Innovation. Climate summits are passionately discussing how mankind can reduce carbon dioxide emissions to limit global warming. Wouldn't it be better to think about how existing CO2 could be filtered out of the atmosphere? The Swiss start-up Climeworks has found a way.
Every year, mankind currently blows more than 36 billion tons of the greenhouse gas carbon dioxide into the atmosphere. Germany alone contributed more than 900 million tonnes in 2016, despite the energy turnaround. There it stays - the average residence time is 120 years - and heats up the earth.
"In principle, it's like pouring water into a barrel every day without knowing when it's going to overflow. Today, we are making a tremendous effort to put a little less in the barrel than in the previous year. I have always wondered why we don't try to draw water from the barrel," explains Christoph Gebald, co-founder and one of the managing directors of the Swiss company Climeworks.
Acting to remove the carbon dioxide from the atmosphere and thus to come to a so-called "negative emission" has long been Gebald's mission. In 2008, he met his current partner Jan Wurzbacher at the Swiss Federal Institute of Technology ETH Zurich by chance. The two mechanical engineers befriended each other and together developed a technology that actually filters CO2 from the ambient air. "Right from the start we had an entrepreneurial drive, we wanted to do something meaningful and at the same time fulfil our desire to found our own company," says Gebald, describing the beginnings. In 2009, Climeworks was created as a spin-off of the university and developed the technology to market maturity.
In the beginning Gebald and Wurzbacher financed their young company with the money of a foundation, but also with prize money from technology and company competitions, such as the Venture Kick of the ETH and the Swiss Startup Award. "In a second step, we were able to acquire investor funds and later received public funding," says Gebald, describing the early years.
In May of this year, the time has come: Climeworks starts operation of the world's first commercial CO2 removal plant in Hinwil, Switzerland - on the roof of the waste utilisation plant of the Zurich Oberland Waste Management Association KEZO. The 18 collectors of the system, which look like oversized hair dryers, are accommodated in three ship containers. They now filter 900 tonnes of greenhouse gas out of the air each year.
It's also worth it financially. "The gas is pumped into a greenhouse 400 meters away, where it ensures that tomatoes, cucumbers or lettuce grow up to 20 percent faster," explains the engineer. In nurseries, CO2 has been routinely used for a long time to "fertilize" plants. Thus the greenhouse operator pays the usual market price for the Climeworks CO2.
However, pure CO2 is not only useful for plants in greenhouses. In the food industry it is used for freezing, as a coolant and as an inert gas for packaging fresh vegetables and fresh meat. In the beverage industry and in bars, it is used as a carrier gas for draught beer and soft drinks.
Although this does not eradicate the CO2, it is at least returned to the cycle and does not have to be synthesized again and again from oil or natural gas.
However, the CO2 from Climeworks is not yet competitive. The price per ton of CO2 on the market is around 100 euros. Climeworks produces at 400 Euro per ton. "Gebald is confident that it should soon be possible to achieve the goal of achieving the usual market price by making technical modifications on the one hand and by installing more and more modules on the other".
Technically, the extraction of CO2 from the air is an ambitious undertaking. "CO2 only accounts for 0.04 percent of the air around us," explains the inventor. A Climeworks system first sucks in the ambient air. The greenhouse gas from the air then binds chemically to special filters. If these are saturated with CO2, they are heated to about 100 degrees. "This releases the CO2 from the filter again and can be collected as concentrated gas and made available to customers. The heating system uses the energy from a waste incineration plant, which would otherwise simply fizzle out."
The filters consist of porous granules coated with amines, organic derivatives of ammonia. They bind the CO2. Gebald and Wurzbacher choose one of around 600 granulates that they have tested, depending on the ambient climate such as humidity and average temperature. The filter then lasts several thousand cycles.
A single filter collector binds 135 kilograms of CO2 per day, and a large system with 36 collectors can absorb it to five tons per day - depending on temperature, humidity and air composition.
Life cycle analyses, among others from the University of Stuttgart, show that the total emissions of the current Climeworks facilities - including building materials, disposal and waste heat recovery - are less than ten percent. For the extraction of 1000 kilograms of CO2, ancillary emissions of 100 kilograms must be expected. "In the next step, life cycle emissions of less than two percent can be expected," promises Gebald.
However, the main objective of any climate strategy must be not only to recycle CO2, but to make it disappear completely from the air. This can be technically made possible with so-called CCS technology. However, carbon capture and storage, in which the captured CO2 is pressed into the ground, is currently still very expensive. It is also unclear how safe such landfills are.
The CO2 filtered from the air by the Climeworks systems is of course also suitable for storage. One of the facilities has been doing its work on Iceland since autumn of this year. Here, the captured CO2 is to be permanently removed from the atmosphere and stored for eternities by means of safe geological storage. Climeworks has formed an alliance with the energy supplier Reykjavik Energy.
