Critical factors in the design,operation and economics of coal gasification plants: The case of the flexible co-production of hydrogen and electricity

Power generation from wind and solar sources is growing in importance, but requires back up from fossil fuel plants, greatly compromising fossil fuel plant economics. This includes the economics of most proposed IGCC–Hypogen type plant schemes which are intended to produce hydrogen and electricity, as well as capturing CO₂. IGCC–Hypogen plants, however, that are able to change the ratio of hydrogen to electricity will be able to operate at maximum capacity all of the time, switching from power generation to hydrogen production as the demand for these two forms of energy changes. Because of the need to provide power to the IGCC–Hypogen ancillaries, some hydrogen from the plant will have to be utilised to supply some of this power. A preliminary economic study examines how the plant could produce electricity and hydrogen at competitive prices.     

Turkey's Renewable Energy Facilities in the Near Future

In this work, renewable energy facilities of Turkey were investigated. Electricity is mainly produced by thermal power plants, consuming coal, lignite, natural gas, fuel oil and geothermal energy, and hydro power plants in Turkey. Turkey has no large oil and gas reserves. The main indigenous energy resources are lignite, hydro and biomass. Turkey has to adopt new, long-term energy strategies to reduce the share of fossil fuels in primary energy consumption. For these reasons, the development and use of renewable energy sources and technologies are increasingly becoming vital for sustainable economic development of Turkey. The most significant developments in renewable production are observed hydropower and geothermal energy production. Renewable electricity facilities mainly include electricity from biomass, hydropower, geothermal, and wind and solar energy sources. Biomass cogeneration is a promising method for production bioelectricity.     

Carbon capture and storage potential in coal-fired plant in Malaysia—A review

Secure, reliable and affordable energy supplies are necessary for sustainable economic growth, but increases in associated carbon dioxide (CO₂) emissions, and the associated risk of climate change are a cause of major concern. Experts have projected that the CO₂ emissions related to the energy sector will increase 130% by 2050 in the absence of new policies or supply constraints as a result of increased fossil fuel usage. To address this issue will require an energy technology revolution involving greater energy efficiency, increased renewable energies and nuclear power, and the near-decarbonisation of fossil fuel-based power generation. Nonetheless, fossil fuel usage is expected to continue to dominate global energy supply. The only technology available to mitigate greenhouse gas (GHG) emissions from large-scale fossil fuel usage is carbon capture and storage (CCS), an essential part of the portfolio of technologies that is needed to achieve deep global emission reductions. However, CCS technology faces numerous issues and challenges before it can be successfully deployed. With Malaysia has recently pledged a 40% carbon reduction by 2020 in the Copenhagen 2009 Climate Summit, CCS technology is seen as a viable option in order to achieve its target. Thus, this paper studies the potential and feasibility of coal-fired power plant with CCS technology in Malaysia which includes the choices of coal plants and types of capture technologies possible for implementation.     

Surface reflectance and conversion efficiency dependence of technologies for mitigating global warming

A means of assessing the relative impact of different renewable energy technologies on global warming has been developed. All power plants emit thermal energy to the atmosphere. Fossil fuel power plants also emit CO₂ which accumulates in the atmosphere and provides an indirect increase in global warming via the greenhouse effect. A fossil fuel power plant may operate for some time before the global warming due to its CO₂ emission exceeds the warming due to its direct heat emission. When a renewable energy power plant is deployed instead of a fossil fuel power plant there may be a significant time delay before the direct global warming effect is less than the combined direct and indirect global warming effect from an equivalent output coal fired plant – the “business as usual” case. Simple expressions are derived to calculate global temperature change as a function of ground reflectance and conversion efficiency for various types of fossil fuelled and renewable energy power plants. These expressions are used to assess the global warming mitigation potential of some proposed Australian renewable energy projects. The application of the expressions is extended to evaluate the deployment in Australia of current and new geo-engineering and carbon sequestration solutions to mitigate global warming. Principal findings are that warming mitigation depends strongly on the solar to electric conversion efficiency of renewable technologies, geo-engineering projects may offer more economic mitigation than renewable energy projects and the mitigation potential of reforestation projects depends strongly on the location of the projects.     

