Expectations for energy storage are high but large-scale underground hydrogen storage in porous media (UHSP) remains largely untested. This article identifies and discusses the scientific challenges ...of hydrogen storage in porous media for safe and efficient large-scale energy storage to enable a global hydrogen economy. To facilitate hydrogen supply on the scales required for a zero-carbon future, it must be stored in porous geological formations, such as saline aquifers and depleted hydrocarbon reservoirs. Large-scale UHSP offers the much-needed capacity to balance inter-seasonal discrepancies between demand and supply, decouple energy generation from demand and decarbonise heating and transport, supporting decarbonisation of the entire energy system. Despite the vast opportunity provided by UHSP, the maturity is considered low and as such UHSP is associated with several uncertainties and challenges. Here, the safety and economic impacts triggered by poorly understood key processes are identified, such as the formation of corrosive hydrogen sulfide gas, hydrogen loss due to the activity of microbes or permeability changes due to geochemical interactions impacting on the predictability of hydrogen flow through porous media. The wide range of scientific challenges facing UHSP are outlined to improve procedures and workflows for the hydrogen storage cycle, from site selection to storage site operation. Multidisciplinary research, including reservoir engineering, chemistry, geology and microbiology, more complex than required for CH
4
or CO
2
storage is required in order to implement the safe, efficient and much needed large-scale commercial deployment of UHSP.
This article identifies and discusses the scientific challenges of hydrogen storage in porous media for safe and efficient large-scale energy storage to enable a global hydrogen economy.
How will the global atmosphere and climate be protected? Achieving net-zero CO2 emissions will require carbon capture and storage (CCS) to reduce current GHG emission rates, and negative emissions ...technology (NET) to recapture previously emitted greenhouse gases. Delivering NET requires radical cost and regulatory innovation to impact on climate mitigation. Present NET exemplars are few, are at small-scale and not deployable within a decade, with the exception of rock weathering, or direct injection of CO2 into selected ocean water masses. To keep warming less than 2°C, bioenergy with CCS (BECCS) has been modelled but does not yet exist at industrial scale. CCS already exists in many forms and at low cost. However, CCS has no political drivers to enforce its deployment. We make a new analysis of all global CCS projects and model the build rate out to 2050, deducing this is 100 times too slow. Our projection to 2050 captures just 700 Mt CO2 yr−1, not the minimum 6000 Mt CO2 yr−1 required to meet the 2°C target. Hence new policies are needed to incentivize commercial CCS. A first urgent action for all countries is to commercially assess their CO2 storage. A second simple action is to assign a Certificate of CO2 Storage onto producers of fossil carbon, mandating a progressively increasing proportion of CO2 to be stored. No CCS means no 2°C.
This article is part of the theme issue 'The Paris Agreement: understanding the physical and social challenges for a warming world of 1.5°C above pre-industrial levels'.
The capture of carbon dioxide at the point of emission from coal- or gas-burning power plants is an attractive route to reducing carbon dioxide emissions into the atmosphere. To commercialize carbon ...capture, as well as transport of liquified carbon dioxide and its storage in exploited oil fields or saline formations, many technological, commercial, and political hurdles remain to be overcome. Urgent action is required if carbon capture and storage is to play a large role in limiting climate change.
Carbon capture and storage (CCS) can help nations meet their Paris CO2 reduction commitments cost-effectively. However, lack of confidence in geologic CO2 storage security remains a barrier to CCS ...implementation. Here we present a numerical program that calculates CO2 storage security and leakage to the atmosphere over 10,000 years. This combines quantitative estimates of geological subsurface CO2 retention, and of surface CO2 leakage. We calculate that realistically well-regulated storage in regions with moderate well densities has a 50% probability that leakage remains below 0.0008% per year, with over 98% of the injected CO2 retained in the subsurface over 10,000 years. An unrealistic scenario, where CO2 storage is inadequately regulated, estimates that more than 78% will be retained over 10,000 years. Our modelling results suggest that geological storage of CO2 can be a secure climate change mitigation option, but we note that long-term behaviour of CO2 in the subsurface remains a key uncertainty.
Hydrogen energy futures - foraging or farming? Hassanpouryouzband, Aliakbar; Wilkinson, Mark; Haszeldine, R. Stuart
Chemical Society reviews,
03/2024, Letnik:
53, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Exploration for commercially viable natural hydrogen accumulations within the Earth's crust, here compared to 'foraging' for wild food, holds promise. However, a potentially more effective strategy ...lies in the
in situ
artificial generation of hydrogen in natural underground reservoirs, akin to 'farming'. Both biotic and abiotic processes can be employed, converting introduced or indigenous components, gases, and nutrients into hydrogen. Through studying natural hydrogen-generating reactions, we can discern pathways for optimized engineering. Some reactions may be inherently slow, allowing for a 'seed and leave' methodology, where sites are infused with gases, nutrients, and specific bacterial strains, then left to gradually produce hydrogen. However, other reactions could offer quicker outcomes to harvest hydrogen. A crucial element of this strategy is our innovative concept of 'X' components-ranging from trace minerals to bioengineered microbes. These designed components enhance biotic and/or abiotic reactions and prove vital in accelerating hydrogen production. Drawing parallels with our ancestors' transition from hunter-gathering to agriculture, we propose a similar paradigm shift in the pursuit of hydrogen energy. As we transition towards a hydrogen-centric energy landscape, the amalgamation of geochemistry, advanced biology, and engineering emerges as a beacon, signalling a pathway towards a sustainable and transformative energy future.
