Nikki Fisher, Anglo American, South Africa, discusses trends in clean coal technology.
Clean coal refers to the process of reducing carbon emissions and other harmful pollutants generated by the burning of coal for power generation to the minimum possible level. Supercritical (SC) and ultra-supercritical (USC) pulverised coal combustion and integrated gasification combined cycle (IGCC) technologies are examples of clean coal technologies that are widely used in new-build coal-fired power plants. These technologies improve the steam pressure and temperature requirements for operating the plants, thereby resulting in improved thermal efficiencies and consequently lower carbon emissions. In addition, carbon capture and storage (CCS) is capable of reducing carbon emissions by 80 – 90%.
In 2009, the term “21st Century coal” was jointly devised by the governments of China and the US when they pledged to promote cooperation on development of near-zero emissions (NZE) technology, including large-scale CCS projects. In 2013, the IEA Coal Industry Advisory Board produced a report entitled “21st Century Coal: Advanced technology and energy solution”, which explores the status of the technologies available and the path to near-zero emissions.
Technologies to reduce emissions of particulates, nitrogen oxides (NOx) and sulfur dioxide (SO2) have been used for several decades, but it is only in recent years that advances in these technologies have substantially improved the effectiveness and reduced the cost of these solutions. Increasingly stringent emissions limits globally have stimulated the uptake of these technologies. This, in turn, encourages further technical advances and cost reductions.
Economic analysis shows that the dual strategy of improving generation efficiency, coupled with CCS, is the best path to competitive advanced coal power generation systems. CCS technology is currently very costly, however. While there is no meaningful regulation or price on carbon, it makes economic sense to pursue supply-side efficiency improvements, as a first step and least-cost option to buy time for improvements and cost reduction in CCS technology.
High efficiency coal combustion technologies reduce the production of CO2 by burning less coal per unit of power generated. Advanced power plant designs, which incorporate gasification and combined cycle power generation, have also been recently commercialised and have significantly higher efficiencies of up to 45%.
By increasing the global average power plant efficiency from the current 33% to advanced USC with efficiencies of 46%, CO2 emissions will decrease by 30%. A less ambitious move to the off-the-shelf efficiencies of 40% could cut 2 billion t of CO2 emissions, the equivalent of India’s annual CO2 emissions or running the Kyoto Protocol three times over.
Given that a fifth of global coal-fired power plant capacity has been built in the last five years, the maturation and deployment of CCS technologies is critical for reducing CO2 emissions at the scale required, particularly when one considers the carbon lock-in of these power plants over their 40 – 50 year lifespan.
The component technologies for the capture, transport and storage stages are well understood and, in some cases, technologically mature. One of the biggest challenges facing CCS is the integration and demonstration of these technologies at a scale that will prove that they are safe and reliable to engender trust with stakeholders. Other technical drawbacks include the reduction in the power plant efficiency and output, increased water consumption, increased control complexity, decreased reliability and availability of the plants, as well as finding suitable storage sites for the CO2.
The IEA estimated in 2009 that the funding required for CCS demonstration projects would need to increase to US$ 3.5 – 4 billion/year between 2009 and 2020. However, the cumulative spend on CCS between 2007 and 2012 was US$ 10.2 billion, of which US$ 7.7 billion was private financing. Although this seems significant, it does not meet the 2009 targeted levels. In contrast, renewable energy subsidies were US$ 101 billion in 2012 alone.
Much of the progress today can be attributed to the policy actions taken 5 – 10 years ago, supported by economic stimulus programmes and partnerships with industry. For CCS to continue gaining momentum, governments must take further policy action and develop enabling regulatory frameworks.
What needs to happen to accelerate CCS deployment?
Deploying CCS requires policy action. Markets alone will not drive deployment of the technology. The appropriate policy for CCS will evolve as the technology matures, moving from technology specific support to technology neutral support, which allows deployment of least-cost abatement options. The approach may also adapt from incentivising CCS through subsidies, to incentivising it through a price on carbon; from cost and risk sharing between public and private sector to cost and risk primarily falling on the private sector.
The long-term liability issues associated with CCS also have to be addressed, as well as any other legal and regulatory issues. Collaborative RD&D programmes involving industry, government and other stakeholders can help achieve self-sustaining, commercially viable technologies.
In addition to policy support, extensive public and private sector funding is needed to accelerate the commercial introduction and deployment of clean coal technologies. For CCS technology to make meaningful progress and achieve the cost reductions brought about by technology maturity, governments will need to support large-scale CCS demonstrations both with capital contributions and backing for the power prices.
Recently, however, there have been significant moves internationally to reduce the financing options available for new coal-fired power generation projects by multilateral development banks (MDBs), such as the World Bank and at the European Bank for Reconstruction and Development. Policy revisions have specified that new coal projects will only be funded under exceptional circumstances where no financially feasible alternative exists. Although seemingly counterintuitive, MDBs phasing out financing for new coal projects could have inadvertent consequences. Countries may go ahead with coal projects anyway, with the risk that cheaper, less efficient and more polluting technologies might be used because they are all that can be afforded in the absence of concessional finance or loan guarantees. Many developing countries cannot secure this finance in private markets, meaning that the role of public institutions, such as development banks, is essential.
The development of advanced coal technologies is proceeding, but not at the pace required. While it is technically feasible to reduce CO2 emissions from coal-fired power to near-zero levels, a variety of policy, technical and funding roadblocks are preventing the technologies from reaching a level of maturity need for affordable, widespread deployment. Financial incentives and greater regulatory certainty are needed to hasten the pace of investment in RD&D in order to overcome the obstacles to technology deployment.
Written by Nikki Fisher. Edited by Jonathan Rowland. The full report appears in the November 2014 issue of World Coal. Subscribers can view the full article by logging in and downloading the issue here.
Read the article online at: https://www.worldcoal.com/special-reports/10112014/world-coal-the-path-to-clean-coal-nikki-fisher-coal1551/