The project newsletter

"Bridging to the future" is the Vattenfall newsletter on work and progress within Vattenfall's project on CCS. The newsletter is distributed three times a year.

Bridging to the future No. 11, October 2008

Below you will find the online version of the project newsletter - Bridging to the future. A choice of shorter articles from October 2008 are presented below.
Two important milestones have been reached
Vattenfall inaugurates the worlds' first pilot plant for Oxyfuel
Equipment for injection on site in Altmark
Seismic investigations initiated in Denmark
Characteristics of carbon dioxide
On the other side of the bridge
Vattenfall receives award for the Oxyfuel Technology

Two important milestones have been reached

On 9 September 2008 Vattenfall’s 30 MWth Oxyfuel pilot plant at Schwarze Pumpe in Germany was inaugurated. The plant is now operating and the first tonnes of CO₂, with a purity of 99.7 %, were produced a week earlier.

The construction of the pilot plant has taught Vattenfall an immense amount about the challenges involved with the Oxyfuel technology and completing this construction phase marks an important milestone.

Now the focus shifts towards the essential work on the test programme. The results of this will provide Vattenfall, the technology partners involved and, through papers and public presentations, the whole CCS community with much more invaluable knowledge. The aim with the pilot plant is to gain the necessary understanding and to validate the technology for scale-up for the approaching demonstration step.

In the shade of the inauguration at Schwarze Pumpe, another important milestone was reached outside Aalborg in Denmark. On 30 August, the seismic investigations of the Vedsted geological storage formation started. These will show whether the bedrock in northern Denmark is as suitable for CO₂ storage as earlier studies imply.

I am very proud to be a part of this development and also to be able to say that Vattenfall is not just all talk, we get things done too. Someone has to show the way, and Vattenfall is doing this now, even in a world-wide perspective. The pilot plant at Schwarze Pumpe and the ongoing seismic study outside Aalborg provide clear evidence of this. However, the project contains so much more; the pre-engineering of the two demonstration plants at Jänschwalde in Germany and Aalborg in Denmark, the cooperation on storage with Gaz de France at Altmark in Germany and our participation in the Mongstad project in Norway are further examples.

When we set our targets eight years ago, we claimed that we would reach a cost for preventing emissions of CO₂ in the future of 20 €/ton, that we would achieve a capture rate of at least 95 % and that we would be able to deliver a technical solution to eliminate the emissions from coal-fired power plants in 2020. With the latest achievements in mind, I would like to say that we are well on the way to fulfilling our ambitions.

To all my hard working colleagues, I would like to congratulate you all on these milestones, say thank you for a job well done so far, and: Let us keep up the
good work!

Lars Strömberg - Head of R&D, Vattenfall Group
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Vattenfall inaugurates the worlds' first pilot plant for Oxyfuel

After almost ten years of work on Carbon Capture and Storage we have now reached a milestone: together with Brandenburg’s Prime Minister, Matthias Platzeck, and the Swedish Minister for Higher Education and Research, Lars Leijonborg, Vattenfall officially inaugurated the world’s first pilot plant for the CCS technology on September 9.
The 30 MWth plant, located in Schwarze Pumpe, Germany, carries forward the Oxyfuel-method on an entirely new scale. After a series of test rigs in cooperation with universities, the pilot plant now marks the step from the laboratory to reality.

Construction succeeded by testing

The groundbreaking ceremony that had taken place in May 2006 in the presence of German Chancellor Angela Merkel had marked the start of the building phase. After two years of construction, the pilot plant now offers the possibility to test the technology on a level that is comparable to a power-plant-scale. The perspective is for the specific emissions to decrease from more than 900 to well below 100 grams of CO₂ per kWh. During a research and development stage extending over several years, the technology will be advanced via a series of phases building upon each other until it reaches a large-scale application level.

The unique thing about Vattenfall’s pilot plant is that all the components of the Oxyfuel technology and the whole CCS chain, including capture, transport and storage, will be tested. The aim is to validate the technology of the different parts and to learn how they all function together. The pilot plant is one important step in our scale-up process towards a full scale power plant with CCS.

“The pilot plant is a milestone on the way to converting coal into electricity that is almost free of emissions. It represents the first ever transition from the lab to reality. Our perspective with this step is to make a decisive contribution to global climate protection,” Vattenfall’s CEO and President, Lars G. Josefsson, announced on the occasion of the official commencement of operations.