Combined geochemical and microbial processes offer a transformative approach to sustainable subsurface hydrogen production.
Carbon capture and storage (CCS) technology is routinely cited as a cost effective tool for climate change mitigation. CCS can directly reduce industrial CO
emissions and is essential for the ...retention of CO
extracted from the atmosphere. To be effective as a climate change mitigation tool, CO
must be securely retained for 10,000 years (10 ka) with a leakage rate of below 0.01% per year of the total amount of CO
injected. Migration of CO
back to the atmosphere via leakage through geological faults is a potential high impact risk to CO
storage integrity. Here, we calculate for the first time natural leakage rates from a 420 ka paleo-record of CO
leakage above a naturally occurring, faulted, CO
reservoir in Arizona, USA. Surface travertine (CaCO
) deposits provide evidence of vertical CO
leakage linked to known faults. U-Th dating of travertine deposits shows leakage varies along a single fault and that individual seeps have lifespans of up to 200 ka. Whilst the total volumes of CO
required to form the travertine deposits are high, time-averaged leakage equates to a linear rate of less than 0.01%/yr. Hence, even this natural geological storage site, which would be deemed to be of too high risk to be selected for engineered geologic storage, is adequate to store CO
for climate mitigation purposes.
Geological hydrogen storage in depleted gas fields represents a new technology to mitigate climate change. It comes with several research gaps, around hydrogen recovery, including the flow behavior ...of hydrogen gas in porous media. Here, we provide the first‐published comprehensive experimental study of unsteady state drainage relative permeability curves with H2‐Brine, on two different types of sandstones and a carbonate rock. We investigate the effect of pressure, brine salinity, and rock type on hydrogen flow behavior and compare it to that of CH4 and N2 at high‐pressure and high‐temperature conditions representative of potential geological storage sites. Finally, we use a history matching method for modeling relative permeability curves using the measured data within the experiments. Our results suggest that nitrogen can be used as a proxy gas for hydrogen to carry out multiphase fluid flow experiments, to provide the fundamental constitutive relationships necessary for large‐scale simulations of geological hydrogen storage.
Plain Language Summary
Developing a hydrogen economy depends on safe and economically viable terawatt hour interseasonal storage and recovery of hydrogen around the world. As such, storage in geological formations is vital for transitioning to the hydrogen economy successfully. Here, we present a combined experimental and modeling study on the flow behavior of hydrogen in porous media at high‐pressure high‐temperature conditions representative of potential storage reservoirs. We investigate the effect of different influencing parameters and compare the flow behavior of hydrogen with other gases. This work provides essential relative permeability data for hydrogen under a range of conditions typical of hydrogen storage and extraction.
Key Points
Drainage relative permeability is measured for H2‐brine at reservoir conditions
The rocks' effective porosity has the most evident impact on H2‐brine relative permeability
N2 gas can be used as a safer proxy for hydrogen to undertake fluid flow experiments
The aggregate technical potential for land-based negative emissions technologies (NETs) in the UK is estimated to be 12-49 Mt C eq. per year, representing around 8-32% of current emissions. The ...proportion of this potential that could be realized is limited by a number of cost, energy and environmental constraints which vary greatly between NETs.
The aggregate technical potential for land-based negative emissions technologies (NETs) in the UK is estimated to be 12-49 Mt C eq. per year, representing around 8-32% of current emissions.
Following the landmark 2015 United Nations Paris Agreement, a growing number of countries are committing to the transition to net-zero emissions. Carbon capture and storage (CCS) has been ...consistently heralded to directly address emissions from the energy and industrial sectors and forms a significant component of plans to reach net-zero. However, despite the critical importance of the technology and substantial research and development to date, CCS deployment has been slow. This review examines deployment efforts over the last decade. We reveal that facility deployment must increase dramatically from current levels, and much work remains to maximize storage of CO2 in vast subsurface reserves. Using current rates of deployment, CO2 storage capacity by 2050 is projected to be around 700 million tons per year, just 10% of what is required. Meeting the net-zero targets via CCS ambitions seems unlikely unless worldwide coordinated efforts and rapid changes in policy take place.
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Carbon capture and storage (CCS) provides a direct means to achieve the transition to net-zero. We show that the gap between what is expected from CCS and what has been delivered is still significant. Facility deployment, proven storage capacity, and storage rates must increase to play a part in CO2 mitigation. There must also be a greater global effort with government and multinational corporation engagement, and a rapid step-change in policy to avoid disillusionment toward the usefulness of CCS.
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