- 1 Technologies in Development
- 2 Power to Gas
- 3 Energy Generation
- 4 Energy Storage
- 5 Energy Efficiencies
- 6 Transportation
- 6.1 Ground Transportation
- 6.2 Aviation
- 6.3 Alternative Fuels
- 7 Infrastructure
- 8 Cement
- 9 Green Ammonia
- 10 Carbon Capture and Sequestration
- 11 Geoengineering
- 12 Systemic Proposals
Technologies in Development
Technological progress is still needed on many fronts to reverse global warming, including:
- Power to Gas
- Energy Generation
- Energy Storage
- Energy Efficiencies
- Carbon Capture and Sequestration
Broad scale but still technological plans are also in development:
- Systemic Proposals
Power to Gas
(From Clean Energy Wire):
Today, synthetic hydrogen and methane are mostly produced from fossil fuels and biomass. Power-to-gas (PtG/P2G), however, refers to the use of renewable electricity to produce these fuels through electrolysis and methanation. Industry and researchers have struggled to agree on what to call renewable PtG products, using terms such as synthetic gases, wind gas, solar gas, or power-based gases, among others.
The first step in the process is to produce synthetic hydrogen (H2) from water and renewable power via electrolysis. This hydrogen can either be used directly – added to the existing gas mix – or put through a second stage that reacts the H2 with carbon dioxide to produce methane (CH4)
Methane is the key ingredient of natural gas and can be used directly in any of today’s standard gas applications. The CO2 used in the methanation process is captured from the air, or from biomass or biogas, to ensure a closed carbon cycle. If the carbon dioxide came from a fossil source, as it does in current industrial processes, it wouldn’t count as carbon-neutral.
Here's a general outline of the overall process:
- Main article: Energy Generation
Electrical energy generation from non-fossil-fuels sources is critical for cutting CO2 emissions. Sources include solar, wind, geothermal, hydropower, nuclear and tidal. Of these New Mexico is particularly well positioned to take advantage of its high solar radiance and abundant winds. While nuclear power is available it comes with high costs and continuing waste disposal technical problems.
- Main article: Energy Storage
Many forms of energy storage are under development, some more than others. Promising technologies include hydrogen, gravity, chemical, mechanical and batteries. The advantages of hydrogen energy storage include the ability to generate hydrogen via the electrolysis of water. Gravity storage systems vary from stacking blocks, to moving railcars around to lowering heavy weights up and down mine shafts. Chemical systems (exclude hydrogen) based on photoelectrosynthesis can store energy from sunlight in the synthesis of bio-fuels. Mechanical systems include compressed-air and flywheels. Advanced battery technology, such as air-flow batteries, have interesting cost and performance characteristics thought they may not be rechargeable in the usual sense.
- Main article: Energy Efficiencies
Demand for energy of all forms can be reduced by improving how we use energy: LED lighting uses considerable less electricity over incandescent lights. While countries and communities continue to rely on energy from fossil-fuels, improved efficiencies help cut CO2 emissions. Even when renewable energy is available improved efficiencies allow less investment in new renewable energy systems. Candidate areas are:
- Buildings & Cities - better insulation, city wide EV public transportation
- Industry - convert furnaces and kilns to run on electricity or direct concentrated solar power.
- Transportation - convert all forms of transportation to use energy storage technologies, develop biofuels for air travel and ocean transportation.
The Electric Vehicle (EV) scene features a number of different technologies:
- BEV - Battery
- FCEV - Fuel-cell - usually using Hydrogen
Battery EVs vs Fuel-cell EVs
Reports towards the end of 2020 point to Elon Musk's passion for Tesla battery powered vehicles, while Jeff Bezos may be making a big play for hydrogen fuel-cells for Amazon. Comparisons of the pros and cons don't seem to make a decision easy, while some developers see a place for both. The saga continues:
- Batteries and Fuel Cells: Understanding differences and opportunities - Cummins - May 14, 2020
Reports on work from automakers GM, Honda, Hyundai and Toyota suggest hydrogen fuel-cells will have a big role in electric vehicles:
- Elon Musk says the tech is ‘mind-bogglingly stupid,’ but hydrogen cars may yet threaten Tesla - Feb. 24, 2019
Automative parts manufacturer Garret Motion Inc, sees fuel-cells with a bright future:
Meanwhile, automaker Volkswagon seems to have made up its mind in favor of BEVs:
- Battery or fuel cell, that is the question - Volkswagon - Dec 3, 2020
A comparison of how each uses energy efficiently is represented in the following schematic from work reported by Arizona State University in:
Dating from around 2003, costs at that time favor BEVs.
There is a small math problem in that multiplying out the efficiencies in the diagram for the Lithium-ion Battery option, gives a wheel delivery of 54.1 kWh. The starting point therefore should be 87.6 kWh instead of 70 kWh. The fuel-cell train is fine. By Nov 2015 reported fuel-cell efficiencies were as much as 60% compared to 54%. This gap is expected to narrow as the technologies improve.
