The use of carbon dioxide (CO2) gas in enhanced oil recovery (EOR) is well-documented and is seen as having the extra benefit of being a carbon storage technique with added economic value. Indeed, geological sequestration of CO2 without EOR has a significant financial burden that is probably the major hurdle to the large-scale deployment of carbon capture and storage (CCS). However, CO2 is already being used in a variety of ways as a raw material in the chemical industry and now there is a growing focus on establishing a CO2 economy, where the gas becomes a major precursor to the production of fuels and chemicals, in a closed system in which the CO2 is captured directly from the atmosphere.
On 24 October 2012, a workshop was held at the European Commission in Brussels on CO2 utilisation, with a view to identifying appropriate policy and regulatory measures that would encourage development in Europe of this sector. Interestingly, delegates at the workshop were split into two camps; those from the CCS community who see 'CO2 reuse', as they call it, being the stepping-stone towards CCS acceptance and implementation; and those who did not want the sector to be seen as a subset of CCS, but rather one that is stand alone and is seen as part of an economy in which fossil fuels no longer play a part. In the latter case, the issue of key concern is what will replace oil, and, to a lesser extent, gas and coal, as the raw materials to the chemical industry.
In the context of Europe, if the EU27 European Chemical Industry were to cover all of its carbon feedstock demand by using CO2, this would utilise 233 million tonnes per year of CO2 (based on 2009 figures). This would equate to 5.5 per cent of the total CO2 emissions from the EU27 countries. Substituting just 10 per cent of the carbon feedstock in the next 10 years would save 3 per cent of the chemical industry electricity consumption just on reforming alone.
Delegates at the workshop were presented with what are seen as the five steps to achieving a CO2 economy. The first is to focus on what is known as 'power-to-gas'. This is where renewable sources of energy are used to generate hydrogen via electrolysis of water, a rather energy-inefficient process. However, in the future, photoelectric techniques will be used, known as 'artificial photosynthesis'. This is seen as the fourth step. The hydrogen is then reacted with CO2 to produce methane. Methanol could also be produced in this way, which has the added benefit that it can be used directly as a transport fuel or as a precursor to other chemicals. Initially, fossil-fuel sources of CO2 will have to be used, mainly the by-product streams from the chemical industry, which are much more pure than the captured gas from coal-fired power stations. The direct capture of CO2 from the atmosphere at a large scale is seen as the fifth step, although laboratory scale studies are already underway and some companies are already attempting to commercialise their own processes. Meanwhile, steps two and three are seen as developing the processes and markets for polymers, other CO2-based chemicals and biotechnology (algae and bacteria) applications. Polypropylene carbonates and polyols are already being produced, and other chemicals and plastics are on track (the chemical giant Bayer is a major player in this field).
The power-to-gas idea is an interesting one, as it provides a route to the storage of renewable energy. Both methane and methanol can be transported using existing infrastructure. Hence, the issues concerning the remote locations of many large-scale wind and solar farms and the balancing of electricity demand with renewable sources of supply in the smart electricity grids of the future are now seen as solvable.
Using CO2 as a resource is not just about developing chemistry – it is about generating new businesses and new energy systems, such as the smart grid and large-scale renewable energy plants. It is about bringing the main players together (such as Bayer, BASF and Normer in the European case) and encouraging more engagement over the value chain. It is about support for fast process research, pilot-scale demonstrations and industry integration. It is also about giving value to the use of CO2, which will greatly alter the business case, establishing a lead in the market and investing in education and encouraging entrepreneurship. Europe recognises that developing such capabilities will secure its technological competitiveness and enable it to achieve its ambitious emission reduction targets. It is already starting to lag behind Japan and the USA. Australia would do well to take heed.