What to do with the Remaining Fossil Fuel Reserves?

The case for geological netzero and CTBO to avoid emissions

As you know, or should know by now, we are headed for inevitable, dangerous global warming. Unfortunately, the 2015 Paris goals are a pipe dream, which means we need to i) brace for serious climate change impacts, ii) consider what we might do to mitigate these (including cooling options as I argue in this post) and iii) get real serious about the root cause of the problem: fossil carbon emissions.

In case you still believe in rapid greening of the economy consider this: “We conclude that the RCB [remaining carbon budget] for a 50% chance of keeping warming to 1.5 °C is around 250 GtCO₂ as of January 2023, equal to around six years of current CO₂ emissions.” (Lamboll et al. in a recent publication in Nature Climate Change). In other words, staying within 1.5C global warming is a fantasy.

It is well established that fossil fuel emissions are the main culprit of global warming and -unsurprisingly- it is proving very challenging to decarbonize the global economy, as the above figure shows. The sobering take home message is that, despite large-scale and widespread efforts to green the economy, fossil fuels still make up about 80% of the global energy mix. In addition the figure shows that the total consumption of fossil fuels is still growing. The growing use of fossil fuels means that fossil carbon emissions are also growing, as the figure below shows.

The emissions dip in the early 2020’s is a consequence COVID 2019 pandemic, but they picked up after 2021 and reached a record high in 2023 according to a publication by University of Exeter and Stanford Doerr School of Sustainability. Although there is some buzz that 2023 might have been the peak-emissions year, it is more likely they will keep rising a few more years and then more or less plateau.

Unfortunately, the 2015 Paris goals are a pipe dream

We must not forget that, while some developed countries are emitting less, because of renewables, outsourcing of production, and demographic factors, other places in the world, such as Africa, are experiencing demographic, and much needed economic growth. As long as there is recoverable gas, oil, and coal we must expect that economic growth will add additional CO2 to the atmosphere, unless we make a plan that allows developing countries to benefit from their fossil fuel reserves without causing more emissions. Either way, it appears inevitable we will exceed the remaining carbon budget before 2030.

To summarize: we are using more fossil fuels than ever and are still very dependent on fossil fuels, while at the same time we cannot afford continued dumping of fossil CO2 in the atmosphere, because of the climate havoc this is causing. It is clear we need to do something. Obviously, we should continue with the development of renewable energy, but will it be enough and on time?

The question I am concerned about is: What to do with the remaining fossil fuel reserves? Whatever we do, we should not allow the continued build-up of fossil carbon in the atmosphere, which leaves us with three options:

• A Leave remaining fossil fuels in the ground,

• B Reduce, Avoid and Remove fossil fuel emissions, or

• C Convert fossil fuels to emission-free alternatives and store the carbon.

Option A has a loud fan-base (Stop Oil Now, Extinction Rebellion etc.), option B enjoys wide societal support (Emission Trading Schemes etc), while option C is less heard of. In this post I would like to advocate for option C, while acknowledging that A and B should be pursued simultaneously. In addition to A and B, I think we need a stop-gap solution to make sure we will actually tackle the problem. And this solution could be option C, I believe.

Why not just A or B you might wonder. The problem with A, in my opinion, is that it seems unrealistic. Is it likely much, if any, of the recoverable oil and gas will stay in the ground? I expect, an energy resource that is relatively cheap to access and very energy-dense, will prove hard to leave untouched. Even the more abundant coal reserves would be consumed within a couple hundred years, at current rates of extraction.

My doubts about option B are manifold. First of all, Reduce and Avoid will slow down emissions, but won’t stop them, while we must stop adding any persistent greenhouse gases to the atmosphere. The Remove bit is problematic in my opinion. Taking a very diluted gas, such as CO2, out of the atmosphere is technically challenging, energy-intensive, and expensive. Regarding nature-based solutions I also have my doubts.

Systemically, I have a hard time believing the biosphere can uptake and store the fossil carbon we are putting into the atmosphere. According to the International Energy Agency: “Global energy-related CO₂ emissions grew by 1.1% in 2023, increasing 410 million tonnes (Mt) to reach a new record high of 37.4 billion tonnes (Gt).” Contrasting these annual emissions of around 37 billion tons to a recent estimate of global carbon uptake by forests of −7.6 ± 0.49  billion tons per year (Harris et al. in Nature Climate Change), I note we would need to increase total forested fraction of the Earth surface almost five-fold, to compensate for anthropogenic emissions. How on earth would we achieve this on a reasonable timescale, I wonder.

To me, expecting forests to clean up our atmospheric CO2 pollution, appears unfeasible for many reasons, including other vital land uses, such as food production, and also considering that, in reality, forests in many parts of the world are being destroyed rather than expanded, and that forests are susceptible to wildfires, which almost instantly put much of the carbon back into the atmosphere.

Systemically, I have a hard time believing the biosphere can uptake and store the fossil carbon we are putting into the atmosphere.

In addition to these technical issues with nature-based solutions, there are also serious management issues. For example, it is difficult to assess the quality of carbon credits, which has led to widespread fraud in the emerging carbon offset market.

I am not saying nature-based netzero is categorically impossible, but I think the nature-based way is at best a very risky strategy to mitigate anthropogenic emissions. Having said this, I fully support reforestation and afforestation efforts, because of the limited climate benefits, and also for biodiversity, for restoration of the hydrological cycle, for clean air, for the cooling effects of evapotranspiration etc.

