Should captured carbon dioxide be buried or reused in circular cycles?
– “I believe in a combination of these options,” says Jens Wolf, Researcher at RISE.
There has been much talk about Norway’s three kilometre deep hole in the North Sea, 100 kilometres off the coast of Bergen. Starting in 2024, 1.5 million tonnes of captured carbon dioxide will be pumped into the hole each year and stored below the seabed to prevent it from entering the atmosphere.
The SOU study “Vägen till en klimatpositiv framtid” (“The path to a climate-positive future”) also recommends that Sweden stores carbon dioxide as a way of achieving zero emissions by the year 2045 and thereafter negative emissions. The study recommends that 1.8 million tonnes of carbon dioxide be separated and stored each year until 2030.
– “In addition to storing captured carbon dioxide, efforts should also be made in terms of reuse,” says Jens Wolf. Among other things in the production of electrofuels.
– “With an electrofuel industry in place, we should be able to store as much carbon dioxide as we need to and reuse the rest. If all goes well, the proportion of reused carbon dioxide could gradually increase,” says Jens Wolf.
Greener chemical industry
Another possibility is to make the chemical industry greener without increasing the need for more biomass. The 20 million tonnes of green carbon dioxide that the twenty largest Swedish pulp and paper industries release each year should, after capture, be able to react with renewable hydrogen. This should, at least theoretically, be enough to produce up to 14 million tonnes of renewable methane or methanol – volumes that can replace nearly all fossil alternatives in the transport sector or compensate for emissions that are practicably difficult to avoid, such as the high greenhouse gas emissions from meat production.
However, this does assume that we have high levels of renewable electricity available. I see electrofuels as an opportunity to reduce our reliance on fossil fuels and biofuels by using as much solar, wind and hydro-power as we can.
The more we are able to reduce the use of fossil fuels in the transport sector, the better, naturally
Supports the UN sustainability goals
Fördelarna är många
Att på det här sättet skapa cirkulära kretslopp med återanvänd koldioxid ger många fördelar, enligt Jens Wolf.
1. Mindre olja går åt
– Motsvarande 20 Mton/år i koldioxidutsläpp. Ju mer vi kan minska användandet av fossila bränslen i transportsektorn, desto bättre är det givetvis. Förutsatt att oljeproducenterna inte lyckas sälja just den oljan, eller delar av de volymerna, till nån annan, så kommer de totala koldioxidutsläppen i världen att minska i samma utsträckning.
2. Electricity surplus will be useful
– During certain times of the year, there is already an overproduction of electricity. We should be able to use this to produce hydrogen and even electrofuels. On the other hand, the electricity surplus is not enough to create the volume of fuels required to replace all current fossil fuels in the transport sector. The production of green electricity must increase by around 150 TWh/year, which means more than doubling the entire annual electricity production in Sweden.
3. We are getting closer to being self-sufficient when it comes to energy
– Not having to rely on fossil fuels from other countries reduces our vulnerability as a country. Currently, for example, the transport sector is unable to last very long without importing oil. The most efficient way to use fossil fuels in the transport sector is through the use of electric vehicles. However, for aircraft, heavy transport and shipping, electric engines will not be relevant for many years yet. Here, electrofuels supplemented by biofuels can be used instead. This is partly to replace fossil fuels and partly to reduce the increasing demand for biomass. Swedish forests are not an infinite resource and excessive pressure on logging leftovers could result in other environmental risks, such as decreased biodiversity, decreased regrowth and high prices.