Replacing diesel and similar petroleum fuels will be a difficult transition, not so simple as for battery EVs.
Heavy transport at 1600 GW uses much more power that the electric vehicle sector just reviewed. Perhaps that power can be reduced; for example, a decade ago half of all ton-miles of railroad freight was hauled by diesel engine locomotives hauling coal to power plants.
Electrifying the rail system is a large opportunity using existing technology.
The International Renewable Energy Agency has these estimates of sector use of power and emissions of CO2. These hard-to-abate CO2 emissions are a big chunk of the ~ 50 Gt/year total.
These 2017 numbers are a bit lower than the IEA 2018 estimates.
As always, all such numbers are rounded to provide memorable insight, not engineering precision.
We’ll be exploring alternative fuels to gasoline and diesel. In the 20th century natural gas at atmospheric pressure was put into gas bags atop buses. There was a fleet of them in China as shown in the old photo on the lower right.
The gas wasn’t really “natural gas” (methane) but city gas, made in coke plants by spraying water on hot coal, producing CH4, CO, and H2 gas distributed through the city. When cheap methane associated with oil drilling became available, it was marketed as “natural” gas.
There are 28 million CNG vehicles in China, Iran, India, Pakistan, Argentina, and Brazil.
For long haul truck routes, hydrogen fuel may be more economical than battery power, partly because of the time lost for more frequent, longer recharging of electric vehicles. The H2 tank only weighs 32 kg, compared to tonnes for equivalent batteries.
Because these trucks only work in the neighborhood of the Port of Los Angeles, they can be refueled by a few local hydrogen fueling stations.
California has the most hydrogen fueling stations.
Advertising featuring truck “under way” turned out to be rolling downhill. Short sellers pounced. The CEO resigned.
Tesla has installed over 10,000 charging stations in the US. Nikola will only need to build H2 refueling stations on heavy trucking routes. An H2 refueling station will be more costly than a battery recharging station, however.
Eliminating trucking of hydrogen lowers its cost. Each station might draw ~14 MW of electric power. This will require support from the local utility transmission and distribution system.
The 240 kW of power from the hydrogen fuel cells may not be enough to haul heavy loads up hills, so the onboard batteries can add 250 kWh of energy. A Tesla car has a ~100 kWh battery.
Even ski areas are joining in the hype about hydrogen to present an environmentally positive image to skiers.
Gasoline, diesel, and carbon-based synthetic fuels are excellent fuels. Replacing them is difficult because the high energy density means they take up little vehicle room.
Their high energy-to-weight ratio makes airplanes economic. The energy expended to fly is directly proportional to the weight of the airplane.
Batteries are substantially inferior in both kWh/kg and kWh/L
To produce attractive synfuels we need a source of carbon. Eventually that carbon is burned and converted to CO2, counter to the objective of zero-CO2.
Some environmentalists argue that getting carbon from carbohydrates in plants and trees instead of carbon from coal and oil is climate neutral, because the CO2 would eventually have been released anyhow as the vegetation dies and rots. Alternatively they say that vegetation will be regrown in its place, absorbing the CO2 during growth. This is the argument for replacing gasoline with ethanol from corn or sugarcane.
This is not borne out in studies, “The use of ethanol as a substitute for gasoline proved to be neither a sustainable nor an environmentally friendly option”.
Nevertheless, you will discover that many proposed “zero-carbon” strategies are really “net zero” using offset arguments such as this.
Removing CO2 from the atmosphere is energy intensive and expensive. The Cell paper has operations data. US carbon tax legislation to pay for such activities assess fees of $10 to $50 per tonne of CO2 emitted. Carbon Engineering built a demonstration plant. At $100 per tonne-CO2 the global cost is $4 trillion/year.
The moral hazard of removing CO2 from the air is that is seems to be justification for continued use of burning fossil fuels that add CO2 to the air.
4 kW per hectare is a rough estimate. I arbitrarily picked 33 MWh/ha/year from the right hand column where numbers range from 10.3 to 63.
Respected writer Vaclav Smil estimates that the average area-specific power densities for biofuels, wind, hydro and solar power production are 3 kW/ha, 10 kW/ha, 30 kW/ha and 50 kW/ha, respectively.
Burning or making ethanol from biomass is not carbon neutral. Later we’ll cover a more energy-productive way to use it.
Food is as important as energy to civilization. When the US Congress ordered converting corn to ethanol to displace 10% of gasoline, prices for corn for tortillas doubled. Now little of this crop is used for food.
Congress was told that the whole corn plant, not just the nourishing kernels, could be converted to ethanol, but this technology never became practical.
To counter deep poverty and accommodate population growth, World Resources Institute recommends world food production increase to 20,500 trillion calories.
Of course they really meant 20,500 trillion kilocalories. The nutrition business uses kcal, sometimes abbreviated to Cal; in CAPS you can’t tell the difference, perhaps the reason for the mistaken vertical axis label, which should be kcal. This is another example of why I convert every energy flow measure to watts.
Here the energy units are correct, Simply quantifying food by its calorific (energy) content does not account for the nutrient value used to build cells.
You can expend some of your 126 watts as work, kinetic energy, but mostly you just produce heat.
I arbitrarily assumed 7 billion people to estimate 1400 GW total food power.