I believe in option C because it is verifiable and controlled. What I envision with option C is that the chemical energy stored in fossil fuels is used for industrial processes directly, or converted to alternative emission-free energy products, such as electric and hydrogen. In this vision, the CO2 produced in these processes is captured, compressed and re-injected into geological formations, thus avoiding both industrial and consumer emissions (scope 3). In the drawing below I have attempted to illustrate and contrast the nature-based and geological netzero scenarios.

Nature-based netzero vs. Geological netzero. The left image shows industry and transportation discharging waste CO2 into the atmosphere and the purported capacity of natural systems to absorb the added fossil carbon. The right picture shows the “industrial carbon cycle” on the left and the natural carbon cycle on the right. In the Geological netzero scenario it is assumed fossil fuel producers are responsible for putting back as much carbon into the subsoil as they take out, and that the chemical energy in the fossil fuels is either used directly with point-source CCS, or converted to emission-free energy carriers with CCS.

Option C can be implemented as a systemic, future-proof solution, considering that we will anyway have to build a fossil-free energy system, simply because fossil fuels will run out within a couple of generations. In other words, if chosen wisely, the investments made in the emission-free energy infrastructure might outlive the very existence of accessible fossil fuels on the planet.

In this post I will focus on electric and hydrogen as feasible alternatives for fossil fuels, because these energy vectors have already gained some traction, but, obviously, different choices could be made along the way (ammonia, methanol e.g.). The point is that whatever choice is made, it should be a long-term choice, so that it may continue to be used when, eventually, the recovery of energy from fossil fuel will be completely replaced by energy harvested from wind and sun.

With “geological netzero”, I envision the system would start with a mix of blue and green hydrogen and end up with 100% green hydrogen within an agreed timeframe. And similarly, for electricity, initially part of the electric power could come from fossil fuel powered power plants with CCS, which also helps solving peak-demand issues, and eventually become 100% green. In both cases, nuclear can also be added to the mix to produce emission-free electric power and hydrogen.

What I envision is that energy conversion from fossil to electricity and hydrogen happens near ports to reduce the need for CO2 transport over land. Porthos in Rotterdam is an example of such a project. As we speak, pipelines are being built to transport CO2 from the harbor to empty offshore gas fields, where it can be safely stored.

What I envision is that energy conversion from fossil to electricity and hydrogen happens near ports to reduce the need for CO2 transport over land.

The figure below, from the EU report Shaping the future CO2 transport network for Europe shows large CO2 point-sources and potential CO2 sinks

Instead of building a temporary CO2 network, I think it makes more sense to invest in a future-proof hydrogen network, and convert existing industries to run on hydrogen. Proposals for such a network have already been made, see for example The Hydrogen Infrastructure Map, a joint initiative of ENTSOG, GIE, EUROGAS, CEDEC, GD4S, and GEODE.

I would like to end this post reiterating that, in order to preserve the livability of the planet, we must find a way to stop adding CO2 to the atmosphere. I believe the most reliable way to achieve this is by outlawing the dumping of fossil carbon in the atmosphere, which could be implemented with a Carbon Takeback Obligation (CTBO).

I would like to end this post reiterating that, in order to preserve the livability of the planet, we must find a way to stop adding CO2 to the atmosphere.

In my opinion, the advantages of CTBO over carbon tax and ETS are that it puts the responsibility for emissions with the producers of fossil fuels, making it more readily enforceable and verifiable. Such an extended producer responsibility would, I expect, leverage the expertise and capital assets of the fossil fuel industry for the energy transition, and effectively make the industry part of the solution.

Embracing responsibility for scope 3 emissions is a big leap for the oil and gas industry and can only be achieved gradually. Existing CTBO proposals foresee the incremental ramp-up of the takeback percentage, starting at say 5% and eventually reaching 100% at a pre-defined point in the future (for example 2050). Although CTBO would decrease the value of fossil fuel assets there is growing recognition that emissions must be avoided.

For example, the association for Dutch fossil gas producers, Element NL, writes about the introduction of producer responsibility on their website:

Emissions from the combustion of natural gas further downstream must also be reduced. With this in mind, we support research into introducing a producer responsibility system such as the Carbon Takeback Obligation (CTBO). Such a policy instrument would impose on obligation on producers or importers of fossil fuels to guarantee that the CO2 released during their use (either in whole or in part) will not be emitted, but either captured or stored.

If you wish to learn more about carbon takeback you may want to explore the Carbon Balance Initiative website. To support the cause you may want to follow Dutch politician and member of House of Representatives of the States General Silvio Erkens, who recently submitted parliamentary questions about CTBO.

Someone else, who I consider one of the pioneers of CTBO, is Margriet Kuijper. Her posts on LinkedIn familiarized me with CTBO and the concept of geological netzero. Margriet is an independent consultant carbon management, with deep knowledge of the oil and gas industry. For more in-depth information about CTBO I refer to: Carbon Takeback Obligation: A Producers Responsibility Scheme on the Way to a Climate Neutral Energy System by Margriet Kuijper (Margriet Kuijper Consultancy), Evert Holleman (Royal HaskoningDHV), and Jan Paul van Soest (De Gemeynt).

I also regularly post about CTBO on LinkedIn: Tycho Huussen. You can support my work by becoming a free or paid subscriber, by sharing this post, or simply by liking it and restacking.

Please feel free to leave a comment below and join the discussion about the future energy system.

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