Natural gas combined cycle plant

Existing capture technologies, however, are not cost-effective when considered in the context of sequestering C02 from power plants. Most power plants and other large point sources use air-fired combustors, a process that exhausts C02 diluted with nitrogen and excess air. Flue gas from coal-fired power plants contains 10%-12% C02 by volume, while flue gas from natural gas combined cycle plants contains only 3%-6% C02. For effective carbon sequestration, the C02 in these exhaust gases must be separated and concentrated. 

The primary source of CO2 is the burning of fossil fuels - specifically gas, oil, and coal - so stabilization of atmospheric CO2 concentration will clearly require substantial reductions in CO2 emissions from these sources. For example, one commonly discussed scenario to stabilize at 500 ppm by the mid-twenty-first century suggests that about 640 Gt CO2 (c. 175 GtC) would need to be avoided over 50 years, with further emission reductions beyond 50 years. As references, a 1000 MW pulverized coal plant produces 6-8MtC02 c. 2MtC) per year, while an oil-fired single-cycle plant produces about two-thirds this amount and a natural gas combined cycle plant produces about half this amount. Thus the above scenario would require that the atmospheric emissions from the equivalent of 2000-4000 large power plants be avoided by approximately the year 2050. 

Suggests favorable capital cost for power conversion system versus natural-gas combined cycle plants... 

A nitrogen Brayton cycle is being considered as an alternative to helium. The major advantage of the nitrogen Brayton cycle is that the turbomachineiy is commercially available—the same as is used by electric utilities in natural-gas combined-cycle plants. However, nitrogen cycles may have slightly lower overall efficiencies. 

It is relatively easy to separate carbon dioxide from water in the anode exhaust stream, thus opening the possibility for carbon sequestration. In a conventional natural gas combined cycle plant, the electrical efficiency drops from 55 to 47-48% if CO2 is captured. The Investment cost also almost doubles due to CO2 capture measures, thus increasing the cost of electricity by about 1 US cent per kWh. The penalty for separating CO2 from SOFC anode gas is far lower (in both investment and electrical efficiency). A CO2 separating SOFC system based on a pressurised SOFC generator combined with a gas turbine is expected to hardly lose any efficiency when CO2 is captured, with the additional advantage that pressurised CO2 becomes available for other applications [34]. 

Table 4. Cost estimates of alternative mitigation technologies in the power generation sector compared to baseline pulverized coal-fired power plant and natural gas Combined Cycle with Gas Turbine (CCGT) power stations and the potential reductions in C02 emissions to 2020 [14]...

Natural gas combined cycle power plants with highest efficiencies (NCCC) and pre-and postcombustion capture of COj. 

Supply side efficiency measures. Here we mean primarily increasing the efficiency of electricity production. Natural gas combined cycle power plants (NGCC) emit less C02 than single-cycle coal-fired power plants first, because natural gas emits about one-half the amount of C02 per fuel heating value than coal, and secondly, because the thermal efficiency of combined-cycle power plants is in the 45-50% range compared with the 35-38% range of single-cycle plants. In the... 

NEI NETPATH NFC NGCC NMR NOx NPP NRA NRC Development Nuclear Energy Institute Interactive code for modelling net geochemical reactions along a flow path Nuclear fuel cycle Natural gas combined cycle Nuclear magnetic resonance NO + N02 Nuclear power plant Nuclear reaction analysis National Research Council... 

Currently, global hydrogen production is 48% from natural gas, 30% from oil, and 18% from coal water electrolysis accounts for only 4%. The distribution of production reflects the effects of thermodynamic constraints on economic choices of the four processes for obtaining hydrogen, partial combustion of natural gas in a natural gas combined cycle power plant offers the most efficient chemical pathway and the greatest off-take of usable heat... 

NGCC/GTCC, Natural gas combined cycle (often termed gas-turbine combined cycle) PC, Pulverized-coal-fired power plant IGCC, Integrated gasification combined cycle, Oxy-fuel (PC boiler) plant. Flue-gas desulfurization and air particulate control is included in the total cost, but not in the separation unit cost. 

For the power production scenario, the hydrogen is co-fired in a turbine at a natural gas combined-cycle (NGCC) plant. Two options were examined ... 