Research and development for steam and gas turbines in low-carbon future

Abstract

Future energy requirements for the UK will need to be met with reduced CO₂ emissions. There is a requirement for 2050 CO₂ emissions to be at 20% of 1990 levels. To achieve this there will need to be considerable investment into the research and development, and construction of renewables technologies. Despite this emphasis on renewable power, fossil fuelled power generation technologies, and in particular turbines, will still have a major role to play in the future. However, the way in which the turbines will be used may change significantly. There will therefore need to be research and development investment for turbines at all levels of technology readiness. The arguments for future R&D investment for steam and gas turbines are reviewed and some directions the R&D may need to take examined.     

Materials problems and solutions in biomass fired plants

Abstract

Owing to Denmark's pledge to reduce carbon dioxide emissions, biomass is being increasingly utilised as a fuel for generating energy. Extensive research and development projects, especially in the area of material performance for biomass fired boilers, have been undertaken to make biomass a viable fuel resource. When straw is combusted, potassium chloride and potassium sulphate are present in ash products, which condense on superheater components. This gives rise to specific chlorine corrosion problems not previously encountered in coal fired power plants. The type of corrosion attack can be directly ascribed to the composition of the deposit and the metal surface temperature. In woodchip boilers, a similar corrosion rate and corrosion mechanism has on some occasions been observed. Cofiring of straw (10 and 20% energy basis) with coal has shown corrosion rates lower than those in straw fired plants. With both 10 and 20% straw, no chlorine corrosion was seen. The present paper will describe the results from in situ investigations undertaken in Denmark on high temperature corrosion in biomass fired plants. Results from 100% straw firing, woodchip and cofiring of straw with fossil fuels are summarised and compared.     

Status of thermal power generation in India—Perspectives on capacity,generation and carbon dioxide emissions

India’s reliance on fossil-fuel based electricity generation has aggravated the problem of high carbon dioxide (CO₂) emissions from combustion of fossil fuels, primarily coal, in the country’s energy sector. The objective of this paper is to analyze thermal power generation in India for a four-year period and determine the net generation from thermal power stations and the total and specific CO₂ emissions. The installed generating capacity, net generation and CO₂ emissions figures for the plants have been compared and large generators, large emitters, fuel types and also plant vintage have been identified. Specific emissions and dates of commissioning of plants have been taken into account for assessing whether specific plants need to be modernized. The focus is to find out areas and stations which are contributing more to the total emissions from all thermal power generating stations in the country and identify the overall trends that are emerging.     

Investigating the need of nuclear power plants for sustainable energy in Iran

Over the decades, the consumption of all types of energy such as electricity increased rapidly in Iran. Therefore, the government decided to redevelop its nuclear program to meet the rising electricity demand and decrease consumption of fossil fuels. In this paper, the effect of this policy in four major aspects of energy sustainability in the country, including energy price, environmental issues, energy demand and energy security have been verified. To investigate the relative cost of electricity generated in each alternative generator, the simple levelized electricity cost was selected as a method. The results show that electricity cost in fossil fuel power plants presumably will be cheaper than nuclear. Although the usage of nuclear reactor to generate power is capable of decreasing hazardous emissions into the environment, there are many other effective policies and technologies that can be implemented. Energy demand growth in the country is very high; neither nuclear nor fossil fuel cannot currently cope with the growth. So, the only solution is rationalizing energy demand by price amendment and encouraging energy efficiency. The major threats of energy security in Iran are high energy consumption growth and economic dependency on crude oil export. Though nuclear energy including its fuel cycle is Iran's assured right, constructing more nuclear power plants will not resolve the energy sustainability problems. In fact, it may be the catalyst for deterioration since it will divert capital and other finite resources from top priority and economic projects such as energy efficiency, high technology development and energy resources management.     

