Cofiring high ratios of biomass with coal

The supercritical CO2 Brayton cycle energy conversion system is an innovative concept that converts heat energy to electrical energy through the use of supercritical CO2 as working fluid rather than through steam and water. In this webinar, Qian will give a brief description of supercritical CO2 power cycles and review the recent technology advances in developing supercritical CO2 cycle power generation systems for fossil fuels.

This webinar examines technical developments in coal beneficiation covering dense-media and dry coal treatment, and upgrading various technologies.

Amid a global trend to use low quality, inexpensive coal, it is now recognised that feedstock quality is a key element of a future power strategy to raise power station performance and meet environmental legislation. Preparing feedstock in order to remove inert matter and reduce contaminants can benefit every aspect of a coal plant operation. We examine technical developments in coal beneficiation covering dense-media and dry coal treatment, and upgrading technologies such as coal refining, digestion, oxidation, fuel blending and biomass substitution.

Lignite or brown coal, the lowest quality coal, is normally used in its raw state resulting in significant energy and reliability penalties. Energy efficient technologies to reduce moisture and ash levels can significantly improve performance. As lignite demand declines in OECD countries, alternate markets are being sought that utilise synthesised humates.

What are the major institutional challenges and financial opportunities emerging for new HELE coal power plants? This webinar will examine the trends in coal project finance worldwide and accompanies one of the latest reports published by the IEA Clean Coal Centre.

Publicly funded financial institutions such as multilateral development banks (MDB) and export credit agencies (ECA) based in OECD America and Europe have, since 2013, adopted strict lending rules for greenfield coal power projects. Greenfield projects may be supported financially, but it they will be authorised under rare and exceptional circumstances only. However, these particular financial institutions form a fairly small proportion of the funding made available to coal power projects worldwide. There is evidence that many other banks are willing to support High Efficiency and Low Emission, or HELE, coal technology in Asia, even in the wake of COP21.

In Asia, public funding agencies and commercial banks in Japan, Korea, and China are pursuing coal projects abroad with the view of exporting their own HELE technologies to other regions, even into Europe. This means the impact of reduced funding from western public agencies might not be so severe. Furthermore, the arrival of the newly formed Asian Infrastructure Investment Bank (AIIB) could provide exciting opportunities for funding of cleaner coal technologies in the future.

The vulnerability of the power generation industry to constraints in water availability is widespread and growing, and this is increasing the pressure on power plant operators to conserve water. This webinar will discuss where water can be conserved or recovered within pulverised coal-fired power plants. It will include ways of saving water in bottom ash handling, pollution control (flue gas desulphurisation), and cooling systems. Cooling typically accounts for the largest usage of water (where water is the coolant), and wet flue gas desulphurisation is the second largest use at wet-cooled plants. Techniques for recovering water from the pulveriser and pre-dryer exhausts, and from the flue gas are also discussed. There is an opportunity for power plants to become a supplier of both electricity and water, if sufficient water can be economically recovered from the flue gas. This could be a way forward for some coal fired power plants in the future, as well as helping to solve local fresh water shortages.

Legislation is being implemented around the world to reduce emissions of pollutants from coal-fired power plants. For those countries that started to apply control strategies several years ago, the control technology market has evolved alongside the legislation in a somewhat piecemeal manner. So the majority of older plants in developed regions have applied controls in series: control technologies for particulates first, followed by controls for SO2, and then controls for NOx. New legislation is introducing requirements for mercury and fine particulate control in some regions, often requiring further retrofitting of additional control systems. For those emerging regions that are just starting to bring in control requirements, there is the option of copying this piece-by-piece approach to control, or alternatively to apply newer technologies which can control several pollutants simultaneously. This multi-pollutant approach could be cost-effective in many regions. However, the applicability of different technologies varies. For example, regions with high ash and/or high sulphur coals may require different control strategies from those with intrinsically cleaner coals. Also, availability of water, land and funds will all play a role in determining which technology will be applied at each plant. And so the control technology market that is currently expanding in Asia may differ significantly from that in North America and the EU. The international marketing strategies for emission control technology manufacturers must take into account differences in performance standards, economic challenges, business traditions and many other factors. This webinar summarises the potential markets for emissions control noting the areas for potential growth, such as China, Poland, India and Indonesia. Each has its own regional issues.

