-Envelope Example
>
> The closest landfill to Sylmar, CA gets 9,000 tons of trash per day.
> Call it 4,000 tons/day of carbon. An installation half the size of
> Sasol’s Oryx plant (17,000 bbl/day) would need about 8,500 tons of
> carbon (half lost to making hydrogen), so it would need ~4,500 tons of
> coal per day in addition. That is around 45 rail cars per day which is
> a modest amount, and there is a nearby rail line. Tires or brush could
> be fed into the vaporizer in place of coal.
>
> Vaporizing this amount of carbon would take 8,500 t/24h x 3 MWh/t, a
> little over a GW. If the peak load (when renewable power is available)
> were 3 times the average, the vaporizer would use 3 GW. That just
> happens to be the capacity of the nearby Sylmar converter station, so
> existing power lines could handle it.
>
> It is about 40 miles from the landfill to a Chevron refinery where the
> syngas could be processed into synthetic jet fuel and diesel. There
> are several old oil fields along the route. It would take effort to
> decide if the oil fields were suitable to store a buffer of syngas,
> but they probably are.
>
> Rough Economic Analysis
>
> Income at $100/bbl ($2.40/gal) for diesel, the gross annual sales of
> this venture would be 17,000 bbl/day x 365 days/year x $100/bbl or ~
> $620 M/year.
>
> Figuring cost, the trash is free, and the coal is $66 million (at
> $40/ton). The power would cost 3,000 MW x 365 days/year x 8 hours/day
> x $20/MWh or $175 million per year. (The least expensive PV is $13.50
> per MWh.) This leaves $405 million gross income per year. Maintenance
> and labor might reduce this to $250 M. For a 5-year return on capital,
> the project could cost up to $1.25 B. The Sasol plant cost a billion
> dollars, but that included a refinery. Is there an unused pipeline
> close to the 405 freeway? If not, pipelines cost around $8 million a
> mile.
>
> Research and Development
>
> The one part of this project that does not exist at scale is a 3 GW
> vaporizer. That’s an awful lot of power but not unprecedented for
> industrial processes. A blast furnace for iron production ranges from
> 1 to 5 GW, most of it from the combustion of coke. Arc furnaces for
> mini steel mills are much smaller, typically 50 MW (they are melting,
> not reducing the iron). Arc is probably not the right approach to heat
> trash or coal, the carbon rods will vaporize in the steam. Induction
> heating might be better, though this is 60 times more power than any
> existing induction furnace. A complicating factor for induction
> heating is that the gasifier shell can’t be a conductor. How much hoop
> stress would be needed to contain the pressure needs to be calculated.
> It should not be much worse than water though that depends on the
> pressure.
>
> Figuring trash at a density of one, and a holding time of an hour, the
> interior volume of the gasifier would be 1,000 cubic meters. The
> largest blast furnace in the world is 6,000 cubic meters. If the
> vaporizer were a 50-meter-tall cylinder, it would be a little over 16
> m in diameter or somewhat larger to accommodate the counter current
> steam pipes.
>
> The trash and coal or tires need to be loaded through an gas lock.
> There are two variations used on blast furnaces, double bell
> https://www.youtube.com/watch?v=EfmXzny-TkE and Rotating Chute
> https://www.youtube.com/watch?v=SKl87k-7PiI
>
> A third option is a rotating drum. If the drum holds 50 tons, it will
> have to cycle 20 times per hour to feed the trash into the vaporizer
> at 1000 tons per hour. Steam might be used to purge the air from the
> trash going in and to prevent raw syngas from escaping. Alternately, a
> vacuum system could be used on the rotating airlock to purge the air
> and return the syngas.
>
> One of these or some variation will be needed.
>
> Should the trash run through a grinder? Perhaps, how is the trash
> treated for incinerators?
>
> One thing which should be added to a conveyer belt is an X-ray and an
> AI up to reading the pictures in real time for human bodies. Tracking
> of the trucks dumping on the belt would also be useful in the event
> bodies are found. There needs to be provision to stop the belt and
> recover a body. As a guess this would happen once a year.
>
> The X-ray could measure the amount of carbon in the trash and a
> control computer would determine the amount of coal or tires needed to
> use the entire electric heat input. Chlorine in plastics should also
> be measured for downstream cleanup.
>
> The belt system will need to be enclosed to prevent wind from blowing
> trash off the belt. It should incorporate cleaning provisions.
> Depending on the control algorithms the same belt could be used to add
> the coal. Coal volume or other carbon like tires should be around ¼ of
> the trash.