Fuel price and technological uncertainty in a real options model for electricity planning

Electricity generation is an important source of total CO₂ emissions, which in turn have been found to relate to an acceleration of global warming. Given that many OECD countries have to replace substantial portions of their electricity-generating capacity over the next 10–20 years, investment decisions today will determine the CO₂-intensity of the future energy mix. But by what type of power plants will old (mostly fossil-fuel-fired) capacity be replaced? Given that modern, less carbon-intensive technologies are still expensive but can be expected to undergo improvements due to technical change in the near future, they may become more attractive, especially if fossil fuel price volatility makes traditional technologies more risky. At the same time, technological progress is an inherently uncertain process itself. In this paper, we use a real options model with stochastic technical change and stochastic fossil fuel prices in order to investigate their impact on replacement investment decisions in the electricity sector. We find that the uncertainty associated with the technological progress of renewable energy technologies leads to a postponement of investment. Even the simultaneous inclusion of stochastic fossil fuel prices in the same model does not make renewable energy competitive compared to fossil-fuel-fired technology in the short run based on the data used. This implies that policymakers have to intervene if renewable energy is supposed to get diffused more quickly. Otherwise, old fossil-fuel-fired equipment will be refurbished or replaced by fossil-fuel-fired capacity again, which enforces the lock-in of the current system into unsustainable electricity generation.     

Keep that fire burning: Fuel supply risk management strategies of Swedish district heating plants and implications for energy security

Recent decades have seen a strong increase in bioenergy utilization in Sweden, from 52 TWh in 1983 to 128 TWh in 2013. Much of this increase has been achieved by replacing fossil fuels with different forms of bioenergy in district heating. Increased use of bioenergy is generally seen as key to reducing fossil fuel consumption and greenhouse gas emissions and improving energy security.However, replacing fossil fuels with solid biomass fuels in stationary heat and power generation entails significantly more complicated fuel supply logistics, with geographically scattered material associated with storage difficulties and low energy density. Given these risks and challenges and the key role of biomass-based district heating in the Swedish energy system, disturbances in fuel supply to district heating could potentially be an energy security issue.Through literature studies and interviews with employees at 18 district heating plants, we mapped present and future risks and risk management strategies in district heating supply in the Mälardalen region, south-east Sweden. We found that although small disturbances to fuel supply are not uncommon, the likelihood of heat supply failures due to fuel supply problems is low. Risk awareness is generally high among fuel supply managers, with widespread use of multilevel redundancies and diversification as key risk management strategies. However, fuel supply to plants is highly dependent on functioning truck transport and, consequently, availability of diesel fuel for trucks. Risk management can be strengthened further by implementation of forward-looking risk assessments that are less reliant on past experiences.     

Assessment of forest biomass for use as energy. GIS-based analysis of geographical availability and locations of wood-fired power plants in Portugal

Following the European Union strategy concerning renewable energy (RE), Portugal established in their national policy programmes that the production of electrical energy from RE should reach 45% of the total supply by 2010. Since Portugal has large forest biomass resources, a significant part of this energy will be obtained from this source. In addition to the two existing electric power plants, with 22 MW of power capacity, 13 new power plants having a total of 86.4 MW capacity are in construction. Together these could generate a combination of electrical and thermal energy, known as combined heat and power (CHP) production. As these power plants will significantly increase the exploitation of forests resources, this article evaluates the potential quantities of available forest biomass residue for that purpose. In addition to examining the feasibility of producing both types of energy, we also examine the potential for producing only electric energy. Results show that if only electricity is generated some regions will need to have alternative fuel sources to fulfil the demand. However, if cogeneration is implemented the wood fuel resource will be sufficient to fulfill the required capacity demand.     

A comparative study among fossil fuel power plants in PJM and California ISO by DEA environmental assessment

This study compares among fossil fuel power plants in PJM and California ISO by their unified (operational and environmental) performance. DEA (Data Envelopment Analysis) is used as a methodology. For comparative analysis, DEA incorporates strategic concepts such as natural and managerial disposability into the computational process. This study explores both how to measure Returns to Scale (RTS) under natural disposability and how to measure Damages to Scale (DTS) under managerial disposability. This empirical study obtains two implications on US energy policy. One of the two policy implications is that California ISO outperforms PJM in terms of the three unified efficiency measures. The result implies that strict regulation on undesirable outputs, as found in California, is important in enhancing the performance of US fossil fuel power plants. Thus, it is necessary for federal and local governments to regulate the fossil fuel power plants under the strict implementation of environmental protection. Under such a policy direction, it is possible for US fossil fuel power plants to attain economic prosperity (by enhancing their operational efficiencies) and to satisfy environmental regulation (by enhancing their environmental efficiencies). The other policy implication is that coal-fired and gas-fired power plants in PJM and California ISO need to reduce their operational sizes or introduce technology innovation on desirable and undesirable outputs and/or new management for environmental protection within their operations. Meanwhile, oil-fired power plants may increase their operational sizes if they can introduce technology innovation and new management on undesirable outputs.     