Following a few early failures of large-scale carbon capture and storage (CCS) demonstration projects due to public opposition to the technology, a considered public communication strategy is now regarded as an essential factor in the success of any prospective CCS project. Most active opposition to CCS has occurred in parts of Europe, where public fears over CO2 leaks, water contamination, or ‘industrialisation’ of rural areas combined with opposition by environmental groups and others to fossil fuels playing any role in a future energy mix. However, many other projects have since won acceptance or even widespread support, thanks either to improved public engagement or more favourable local context. Several key features of a successful communication strategy have been identified, including the need for engagement early in the process, encouraging and responding to community feedback, building and maintaining trust in the project developers, and use of a dedicated communications team with clear messages which are tailored to their intended audience. This report provides a comprehensive review of the public outreach strategy and results at most notable CCS demonstrations to date, and looks to future challenges for CCS communication. With the barrier of local acceptance appearing surmountable in most regions, the problem of making the wider case for CCS as a viable option for climate change mitigation largely remains. This could potentially be addressed through education initiatives and more effective use of mass media.

The webinar opens with an overview of the current status of coal power generation. This will be followed by discussion of the operating ratios for power generating companies. Operating ratios represent revenue and expense categories found on a typical financial statement. They can be presented as a ratio or a percentage value. The smaller the operating ratio, the greater margin an organisation has to make a profit. These ratios allow a company to compare its operational performance across various times, analyse its data and take the necessary steps in order to maintain its operational performance and as such, as low an operating ratio (%) as possible. Many factors contribute towards the operating costs of a power generating company including the cost of fuel, staff, operation & maintenance (O&M) costs and depreciation and amortisation. The higher costs these factors are, the higher the operating ratio will be and, therefore, the lower the operational efficiency of a company. The cost of coal-fired power generation varies at the national and plant level. However, due to the increase in renewable energy, coal-fired power has shifted in many countries from baseload to load following mode necessitating flexibility in power plant operations. The more frequent cycling of coal-fired power plants can cause thermal and pressure stresses. Over time, these can result in premature or unplanned component failure and increased maintenance. Repeated starting up and shutting down of a unit, or operating at part load, can also increase emissions compared to non-cyclic operation. Measures can be taken to minimise the impact of cycling on plant performance. Assessment and control of O&M costs play a major role in calculating operating ratios. The webinar finishes with future projections for coal in power generation.

Around half of the world’s estimated recoverable coal reserves comprise coals of low quality and value. These are mainly subbituminous and high-ash bituminous coals, and various grades of lignite. All are important for power generation and cogeneration. Each coal type brings its own combination of advantages and disadvantages. Despite the latter, a number of countries have turned increasingly to the use of such coals.
In the last decade, subbituminous coals and coals with higher ash content have been introduced into the market and traded in increasing quantities. As reserves of some better quality export coals have been depleted, there has been a shift towards the greater use of variants of lower quality, often to cut costs. However, switching may reduce power plant efficiency, increase emissions, and escalate plant maintenance requirements.
A number of major economies rely heavily on indigenous resources of lower quality coals as they may be the main energy resource available and are often cheap to mine using large scale opencast techniques. They can provide a secure source of energy and help minimise dependence on imported supplies.
The webinar examines the current production and use of these three categories of coal and discusses what the future may hold. All three are expected to continue to play a major role in energy production for some time.

India’s future energy needs are likely to grow more than any other country in the period to 2040. Energy consumption is predicted to more than double by 2040, with a consequent growth in the use of coal and oil.

India’s coal fleet is relatively young, predominantly subcritical but with a large tranche of future capacity planned or under construction. However, the planned future capacity is largely supercritical, rather than the current state-of-the-art ultra-supercritical technology that has been extensively proven in other countries. Indian projections and current policy seem to indicate that this trend will continue in the near future. This appears to be a missed opportunity for India to have the most efficient and modern plant to drive her economic growth; lower efficiency plant built in preference to the best high efficiency low emission (HELE) alternatives now would be “locked in” to the generating sector for the lifetime of that plant, possibly forty years.

The choice of subcritical, and now supercritical plant, over more advanced options is attributed to a cautious and conservative approach, gathering “home grown” experience on plant performance and maintenance in the light of challenges posed by India’s high ash coal resource. While this was undoubtedly a reasonable approach where power generation technologies were developed and built using regional skills and facilities, in the modern globalised power market a huge body of experience exists in dealing with all types of coal and manufacturers are prepared to design and offer high performance plant to burn even the most difficult coals, with full commercial guarantees. Fortunately, recent developments show that the Indian market is becoming more receptive to ultra-supercritical as the technology of first choice, but there is still much to be done to avoid the Indian coal fleet becoming locked into mainly supercritical plant.