The International Energy Agency report yearns to solve the energy crisis by burning 3 times the biomass used for food! My critique:
- not climate neutral
- depletes the soil because crops with absorbed nutrients are removed
- cropland competition raises prices of and lessens availability of food
There is a better way, by using external energy from fission power.
The necessary hydrogen and heat can be derived from fission power.
I took this picture on a trip through India. Collecting dung fuel is labor intensive. Almost everything collected by a sewer system is hydrocarbons.
Forsberg compares energy released by burning biomass in a woodstove, feeding it to a corn-to-ethanol refinery, or adding external heat and hydrogen to make diesel fuel. This is almost 3X better than today’s biomass-to-energy processes.
Dietenberger and Anderson come to similar conclusions, that hydrogen-enriched biomass gasification can triple the fuel production for a fixed amount of biomass.
Do you this this 3X improvement will make biomass-derived fuels feasible?
Ditenberger and Anderson outline how such a refinery might work.
World War II and Aparthaid sanctions created many industrial processes to convert coal to liquid fuels. This knowledge can be used in developing Dietenbergers’s hydrogenated biomass refineries.
5% is the best case, using hydrogenation. It would be 15% with current biomass conversion practice. Best case (5%) assumes tripling biomass productivity using hydrogenation process factories and hydrogen electrolized with CO2-free electricity from 24×7 fission power plants.
If you google “aviation biofuels” your results are overwhelmed by greenwashing articles about how every airline is converting to biofuels. Small amounts have been added to standard jetfuel to enable boasting. Airlines are are promoting a 2025 goal to use 2% “renewable” fuel by 2025.
Biofuel greenwashing reaches Wikipedia, which writes “Sustainable biofuels do not compete with food crops, prime agricultural land, Natural forest or fresh water.” I heard the same story about the biomass electric power plant I visited in New Hampshire and then watched whole tree trunks chipped into the furnaces.
It would take 75% of it unless we we use biomass hydrogenation with CO2-free hydrogen.
It’s difficult to imagine viable fuel substitutes for aviation, because of the wonderful energy density of jet fuel, so I propose using C-synfuels only for airplanes in the Grand Strategy.
CO2 in the atmosphere is absorbed by surface ocean water, reaching a stable concentration balance in time scales of decades. Removing CO2 from ocean water is tantamount to removing it from the atmosphere.
The Navy’s interest is making jet fuel to power aircraft on carriers in remote locations far from jet fuel supplies.
In 2014 the lab did make enough jetfuel from seawater to fly a model airplane.
The 1.0 kW(e) → 0.6 kW(t) is cost effective. To make hydrogen by steam electrolysis Lucid Catalyst projected 1.0 kW(e) → 0.95 kW(t), in the same ballpark. The above $1.67/gallon electricity cost excludes other plant opex and capex. Even if this sort of diesel fuel costs $6/gallon, it’s less than what Europeans pay today for their fuel, so it’s certainly economically viable.
Cheap, 24×7 electric power is a key technology for this process to substitute C-synfuel for petroleum.
Willauer’s video describes the process in detail. It does require pumping large volumes of seawater for CO2 extraction.
This process has great potential for producing carbon synfuels, yet there is little investment in it. Organizations like IRENA and IEA foolishly continue to promote biofuels, whose CO2 neutrality is strongly debated. Oil and gas companies will oppose fuel synthesis from seawater.
Liquid hydrogen has the highest energy/weight ratio of suitable fuels. Compressed hydrogen is not so feasible because of the weight of the strong tanks to contain 700 bar pressure. Click the graphic to see the Tu-155 fly.
IAC partners analyzed alternative fuels for commercial aviation and concluded “Hydrogen is the only viable low emission option for large-scale commercial aviation.“
Reducing airline flights is one way to reduce jet fuel burning. High speed trains using electric power can compete with short haul airlines.
Electrification of existing rail lines will end emissions from diesel locomotives. Freight traffic may decrease as coal-fired power plants cease operation. About half the ton-miles of US rail freight were to carry coal to power plants.
Musk’s plan is to use small tunnels to guide automated Tesla-like vehicles beneath cities’ infrastructure and avoid right-of-way and social barriers to public transit.
The concept could be expanded to larger tunnels for high speed trains.
Is it possible to power heavy transport with 1600 GW of hydrogen, electricity in overhead wires, and batteries? Can we find more C-sources for C-synfuels?
Airplanes consume 400 GW. Diesel engines power estimates 1400 GW (IRENA) to 2100GW (IEA).
Hydrogen has good, high energy per unit of weight, but it takes up much more room than petroleum fuels.
There is very little infrastructure for refueling hydrogen vehicles.
Making desirable synthetic hydrocarbon fuels requires a net-zero carbon source. Can it be biomass? Can we develop new refineries that add hydrogen’s energy to carbon?
Seawater is a CO2 source; Navy research projects $5/gallon jet fuel.
Carbon capture is often proposed, but it costs $100/tonne-CO2, which would be $400/tonne-carbon.
Airplanes have to be light, so carbonaceous C-synfuel for is the only realistic alternative to petroleum sourced jet fuel.
High speed electric trains are a competitive alternative to airplane transportation for distances up to 800 km.
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