In our previous conversation with conservation engineer John Mitchell, we explored the widespread change that would be needed to move the existing U.S. electric grid from fossil fuels to wind, solar and other so-called renewable power sources. What makes Mitchell’s opinions on the matter particularly important is the fact that he currently draws up such policy proposals for groups like the Climate Mobilization.

Mitchell’s blueprints go far beyond the energy grid itself, however. Nearly the entirety of the U.S. is tied to fossil fuel, as is true for the industrialized world overall. If the industrialized world wants to maintain any semblance of its current form while preventing the total collapse of the global ecosystem, its agriculture system will need to be made sustainable and vehicles will need to be electrified.

Replacing Fertilizers

The existing industrial agricultural system relies on fossil fuels in various ways and has destructive impacts on the global ecosystem, including the maintenance of the stable climate we’re accustomed to in the current Holocene era.

Nitrogen fertilizers are the result of ammonia created from the removal of hydrogen from natural gas. About 100 megatons of nitrogen fertilizer were used on the planet in 2010, compared to just three in the 1950s. Phosphorous and potassium fertilizers may not be derived from fossil fuels, but they are mined, which requires considerable energy.

This year, we learned that methane, a greenhouse gas roughly 30 times more potent in the near-term than carbon dioxide, from fertilizer production is 100 times greater than what companies are reporting. Additionally, fertilizer flows from fields to our waterways, creating algae blooms and dead zones in the ocean.

According to Mitchell, these issues and more could be addressed by abandoning chemical fertilizers.

“Several organizations around the world have determined that we could sequester as much carbon from the atmosphere as we’re currently emitting each year if we shifted to 100 percent regenerative agricultural practices,” he said.

Regenerative agricultural practices include the following, among others:

• Replacing fertilizer with compost
• Implementing no-till agriculture
• Abandoning herbicides
• Regular crop rotation
• Replacing monoculture crops with polyculture planting
• Holistically managed grazing

The point of regenerative agriculture is to think of crop production as a holistic process that considers the larger ecosystem, deploys techniques that actually restore topsoil, increases biodiversity, improves the water cycle and even sequesters carbon—all aspects of the ecosystem that have been greatly degraded by industrial farming.

“One thing that people don’t quite realize is that the amount of carbon weight in an old-growth forest above the surface of the earth is approximately equal to the weight of carbon that is being stored in the microbiome fungus beneath the forest that is being fed by the tress in a symbiotic relationship between tree and fungus,” Mitchell explained. “The fungus gets minerals and supports the trees, storing carbon in the form of sugars in the soil that way. The use of glyphosate [the primary ingredient in RoundUp and other herbicides] necessarily destroys these microbiomes. It kills off the fungus beneath the surface of the earth, so you don’t have that flow of carbon to the soil.”

The state of Connecticut has been moving in the right direction, according to Mitchell. The state performs food waste collection, which can then be used both for the generation of biogas and the creation of compost. In some parts of Connecticut, companies like BlueEarth collect food scraps and deliver the resulting compost back to customers three times a year.

The actual composting is performed by firms like Quantum Biopower, which places the food waste in an industrial anaerobic digesting facility. During decomposition, the waste gives off methane, which is collected and burned in the same way that natural gas is. However, the food has already participated in sequestering carbon dioxide from the atmosphere that was emitted within the lifespan of the crops. For this reason, biogas is said to be carbon neutral.

Municipal composting also opens an opportunity for producing biochar, a carbon-rich type of charcoal made from heating organic biomass (such as food and agricultural waste) in an oven with little to no oxygen present, a process known as pyrolysis. Biochar is thought to have soil-enriching and water-retention benefits and, therefore, could be important for soil regeneration.

Compost and biochar production can be compatible operations due to the fact that feedstocks for compositing (biomass with high moisture, low lignin content) aren’t always ideal for biochar (low moisture and high lignin content) and vice versa. Moreover, biochar could play an important role in carbon sequestration.

“Combining compost, and anaerobic digestion with biochar work together for high efficacy amendments, that re regionally sourced and carbon negative,” Mitchell said.“Biochar production and anaerobic digestion facilities actually generate and sell electricity as an added bonus.”

Sequestering Carbon in the Seas

Because capturing and transporting all food and agricultural waste will be expensive, Mitchell proposes an additional method for generating biomass for the aforementioned purposes. The idea is based off of existing research by the USC Wrigley Institute of Environmental Studies in which elevators off of the coast of Catalina Island are used to grow kelp.

The platform raises to the surface of the ocean during the day to receive sunlight and drops deep into the ocean, where nutrient levels are higher, at night. With growth rates of 2 to 3 feet per day, kelp is already one of the fastest growing plants in the world. This process is thought to increase the speed with which it can grow. 