>
> Gas Flow
>
> The flow of syngas would be 1/6 ton of H2 per ton of carbon. Hydrogen
> is 500 mol/kg, 500 k mol/ton; 1/6 ton would be 83.3 k mol. At STP, a
> mol of a gas fills 22.4 l, 1/6 ton would have a volume of 1867 kl. The
> CO volume is equal, so 3,733 cubic meters of gas flow per hour per ton
> of carbon vaporized. For a peak of 1,000 tons per hour, the gas flow
> would be 3,733,000 cubic meters per hour, half of that if pressurized
> to 2 bar. The proposed vaporizer is 200 square meters in area making
> the upward gas flow around 3,733,000 m3/200 m2 per hour or ~5 m/s (11
> mph). That does not include the pyrolysis gas or the water vapor from
> drying out the trash. This is probably not too fast to lift the trash,
> but further research is needed.
>
> Vaporizing 9,000 tons of carbon per day (9 hours) would need about
> 13,500 tons of steam or 1500 tons per hour or 417 kg of steam per
> second. Assuming water at 100 degrees C, and 2,257 kJ/kg to boil, it
> would take 940,000 kJ/sec to boil the water or 940 MW, or about 30
> percent of the power input to vaporize the carbon in steam. The steam
> could be generated in counter current pipes lining the induction
> gasifier and blown through or across the pool of slag to react with
> the carbon. The shape of the induction gasifier might be like the
> upper part of a blast furnace, opening up to channel the syngas along
> the steam generator pipes. (The newly made syngas has to be cooled,
> and it is hotter than 100 C.)
>
> Steam generation tube area can be calculated from the days of locomotives.
>
> The ASME determines boiler horsepower as: The amount of energy needed
> to produce 34.5 pounds (15.65 kg) of steam, per hour, at a pressure
> and temperature of 0 Psig (0 bar) and 212oF (100oC), with feed water
> at 0 Psig and 212oF. One boiler horsepower is about 33,479 Btu per
> hour (about 9,810 watts, 8430 Kcal/Hr).
>
> 531,000 /15.65 is 34,000 boiler HP. Area would be 577,000 square feet
> or 53600 square meters. (An AI using somewhat higher heat transfer got
> 19,600 square meters.) The inside of the vaporizer is 56.5 square
> meters per meter of height. 30 meters would be short of the needed
> area by a factor of 31. This indicates that the water boiler part of
> the vaporizer will need many steam pipes around the edges to give
> enough heat transfer surface. Keeping the pipes from absorbing the
> induction heat will be a problem. They may have to be ceramic.
>
> Induction coil
>
> The external coil for the induction heater requires cooling. At 3 GW
> even a 0.1% loss will be 3 MW. Coils are often cooled by circulating
> water but this requires high resistivity water and an insulating
> section between the ends of the coil. Even though it is not thermally
> as good as water, the high voltage across the coil may make silicon
> oil a better choice. The turn to turn voltage is high as well. 3 GW is
> 3000 A at a million volts. Turn to turn voltage for 100 turns would
> 10,000 volts. The entire coil might be immersed in silicon oil.
>
> The coil is in a resonate circuit with capacitors. These will need to
> be cooled as well.
>
> While modeling is essential to the design, a 1/10 scale engineering
> test prototype or even a smaller unit might be required. This work is
> from first chemistry and physics principles so there is much to learn.
>
> Gas Cleanup
>
> The bottom of the induction gasifier will have a pool of slag (mostly
> metal and glass) that must be drained off from time to time. The slag
> is useful road construction material.
> https://wasterecyclingmag.ca/feature/energy-conversion/ Aluminum and
> iron in the trash will probably react with steam to make hydrogen.
> Blowing steam through the slag should take out most of the carbon plus
> heat the steam to the 1600 C it takes to react with carbon. How
> efficient this will be is unknown, but there are a lot of studies
> about how much carbon remains in slag.
>
> The gas flow would be up through 40 meters of trash. This should
> remove most of the pyrolysis products (smoke, bio-oil) and recycle the
> carbon down where it can be reacted with steam. This needs further
> study. The remaining gas will be cleaned up with an electrically
> heated catalytic grid or alternately a plasma torch. The steam content
> of the output gas stream must be controlled to assure enough steam to
> react with the carbon.
>
> https://www.sciencedirect.com/science/article/pii/S0306261924019391
>
> The design of this subsystem will need careful consideration and
> probably counter current flow to get the smoke containing gas hot
> enough to react without requiring excessive power.
>
> One safety issue is apparent. If the syngas is going to be used to
> make liquid fuels, about 1/3 would be CO. A leak of the magnitude of
> the Aliso Canyon leak could kill a large number of people from the CO.