Solar energy with chemical storage for cogeneration of electric power and heat

U.S.A. energy use by the year 2000 is estimated to be 116–130 quads, compared to 82 quads for 1978. Solar energy, utilized both at the individual residence-building level plus power plant level, along with all other conventional and new energy sources, will be needed to meet future energy demand. In order to make maximum utilization of energy sources to meet national energy-conservation and energy-economic policy, a power plant of the future must cogenerate electrical energy and heat medium, whether it burns fossil fuel or uses solar energy.A solar energy Central Receiver-AHS Chemical Storage cogeneration power plant can be configured to give complete flexibility for day-night and seasonal load combinations, with work efficiencies up to 46 per cent. Such a plant, as a stand-alone or network station, is a real possibility in the not too distant future. Electrical energy and heat medium produced therefrom will be competitive with fossil fuel powered generating plants.A 100 MWe Central Receiver-AHS Cycle cogeneration power plant is discussed in detail; cycle analysis, preliminary cost estimates, and unit energy costs are discussed.     

Reducing cycling costs in coal fired power plants through power to hydrogen

The increase of renewable share in the energy generation mix makes necessary to increase the flexibility of the electricity market. Thus, fossil fuel thermal power plants have to adapt their electricity production to compensate these fluctuations. Operation at partial load means a significant loss of efficiency and important reduction of incomes from electricity sales in the fossil power plant. Among the energy storage technologies proposed to overcome these problems, Power to Gas (PtG) allows for the massive storage of surplus electricity in form of hydrogen or synthetic natural gas. In this work, the integration of a Power to Gas system (50 MWe) with fossil fuel thermal power plants (500 MWe) is proposed to reduce the minimum complaint load and avoid shutdowns. This concept allows a continuous operation of power plants during periods with low demand, avoiding the penalty cost of shutdown. The operation of the hybrid system has been modelled to calculate efficiencies, hydrogen and electricity production as a function of the load of the fossil fuel power plant. Results show that the utilisation of PtG diminishes the specific cost of producing electricity between a 20% and 50%, depending on the framework considered (hot, warm and cold start-up). The main contribution is the reduction of the shutdown penalties rather than the incomes from the sale of the hydrogen. At the light of the obtained results, the hybrid system may be implemented to increase the cost-effectiveness of existing fossil fuel power plants while adapting the energy mix to high shares of variable renewable electricity sources.     

Oxyfuel concept development

Abstract

The reduction of greenhouse gas emissions and replacement of fossil fuels by renewable energy sources are important national and international targets. Oxyfuel (oxygen combustion technology) is one of the most promising technologies enabling carbon capture and storage from flue gases. The aim of oxyfuel concept development is to study different oxygen production technologies, combustion processes, CO₂ capture methods and integrate those to optimised concept. The goal is to create technical readiness for demonstration of oxygen combustion by using state of the art knowledge, experiments, modelling and simulation. Demonstration plan for oxygen combustion for an existing power plant(s) in Finland will be prepared. Main results will be an evaluation of oxygen combustion business potential for implementation in existing and new power plants, and improvement of competitiveness of Finnish companies in energy sector by developing CO₂ free power production technologies.

Before oxygen combustion can be demonstrated in full scale, small scale testing and model development must be done. Material exposure conditions in oxygen combustion will differ from any present day environment. Current high temperature steel grades have not been developed or tested for such aggressive conditions. VTT (Technical Research Centre of Finland) has in Jyväskylä unique small scale combustors applicable for oxygen combustion research.     

Technical efficiency and CO2 reduction potentials — An analysis of the German electricity and heat generating sector

In this paper, we analyze the technical efficiency and CO₂ reduction potentials of German power and heat plants, using a non-parametric sequential Data Envelopment Analysis. We apply a metafrontier framework to evaluate plant-level efficiency in the transformation of inputs into desirable (energy) and undesirable (CO₂ emissions) outputs, taking into account different fossil fuel generation technologies. We use a unique data set of coal-, lignite-, gas- and biomass-fired power plants from 2003 through 2010 that provides an unbalanced panel of 1459 observations; the results are also checked against a balanced panel with a smaller number of observations. Although we find intra-group differences within energy generation technology, natural gas fired power plants clearly have the highest efficiency. Furthermore, the analysis points to significant savings potentials for CO₂ and fuel-input, and derives policy conclusions for the ongoing electricity sector reformation.     