Mitchell takes kelp farming a step further by linking hypothetical seaweed elevators with off-shore wind farms, such that the turbines power the elevators. Additionally, he envisions a wind-powered conveyor system bringing the kelp to shore where it can be harvested for livestock feed, dried and converted to biochar or other applications.

“This would be a great way to remove carbon from the Earth’s oceans and sequester it in the land or produce net zero feedstock,” he said.

In Sweden, seaweed farming is used to produce food, making livestock feeds, and extracting polymers for bioplastics, adhesives and textiles. The remainder is used for biofuel. Mitchell sees materials like hemp serving a similar purpose to capture carbon and be used for clothing, rope, bioplastics, papers, biochar and agricultural feedstock.

Victory Gardens

“A more equitable distribution of resources is fundamental to the decarbonization of society,” he said. “The fossil fuel, food and water, and medicine industries are all hegemonic forces that are basically working to extract wealth and resources from the general population, but the shift away from fossil fuels changes that relationship in society, leading to more equitable distribution of resources and goods and the retaining of household expenditures locally to prevent the outflows from local communities and reduces significantly the velocity of money which is a benefit to the local economy.”

What that looks like and how that effects the agricultural sector isn’t clear, although Mitchell does see a precedent set in the concept of victory gardens established during World Wars I and II. These plots of fruits, vegetables and herbs were planted at homes and in parks in the U.S., U.K, Australia, Canada and Germany as a means of reducing pressure on the general food supply. Using victory gardens, the U.S. was able to generate about 40 percent of its national food products in private and community gardens.

“We certainly have much greater potential today,” Mitchell said.“We could create up to 80-90 percent of our household produce consumption in our local communities through a front- and backyards program. The provision of compost biochar and biodigestion will also be a way to sequester carbon in local regions, without having to transport goods. This leads to a reduction in emissions associated with production, transport, storage and refrigeration of the foodstuffs.”

Mitchell argued that with this transformation to a sustainable society, aspects of the country’s collective persona will probably end up changing or falling away. This includes the way we consume things and “aspects of our rugged individualism.”

“We will become more interdependent if everyone is growing food and has communal kitchens, people can get value-added products in the sale of locally generated food stuffs in farmers markets, the production of cottage industries in clothing and other applications,” he said.“We’ve definitely gotten away from it because we’ve been moving toward a top-down hierarchal employment structure. So, we tend to make our money and spend it instead of making things that are actually adding value.”

Transportation

Autonomous Vehicles as Public Transit

While large-scale public transportation infrastructure (e.g., busses and subways) has worked in dense urban environments, such as New York City, Mitchell isn’t sure that the same will be feasible in suburbs and rural environments. To tackle locations where busses and subways won’t work, he suggests autonomous vehicles (AVs).

“I’m telling you, there’s no way we can get Americans to both relocate to high-density cities and to rely on public transportation and honestly we wouldn’t need it because it turns out that the autonomous vehicles are a kind of public transportation,” he said. “I strongly believe that they should be publicly owned systems, not private like Uber, Lyft or Tesla.”

The Rocky Mountain Institute (RMI) believes that we’re headed toward peak car ownership, one of the reasons being that AVs combined with ride-sharing services will replace the need for private transportation. By 2025, RMI projects that Los Angeles may generate $11.5 billion in revenue from automated mobility. If this is done in the public sector, according to Mitchell, this could be used to fund AVs as public transportation.

He used the example of Tesloop’s Model S 90D as evidence that AVs could provide low-cost transportation, compared to taxi services. The car racked up over 400,000 miles shuttling people between Los Angeles and Las Vegason autopilot 90 percent of the time, according to the company. It required three battery replacements (under warranty) and totaled $19,000 in maintenance repairs, about $0.05/mile Tesloop estimated.

“If you can run a car three times longer without replacing the car itself three times, that’s a significant reduction in cost. Then AVs, without the cost of the driver and the ability to have more passenger seating, allows the reduction in per mile cost through shared transportation that can get the cost down to 4 cents per mile,” Mitchell said.“That compares to the current taxi, which is $1.50 per mile in New York. It’s actually coming in at a price that’s about one-fifth the current cost of bussing in Los Angeles.”

Obviously, the AV is even more convenient, given the fact that it provides door-to-door pick-up and drop-off. The addition of solo-driving penalties would drive even more people to use autonomous shuttling services over private vehicles.

Tying pack to our first article, electric AVs have the added benefit of working as portable power storage devices. Mitchell pointed out that they can automatically move about the electrical grid when not in use to provide local power generation.

Autonomous Vehicles as Shipment Fleets

He also sees a role for AVs in the freight industry, with land transport replacing a good deal of the air shipments that occur in the U.S. He advocates platooning-as-a-service, in which interstate transport is performed by a fleet of smart electric AVs following a leader vehicle. Already being explored by researchers and businesses alike, these platoons would allow EVs to maintain very minimal distances of eight to 12 inches apart, constantly communicating and moving as a single unit.  