As the world’s largest consumer of coal and leading CO2 emitter, China’s role in the international effort to combat climate change can hardly be overstated. The challenges China faces to control emission and pollution levels while meeting the country’s increasing energy demand are enormous. Over the years, China has made considerable efforts to reduce CO2 emissions and control pollution levels, and notable progress has been made through the implementation of ambitious programmes aimed at improving energy efficiency across a number of industrial sectors and a rapid scale up of renewable energy. This study reviews China’s policy and regulatory initiatives, in particular those aimed at improving energy efficiency and reducing emissions, HELE (high efficiency low emissions) upgrades, diversify the energy mix, as well as the progress to date in reaching a series of ambitious goals. China’s rapid expansion of non-fossil energy which affects the structural change of the power sector and coal use in electricity generation, and therefore, CO2 emissions from coal-fired power generation are also discussed.

China has provided strong financing and policy support for the R&D of HELE technologies. China now possesses a range of HELE technologies that are applicable to new and/or retrofitting of the existing coal-fired power plants and they are described in the webinar. Finally, the peak of coal consumption and CO2 emissions from power generation from coal, in light of China’s economic and policy trends affecting the structure of the economy and the coal consumption, are assessed.

Global energy demand is rising, while water is becoming a scarcer commodity in many parts of the world due to over-exploitation, droughts, heat waves, and other factors. Meeting the growing demand will place
increasing stress on limited fresh water resources. The power generation industry is typically the largest industrial user of fresh water in a country. Consequently, the vulnerability of the power generation
industry to constraints in water availability can be expected to increase. Hence non-fresh water sources will become increasingly important. This report examines the availability and use of potential non-fresh water sources in China, India, South Africa and the USA. These are the four top thermal coal consuming countries in the world. The alternative sources are municipal waste water, brackish and sea water, mine
water, produced water from oil and gas wells (including coalbed methane wells), and water extracted from deep saline aquifers during CO2 storage. In certain cases, and with suitable design of the on-site
water treatment plant, a coal-fired power plant could become a supplier of both energy and fresh water, instead of a water consumer.

Countries are setting ever higher goals for producing power from clean, renewable energies and some are actively turning their backs on fossil fuels. However, many of these regions are discovering the real challenges of trying to produce baseload power for public consumption from renewable sources which are, at best, intermittent, and, at worse, unpredictable and unreliable. Until large scale energy storage is available and affordable, baseload power from coal, gas, and/or nuclear will remain necessary in many regions for several more years. Obviously this baseload power is required when renewable output is low (when the sun doesn't shine and the wind doesn't blow). However, it is also still required to make up the balance of power in a diverse energy mix. Under the new energy policy regimes in many regions, renewable sources have priority into the grid and sit in the guaranteed dispatch mix in the base region which coal used to occupy. Coal has now been nudged into the dispatchable area of the mix, being asked to ramp up or down or even to idle or run beyond normal capacity, sometimes at short notice, to produce the balance of power required to maintain grid output. And whilst coal plants can run relatively flexibly, this does not come without cost. Most older coal-fired units were designed to run at steady output. Asking these plants to cycle and ramp puts stresses on the plant which can result in added cost, less efficient production, increased wear and tear and, in some cases, damage causing enforced outages for repair and/or upgrade. This webinar, looks at the stresses placed on coal-fired plants as they are asked to help levelise and counterbalance the intermittency of renewable sources, concentrating on the risks and costs. Case studies and examples of issues being encountered in the USA, the UK and Germany are included.

It is a concern that emissions from coal combustion may pollute the air. A lot of effort has been made to
regulate, control and prevent the pollutants emitted from coal-fired power plants. The coal industry is
facing increasingly stringent emission regulations, for the release of SO2, NOx, toxic volatile organic
compounds, heavy metals, and particulate matter (PM). PM can contain any or all of the aforementioned
chemical species or their compounds, plus water and biogenic organic species. PM2.5, as fine PM, can be
inhaled into human respiratory systems and travel deep into the lungs causing health problems. PM2.5 is
also considered to be a major cause of smog in cities and elsewhere. This webinar describes the
international and selected countries’ national air quality and PM emission standards for stationary
sources that are relevant to coal-fired power plants. Emission standards for SO2 and NOx are included
since they are precursors of secondary fine PM. International and national measurement standards are
summarised. Recent developments in PM emission control technologies are reviewed.

