Decarbonizing Aviation: Active Carbon Removal (Part 2)
The environmental consequences of carbon emissions have made active carbon removal (ACR) a Federally tax-privileged investment. Is this plus other Federal and State policies and incentives, and improving technology, enough to overcome ACR’s cost and technical challenges?
What is Active Carbon Removal?
Active carbon removal captures and stores human-generated carbon dioxide emissions. Because carbon levels will continue to rise for decades, cost-effective ACR could be a “magic bullet” to stabilize and even reduce the concentration of CO2 in the atmosphere.
Active Carbon Removal Technologies
Carbon Capture and Storage (CCS)
CCS captures carbon emissions at their source, such as power plants, and stores them underground. This technology, in use for years and constantly improving, is proven to reduce emissions but is limited to specific applications, and costly.
Direct Air Capture (DAC)
DAC is a cutting-edge technology that captures carbon dioxide directly from the air and so can be located wherever the captured carbon will be sequestered. In the future, this captured carbon may replace organic feedstock to directly create electrofuels (eFuel) including a new type of Sustainable Aviation Fuel (SAF).
Ocean-Based Solutions
Some innovative methods involve using the oceans to remove carbon from the atmosphere – essentially indirect air capture. It takes advantage of the vast scale that oceans absorb CO2 and ample sequestration opportunities including offshore rigs (essentially putting the carbon right back where it came).
Reforestation/Afforestation
Trees are a natural carbon sink. Planting trees at scale – reforestation if replanting; afforestation if planting where there was no recent growth. Regenerative forestry, especially with fast-growth lumbar, has the advantage of creating building material which permanently sequesters carbon and allows for premium financial yield.
Economics of Active Carbon Removal
While active carbon removal technologies face limitations in scalability and efficiency, the primary barrier is cost.
Economic Considerations
1. Technology Selection
The type of direct carbon capture technology chosen plays a significant role in cost determination., Each method such as chemical absorption, membrane separation, and solid adsorption. Technology selection is a major factor in costs and efficiencies.
2. Scale of Implementation
The scale at which direct carbon capture is implemented can vary widely, and with it cost. Sequestration and/or transportation logistics, and their costs, are also scale dependent, as described in (4).
3. Energy Requirements
The energy cost of operating direct carbon capture can be a substantial, and includes the energy required both to capture CO2 and transport it to storage sites. As such, carbon capture initiatives often encompass renewable energy to remove this cost and further environmental impact .
4. Storage and Utilization
Captured CO2 needs to be safely stored or put to use, factoring in costs associated with storage facilities, transportation, and chosen utilization. Captured CO2 currently has various applications, such as carbonating beverages or enhancing oil recovery which offset some of the expense. In the future, eFuel’s will rely captured carbon rather than organic feedstocks.
The Bottom Line
Active carbon removal initiatives in the US are accelerating due to technological advancements, policy support including R&D and deployment incentives, and corporate engagement. It’s challenging to derive the exact costs of direct carbon capture the many contributing factors. Currently, without incentives, carbon removal isn’t cost effective, and even then is too expensive for widespread deployment. It’s anticipated that current incentives will jump-start technology advances and begin delivering economies of scale come to reduce costs.
Total energy independence and resilience
Once challenging or impossible, going “off-grid” – relying solely on self-generated power – is increasingly common due to lower cost, new incentives, better technology, and more frequent extreme climate events leading to utility outages.
Depending on situation, off-grid can mean completely – relying strictly on solar power and storage without any utility connection at all. This allows use of land without accessible electrical service. More commonly, structures are still grid-connected to retain the option of buying power, and because some incentives require it.
How does it work?:
- Solar Panels: Solar panels installed on your property convert captured sunlight
into electricity used to power your home and charge batteries. Panels can be mounted on roofs or ground mounted, and multiple structures can be powered centrally or independently.
- Inverter: Solar panels generate direct current (DC) as used in cars and electronics. A solar inverter convert this power into the alternating current (AC) electricity used in virtually all homes.
- Battery Storage: Mainstream off-grid adoption is driven by advances and lower costs in battery technologies. In addition, new chemistries eliminate the fire hazard of lithium ion batteries and make it feasible and cost effective to fully power any size home (or multiple homes), including HVAC. NREL estimates that properly sized batteries provide at least 3 days or power in most climates, and as long as panels aren’t covered power continues to generate and lasts indefinitely.
- Battery systems include a control unit that controls charging based on usage profiles. For example, a grid connected system can have a storm mode that ensures batteries are always fully charged using the grid as needed,
- Optional Backup Generator: Some systems also include a backup generator, often propane or natural gas, to provide an added level of resiliency and safety in case of an extended period of low sunlight. A whole house battery system can, if necessary, be fully charged in these situations by a relatively small generator.
Here are some key considerations:
- Initial Cost: As of 2023 Federal, state and local incentives now cover 30% – 70% of system costs. Because solar/storage systems have no maintenance or fuel costs and provide perpetually free power, they are often more cost-effective than just a backup generator.
- Energy Usage: Systems are sized based on of seasonal energy consumption patterns and daily electricity needs. Off-grid in particular requires an accurate assessment to ensure sufficient generation.
- Location: The effectiveness of a solar system depends on your location, climate, and the amount of sunlight you receive. While some areas are more suitable for solar energy generation than others, the difference is surprisingly small: for example, identical systems generate about 20% more power in LA than Minneapolis. And even in areas with persistent snow cover, the dark color, smooth glass and tile of solar panels means snow tends to quickly fall off even while the ground and roofs are covered.