>
> https://en.wikipedia.org/wiki/Aliso_Canyon_gas_leak
>
> This will have to be addressed. Leaking syngas could be burned to make it safe.
>
> Another consideration is that considerable energy is released in the
> FT reaction and the reaction runs away at higher tempature. The
> possibility of this happening in a storage reservoir needs to be
> addressed. It would be quite embarrassing to have an oil field
> explode.
>
> Funding a Study
>
> Modern warfare is completely dependent on jet fuel and diesel.
> However, we live at the tail end of the fossil fuels era. While
> supplies are currently adequate, this will not be true in the long
> term. The US DoD had an experimental project that made 11 gallons of
> diesel from a ton of trash. This method, using renewable energy for
> heat, would make about 80 gallons per ton of trash supplemented with
> coal or other carbon sources.
>
> The proposal which might be presented to DARPA is to use trash and
> coal heated by renewable power in steam to make syngas. The syngas can
> be turned into jet fuel and diesel by FT plants.
>
> There are lots of engineering and economic problems to solve, but the
> point is that intermittent renewable energy can be used to make
> synthetic fuel to replace that made from oil.
>
> The induction-heated vaporizer will be a major design effort. It would
> take 8-10 of these to make all the Los Angeles trash into diesel. At 5
> square km/GW for PV, 15 km2 for one of them, 150 km2 for enough power
> to make diesel out of all the Los Angeles trash. The existing Pacific
> Intertie is 3 GW, so to get the power into the vaporizers would take
> ~10 new high-voltage DC lines.
>
> It’s a huge job, but within existing technology.
>
> Other possible sources of funding at least for studies is the airlines
> or possibly rail companies.
>
> Environmental Considerations
>
> A problem this solves is that the US has been overrun by landfills.
> The EU and China use incinerators that could be replaced by this
> method to make syngas.
>
> This proposal would stop landfill leakage of methane. Landfill leakage
> is a substantial source of methane.
>
> The process would eliminate persistent chemicals and drugs if sewer
> digester sludge were included in the feed. (Included water is not a
> problems.)
>
> This process eliminates plastics of all kinds. Unlike incinerators, it
> releases no dioxins into the environment from PVC.
>
> Tires and harvested brush could be used in place of coal.
>
> Energy Considerations
>
> A problem with renewables is that the grid cannot absorb them when the
> load is smaller than the supply, leading to curtailment.
>
> This is wasteful, but using this energy to make hydrogen is too
> expensive. The electrolyzes are expensive largely due to the platinum
> in them and using them less than all the time increases the effective
> capital cost. (Any capital eqipent used ¼ of the time increases the
> capital cost by a factor of 4.)
>
> This proposal would purposely install much more renewable power than
> the grid could absorb and use all the power in excess of grid need to
> make fuel.
>
> Objections > Trash is “not a resource.”
>
> It is a source of carbon, though. If you have lots of excess renewable
> power and a low cost source of carbon, you can make diesel for around
> $100/bbl. The big problem is that we don’t make enough trash.
>
> Converting syngas to jet fuel or diesel is around 75 percent
> efficient. It is well understood. The Sasol plant in Qatar has been
> operating since 2007 and a previous version that ran on coal was
> supplying much of the fuel for South Africa during the apartheid era.
>
> > What are the specific challenges in scaling up this process to a commercially viable level, especially in terms of integrating intermittent renewable energy?
>
> The one piece that does not exist at scale is the electrically heated vaporizer.
>
> > What is the most efficient way to store and transport the syngas produced by this reaction?
>
> The only economical way I am aware of for storage is an empty gas or
> oil field. Transport is by pipeline.
>
> > How do you plan to address the long-term sustainability of this process, especially in terms of CO2 emissions and air capture?
>
> If you are making hydrogen from coal this way, you can capture and
> store all the CO2. In making fuel, half the carbon is in the fuel and
> is released when the fuel is used. If half the carbon comes from
> biomass or trash, the accounting is more complicated. The fuel might
> be rated as carbon neutral. Eventually, all the carbon will have to
> come from biomass or be taken out of the air if humans are still using
> hydrocarbon fuels. None of these will be problems after nanotechnology
> comes along, but who knows how long that will take?
>
> >What are the potential costs and environmental trade-offs compared to other forms of renewable energy storage or synthetic fuel production?
>
> There isn’t any storage out there for renewable energy that scales to
> seasons. Such synthetic fuel production that exists is many times as
> expensive as oil. All the trash that Los Angeles produces plus about
> half that much in coal would supply the US military with fuel.
> Alternately, the trash could supply all the jet fuel LAX uses.
>
>
> Best wishes,
>
> Keith