A fuel cell is an electrochemical cell that converts the chemical energy of a fuel and an oxidizing agent into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requiring a continuous source of fuel and oxygen to sustain the chemical reaction, whereas in a battery the chemical energy usually comes from substances that are already present in the battery. Fuel cells can produce electricity continuously for as long as fuel and oxygen are supplied.
Syngas, or synthesis gas, is a mixture of hydrogen and carbon monoxide, in various ratios. The gas often contains some carbon dioxide and methane. It is principally used for producing ammonia or methanol. Syngas is combustible and can be used as a fuel. Historically, it has been used as a replacement for gasoline, when gasoline supply has been limited; for example, wood gas was used to power cars in Europe during WWII.
Gasification is a process that converts biomass- or fossil fuel-based carbonaceous materials into gases, including as the largest fractions: nitrogen (N2), carbon monoxide (CO), hydrogen (H2), and carbon dioxide (CO2). This is achieved by reacting the feedstock material at high temperatures (typically >700 °C), without combustion, via controlling the amount of oxygen and/or steam present in the reaction. The resulting gas mixture is called syngas (from synthesis gas) or producer gas and is itself a fuel due to the flammability of the H2 and CO of which the gas is largely composed. Power can be derived from the subsequent combustion of the resultant gas, and is considered to be a source of renewable energy if the gasified compounds were obtained from biomass feedstock.
The alkaline fuel cell (AFC), also known as the Bacon fuel cell after its British inventor, Francis Thomas Bacon, is one of the most developed fuel cell technologies. Alkaline fuel cells consume hydrogen and pure oxygen, to produce potable water, heat, and electricity. They are among the most efficient fuel cells, having the potential to reach 70%.
In industrial chemistry, coal gasification is the process of producing syngas—a mixture consisting primarily of carbon monoxide (CO), hydrogen, carbon dioxide, methane, and water vapour —from coal and water, air and/or oxygen.
A fossil fuel power station is a thermal power station which burns a fossil fuel, such as coal, oil, or natural gas, to produce electricity. Fossil fuel power stations have machinery to convert the heat energy of combustion into mechanical energy, which then operates an electrical generator. The prime mover may be a steam turbine, a gas turbine or, in small plants, a reciprocating gas engine. All plants use the energy extracted from the expansion of a hot gas, either steam or combustion gases. Although different energy conversion methods exist, all thermal power station conversion methods have their efficiency limited by the Carnot efficiency and therefore produce waste heat.
Coal liquefaction is a process of converting coal into liquid hydrocarbons: liquid fuels and petrochemicals. This process is often known as "Coal to X" or "Carbon to X", where X can be many different hydrocarbon-based products. However, the most common process chain is "Coal to Liquid Fuels" (CTL).
Coal pollution mitigation, sometimes labeled as clean coal, is a series of systems and technologies that seek to mitigate health and environmental impact of burning coal for energy. Burning coal releases harmful substances that contribute to air pollution, acid rain, and greenhouse gas emissions. Mitigation includes precombustion approaches, such as cleaning coal, and post combustion approaches, include flue-gas desulfurization, selective catalytic reduction, electrostatic precipitators, and fly ash reduction. These measures aim to reduce coal's impact on human health and the environment.
Underground coal gasification (UCG) is an industrial process which converts coal into product gas. UCG is an in-situ gasification process, carried out in non-mined coal seams using injection of oxidants and steam. The product gas is brought to the surface through production wells drilled from the surface.
An integrated gasification combined cycle (IGCC) is a technology using a high pressure gasifier to turn coal and other carbon based fuels into pressurized gas—synthesis gas (syngas). It can then remove impurities from the syngas prior to the electricity generation cycle. Some of these pollutants, such as sulfur, can be turned into re-usable byproducts through the Claus process. This results in lower emissions of sulfur dioxide, particulates, mercury, and in some cases carbon dioxide. With additional process equipment, a water-gas shift reaction can increase gasification efficiency and reduce carbon monoxide emissions by converting it to carbon dioxide. The resulting carbon dioxide from the shift reaction can be separated, compressed, and stored through sequestration. Excess heat from the primary combustion and syngas fired generation is then passed to a steam cycle, similar to a combined cycle gas turbine. This process results in improved thermodynamic efficiency, compared to conventional pulverized coal combustion.
Hydrogen gas is produced by several industrial methods. Nearly all of the world's current supply of hydrogen is created from fossil fuels. Most hydrogen is gray hydrogen made through steam methane reforming. In this process, hydrogen is produced from a chemical reaction between steam and methane, the main component of natural gas. Producing one tonne of hydrogen through this process emits 6.6–9.3 tonnes of carbon dioxide. When carbon capture and storage is used to remove a large fraction of these emissions, the product is known as blue hydrogen.
