The goal of steering towards an increase in global temperature less than 2 degrees, preferably 1,5, by 2030 will be challenging to reach. Even harder without combing bio-energy with CCS, and this way mitigate the CO2 emissions to “less than zero”. Of all the potential suggestions in the “net zero” category, this is seen as the most realistic at present. This does not mean that we now have the answer with two underscores. Net zero thinking and the development of bio-CSS raises important questions, and poses some challenges.
Robert J. Finley at the injection start up. Source: www.netl.doe.gov
Running up to, and during the climate meeting (the COP21) in Paris late last year, the term “net zero emissions” became a hot topic. With some variations in words, like “removing CO2 from the atmosphere” and “negative emissions” – this all stems from the notion that one can, and must, not only cut emissions of carbon dioxide, but also make sure that an increased uptake of CO2 takes place.
Requires awareness The increased focus on “net zero” has many possible traps, which it is important to be aware of and deal with. It can be a distraction from more potent, developed and used solutions. It is also a great risk of being an excuse for postponing other measures. The proposal implies that global emissions can equal the amount we somehow manage to suck out of the atmosphere. And this way the urgency may seem less.
Also, there are many, creative suggestions on how to achieve the goal of negative emissions, some of them seemingly unrealistic.
But most likely it will be a question of measures like protecting forests, planting forests, or creating bioenergy with carbon capture and storage, so called Bio-CCS or Bio-Energy with CCS (BECCS). All of these are measures that have been used globally, at various scales.
Careful use of biomass When combined with the use of biomass at large point sources, CCS has a large potential for delivering net negative CO₂ emissions. As biomass grows, it absorbs and binds atmospheric CO₂. When the CO₂ from biomass combustion or conversion is captured and permanently stored, the value-chain becomes carbon negative, which means that more CO₂ is taken out of the atmosphere than is released into it. Thus, a service that would have otherwise likely relied on a fossil fuel is obtained with the net result of atmospheric carbon being injected underground.
Bio-CCS is only a climate change mitigation measure when biomass can be acquired without causing permanent deforestation or otherwise causes land-use changes that reduce the biological storage of carbon. Biomass is currently a limited resource, which also limits potential for bio-ccs. However, alternative biomass sources, like algae, may increase the available biomass in the future.
Strict rules The prospect of atmospheric removal of CO₂ through BECCS does not mean that we can afford to delay other mitigation efforts. In addition, achieving substantial carbon negative emissions through BECCS requires increasing the sustainable supply of biomass substantially. This clearly requires new pathways to biomass supply, along with strict accounting and enforcement to ensure the sustainability and beneficial carbon balance of the source and supply chain.1 It remains to be seen whether, in practice, large biomass-based energy systems can be managed sustainably.
A technology in use BECCS is neither nothing new, nor not tested and deployed. BECCS applications are already operational and have shown that simple and relatively cheap carbon negative solutions can be put into place today. Further, several solutions exist to make bio-CCS more viable. One solution is to build a pipeline infrastructure where small amounts of CO2 captured from several sites are combined to generate a CO2 stream with enough volume to be viable for storage. One example of this is the pipeline system Alberta Carbon Trunk Line (ACTL) in Canada. This line has a fertilizer producer connected to the system,and a cummulative capacity of 2 billion tonnes of CO2. Another solution is to co-fire biomass with fossil fuels. Co-firing of coal and biomass already takes place in a number of countries. Integration of energy plants based on biofuel with CO2 emitting industry like cement and steel producers is an interesting option for the future.
A third option is to capture from facilities using biomass in their production. One of the most successful CCS projects worldwide so far, the Archer Daniels Midland CCS project in Illinois, is actually a “net zero” provider.
The project capture CO2 directly using compression and dehydration. The facility has stored up to 1 million tonnes of CO2 over three years, and will scale up to 1 million tonnes a year. The CO2 is created as a byproduct of biofuels production, which is transported 1.5 kilometres by pipeline for storage in onshore deep saline formations (Mount Simon Sandstone formation).
This is a highly successful project in every way. The project has held both budget and timing frames, and the storage site has proved to be very suitable and safe. This is illustrating the great potential of deploying BECCS to remove CO₂ from the atmosphere.
A great responsibilty As for all issues connected to CCS, it is justified to question the realism in fast and large deployment timelines. Also in scenarios where success is solely dependent on issues like net zero solutions, bio-energy and CCS. Having said that, BECCS can be one solution amongst many, as the ADM project shows. But only if the industry and authorities proves the skepticism wrong and move ahead, carefully avoiding traps described.
The most important tasks ahead is still increased use of renewables, energy effiency and mitigation of CO2 emissions in all sectors. This is the main path towards a zero carbon society.
A clear message delivered by the IPCC’s 5th Assessment Report is that reaching the 450 ppm CO₂eq concentration by 2100 becomes much harder under delayed or limited availability of key technologies, such as bioenergy, CCS, and their combination (BECCS). In fact, almost all models that manage to limit warming to two degrees Celsius rely on some means of atmospheric carbonremoval.2
The IPCC estimates that the requirements for CO₂ removal from the atmosphere would peak at between 10 – 35 Gt of biogenic CO₂ to be stored globally.3
This is an alarming reliance in many ways, given that few, if any, technologies except BECCS are available or economic today to achieve this.
1. Not all biomass is created equal, and some sources or practices are actually carbon positive. Achieving a net-negative carbon balance over the entire lifecycle can be achieved only if practices are screened and selected accordingly. This will require accounting and oversight. See for example: Think Wood Pellets Are Green? Think Again, Natural Resources Defense Council, Issue Brief 15-05-A, or Palm Oil and Global Warming, Union of Concerned Scientists,
3. IPCC, 2014: Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)]. IPCC, Geneva, Switzerland.