The project newsletter

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

Bridging to the future No. 12, January 2009

Below you will find the online version of the project newsletter - Bridging to the future. A choice of shorter articles from January 2009 are presented below.
A project of strategic importance
Seismic investigations in Northern Denmark
Vattenfall commissions Oxyfuel pilot plant
CFB an option for Oxyfuel?
Vattenfall joins the OxyCoal UK collaboration
Procedures to qualify aquifers and transport links for CO₂ storage
A landmark in a land of ideas
On the other side of the bridge
Developing CCS – people in our project

A project of strategic importance

CCS is a strategic project for Vattenfall. In December 2008, we decided on a new organisation for the Vattenfall Group including, among other changes, a new CCS manager, Bjarne Korshøj, who reports directly to me. With this new function we clearly underline how important CCS is both to Vattenfall and to society. His first task will be to review our CCS portfolio and propose how we can enhance our further efforts.

Our ambition is to be a leading energy company – today and tomorrow. We have earlier communicated our targets to reduce our CO₂ emissions by 50 per cent by 2030 and to become CO₂ neutral by 2050. As everyone can understand, this is a huge challenge and we definitely need CCS to reach these targets, but it is important to remember that we cannot rely on CCS alone as that will not be enough. Therefore, we attach a great deal of importance to further investments in wind power and biomass and are also enhancing our efforts to develop ocean energy.

The official 3 to 5-year test programme at the 30 MW Oxyfuel pilot plant at Schwarze Pumpe is scheduled to start in the beginning of February 2009. In December 2009, we announced another step forward in our work with CCS by joining the OxyCoal UK collaboration. This project aims to develop a competitive Oxyfuel technology suitable for full-scale plant application. It will act as an important complement to the pilot plant at Schwarze Pumpe and our other efforts on the development of the Oxyfuel process. The preparations for demonstration plants at Nordjyllandsværket in Denmark and Jänschwalde Power plant in Germany continue with ever increasing intensity.
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Seismic investigations in Northern Denmark

The 2D seismic investigations in Northern Denmark were concluded in October. We are now one step closer to determining if the area is suitable as a storage site for CO₂.

The work was completed as planned and a huge amount of data was collected along lines in excess of 220 km in length. The measurements are now being processed by DMT, the German company that executed the surveys, and will subsequently be processed by GEUS, the well-known Danish Geology Institute. By February 2009, we will have a well-documented 2D image of the underground strata.

The results will form the basis for the next stage in the process. This will be a 3D seismic investigation of a much smaller area, in other words. the area where we expect to locate the CO₂ storage. The three-dimensional seismics will provide a spatial image of the underground strata.

Promising preliminary results

The preliminary results from the 2D seismics are promising and confirm the expected formation at a depth of approximately 2 km. The results also show that the formation is situated further south in relation to the measurements from the 1950s and 1970s, which formed the basis for the 2D seismics. There is also some evidence to suggest that the formation is slightly larger than first assumed. It has therefore been necessary to narrow down the area to be covered by the 3D seismic investigation.

A 3D investigation is considerably more comprehensive than a 2D investigation, as a dense grid of measurement lines is used. The investigations will be carried out in an area with relatively soft soil, which complicates the collection of data. It has therefore not yet been clarified how the seismic investigations will be carried out.

The process of planning the 3D seismics is well under way. Many considerations have to be taken into account. These considerations include both agricultural land and a nature conservation area for migratory birds. The preliminary plans indicate that the investigations, which will last around three months, can be carried out during the period May to July.

We have learned from our mistakes

We have of course made mistakes during the process, and we have learned from them. We will for example be even more meticulous about providing information to residents in the area. Even though we believe we have done a lot in this area, the information will be more targeted at the individual plot owner next time.