The plant is located at Hellisheidi, 25 kilometers east of Reykjavik, on the site of one of the world's largest geothermal power plants. It filters the CO2 from the air, which, dissolved in water, is then conducted 700 metres deep into the hot basalt underground of the island. Due to the geological constellation with high pressure and high temperatures, the bubbling mixture can no longer escape from here. Instead, it reacts with the basalt rock and converts into solid minerals in less than two years. "We are the only company in the world that both filters CO2 and sells plant modules. When states realize at some point that climate targets can only be met if we actively remove CO2 from the atmosphere, our technology is at the forefront."
Currently, Climeworks has ten more plants running in different countries as part of funded projects. Seven of them supply the CO2 obtained to companies and research projects specializing in the synthesis of fuels from greenhouse gases. Among them is also the company Sunfire from Dresden, whose production technology is particularly advanced (box on the right).
Climeworks is also involved in other projects under the umbrella of the so-called Copernicus projects for energy system transformation, which have so far been funded by the German Federal Ministry of Education and Research with 120 million euros and for which it has promised a further 280 million euros by 2025. These include, for example, the Power-to-X project, in which electricity from renewable sources is to be converted into material energy stores, energy sources and energy-intensive chemical products. The idea of using CO2 from the air is also supported.
In Norwegian Herøya west of Larvik you are already one step further. Nordic Blue Crude is planning a gigantic synthesis factory here. Diesel and petrol are to be produced from CO2, water and hydropower. The Climeworks plants would extract the required synthesis raw material CO2 from the air. In a techno-economic planning study, Nordic Blue Crude is currently investigating how expensive and efficient such a factory is, which other products can be made from CO2 and where there are customers for them. One of these could be carmaker Audi, which has long been interested in this new type of synthetic fuel and is already working with Nordic Blue Crude.
Despite the many new, rapidly advancing technical developments, the question arises: is it worth all the effort in view of the mammoth task of removing billions of tons of carbon dioxide from the atmosphere?
The largest Climeworks plant to date with 36 collectors only manages to filter 2000 tons of CO2 out of the atmosphere once a year. This is 0.02 percent of Germany's annual CO2 emissions. Gebald therefore sees his technology only as a building block in a mix of measures to avoid greenhouse gases in the future and to remove them from the air with other measures - through afforestation, changes in land use and methods of food cultivation.
But at least - the Climeworks technology shows new ways. "With 500,000 of our facilities, a quarter to half a billion tons could be taken out of the air." This would already correspond to almost half of Germany's CO2 emissions and would be roughly comparable to the amount resulting from Shell's oil production. "Within the next 20 to 40 years, a completely new industry will be built up in which I think we are currently in pole position."
Air traffic, for example, which cannot do without kerosene and contributes around five percent to global CO2 emissions, could be revolutionized. "Here, the technical carbon dioxide collectors are an ideal way of closing a cycle," explains Gebald. The filter systems capture the CO2 blown into the air by the aircraft. It is then synthesized into kerosene using techniques such as Sunfire.
If the atmosphere were relieved, this would also have a positive effect on the oceans. Since the beginning of industrialization, the oceans alone have stored 140 billion tons of CO2. As a result, their water became acidified, which confused the marine ecosystems. If the atmospheric CO2 of a distant day were to really decrease, the oceans would empty their reservoirs and continue to fill the atmosphere for a long time to come.
Admittedly - many of these perspectives still have to be written in the subjunctive today. But it's a start. An idea. A hope. It shows what technical progress is capable of. For Climeworks, which now has 45 employees, these are of course good prospects. But the investments in the expansion of the Icelandic plant and the new buildings in Central Europe will initially require more capital. The two managing directors are therefore also scheduling a financing round for the first quarter of 2018, to which they will invite very wealthy private individuals. "We are planning a capital increase in the double-digit million range," announces Gebald. "So far, with one exception, we've been funded by private individuals. We'd like to keep it that way."
It's a fascinating idea. From the ingredients CO2, water and renewable energy, so-called Blue Crude can be produced, a crude oil that can then be further processed into synthetic fuels - petrol, diesel, kerosene.
If the CO2 was previously extracted from the air using a process such as Climeworks, no additional CO2 is released into the atmosphere when the fuel is burned. The good old combustion engines would become climate-neutral. Moreover, such synthetic fuels do not contain harmful sulphur or dangerous nitrogen oxides.
The technology itself is ancient and has been known as Fischer-Tropsch synthesis since 1925. Liquid oil is produced synthetically from coal and hydrogen. The carbon (C) came from coal, the hydrogen (H) from hydrogen gas, including mine gas. The company Sunfire from Dresden has now changed this process for coal liquefaction so that it can now use CO2 instead of coal and water instead of hydrogen as raw materials. What remains are the oxygens from CO2 and H2O.
Sunfires technology is now being used on a large scale in Norway. Nordic Blue Crude is building a factory for synthetic fuels in Herøya on the western shore of the Oslofjord near Larvik on an area of 40000 square metres.
Norway is an ideal location because the country does not only have huge, cheap hydroelectric energy capacities for the production process. There is also an urgent need for action there. As of 2025, Norway will no longer permit combustion engines that use fossil fuels.
Production is scheduled to start in four years. In addition to Sunfire and Climeworks, the German car manufacturer Audi is also on board.
Author: Hanns J. Neubert