Technology development also important for the region

The pilot plant is not only an important step in pushing forward the technology. It is, furthermore, a crucial component in securing the future of coal mining and electricity generation in the Lusatia region where Vattenfall is one of the most important companies.

Matthias Platzeck, Prime Minister of the German federal state of Brandenburg, stressed this importance when saying: “When the people in the Lusatia region stand by their abilities and traditions today, then they’ll accomplish the technological advances of tomorrow. With today’s start of the pilot plant here as well as its use of regenerative sources of energy, Brandenburg is now also at the head of this industrial development. In this way we can manage to make the region become an “innovation lab” for an environmentally-friendly and secure supply of energy. Not only does that secure jobs here, it also serves to protect our climate.”

The inauguration was accompanied by a smaller demonstration by activists from German environmental NGOs. “We know that not everybody is in favour of CCS” says Staffan Görtz, project head of communication and continues, “we want to listen to what they say. CCS is new and there are still issues that are open for discussion.”

Specially-designed trucks for CO₂ transport

Parallel with the official inauguration with Lars Leijonborg, Matthias Platzeck, Lars G. Josefsson and Tuomo Hatakka, the first trucks that will serve to transport the liquefied CO₂ were presented to the journalists and guests. These special trucks will commence operation as soon as construction at the injection facility in the Altmark field is finished. The start of this project is scheduled for spring 2009.
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Equipment for injection on site in Altmark

At the same time as the pilot plant in Schwarze Pumpe is being commissioned, the preparations for receiving the CO₂ and storing it underground are in full swing. The injection equipment and large tanks for intermediate storage of the CO₂ are being set up in Altmark.

We have written earlier about the cooperation with Gaz de France, in which the CO₂ produced in Vattenfall’s pilot plant in Schwarze Pumpe will be used for an R&D project involving on-shore EGR, Enhanced Gas Recovery, see Bridging to the Future #9, December 2007. Besides testing the feasibility of CO₂ as an agent that facilitates the extraction of natural gas, the suitability of the largely depleted natural gas field in the Altmark region for long-term underground CO₂ storage will be investigated.

Intermediate storage in tanks

Following liquefaction by means of pressure and temperature the CO₂, at minus 28°C, will be trucked from Schwarze Pumpe to the Altmark region; a distance of around 350 kilometres. This logistics solution is the only available technology at this scale. For our demonstration and commercial size power plants, onshore CO₂ transport will be conducted in pipelines. When the CO₂ has reached its destination it will be loaded into an intermediate storage facility consisting of two tanks, both maintaining a pressure of 15 bar. The tanks have a storage potential of 300 m3 of CO₂ each. These tanks were delivered in the middle of July.

In order to keep the pressure in the tanks constant, evaporators and reliquefiers are installed and connected to the tanks. When the pressure in the tanks decreases, which occurs when liquid CO₂ is drawn off from the tank, CO₂ from the tanks will be fed into the evaporator where it will evaporate and then be fed back to the tank.

If no CO₂ is drawn off from the tank for a while, there is a risk of pressure increase due to the evaporation of CO₂ in the tanks because of heat absorption from the surroundings. If this occurs, the CO₂ reliquefier is operated to liquefy some of the CO₂ in the tank.

Injection at varying conditions

The CO₂ injection plant in Maxdorf in the almost depleted gas field in Altmark is designed to enable injection of CO₂ of differing aggregates and characteristics. This means that CO₂ in the liquid, gas and supercritical phases will be injected, and at differing pressures and temperatures within these phases. This is to see how different CO₂ characteristics influence the amount of natural gas that can be recovered from the gas field.

Using pumps and possibly the heat exchanger, the CO₂ will be given the required pressure and temperature and then be injected into a closed-off underground natural-gas-bearing structure.
At full operation, about 16 tonnes of CO₂ will be injected every hour. Around 100 000 tonnes of CO₂ will, according to plan, be injected into the underground reservoir during the three years long test phase. The first CO₂ will be transported to the Altmark project site for injection during the first half of 2009.
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Seismic investigations initiated in Denmark

During September and until mid-October, Vattenfall will undertake seismic investigations covering an area of 20 x 25 kilometres in the north of Jutland. The results of these investigations will form the basis for additional work relating to the assessment of whether the geological conditions should be investigated further with the aim of establishing a CO₂ store in the Birkelse area.