We will therefore suggest that a plot-owner group be established, which will be able to provide advice regarding when the investigations will have the least impact on farming and how the compensation packages for the inconvenience caused will be calculated and put together. This committee will hopefully be established at a plot owners’ meeting on 22 January 2009. The committee will not replace the local monitoring group that we set up at the start of the project. It will continue to act and work to ensure local acceptance of the project.
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Vattenfall commissions Oxyfuel pilot plant

Vattenfall’s Oxyfuel pilot plant was officially inaugurated
on 9 September 2008. The week before the inauguration, the first tonnes of CO₂ were produced in the plant, showing that the plant works and is able to produce the desired liquefied CO₂. Some work on stabilising and optimising operation is, however, still required.

Facing new challenges

The Oxyfuel pilot plant is not a standard power plant and this means that other commissioning and control strategies are required. For example, the pilot plant does not contain a steam cycle, as this is not the focus of this new technology. The main difference compared to a conventional power plant thus relates to the handling of pure oxygen and carbon dioxide. Large quantities of ammonia are also handled in the cooling loop of the CO₂ plant.

Another very important difference, compared to the operation of a conventional power plant, is that three different operation modes are possible and necessary: the air-firing mode, the Oxyfuel mode with flue gas exhaust through the stack and the Oxyfuel mode with flue gas fed to the CO₂ compression plant.

The firing modes imply various flue gas paths and bypass systems, a new boiler design, a new control system and many more novelties compared to conventional power plants. All this has been a great challenge to the equipment suppliers and the Vattenfall engineers in the design and construction phase, but also now when operation starts. As yet, the pilot plant is not running non-stop. It is regularly restarted, operated on an hourly or daily basis and constantly improved. The plan is for Vattenfall to begin test operations in the beginning of 2009, after a longer shutdown during the holidays.

Experience from the commissioning

The Air Separation Unit (ASU) operates at low temperatures and the commissioning has shown that a cooling-down time of 60 hours is required to reach the operating temperature, if the ASU is started from ambient temperature. Liquid nitrogen, which is also produced in the ASU, can be used for cooling purposes and thus speed up this start-up period.

The first operational experience gained during the commissioning with the steam generator and its indirect firing system in the air-firing mode did not show any unexpected results. The pre-dried lignite ignites well and develops a stable flame. Controlling the flue gas recirculation in the Oxyfuel mode has been both a challenging and time-consuming task, but absolutely necessary for safe Oxyfuel operation. To stabilise the flame and ensure safe ignition, adjustments to the swirl and the oxygen concentration at the burner were required. In both the air-firing and Oxyfuel modes all the required emission limits could be kept safely without any further optimization.

The operation of the CO₂ compression plant is also a rather complex task for the control system, because of the dependence on what happens upstream. Stable pressure levels at specific places in the flue gas ducts have to be established and a minimum concentration of 50 % CO₂ in the flue gas is required in order to start-up the CO₂ compression plant.

More details about the pilot plant and its first period in operation can be found in the paper by Strömberg et al., presented at GHGT-9 in Washington in November 2008.
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CFB an option for Oxyfuel?

Vattenfall works intensively with the investigation and evaluation of different proposed concepts for future power plants with carbon dioxide (CO₂) capture. For us, it is important to increase the general understanding of the field and also to identify and evaluate opportunities to minimise the parasitic energy consumption in power plants with CO₂ capture and the investment costs for the necessary additional equipment, and to widen the fuel spectra for CCS.

CFB vs. PF

The Circulating Fluidised Bed (CFB) technology is a way of combusting solid fuels for power generation. The combustion takes place in a fluidised bed in which the fuel, the ashes and the sorbent (usually limestone) are recycled many times. The low operating temperature (~800-900°C), long residence times and high combustion efficiency inherent in the CFB process result in low emissions and the possibility to burn a wide variety of fuels.

Traditionally, CFB technology has not been of interest for large utility-scale power generation due to relatively small unit sizes and moderate steam data, thus limiting the existing units to sites where conditions were just right. In many cases this means low-quality coals, waste incineration and biofuel-based combined heat and power generation (CHP).

The dominating technology among Vattenfall’s coal-fired power plants today is the pulverised fuel type, PF. Therefore, the main focus of our studies of the Oxyfuel technology, has so far been on this type of boiler. However, due to developments regarding both steam data and unit size in recent years, the CFB boiler technology must today also be seen as a competitive alternative for large-scale power generation.

