- How large emission reductions are possible with the use of CCS?
There are different technologies for CO2 capture, and they have different potentials for CO2 capture. With the oxyfuel technology up to 100 % of the CO2 emissions from a coal power plant can be captured and stored. Another way of capturing CO2 is post-combustion CO2 capture, which will remove 85 to 90 % of the CO2 produced by the power plant.
There are more than 8000 currently polluting factories and power plants worldwide where CCS is applicable. These factories and power plants are responsible for about half of the global man-made CO2 emissions. If CCS is implemented to all these factories and power plants up to 50 % of global CO2 emissions could be eliminated, greatly reducing the effects of climate change.
- Is CCS a mature technology?
CCS is a maturing technology that so far has been demonstrated in laboratories, pilot plants and at real world power and industrial plants. This means that there is still huge potential for CCS technology to become more cost efficient through further advances in technology. Just as with renewables such as solar power, the cost of CCS will reduces as it is increasingly deployed.
- Is CO2 storage safe?
Before a CO2 storage site is chosen, a detailed survey takes place to ensure permanent safe storage. The aim is to find storage sites that can be well characterized and classified as safe prior to the injection of CO2.
A safe storage site means that the CO2 will be injected into a layer deep underground with porous rocks where CO2 will be stored in the pores. The CO2 might try to move upwards, but there will be one or more layers of solid rock on top of the porous layer that prevents the CO2 from moving upwards towards the surface.
This way of storing CO2 is the same mechanism that has stored oil and gas below the ground for millions of years, including naturally occurring reservoirs of CO2 . The fact that oil and gas have been trapped underground for millions of years is a very good indication that CO2 will remain safely stored in a similar manner.
- Can problems occur when CO2 is stored?
There can never be an absolute guarantee that CO2 will not leak, but CO2 will be stored at locations where the risk of leakage is very low. To be prepared for the unlikely case of a leakage, monitoring instruments and routines will be required, such that remediation actions to stop the leak can be performed. If, despite the precautions taken in selecting a site, it does leak in practice, corrective measures must be taken to rectify the situation and return the site to a safe state. At present without CCS, 100% of the damaging CO2 produced at power plants and industrial facilities “leaks” into the atmosphere.
- Where can CCS be used?
CCS is applicable for all stationary CO2 emission sources. That includes coal and gas power plants, refineries, and factories for production of steel, aluminium, cement, and ammonia among others.
- What is the cost of CCS?
The cost of CCS involves partly capital investment on equipment to capture, transport and store CO2, and partly the cost of operating this equipment to store the CO2 in practice – such as the amount of energy required to capture, transport and inject the CO2. These costs are expected to substantially decrease as the technology is proven on a commercial scale.
In general, retrofitting an existing power plant would lead to a higher cost for CCS, but these are highly dependent on specific site characteristics, including plant specifications, remaining economic life and overall site layout.
- Will CCS reduce the efficiency of a power plant?
Operating a CO2 capture plant will require energy primarily to capture and then compress CO2 for transport. If a coal power plant is equipped with a CO2 capture plant, a share of the energy produced by the power plant is needed to operate the CO2 capture plant.
The electricity output penalty results in a net reduction in efficiency in return for low carbon electricity. The IEA report “cost and performance of carbon dioxide capture from power generation 2011” estimates post combustion capture at a coal plant to reduce net efficiency by 25% resulting in an increase in fuel consumption to generate equivalent power output.
However when replacing or upgrading existing plants with CCS enabled facilities, net efficiency can increase over the original antiquated generation facilities. This is due to the installation of modernised boilers and turbines along with capture equipment, resulting in decrease in fuel use and the production of low carbon electricity. In Saskatchewan Canada, the comprehensive upgrading of unit 3 and the installation of post combustion capture at the Boundary Dam coal power plant resulted in an efficiency increase from the original 31% to 34%. Similarly the front end engineering and design (FEED) study for the proposed Jänschwalde CCS project in Germany concluded that a new CCS equipped unit would match the net efficiency (36%) of existing polluting units operating at the plant. This effectively means that there would be no energy penalty between a new low carbon generation unit including compression and an older unabated operating plant.
- Does a storage site require regular maintenance? Who is responsible for this?
Monitoring, measurement and verification is a critical component of all CO2 storage campaigns. Identification and tracking of CO2 in the subsurface is necessary to optimise operations, insuring that the CO2 remains within performance predictions and demonstrating long term storage security. Monitoring plays a critical role in the handover of the storage site to the state after storage security if sufficiently demonstrated. A wide variety of monitoring techniques may be used, with technologies selected on a site by site basis, depending on the legislative, geographical and geological characteristics. Monitoring will begin prior to injection and continues throughout and after injection is completed, until sufficient storage security can be demonstrated and site closure.
As the CO2 will remain stored underground indefinitely, long-term responsibility will follow the example set by the petroleum industry, whereby the state assumes responsibility after a regulated storage process. Indeed, EU law governing the safe and permanent storage of CO2 has already been approved and is currently being implemented at national level.
- To what extent is CCS deployed today?
According to the Global CCS Institute, there are 60 large-scale integrated CCS projects identified around the world in 2014. 21 of these are active projects, meaning that they are in operation or under construction. Their total capture capacity is currently 40 milliontonnes CO2 annually.
- Is CCS regulated on the international and EU level?
On the international level, CCS is mainly regulated by the London Convention, which is a global convention to protect the marine environment from human activities, and OSPAR, which is a mechanism by which fifteen Governments of Europe cooperate to protect the marine environment of the North East Atlantic. They have both been amended to allow CO2 storage under the seabed.
On the EU level, the CCS Directive (Directive 2009/31/EC) is the central piece of legislation. The directive contains a set of guidelines ranging from exploration and storage permits to liabilities and closure procedures for CO2 storage sites. Furthermore, it is an enabling directive, which means that it does not require CCS to be developed, but if an EU Member State or company chooses to develop a CCS project, then the provisions of this directive must be followed.
- Is CCS supported by the EU?
The Commission has acknowledged that CCS may be the only option available to reduce direct emissions from industrial processes at the large scale needed in the longer term, and that increased research, development and commercial demonstration is essential over the next decade so that the technology can be deployed in the 2030 timeframe. Moreover, the 2050 European Energy Roadmap anticipates the deployment of CCS both in energy and industry.
- How is CCS treated under the EU Emissions Trading System?
CCS was made part of the EU ETS following the major revision of the system, which entered into force in 2013. The EU ETS Directive now recognises the role and value of CCS as a climate change mitigation technology, so that CO2 captured and reliably stored is considered as not emitted. Moreover, stronger economic incentives exist for industrial operators to prefer low emission technologies, such as CCS.