Musings, politics and environmental issues

Posts tagged ‘Hydrogen sulphide’

Iceland’s CarbFix CCS scheme hopes to reduce carbon emissions from large-scale industry

I’ve just had an article published in BBC Future about how the CarbFix version of CCS (carbon capture and storage) can potentially be used to reduce CO2 emissions from large-scale industry, which in Iceland’s case consists of three aluminium smelters, a silicon metal smelter and a ferro-silicon plant.

The CarbFix method is adapted for Iceland’s porous, permeable basalt rock. Instead of taking thousands of years for mineralization to take place underground, with CarbFix it only takes 1-2 years. The procedure has been used to capture both CO2 and hydrogen sulphide from the Hellisheidi geothermal power plant, where CarbFix is in operation, but potentially it could be used for other gases. Read the article to find out more!

A great deal of emphasis in CCS has been put on Direct Air Capture, which is also discussed in the article. Part of the reason for the expense is the need to capture and fix small concentrations of target gases, which is more challenging. A small DAC system is now in operation at Hellisheidi.

Using funds from the EU’s Horizon 2020 programme, the four-year Geothermal Emission Control (GECO) project is investigating the use of CarbFix in Germany, Italy and Turkey near geothermal fields as well as Iceland. As the bedrock in these countries is not basalt, the initial groundwork involves carrying out background studies of potential injection sites, such as the potential of different rock types to mineralize CO2 and permeability. Injection is due to start in 2021.

Emissions from Iceland’s power plants are minimal compared to those in other countries. Nevertheless, Landsvirkjun, Iceland’s national power company that operates three geothermal power stations, is going to build a gas capture plant at one of its geothermal plants, Krafla, using CarbFix to capture the CO2 that is emitted, and in so doing intends to work towards becoming carbon neutral by 2025.

Because BBC attracts a global audience, my editor wanted me to include information on the processes involved in  conventional CCS as well, which I did. Currently, there are 2 large-scale power plants with CCS in operation, but the number of large-scale CCS facilities globally number 21: 2 of these are in power, while the remaining 19 are in industrial applications. I was originally given misleading information on the number of large-scale CCS plants operating, but after the article was published I was told the correct figures (see above), with which my editor says she’ll amend the article (she hasn’t done so yet).

 

 

Heavy industry in Iceland looks to CarbFix to become carbon-neutral

Iceland’s four largest CO2 emitters, three of which are aluminium smelters and the other a ferro-silicon plant, have signed a Letter of Intent with the Icelandic government to look for ways to become carbon neutral by 2040. The PCC silicon metal smelter at Bakki, which is another large emitter, is also expected to sign – “although our first priority is to get the operation running properly,” according to the environmental officer there.

The aim is to thoroughly investigate whether the CarbFix method for storing CO2 can become a viable option, both technically and financially, for storing CO2 emissions from these companies.

CarbFix was set up originally in 2007 in conjunction with the Hellisheidi geothermal power station, where CO2 is captured from steam and dissolved in water at pressure. The water is then injected into underground basalt rock at a depth of 500-800 m, where it forms carbonate minerals such as calcite within a few years. These carbonate minerals are stable on a geological time-scale.

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Annual capacity at the Hellisheidi plant is around 12,000 tonnes CO2, which accounts for about a third of the plant’s CO2 emissions. The Hellisheidi plant also removes hydrogen sulphide (H2S) from the steam, but this will not be an issue with the companies intending to become carbon-neutral by 2040.

In 2017, a pilot-scale Direct Air Capture unit was added to the system: this process is independent of location as it mostly relies on energy in the form of heat, which is available as a by-product in numerous industrial processes. Unfortunately the technique is currently too expensive to be used  for making heavy industry climate-neutral.

The project with heavy industry, which is expected to span five to ten years, will involve analysing the concentration of CO2 in emissions, so that similar removal techniques can be applied to those at Hellisheidi. The next step will involve design and manufacture of experimental equipment for capturing and injecting CO2, followed by design and manufacture of similar equipment on a larger scale.

The standard method of carbon capture and storage (CCS) involves pumping oil into old gas fields or using some form of carbon capture and usage (CCU). Edda Sif Aradóttir, who is project manager of CarbFix, says there are both advantages and disadvantages to traditional methods.