Benefits with CFB – also for Oxyfuel?

A key advantage of the CFB technology is that pollution control is built right into the combustion process. By adding low-cost limestone into the CFB, SO_x is captured and removed right at the point where it is formed as the fuel burns. The CFB boilers’ low combustion temperature, together with staged air optimisation, also minimises NO_x formation, typically below 200 mg/Nm3 depending on the fuel. If further NO_x removal is necessary, this can quite easily be performed by means of SNCR (Selective Non-Catalytic Reduction) systems, in other words. adding urea or ammonia with the result that NOx reacts to form N₂, O₂ and H₂O.

Another key feature of the CFB technology is high fuel flexibility. A large variety of solid fuels can be burned, which also offers the possibility of co-combustion with biofuel, for example. As the fuel does not need to be pulverised, the fuel feeding system is also simpler. The higher parasitic electricity consumption in the Oxyfuel process, in comparison to conventional power generation, is yet an argument for high fuel flexibility as the utilisation of cheap fuels becomes more important.

The above mentioned advantages for air CFB boilers are also expected to be valid for Oxyfuel CFB boilers. In addition, the Oxyfuel CFB technology could offer some advantages such as the possibility to more easily fire with higher O₂ concentrations in the oxidant since the CFB’s low combustion temperature and the turbulent bed provide good means of equalising temperature levels. This would lead to reductions in volume flows with decreased investment as a result.

Another advantage is that, since the fuel feeding system is simpler, the so-called primary flue gas recycle flow necessary in pulverized coal boilers to transport the fuel to the burners can be excluded, which reduces the overall complexity of the system. It could also be easier to minimise air ingress to the system since a large part of the furnace operates at slight overpressure.

Study together with Foster Wheeler and Praxair

To investigate and further elucidate the possible features of Oxyfuel CFB firing, Vattenfall has during 2008 conducted a conceptual design study together with the leading CFB boiler supplier, Foster Wheeler. Foster Wheeler has a long tradition in the development of the CFB technology and works extensively with the development of the technology for Oxyfuel firing. Praxair, a supplier of air separation and CO₂ purification and compression units, has also participated in this project to provide the conceptual design and performance of these units.
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Vattenfall joins the OxyCoal UK collaboration

Vattenfall takes yet another step forward in its committed work on CCS, Carbon Capture and Storage, by joining the OxyCoal UK collaboration. The project aims to develop a competitive Oxyfuel technology suitable for full-scale plant application.

The OxyCoal UK project is developing the Oxyfuel technology for the capture of carbon dioxide. This involves burning coal in a mixture of high-purity oxygen and recycled gas to produce a gas rich in carbon dioxide that can be purified and compressed for transportation and storage.

“As Vattenfall has been working with the development of CCS technology since 2001, we think it is very interesting to be part of the OxyCoal UK project. This is one of the projects in Europe, besides our own pilot plant in Schwarze Pumpe, that is most advanced,” says Göran Lindgren, Vattenfall's CCS R&D Programme manager.

The OxyCoal UK project is led by the technology supplier Doosan Babcock and run by a group of industry sponsors and university partners. Vattenfall’scontribution to the project is, besides extensive knowledge and experience of CCS technology, about £330 000. The project will run until November 2009, with a possible two-year extension.

“Earlier this year, Vattenfall announced its vision to be climate neutral by 2050. We strongly believe that CCS technology is a vital part of reaching our goal,” says Göran Lindgren.

The OxyCoal UK project consists of two phases. The first phase includes mapping of the underpinning technologies for the Oxyfuel process, such as combustion fundamentals, including CFD modelling, furnace impacts and CO₂ product gas clean-up and purification.