What are seismics?

Seismic investigations are based on a geophysical investigation method in which sound waves are transmitted down through the layers of the earth. This enables geologists to get an impression of the layer sequence and structure, whether it is sand, clay or chalk. The sound waves can be generated either through an explosive charge or, in the case of marine investigations, using a compressed air gun or, as will be the case in these investigations, vibrations.

In these investigations, the vibrations will be generated by three vehicles, each of which is fitted with a vibrator plate that will be driven along premarked lines. Every 10m or so, the vibrator plate will be lowered and then vibrated for 20–30 seconds at a time. Along the lines that are to be surveyed, cables have been laid out with geophones (comparable to microphones) which capture the sound waves that are generated when they return to the surface.

The fact that the sound waves return is due to the layered structure of the earth. The aim of these investigations is to explore the layers down to a depth of 2–3km. On their way down through the earth, the sound waves will encounter transitions between rock layers with different properties. At these transitions some of the sound waves will be reflected back to the surface. The time difference from generation of the sound waves until they are recorded by the geophones again makes it possible to form a visual picture of the layer sequence (a seismogram).

Known geology

Before any type of investigation concerning the underground is commenced, the geologist will always prepare a model of what he or she expects the underground area to be like. In the case of Birkelse, it is fortunate that oil exploration drilling was carried out in 1958, and it is because of the information provided by this drilling that we know there is a structure which could be suitable for storing CO₂. As the area has more recently been subject to further oil exploration, a number of seismic investigations have been carried out over time. Together with the earlier drilling they form the basis for the current geological model, which is being used until new and better data can be collected.

A simplified model is based on the assumption that there is a layer of sandstone at a depth of approximately 2km which will act as a CO₂ store. Above this sandstone layer is a several hundred metre thick layer of shale, which will act as a seal that the CO₂ cannot penetrate. Uppermost in the sequence is a layer of chalk, the same that is quarried in a number of locations in North Jutland, which will trap and bind the CO₂ chemically if it were to seep through the shale cap.

The results of the planned seismic investigations will be used to confirm whether or not the various layers are present with the thickness and distribution necessary in order for work on the project to continue.
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Characteristics of carbon dioxide

Carbon dioxide (CO₂) is the fourth most abundant gas in the earth’s atmosphere, accounting for approximately 380 ppm (0.0380 %). In the past, however, the atmospheric concentration was lower. Since the industrial revolution, levels have increased by about 100 ppm. There are several contributing factors that determine the CO₂ concentration in the atmosphere, but most researchers agree that the main cause of the increase in concentration is the release of CO₂ previously bound in fossil fuels.

CO₂ is, at atmospheric conditions, a colourless gas. It is also odourless, non-poisonous, non-flammable and not explosive. CO₂ is denser than air, which means that CO₂ has a tendency to sink into depressions and low-lying areas. At most times, atmospheric turbulence prevents any accumulation of CO₂.

Carbon dioxide is an integral part of the carbon cycle and is produced by most living organisms during respiration. Exhaled air from humans consist of about 4 % CO₂ (40 000 ppm). CO₂ is also a part of the photosynthesis process, in which plants use CO₂ and sunlight to grow. CO₂ concentrations in a greenhouse vary substantially over a 24-hour period. During the day, concentrations may sink as low as 150–200 ppm due to plant uptake. At night, plant respiration increases when uptake drops in the absence of solar energy, and the CO₂ concentration can increase to about 500–1000 ppm. The CO₂ concentration in greenhouses is often increased through the addition of CO₂ in order to increase plant growth.

Effects well investigated

The physiological effects on human health and safety due to elevated CO₂ concentrations are well understood and a considerable amount of research has been conducted in this field. (The research has been based mainly on healthy adult males, and the effects on children and weak individuals may differ to some extent). Exposure studies have not revealed any adverse physiological effects for humans chronically exposed to CO₂ concentrations below 1 % CO₂ (10 000 ppm).

The potential health and safety effects associated with CO₂ mainly relate to CO₂ being an asphyxiant, that is, if it replaces oxygen in the air to such a degree that there is a risk of suffocation. CO₂ is to some extent also physiologically active, in that it at higher concentrations can affect circulation and breathing.