Hydrogen technologies are technologies that relate to the production and use of hydrogen as a part hydrogen economy. Hydrogen technologies are applicable for many uses.
Edwardsport Power Station is a 618 MW Integrated gasification combined cycle (IGCC) coal based power plant in Vigo Township, Knox County, near the town of Edwardsport, Indiana. The integrated gasification combined cycle power plant construction started in June 2008 by Duke Energy near the site of an older 160 MW coal-fired electrical power plant, which was decommissioned in 2010.
The milestones for carbon capture and storage show the lack of commercial scale development and implementation of CCS over the years since the first carbon tax was imposed.
Linc Energy was an Australian energy company that specialised in coal-based synthetic fuel production, as well as conventional oil and gas production. It was engaged in development and commercialisation of proprietary underground coal gasification technology. Produced gas was used for production of synthetic fuel through gas-to-liquid technology, and was also used for power generation. The company had its headquarters in Brisbane, Queensland.
AFC Energy PLC is a developer of hydrogen fuel cell technologies which focus on the displacement of diesel generators in stationary and maritime applications. The technology utilises hydrogen fuel for zero emission electricity generation. The company is based in Cranleigh, Surrey, United Kingdom. It is listed on the London Stock Exchange.
The Kemper Project, also called the Kemper County energy facility or Plant Ratcliffe, is a natural gas-fired electrical generating station currently under construction in Kemper County, Mississippi. Mississippi Power, a subsidiary of Southern Company, began construction of the plant in 2010. The initial, coal-fired project was central to President Obama's Climate Plan, as it was to be based on "clean coal" and was being considered for more support from the Congress and the incoming Trump Administration in late 2016. If it had become operational with coal, the Kemper Project would have been a first-of-its-kind electricity plant to employ gasification and carbon capture technologies at this scale.
Hydrogen Energy California (HECA) was a proposed alternative energy hydrogen power project developing with support from the U.S. Department of Energy in Kern County, California which was not approved for construction.
Coal gasification is a process whereby a hydrocarbon feedstock (coal) is converted into gaseous components by applying heat under pressure in the presence of steam. Rather than burning, most of the carbon-containing feedstock is broken apart by chemical reactions that produce "syngas." Syngas is primarily hydrogen and carbon monoxide, but the exact composition can vary. In Integrated Gasification Combined Cycle (IGCC) systems, the syngas is cleaned and burned as fuel in a combustion turbine which then drives an electric generator. Exhaust heat from the combustion turbine is recovered and used to create steam for a steam turbine-generator. The use of these two types of turbines in combination is one reason why gasification-based power systems can achieve high power generation efficiencies. Currently, commercially available gasification-based systems can operate at around 40% efficiencies. Syngas, however, emits more greenhouse gases than natural gas, and almost twice as much carbon as a coal plant. Coal gasification is also water-intensive.
Lower-temperature fuel cell types such as the proton exchange membrane fuel cell, phosphoric acid fuel cell, and alkaline fuel cell require pure hydrogen as fuel, typically produced from external reforming of natural gas. However, fuels cells operating at high temperature such as the solid oxide fuel cell (SOFC) are not poisoned by carbon monoxide and carbon dioxide, and in fact can accept hydrogen, carbon monoxide, carbon dioxide, steam, and methane mixtures as fuel directly, because of their internal shift and reforming capabilities. This opens up the possibility of efficient fuel cell-based power cycles consuming solid fuels such as coal and biomass, the gasification of which results in syngas containing mostly hydrogen, carbon monoxide and methane which can be cleaned and fed directly to the SOFCs without the added cost and complexity of methane reforming, water gas shifting and hydrogen separation operations which would otherwise be needed to isolate pure hydrogen as fuel. A power cycle based on gasification of solid fuel and SOFCs is called an Integrated Gasification Fuel Cell (IGFC) cycle; the IGFC power plant is analogous to an integrated gasification combined cycle power plant, but with the gas turbine power generation unit replaced with a fuel cell power generation unit. By taking advantage of intrinsically high energy efficiency of SOFCs and process integration, exceptionally high power plant efficiencies are possible. Furthermore, SOFCs in the IGFC cycle can be operated so as to isolate a carbon dioxide-rich anodic exhaust stream, allowing efficient carbon capture to address greenhouse gas emissions concerns of coal-based power generation.