In the second phase of the project, Doosan Babcock will modify its Multi-Fuel Burner Test Rig at Renfrew in Scotland to accommodate Oxyfuel firing on pulverised coal. The Oxyfuel state will be created by supplying oxygen from tanks and recycling the flue gas. The facility will demonstrate the operation of a full-scale 40 MW burner for use in coal-fired boilers, suitable both for new power plants and for retrofit applications. For Vattenfall, the project is an important
complement to our own efforts in the Oxyfuel pilot plant in Schwarze Pumpe.
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Procedures to qualify aquifers and transport links for CO₂ storage

With the need to start CO₂ reductions using CCS in Europe by 2015, and on a commercial basis by 2020, there is a strong need for acknowledged quality assurance of the methodologies used to qualify deep geological formations as suitable for CO₂ storage projects, as well as qualifying the related CO₂ pipeline transportation projects.

The harmonised regulation that is underway on CO₂ storage through the EU Directive on CO₂ Storage will secure implementation of the technology in a safe and environmentally responsible way. The Directive stipulates that starting the operation of a CO₂ storage site must be authorised by a storage permit. The permit is the main instrument whereby authorities secure that the stipulated environmental conditions of the Directive are fulfilled. Along with the implementation, the member states will need to bring existing relevant national regulations into line with the Directive.

Guidelines under development

Well-established qualification procedures are one way of assisting both the developers of CCS projects and the authorities that will have to handle the approval and authorisation of these projects. Two examples of such guidelines are under development in the joint industry projects CO2QUALSTORE and CO2PIPETRANS, led by DNV (Det Norske Veritas).

CO2QUALSTORE is developing a guideline suited to the selection and qualification of geological sites and projects for the geological storage of CO₂, while CO2PIPETRANS is developing a guideline for the safe, reliable and cost-efficient transmission of CO₂ in pipelines.

Conversion into Recommended Practices

Both guidelines are expected to be finalised by mid-2009, and thereafter converted into a set of publicly-available Recommended Practices by DNV. The Recommended Practices on CO₂ Storage Site Qualification and CO₂ Transmission will establish a common basis for CCS project developers and national authorities in their common effort to establish and secure high-quality projects.

Vattenfall is one of the industrial sponsors of CO2QUALSTORE and CO2PIPETRANS. Both projects started in mid-2008 and have completed about 6 months of work so far. The participating companies and leading national research institutes, with their extensive collective experience and knowledge from successful work carried out in predecessor European and national R&D projects, are well positioned to establish the foundation for new qualification codes and standards on CO₂ storage and CO₂ transportation.
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A landmark in a land of ideas

On December 7, Vattenfall’s CCS pilot plant in Schwarze Pumpe opened up its gates for interested visitors. More than 2 000 people took the opportunity and visited the plant to take part in tours around the site, test their knowledge about carbon dioxide and the greenhouse effect and gain information about Vattenfall and the region.

There was an additional reason to celebrate: the pilot plant and the town of Spremberg was appointed “A landmark in the land of ideas”, an award granted by the initiative “Germany - land of ideas”. This initiative, under the patronage of German Federal President Horst Köhler, annually points out 365 landmarks in Germany where ideas and innovations are advanced. The award was handed over to Reinhardt Hassa, from Vattenfall and Klaus-Peter Schulze, the Mayor of Spremberg.
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On the other side of the bridge

Vattenfall’s strategy for fighting climate change is made up of three elements, 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 carbon dioxide, CO₂.

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 renewable and low CO₂-emitting energy sources.

Our history of wind power – a solid foundation for expansion

For more than 30 years, Vattenfall has performed significant research and development regarding large-scale wind technologies.

Today, Vattenfall owns 60 per cent of the world’s largest offshore wind facility, located off Denmark’s Jutland Peninsula (160 MW), and 100 per cent of the world’s third largest offshore wind farm, Lillgrund between Sweden and Denmark (110 MW). We also own and operate the Kentish Flats offshore wind farm outside the UK (90 MW).

Together, Vattenfall’s three largest wind farms provide renewable electricity equivalent to the consumption of around 200 000 households.

Wind power acquisitions in the UK

We aim to produce 50 TWh from wind developments, equivalent to the consumption of some 10 million households, by 2030. The UK is one of our key markets for growth, with excellent potential for clean electricity generation from wind power.