A fact sheet from the Fuel Cell Technologies Office at the US Department of Energy from November 2015 also includes a comparison of different types of fuel-cells:
Comparison of Fuel Cell Technologies
Bloomberg NEF reported in 2020 that a battery pack for an electric bus in China dipped below the $100/kWh for the first time, the crucial price point where electric cars become fully competitive with gasoline vehicles. Bloomberg NEF predicts battery packs for passenger vehicles to reach about $101/kWh by 2023:
- Battery Pack Prices Cited Below $100/kWh for the First Time in 2020, While Market Average Sits at $137/kWh
Electric Vehicles & Infrastructure
From the Sierra Club and Plugin America Model Policies to Accelerate Electric Vehicle Adoption (Version 3.0 July, 2019) advise:
Policymakers must prepare for this major shift in how transportation is fueled by implementing bold policies that will support—and accelerate—this transformation to plug-in electric vehicles (EVs). This toolkit is designed to accelerate the switch to these clean vehicles in an effective, sustainable, and equitable way by providing public officials and advocates with model EV policies.
Cox et al. (2020) studied the effects of the energy transition on ownership cost and environmental impact of vehicles with different powertrain configurations. Increasing energy sector decarbonization increases the benefit of full electrification of passenger vehicles.
Hydrogen Fuel Cell Transportation
Fuel cell technology advances are allowing trials in busses, trains and even airplanes. Hydrogen Powered Transportation is being demonstrated around the world.
Battery Electric Aviation
Regular commercial though short range electric air travel may be coming closer according to this report from Canada of a retrofitted de Havilland DHC-2 Beaver seaplane:
- "Is this the start of an aviation revolution?" BBC Future Planet - February 11, 2020
Norway has plans too:
- Norway's plan for a fleet of electric planes BBC Future Planet - August 22, 2018
According to consultants Roland Berger,
- The number of electrically propelled aircraft developments grew by ~30% in 2019 - January 15, 2020.
Fuel-cell Electric Aviation
ZeroAvia’s six-seater Piper M-class aircraft — which has been retrofitted with the device that combines hydrogen and oxygen to produce electricity — undertook a taxi, take-off, full pattern circuit and landing:
- Hydrogen-powered passenger plane completes maiden flight in ‘world first’ - CNBC - September 25, 2020
Airbus is conducting studies to determine how scalable a hydrogen fuel cell “pod” configuration, among others, could be to large commercial aircraft. The aviation industry has developed numerous configurations—twinjet, s-duct, winglets, contra-rotating propellers—over the last five decades that have enabled aircraft to fly higher, faster and longer. Now, Airbus engineers are unveiling a new configuration as part of the ZEROe program (earlier post) that could enable a passenger aircraft to fly farther than ever without emissions.
- Airbus exploring hydrogen fuel cell propellor “pods” for aircraft propulsion - Green Car Congress - Jan 3 2021
The International Energy Agency (IEA) produced a report:
- The Future of Hydrogen - June 2019
A coalition of major oil & gas, power, automotive, fuel cell, and hydrogen companies would like to consider hydrogen as an alternative fuel to high carbon content fuels. Mostly this involves 'blue' hydrogen made by reforming methane. The coalition has prepared and released its report to explain the concept.
- Roadmap to a US Hydrogen Economy - October 5, 2020
Cobalt and titanium have been used to produce a new catalyst that can be used to split water molecules into oxygen and hydrogen, allowing the hydrogen to be stored as energy. The catalyst is described in Sci Tech Daily as durable and efficient, and use of these elements, and more sustainable when using these elements as opposed to precious metals.
- Oxygen evolution reaction over catalytic single-site Co in a well-defined brookite TiO2 nanorod surface - December 14, 2020
Julie McNamara, senior energy analyst of the Union for Concerned Scientists, advocates for strategic hydrogen decarbonization interventions rather than an energy sector funded transition to a fully hydrogen based economy for two reasons: (1) the impracticality and unanswered questions of such a transition, and (2) the potential negative influence of stakeholder commitment once such a transition were to begin. Unanswered questions include the scalability of "green" hydrogen (which "uses renewable electricity to split water into hydrogen and oxygen through a process called electrolysis"), the carbon impact of "blue" hydrogen, potential to mitigate increased NOx pollution, the extent of infrastructure upgrades necessary to support hydrogen decarbonization, mitigation of safety effects to the home user, and suitability of hydrogen for use in motor vehicles.
- What’s the Role of Hydrogen in the Clean Energy Transition? - December 9, 2020
Aviation and ocean shipping have distinct disadvantages when it comes to using batteries for energy storage. Until electrification of airplanes becomes feasible at scale, biofuels would reduce the impact of the current use of fossil fuels. Similarly, the large amounts of bunker fuel used by large cargo ships make battery storage difficult again. Until cargo ships and perhaps cruise ships can be electrified, there will be a need for biofuels.
These fuels yet need to be developed economically, at scale either from fast growing bio-sources or recycled sources.
- Ethanol based fuels
- Bio-jet fuel
- Algal based fuels
Development must consider any impacts on farming for food. Corn ethanol for example can take agricultural land away from food production for transportation purposes, when transportation benefits from electrification as battery prices continue to fall.
