Moving Towards Net Zero: Imperative of Scale and Speed for Green Hydrogen and Carbon Capture

August 24, 2023

Asset-intensive companies - refining, petrochemicals, fertilizers, mineral processing and steel, for example - are major energy users and face challenges in progressing towards net zero. Energy efficiency is the obvious low-hanging fruit, able to reduce asset emissions by 20%. What are other strategies these companies can and will embrace? Surveys conducted globally in 2022 by AspenTech suggest that the “crowd-sourced” answer, evidenced by revealed capital plans, is a basket containing green hydrogen, carbon capture and storage (CCS), and electrification via renewables, in that order. For all three of these to scale fast enough to move the needle for these companies, digitalization; or an approach we call “born digital” will be absolutely required as a crucial element.

The particular challenge asset-intensive companies face, and the reason they are termed “hard to decarbonize,” is their energy intensity (constrained by the basic laws of chemistry and physics) and their corresponding dependency on very high temperature energy in particular, to successfully operate. Heat transfer and high temperatures involved in key refining units, ethylene crackers, iron smelters, and high electricity consumption by aluminum refining and electric-arc steel processes exemplify the challenge. 

These are all high volume, low margin processes, so the requirements for carbon removal present a challenging “green-premium,” which must be overcome. Approaches which are energy inefficient, no matter how green the energy, will not be an ultimate answer (although they may work short term due to government incentives). The scale-up and improved operating economics of carbon abatement and carbon avoidance processes – hydrogen, CCS, and direct air capture (DAC) in particular - will be a key benefit of digitalization.

My colleague Paige Morse, in her recent blog, has laid out the acceleration of interest in hydrogen and carbon capture attributable to the US IRA funding sources. Digitalization will be a key component of turning those government incentives into scale, speed and dramatically improved economics for these new technologies.


Green Hydrogen

Green hydrogen is attractive from a zero-carbon viewpoint because it can be produced from water and renewable power without carbon emissions. The further production of green ammonia as an option of this strategy can have an important and sizeable decarbonization impact on fertilizer production, and indirectly on food production (the CO2 cost of fertilizer manufacture is often skipped from the lifecycle analysis of food production today.) The challenges include the capital and operating cost of hydrogen electrolyzers, and also the capital cost penalties of adding significant battery storage into the green hydrogen system. Operating cost challenges are driven by the stochastic and variable nature of solar and wind production which lead to low “load factors,” i.e., low average utilization of the electrolyzer and ammonia conversion process units. The accompanying chart (recently published by the USDOE) shows the targeted improvement in green hydrogen economics that the US DOE’s hydrogen program hopes that its industry project grants will help achieve (see figure 1).


Figure 1: US DOE “Moonshot” Goals for Improvement of Green Hydrogen Economics through grants


Digitalization will have a crucial and strategic role to play in scaling up the hydrogen economy. Systems-level probability-based models (using Aspen Fidelis) are helping project sponsors sort through the dizzying array of options for designing the desired hydrogen systems, ensuring investor confidence and certainty. Accurate electro-chemical models (employing Aspen Plus) are crucial in improving and optimizing designs for renewables tied to the electrolysis process and so-called “balance-of plant” (the systems that surround the electrolysis system and make it work at an industrial scale). Optimization systems (in particular Aspen DMC3), assisted by predictive AI, will maximize load factors and minimize the operating impacts of variability of the incoming renewable power. According to one of our customers employing Aspen DMC3 and Aspen Plus digital twins in the water-to-hydrogen-to-ammonia train, this digitalization approach will reduce the cost of production of hydrogen from $6 per KG to $2.50 per KG and microgrids can be expected to additionally increase the efficiency of tying renewables to the hydrogen process, increasing power yields from the renewable arrays by up to 10%.


Carbon Capture Utilization and Storage

Carbon capture is recognized by the UN, IEA and industry as a crucial element of the pathway to net zero emissions. Carbon capture and carbon removal via direct air capture both face a key techno-economic challenge. Namely, these technologies have been proven technologically, and in fact work well, however they remain challenging in terms of long-term economic viability. Ultimately, the lifecycle cost of CCS and DAC must be driven below $100 per metric ton of CO2 removed to make economic sense globally. In the short term, subsidies are spurring projects to proceed. Political uncertainties around these subsidies are creating risk, while financial market penalties of not acting, are creating a risk in the other direction for companies. 

The key challenges surrounding carbon capture include increasing the process efficiency of both capture and solvent (catalyst) recharge. This will happen through continued and high-paced innovation and scale-up of technology. For carbon removal through direct air capture, a key challenge is optimizing the integration of renewable power sources with the mechanical (fans to blow air through the system) and chemical capture process. As with green hydrogen, digital twin models that combine highly accurate first principle models (Aspen Plus) with AI based analytics to achieve hybrid models, have been the key tools in the ongoing economic improvement. Carbon Capture Inc, for example, is heavily using our first principle models and AI approaches to optimize solar power with direct air capture (Bill Gross, Founder, at Optimize 2021). Carbon Engineering, whose technology is driving the world’s largest announced project from 1PointFive, also has used our rigorous digital twin models to move from experiment to demonstration plant, to scaling to the world’s largest implementation. Technology Centre Mongstad, the Norway-based consortium, uses similar comprehensive modeling approaches to rapidly test and establish economics for new materials and processes for carbon capture (Matthew Campbell, TCM, Optimize 2021).

Another challenge for CCS and DAC is permitting geological carbon storage and monitoring stored CO2 over the long-term. The same subsurface modeling systems that help the oil and gas industry optimize their production from hydrocarbon-bearing formations, also help characterize target depleted reservoirs and saline aquifers for CO2 sequestration (AspenTech SSE Suite). Here, AI applied to the interpretation of subsurface data is also a key resource in predicting the best and most stable subsurface target zones. The net result is the crucial role of digital models in accelerating the permit process and assuring companies investing in carbon offsets that sequestered carbon is being securely stored in place.

The biggest challenge at an industry-wide level is the speed with which carbon capture and hydrogen projects must proceed. Figure two gives a picture of the size of the challenge.


Figure 2: The Formidable Scale-Up of Hydrogen and CCS Projects Required by 2050


The only way to accomplish this is to use automated engineering workflows to achieve design and project certainty through repeatable and accelerated project designs. One company, ENI Progetti, the research and project arm of ENI, has fully captured their invented CO2 capture process in our automated front end design system (Aspen Basic Engineering). This enables new CO2 capture projects to proceed through the front end design (FEED) phase of projects from 30 to 90% faster. Project sponsors and engineering contractors will need to adopt such “born digital” approaches to project execution to meet company and industry-wide goals for net zero. Today’s approach to project-by-project engineering simply is an approach that will not meet the requirement. 

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