Capturing CO2 by itself does not provide a solution, it subsequently either needs to be stored underground or put to use. While utilizing CO2 is a hot topic and covered extensively in academic literature, studies that provide a general yet accessible overview of different CCU options and how they would fit with a certain point source profile are rare. Therefore, this part of the MAP-IT CCU project aims to provide such an overview, informing interested parties who do not have an extensive background in the field, allowing them to start reflecting on how CCU could fit in their decarbonization trajectory.
In each case study, aspects ranging from technology over economics and policy up to an overview of recent investment projects are covered. The main purpose is to allow the reader to get familiar with these cases, and evaluate whether it may be worthwhile to explore them further. As with the CO2 capture technologies, what is most suitable as utilisation option depends on the profile of the CO2 emitter. It is therefore strongly warranted to start with the executive summary of each case study, which provides a basic overview, and then to proceed with the detailed reports of cases that are deemed to be most relevant.
Process overview
The most mature technology for producing e-fuels usually involves the capture of CO2 from a point source, the production of hydrogen (H2) via water electrolysis, and the conversion of CO2 and H2 into the target product in one or more thermocatalytical units. Below, this is illustrated for methanol production. These technologies are relatively mature, although few have been built yet at very large scale, meaning there are still upscaling risks. The molecules that are produced as such can be used to substitute for fossil fuels, and will likely have an important role to play to decarbonize long distance transport modes such as shipping and aviation.
Source: VITO
Producing e-fuels is costly, however. Compared to their fossil counterparts, the production cost can be several times higher. Often the capital cost and electricity use of the water electrolyser, required to produce the necessary H2, will be the most dominant factor. Also mature biofuel routes usually are more attractive from an economic point of view. The spontaneous offtake of e-fuels in the market is therefore low.
Scale and CO2 purity requirements
Commercial projects usually envisage a CO2 input of 50-100 kton/yr, which is essential to reach sufficient economies of scale. These projects generally connect to one point source (often nearby the site where the fuel is produced), although in theory CO2 can also be sourced and transported from different locations.
The norm is to work with pure CO2. Since catalytical processes are involved, anything that could lead to catalyst poisoning (e.g. sulfuric compounds) need to be removed. Inert gases (e.g. N2) could be tolerated in some processes, but it may not be cost-optimal to leave these in since it leads to higher capital and operational costs (e.g. compression). Low TRL technologies (e.g. electrochemistry) which work directly with flue gases are currently being investigated.
Policy aspects
To promote the roll-out of e-fuels, specific targets have been set in the EU Renewable Energy Directive, effectively creating a market for these fuels. Towards 2030, some moderate targets have been set, e.g., 1% for transport as a whole. For aviation, there are specific subtargets defined in the Renewable Energy Directive from 2030 (1.2%) until 2050 (35%), providing a longer-term perspective for this sector. While molecules such as methanol are also very valuable chemicals, the CO2 based production of these is currently pushed towards fuels applications, since no similar targets exist for use as feedstock in the chemical industry.
However, EU policy provides some major restrictions as to how the e-fuels should be produced to participate in that market. For example, there are several provisions to ensure that the renewable electricity used in this process is ‘additional’ and not taken from an already existing installation, unless in areas which already have a very high penetration of renewable energy. Furthermore, as CO2 is inevitably released again when the fuel is combusted, from 2040 onwards only biogenic CO2 (or CO2 capture directly from the air) will be eligible as CO2 source.
Detailed reports will be added soon.