Bio-jet Fuel and Other Jet Fuels
The current technologies for producing renewable jet fuels can been categorized as alcohols-to-jet, oil-to-jet, syngas-to-jet, and sugar-to-jet.
In 2016 Anthropocene Magazine reported that, with the help of a hardy new strain of the common gut bacteria E. coli, researchers have invented a one-pot process to convert switchgrass into a chemical compound used to make jet fuel. The simple, low-cost method could make the bio-jet fuel more competitive with kerosene-based jet fuels, of which the aviation industry uses 1.5 billion barrels every year. See:
- Green jet fuel in one easy step - Anthropocene Magazine - May 16, 2016
Yao et al. (2020) have created an iron-based catalyst that converts carbon dioxide into a carbon-neutral jet fuel.
- Transforming carbon dioxide into jet fuel using an organic combustion-synthesized Fe-Mn-K catalyst - Nature Communications - December 22, 2020
[topic being researched]
Algal based fuels
[topic being researched]
Highway construction generally relies on either cement or asphalt road beds (pavements). The industry claims asphalt roads actually have far fewer GHG emissions than cement over their life cycle:
According to the article, for a 50 year life-cycle, conventional asphalt was calculated to have 500 CO2e tonnes/km while (Portland cement) concrete was 1610 CO2e tonnes/km. In 2017, there were 4.18 million miles of road in the United States, including Alaska and Hawaii, according to the Federal Highway Administration. About one third are unpaved. The 50 year total emissions, assuming all paved highways were asphalt (and presumably the same average width and thickness) comes to 2.24 GTe, versus over three times that for concrete. For comparison, Project Drawdown estimated that over 20 years (2030-2050) worldwide composting - number 60 on the list - would reduce GHG by a similar 2.28 GTe. It should be noted that most asphalt contains bitumen a byproduct from oil and gas refining, and can be recycled by reheating into new construction. Some bitumen occurs naturally.
- Main article: Cement
Advances in cement technologies aim at reducing the CO2 emissions during manufacture, cutting the amount of cement used in construction and making concrete without any cement at all. There are a number of initiatives that private industry is already pursuing.
Green ammonia is ammonia made completely carbon free. Green ammonia is made when green hydrogen is used as a feed stock and renewable energy is used to drive the manufacturing process.
Currently ammonia (NH3) is at the core of nitrogen fertilizers deemed essential for worldwide food production. Without ammonia based fertilizers there are claims that as many as 1 billion people worldwide would starve. Ammonia is made in the Haber-Bosch process from nitrogen in the air and hydrogen, generally made via methane reforming, i.e. from fossil fuels. The process also uses fossil fuels to generate the high temperatures needed. Current ammonia production accounts for over 1% of global CO2 emissions, according to Siemens. 'Pure' ammonia is sometimes referred to as anhydrous ammonia. When used as a household cleaner it is dissolved in water as ammonium hydroxide.
Ammonia can be used as an energy storage medium, as a fuel and as now a feedstock for other chemical processes. Burning ammonia produces nitrogen and water and trace NOx.
Even though ammonia is toxic, storing and transporting ammonia has been practiced safely for a long time.
Siemens Energy have developed an infographic illustrating most of the pros and cons of green ammonia:
Carbon Capture and Sequestration
- Main article: Carbon Capture and Sequestration
Artificial carbon capture technologies are being pursued to capture CO2 in the atmosphere directly, to capture CO2 in the emissions from factories and power plants. A variety of relatively exotic technologies for artificial carbon capture include metal-oxide frameworks, Cerium catalysts and Zeolite absorption. Improvements in membrane technologies allow concentration of CO2 enabling some of these approaches.
Land Based Solutions such as reforestation, afforestation, regenerative farming and soil management are ways to effect carbon capture with natural processes.
Often prescribed as an emergency action to get control over climbing temperatures, geoengineering is a controversial strategy:
- As Climate Disasters Pile Up, a Radical Proposal Gains Traction - NYTimes - October, 2020.
The idea is to use physics to change the heat balance of the biosphere so that instead of rising greenhouse gases trapping heat some mechanism is used to reduce the amount of solar gain. Most methods involve changing the atmosphere so that it reflects more sunlight. Methods to reduce atmospheric CO2 in our caae is included under Carbon Capture and Sequestration.
Some of the possible downsides include:
- the fossil fuel industry will see it as a technological solution that they can brandish to delay real action on global warming and the burning of fossil fuels.
- it does nothing for ocean acidification, and the marine food chain we and other ecosystems sit on top of.
- the law of unintended consequences that could easily kick in as some of the methods are adopted wide-scale.
- we only have one planet to experiment on.
- the technology could be used for political purposes.
Research and discussions continue.
- Main article: Systemic Proposals
Detailed academic models show ways to transition entire economies over to renewable energy sources. Integration issues between intermittent solar and wind energy generation and storage needs are being addressed using real-world data in order to engineer energy infrastructure. Such system solutions are needed to meet actual demand and generation patterns.