Established CO2 capture technologies such as absorption with amine solvents are associated with significant energetic and economic penalties, reducing power plant efficiency by around 10% points and increasing the cost of electricity production by up to 80%. Dedicated research programmes worldwide have pursued the development of a wide range of innovative, alternative technologies for CO2 capture, largely by addressing the fundamental gas separation step at the heart of post-combustion, pre-combustion or oxyfuel combustion processes. Novel solvents with lower energy requirements than conventional amines, using phase change systems, ionic liquids, enzyme-activation, or non-aqueous solvents, are promising approaches for post-combustion capture. Alternatively, techniques used in other commercial gas separations, including solid sorbents, membranes, and cryogenic separation, have also been developed for carbon capture through extensive materials research and process optimisation. Whilst challenging for post-combustion capture applications, these techniques may be of particular benefit to pre-combustion capture systems where much higher partial pressures of CO2 are available, and integration of the CO2 capture step and water gas shift reaction can be achieved using sorbents or membranes. In oxyfuel combustion, membranes are also an option for efficient oxygen production, but pressurised combustion systems have demonstrated the most potential for efficiency improvements, potentially in combination with novel power cycles which are better-suited to exploiting the altered combustion conditions. Finally, chemical looping combustion is a unique approach to carbon capture which can achieve dramatic energy savings through its inherent avoidance of any gas separation step, and is undergoing significant scale up. This webinar will review these developments in novel capture technologies and highlight the most promising strategies for achieving major cost reductions.

The lignite power industry produces low cost electricity but the associated pollutant emissions are higher than from other fossil fuels. Tighter environmental legislation requires older facilities to either upgrade or face closure. Plants designed to operate until 2040 already possess the latest effluent treatment systems while older facilities seek lower cost solutions. The rising contribution of renewable energy sources obliges plants to operate more flexibly, responding to variable demands.
This webinar reviews suitable technologies for the retrofitting of lignite PC power plants to lower emissions while raising plant performance. Drying and pre-treatment of the lignite fuel is explored as one route to improved heat rate. Adaptations based upon the existing plant technology include: combustor modification and boiler re-engineering, advanced instruments and controls, anti-fouling systems and steam turbine upgrades. Alternatives to mainstream effluent treatments are discussed, including hybrid and multi-component technologies to lower emission of NOx, SOx, particulates and mercury. Flexible plant options reviewed include energy storage, indirect firing and natural gas integrated co-generation. Latest developments on the introduction of CCUS techniques applied to lignite plants are discussed together with other means to lower plant carbon footprint.

The webinar presents the recent regulatory trends, practices and developments in major coal producing and consuming countries, which are affecting and may influence future demand for coal and coal-fired power generation. As legislative requirements become more demanding and environmental pressures increase, especially with regard to greenhouse gas emissions (GHGs) and climate change, investment in coal fired power-generating facilities is declining rapidly in most developed countries and to a lesser extent in some developing regions of the world, except Asia where forecasts indicate that demand will increase for some time to come. The report explores the implications of further curbs on GHG emissions from coal-fired plants in the most recent and forthcoming national regulations and international agreements. Policy, legislation and pollution reduction strategies are presented as well as future projections of coal utilisation in major coal consuming economies, including those where forecasts indicate that coal will remain a major player in power generation for the estimable future, such as China and India.

Greece’s financial crisis continues to have a major impact on all facets of the country’s economy. In 2015, the financial crisis continued unabated. When significant economic recovery does occur, the energy sector will have a major role to play. The country has a high energy import dependency, which is expensive ‒ reportedly, about ~US$ 20 billion/year. The overall diversification of the energy mix is rather limited. Greece’s main indigenous energy resource is poor quality lignite, used to generate a significant proportion of the country’s electricity. The state-owned energy company Public Power Corporation S.A. (PPC) is the largest lignite producer. More than 93% of Greece’s energy is provided by fossil fuels, (EU average is 75%). In 2014, a new government was elected and energy policy changed direction as earlier plans to privatise parts of the energy sector were curtailed. However, conditions demanded recently by EU and IMF creditors, mean that privatisation schemes may be back on the table. This is likely to encompass natural gas and electricity supply. There has been a renewed focus on the potential of the country’s lignite resources. In order to minimise the cost of imported energy and improve security of energy supply, the present government intends to increase their use, primarily for electricity generation. The webinar examines the situation prevailing in the Greek energy sector, and how this might change in the future. Existing and proposed clean coal-based activities are discussed. However, major uncertainties (in terms of scope and timescale) remain over many aspects of energy production ‒ the nature of, and rate of economic recovery will undoubtedly have major impacts.

The output and efficiency of a coal-fired power station unit fitted with CO2 capture equipment will be significantly lower than that of a similar plant without capture because some of the energy produced by burning the fuel will be needed to operate the added systems. Incorporating an aqueous amine-based CO2 scrubbing system in a simple arrangement could decrease the efficiency by as much as 30% of value. However, work at various research institutes and universities shows that the decrease in performance could be reduced by improved heat integration and other techniques. The webinar reviews these studies.