For the ZEPP system presented in Fig. 2.7 the allowable installed costs for the capture plant have been estimated to be in between 80 and 120M for a 1.4GWthermai input natural gas combined cycle (NGCC) plant. To meet the cost targets, an ITM based ZEPP power plant should have an electric efficiency of at least 52%. Capture ratios (carbon captured/carbon fed to the process) of 100% result in plant efficiencies lower than 50%. Capture ratios of the order of 85% are accompanied with plant efficiencies of about 52%. The allowable installed costs window is satisfied when the oxygen flux is at least 20 ml/cm min and the costs of the ITM tubes should be less than 1,500 /m. This clearly sets the targets for materials and turbine development in order for the system to be economically viable within the capture cost boundary conditions. 

Nowadays, natural gas combined cycle (NGCC) power plant represents the most efficient thermodynamic cycle for power production. The modern unit achieves more than 60% of net electrical efficiency. NGCCs have been discussed with pre-combustion and post-combustion capture leading to around 8-10 percentage points of efficiency penalty [70]. 

Electricity Price 0.0977 /kWh Ecoinvent 3, electricity production, natural gas, combined cycle power plant. Comment for electricity produced in steam turbine... 

Total installation costs depends on type of plant and its complexity 80% is a correct figure for power plants with CO2 capture or coal based plant as Integrated Gasification Combined Cycles for Natural Gas Combined Cycles, this coefficient decreases to 68%. 

NETL, 2010. Life Cycle Analysis Natural Gas combined cycle (NGCC) power plant. DOE/NETL-403-110509. www.netl.doe.gov/energy-analyses/pubs/SCPC LCA final.zip, accessed June 2011. 

Improved efficiency, fossil-fuel power generation through the use of ultra-supercritical steam-cycle plants, integrated gasification combined cycle coal plants, and natural gas combined cycle units. 

Natural gas combined cycle (NGCC) Power plant with post-combustion capture... 

Nord LO, Anantharaman R, BoUand O Design and offtdesign analyses of a pre-combustion CO2 capture process in a natural gas combined cycle power plant, Int J Greenh Gas Con 3 385-392, 2009. 

The last phase of phased construction usually means natural gas replacement with coal gas. However, coal gas can also be used in any natural gas or oil-fired power plant, especially in combined-cycle power plants. This capability is important in today s environment of intense competition, low natural gas prices, and high electrical load growth. Because of these factors, most new electric generation capacity project announcements are for natural gas combined-cycle projects. As the natural gas consumption in electric generation increases, natural gas supplies and prices become important long-term issues. Utilities can effectively use coal-derived fuel gas to replace natural gas. 

The air emissions from coal gasification plants u e quite low. In fact, it is possible to design an IGCC power plant whose air emissions are as low as those firom a natural gas combined-cycle power plant. Specific provisions of the Qean Air Act Amendments (CAAA) of 1990 favor coal gasification over direct coal combustion. These provisions include maximum SO2 emissions or "caps" reductions and offsets for SO2/NOX, restriction on trace component hazardous air pollutants, and incentives for coal gasification repowering of existing power plants. 

HG. C-14 Process scheme for an NGCC (natural gas combined cycle) power plant with CO2 capture. (Source Vattenfall Utveckling AB.)... 

Natural gas is the fuel of choice wherever it is available because of its clean burning and its competitive pricing as seen in Figure 1-30. Prices for Uranium, the fuel of nuclear power stations, and coal, the fuel of the steam power plants, have been stable over the years and have been the lowest. Environmental, safety concerns, high initial cost, and the long time from planning to production has hurt the nuclear and steam power industries. Whenever oil or natural gas is the fuel of choice, gas turbines and combined cycle plants are the power plant of choice as they convert the fuel into electricity very... 

Fig. 8.1 shows a diagram of a chemical absorption process described by Chiesa and Consonni [1], for removal of CO2 from the exhaust of a natural gas-fired combined cycle plant (in op>en or semi-closed versions). The process is favoured by low temp>erature which increases the CO2 solubility, and ensures that the gas is free of contaminants which would impair the solvent properties. 

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