Pathways to a more sustainable production of energy: sustainable hydrogen—a research objective for Shell

Towards a sustainable energy supply is a clear direction for exploratory research in Shell. Examples of energy carriers, which should be delivered to the envisaged sustainable energy markets, are bio-fuels, produced from biomass residues, and hydrogen (or electricity), produced from renewable sources. In contrast to the readily available ancient sunlight stored in fossil fuels, the harvesting of incident sunlight will be intermittent, efficient electricity and hydrogen storage technologies need to be developed. Research to develop those energy chains is going on, but the actual transformation from current fossil fuel based to sustainable energy markets will take a considerable time. In the meantime the fossil fuel based energy markets have to be transformed to mitigate the impact of the use of fossil fuels. Some elements in this transformation are fuels for ultra-clean combustion (hydrocarbons and oxygenates), hydrogen from fossil fuels, fuels for processors for fuel cells, carbon sequestration.     

Use of the castner reaction for hydrogen fuel production

Abstract

The predicted increase in global temperatures requires that greenhouse gas emissions, especially carbon dioxide, are reduced. This may necessitate the development of alternative methods to produce fuel for electricity generation and transport. Adaptation of the Castner process provides a method by which hydrogen can be generated in industrial quantities from all forms of fossil and other carbon based fuels from any source, i.e. natural, biomass and waste. The amount of carbon dioxide produced by this method is less than that presently generated by fossil fuel burning power stations. Also, the carbon dioxide produced is in a form suitable for capture and disposal by the Weldon process. The component processes of the Castner–Weldon cycle for hydrogen generation and CO₂ capture are well established, despite the fact that these processes have not been in use for about 100 years. The Castner–Weldon process can be operated in the UK from materials available within the UK and is sustainable as long as any form of carbon based fuel is available. Initially development of this method only requires information concerning the efficiency and cost compared to existing methods. The costs involved for this stage are unlikely to exceed £1 000 000. It is envisaged that most of the present coal fired power stations would not have to be rebuilt immediately but merely adapted, thus reducing the cost of conversion to hydrogen use. The cost of conversion cannot be in excess of the present construction cost of these power stations at £0.5 billion and is considerably less than the construction cost of equivalent nuclear power station at £1.5 billion.     

Solar aided power generation of a 300 MW lignite fired power plant combined with line-focus parabolic trough collectors field

Nowadays, conventional coal or gas fired power plants are the dominant way to generate electricity in the world. In recent years there is a growth in the field of renewable energy sources in order to avoid the threat of climate change from fossil fuel combustion. Solar energy, as an environmental friendly energy source, may be the answer to the reduction of global CO₂ emissions. This paper presents the concept of Solar Aided Power Generation (SAPG), a combination of renewable and conventional energy sources technologies. The operation of the 300 MW lignite fired power plant of Ptolemais integrated with a solar field of parabolic trough collectors was simulated using TRNSYS software in both power boosting and fuel saving modes. The power plant performance, power output variation, fuel consumption and CO₂ emissions were calculated. Furthermore, an economic analysis was carried out for both power boosting and fuel saving modes of operation and optimum solar contribution was estimated.     

Use of waste for heat,electricity and transport—Challenges when performing energy system analysis

This paper presents a comparative energy system analysis of different technologies utilising organic waste for heat and power production as well as fuel for transport. Technologies included in the analysis are second-generation biofuel production, gasification, fermentation (biogas production) and improved incineration. It is argued that energy technologies should be assessed together with the energy systems of which they form part and influence. The energy system analysis is performed by use of the EnergyPLAN model, which simulates the Danish energy system hour by hour. The analysis shows that most fossil fuel is saved by gasifying the organic waste and using the syngas for combined heat and power production. On the other hand, least greenhouse gases are emitted if biogas is produced from organic waste and used for combined heat and power production; assuming that the use of organic waste for biogas production facilitates the use of manure for biogas production. The technology which provides the cheapest CO₂ reduction is gasification of waste with the subsequent conversion of gas into transport fuel.