Vattenfall invested heavily in the UK during 2008 and acquired both Amec Wind Energy and Eclipse Energy. In the late autumn of 2008, Vattenfall also acquired the Thanet Offshore Wind project off Margate, Kent, for the sum of about € 42 million. On completion, the wind farm will have an installed capacity of some 300 MW. The acquisition of Thanet Offshore Wind will make Vattenfall one of the biggest wind power operators in Britain.

Further offshore projects

Vattenfall has also entered into partnership with Scottish Power Renewables, to work together developing offshore wind farms in the UK. The common goal is to establish 6 000 MW of installed wind power capacity, corresponding to enough clean energy to power four million homes by 2020.

In Sweden, Vattenfall has been granted permission to build 30 offshore wind power plants in Kalmarsund but has not yet taken the final investment decision.

Ocean energy

Vattenfall is evaluating several ocean energy technologies, such as wave, salinity (power generation by osmosis), tidal and marine current technologies. Substantial research is in progress and considerable demonstration activities have been initiated by many operators around the world.

Most of our attention is focused on wave energy, which is estimated to be the next renewable technology to be commercialised (after wind power). It has been estimated that the total wave energy resources of all European coastlines are around 2 000 TWh yearly.

Most wave power concepts have been developed for the energetic wave climate along the European west coast. The most interesting places for Vattenfall, right now, are on the Swedish and Norwegian west coasts and outside Ireland. At Vattenfall, we focus our efforts on four different wave power technologies, the Seabased concept developed by Uppsala University in Sweden being one of them.

Full-scale test

The Seabased concept for wave power consists of a linear generator driven by a buoy at the surface. Vattenfall is carrying out a full-scale test of this technology at Islandsberg on the Swedish west coast. The project started in 2004 and will be finished in 2014. Ten buoys will be connected to ten linear generators on the seabed.
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Developing CCS – people in our project

Many people are involved in the R&D work within different areas of Vattenfall’s CCS project. In Denmark, geologists are performing seismic investigations of an area we believe to be very well suited for CO₂ storage. Ann Troelsgaard Sørensen is one of these geologists and she has high hopes of the storage potential in Denmark.

Going underground

Geologists are currently examining the subsurface in Vedsted in northern Denmark. The idea is to deposit carbon dioxide in the bedrock here, starting in late 2013. The demonstration plant in Denmark is Vattenfall’s first large-scale CCS project in the Nordic region.

The northern Jutland power station is one of the most efficient coal-fired plants in the world and produces both district heating and electricity. By 2013, the power station will release only a small amount of carbon dioxide into the atmosphere. Instead, approximately 90 per cent of the carbon dioxide produced will be separated, compressed and transported in pipes to the future storage plant at Vedsted. At least 100 million tonnes of carbon dioxide are expected to be stored there. The first step is to examine the structure and properties of the subsurface

Two kilometres down

Carbon dioxide will be stored at a depth of two kilometres in a sandstone structure. A thick layer of clay on top of the structure will serve as a cap and hold the carbon dioxide in position.

One of the project’s geologists is Ann Troelsgaard Sørensen. She joined Vattenfall in July 2007 and her duties include working on the development of the baseline investigation plan and monitoring programme for the future CO₂ storage site. “It is exciting to see the results,” she says. “Hopefully we’ll get confirmation of our assumptions on the geology. We are fairly sure regarding the types of sediment we expect to find, but they are situated in a complex structural setting which needs to be further investigated and mapped.”

It is crucial that the inhabitants in the vicinity of the storage area feel safe. Therefore, Vattenfall is putting a lot of effort into providing information about the project in the local press and at public meetings. Sørensen and her colleagues often talk about the project, both at these local information meetings and at scientific conferences and so on. The message is the same: the site chosen for investigations displays excellent sealing capacities comprising about 400 metres of chalk on top of several hundred metres of thick marine clay and can therefore be regarded as a safe site for CO₂ storage.
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