“This would reduce the amount of electricity demand per mile by about 20 percent. One-third of that savings would be paid to the shipper, which has the large freight vehicle with an attached wind clip screen to achieve greater energy savings,” Mitchell said.“If you get 10 of them moving on interstate highways saving 20 percent of the energy costs and paying off one-third to the shipper, then your transport can become practically free. You’re basically subsidizing the cost of transport.”

High-Speed Rail

With platoons of electric, autonomous trucks performing the bulk of the freight shipments across the country, rail would no longer be necessary for the task. That’s a good thing because, currently, high-speed rail (HSR) can’t pull of the speeds it needs to with heavy loads of shipments onboard, though small freight HSR experiments are underway.

Instead, HSR could be used to replace a good deal of national air travel. We’ve covered HSR as it has been implemented in China and how it hasn’t been deployed in the U.S. One problem with rail in the U.S., however, is that it relies on fossil fuels. Andy Kunz, president of the U.S. High Speed Rail Association, believes we need to electrify the rail lines themselves.

Mitchell is also an advocate of replacing current lines with HSR-capable lines that are electric; however, he believes that believes that electrification of entire rail lines would be too expensive. Instead, he suggests a combination of on-board electricity storage and electrifying rails at discreet intervals. 

He imagines train cars maintaining lithium-ion style batteries that are charged via induction or other contact charging system along the rail line. Super capacitors with higher rates of charge, currently in development, would make it possible to extract energy very slowly over time but charge the batteries very quickly. (Read about some of the issues with lithium batteries in our previous article.)

“Sweden currently has been installing electrified roads that allow electric vehicles—mostly freight—to charge while driving, in their very wet and snowy environment. It’s definitely feasible especially for rail,” Mitchell said.

HSR could be used to significantly reduce air travel. For the rest, there is the possibility of biofuels—perhaps made from the seaweed and food scraps mentioned above. Mitchell believes biofuels and hydrogen fuel cells to be red herrings.

“Generally everything I’ve looked at has said that biofuels and hydrogen are unsustainable and primarily a way to prevent real discussion about renewable energy solutions by the fossil fuel industry,” he explained.

He does believe electric planes could be viable for 150- to 200-mile trips and is curious about SpaceX’s plans for Earth-based rocket travel, which Elon Musk boasts would be able to carry 100 passengers from London to Shanghai in 39 minutes for the price of a standard economy plane ticket. 

Issues with AVs

For the idea of AVs as a solution to both mass transit and freight shipment in the U.S., there are important issues worth noting. In addition to problems with electric batteries discussed in our first interview, there is the fact that the climate crisis is an emergency that must be addressed as soon as possible and, as with any technology that has yet to be delivered to the public, AVs don't yet quite exist exactly. 

Tesla has provided a first step in autonomous driving with its autopilot feature, but as covered in other articles on engineering.com, AVs are still unproven and may be potentially dangerous in their current state. To suggest a yet-to-be-fully-developed concept as a major solution to reducing emissions, which must be cut by at least 45 percent from 2010 levels by 2030, may represent poor planning. 

USHSRA's Andy Kunz concurred, particularly with regards to replacing freight trains with platoons of trucks. "To suggest proposing to replace an incredibly successful system (our current freight rail system) with an unproven, problematic system is itself problematic," Kunz said. "The future of freight is not trucks at all. The future of freight is two forms of rail. Trucks will scale way back, especially long distance trucks. The current heavy freight network will remain as the heavy hauler of bulk freight like lumber, chemicals, etc. The express freight (which is now hauled by long distance trucks and airplanes) will all be moved onto high speed rail as that will be the most economical, efficient, and sustainable way to move goods."

When considering platooning-as-a-service and wireless highways, the full complement of infrastructure that is needed includes a huge new infrastructure network of antennas, cameras, and sensors that could cost as much as a trillion dollars to install. These antennas and sensors require energy to run, which means that large amounts of additional energy will be required just to run the infrastructure, in addition to the energy to run the vehicles.

This is important to consider in terms of literally any future technology or tech proposal, including SpaceX's supposed plans for ultra-fast rocket travel (which, unless it begins using electric rockets, would contribute substantially to emissions). A capsule explosion in July 2019 already set back some of the company's manned spaceflight plans, which was just one of a series of failures the company has faced. 

How This Will All Happen

Again, Mitchell argues that this will require a massive mobilization on the scale of WW2, with huge government subsidies. He doesn’t just believe that it’s going to happen, but that it has to happen in part because of the looming financial crisis that will occur due to how inextricably linked our global financial system is with fossil fuels.

That topic, along with the estimates and misestimates of the current climate science and the role of carbon capture in a hot, hot world will be covered in our final installment in this series.