Headache because of poor air quality

Most people have probably felt the effects of poor air quality after spending some time in poorly ventilated areas. Typical office levels are 600–1200 ppm. CO₂ concentrations in tightly packed conference rooms with poor ventilation may reach levels around 2 000 ppm. However the effects then felt, such as poor ability to concentrate, headache or fatigue are to a large extent due to other residual products that form during respiration.

At concentrations above 3 % (30 000 ppm) the respiratory rate is significantly affected, the blood pressure is increased and some discomfort is experienced. At concentrations above 5 %, mental and physical abilities are impaired, and loss of consciousness can occur. Exposure to concentrations above 10 % may in the worst case be fatal.

There is substantial experience on how to handle CO₂. It is one of the most thoroughly mapped substances there is – CO₂ has been used in industrial applications, for example in the chemical industry, for a long time. This experience is now being utilised to ensure the safe operation of CO₂ capture and storage facilities.
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On the other side of the bridge

Vattenfall’s strategy for fighting climate change is made up of three prongs, of which capture and storage technology is one. The other two are the optimisation of existing technology and the increased use of energy sources without emissions of fossil-fuel carbon dioxide.

In every issue of Bridging to the Future, we present work performed within the Vattenfall Group that aims to reduce emissions of greenhouse gases. The topic for this issue is our work with the first part of our strategy for combating climate change: improving the efficiency of our existing plats.

Better efficiency in thermal power plants

The coal and lignite-based thermal power plants in the Vattenfall Group generate around 80 TWh annually. An efficiency increase of only one or two per cent in a power plant would give several extra GWh every year. Increasing the pressure and temperature of the steam generated is a measure for increasing the efficiency and output.

This modern technology is realised in Vattenfall’s new power generating block in Boxberg, Boxberg R, which is currently under construction. A live steam temperature of 600 ºC and a pressure of 285 bar will be utilised and the net power efficiency in Boxberg R will be more than 43 %.

More power from the Luleälv River

Earlier this year, the decision to refurbish the Akkats hydro power station was taken by the Vattenfall board. Akkats is one of fifteen power stations on the Luleälv River in the very north of Sweden and together they generate almost 14 TWh annually. The first power station along the river was inaugurated already in 1914.

The planned refurbishment of Akkats includes replacing the old 150 MW turbine with two smaller machines of 75 MW each. The old inlet tunnel will remain and feed one of the new turbines with water. A second inlet tunnel will be built to supply the second turbine. Stones and other material from incidents in the past in the outlet tunnel will be removed, which will facilitate the water discharge.

The work will result in an increase in the electricity generated of around 25 GWh annually and Akkats will then generate around 590 GWh of low CO2 emissions electrical power each year. The cost of the project is estimated at €100 million. The project will start in the autumn of 2008 and run for around 5 years.

Increased output in the nuclear power plants

In total, about 50 TWh of nuclear power is generated annually in Vattenfall’s nuclear power plants in Sweden and Germany. In the Swedish plants, Ringhals and Forsmark, work to increase the generation in the existing plants is ongoing.

Ringhals’ four reactors, both boiling water and pressurised water reactors, produce around 28 TWh in a normal year. The first reactor came into operation in 1975 and with the modernisation work that is currently underway we will be able to run the facilities for many years to come.

An investment programme was initiated in 2002 and in the period up until 2012, € 1.4 billion will be invested in regeneration, improved safety, reduced environmental impact and increased output. The programme consists of 300 different projects, involving among other things new turbines and generators, a new digital control room and new cooling water systems. The investments will increase the power output from Ringhals by 4 TWh per year.
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Vattenfall receives award for the Oxyfuel Technology

Vattenfall’s CCS project is at the vanguard of development. In the spring of 2008, Vattenfall received an Emerging Technology Award for its Oxyfuel pilot plant project in Schwarze Pumpe from the Institute of Electrical and Electronics Engineers (IEEE), the world’s leading organisation for electrical and electronics engineers.

Dr. Lars Strömberg, former project manager of Vattenfall’s CCS project and now head of R&D at Vattenfall, and Dr. Helmar Rendez, Head of Strategy at Vattenfall, received the award at a gala in San José on the American west coast in April this year. The prize was shared with Alstom Power Inc., as the developer and supplier of the Oxyfuel boiler in the Schwarze Pumpe pilot plant. Alstom Power was represented by Steve Orsini at the gala in San José.

Of all the new innovations that have been developed over the past year, this project is considered to have “the potential to provide the greatest social benefit”, according to IEEE.
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