“The CarbFix method transforms CO2 into minerals within two years through a chemical process that happens naturally in nature, while traditional methods store CO2 in gas or liquid form. The procedure is thus of a completely different nature and CO2 is permanently removed,” she says.

She says that the main disadvantage is that it requires a considerable amount of water to dissolve the CO2 where chemical changes occur between water and rock. “On the other hand, the water needed by the procedure may be reused, which we in fact do up at Hellisheidi … we are working at developing the process even more so that seawater can be used,” she explained.

Funding for the CarbFix2 project has come from various programmes within the EU, including Horizon 2020, with collaborators in Toulouse, Barcelona and Zurich. CarbFix2 is designed to move the project on from a demonstration phase to one which will lead to an economically viable, complete CCS chain that can be used within Europe and globally.

Future research involves exporting the method to new injection sites in Germany, Italy and Turkey as well as Iceland, and further developing the method so it can be used offshore for permanent mineral storage of CO2 on the sub-sea floor. CarbFix proponents say that there is far more storage available in porous sub-marine basalts than required for the geologic storage of all the anthropogenic CO2 that will ever be produced.

I also wrote about this for ENDS Europe Daily today.

 

Geothermal plant in Iceland in danger of losing its licence

Iceland’s Hellisheidi geothermal power plant is in danger of losing its operating licence because from July 1 this year, hydrogen sulphide (H2S) concentrations may never exceed 50 micrograms per cubic metre over a 24-hour period – and they probably will.

Since 2010, levels have been allowed to exceed the maximum level 5 times a year.

The operators of the Hellisheidi plant, Orkuveita Reykjavikur, have applied for a 5-year extension but it is by no means certain that they will receive one. Various institutions and health authorities have given their opinion, which ranges from no extension being granted to a 2-year extension being granted. The 5-times-a-year limit is already exceeded at a Waldorf preschool and primary school located midway between Reykjavik and the power station. The local newspaper for the city, simply called  Reykjavik  (and which happens to be edited by a former colleague of mine, Ingimar Karl Helgason) covers the issue in detail in its current issue and quotes the Environment Agency as saying: “Chemical emissions from large geothermal plants are usually very high and can be in the air, soil, surface water, groundwater, sea and deep underground. The sulphur emissions from the Hellisheidi plant are, for instance, greater than the emissions from the Alcoa Fjardaál plant [the East Iceland aluminium plant] measured in sulphur equivalent units.” The EA want the plant to be granted a 2-year extension, which will give the operators time to evaluate the results of their Sulfix project which involves injecting the sulphur deep into the ground.

I’m a member of the Icelandic natural scientists association and they have a paper in the current issue of their journal which covers the H2S issue and the health effects arising from it. It’s an interesting issue because little is known about H2S.

If anyone is interested in an article that looks deeper into this issue, let me know.

 

Hydrogen sulphide pollution adversely affects sound equipment

Sound technicians are complaining that expensive sound mixing equipment in Reykjavik has a much shorter service life than the equivalent equipment in Europe, the US or even in North Iceland. The reason? Hydrogen sulphide (H2S) pollution from the Hellisheidi geothermal power plant, 30 km east of Reykjavik.

The problem first became apparent after the Svartsengi geothermal power plant was opened  southwest of the capital in 1976, but worsened considerably after the Hellisheidi plant was opened in 2006.

The technicians say that H2S precipitates on the copper and silver parts of the equipment, increasing the corrosion rate. Sometimes the buttons start creaking after only a few weeks of use. In expensive equipment, the contacts are made of silver as this normally accelerates conductivity, but this does not happen if they are subject to H2S deposits. Prior to Hellisheidi, the equipment was subject to routine maintenance several years after being brought into use, but now it has to be replaced after one to two years.

In cheaper equipment, plastic or nickel are used as conductors. These are less affected by H2S pollution – but the sound quality is also inferior.

But at least the problem should not worsen. Last week, the environment ministry rejected a request by energy companies to delay until 2020 the introduction of more stringent rules on H2S emissions that are due to take effect on July 1 2014. After this time, the concentration of H2S must never exceed an average of 50 µg/cubic metre over a 24-hour period. The ministry said that the solutions that were being researched had not been exhausted. This means that another geothermal power plant near the Hellisheidi plant (pictured below), which was intended to power the Helguvik aluminium smelter that is still under construction, will not be built until a solution has been reached.Image