Economic analysis of power generation from floating solar chimney power plant

Solar chimney thermal power technology that has a long life span is a promising large-scale solar power generating technology. This paper performs economic analysis of power generation from floating solar chimney power plant (FSCPP) by analyzing cash flows during the whole service period of a 100 MW plant. Cash flows are influenced by many factors including investment, operation and maintenance cost, life span, payback period, inflation rate, minimum attractive rate of return, non-returnable subsidy rate, interest rate of loans, sale price of electricity, income tax rate and whether additional revenue generated by carbon credits is included or not. Financial incentives and additional revenue generated by carbon credits can accelerate the development of the FSCPP. Sensitivity analysis to examine the effects of the factors on cash flows of a 100 MW FSCPP is performed in detail. The results show that the minimum price for obtaining minimum attractive rate of return (MARR) of 8% reaches 0.83 yuan (kWh)^?1 under financial incentives including loans at a low interest rate of 2% and free income tax. Comparisons of economics of the FSCPP and reinforced concrete solar chimney power plant or solar photovoltaic plant are also performed by analyzing their cash flows. It is concluded that FSCPP is in reality more economical than reinforced concrete solar chimney power plant (RCSCPP) or solar photovoltaic plant (SPVP) with the same power capacity.     

Economic implications of thermal energy storage for concentrated solar thermal power

Solar energy is an attractive renewable energy source because the sun's energy is plentiful and carbon-free. However, solar energy is intermittent and not suitable for base load electricity generation without an energy backup system. Concentrated solar power (CSP) is unique among other renewable energy options because it can approach base load generation with molten salt thermal energy storage (TES). This paper describes the development of an engineering economic model that directly compares the performance, cost, and profit of a 110-MW parabolic trough CSP plant operating with a TES system, natural gas-fired backup system, and no backup system. Model results are presented for 0–12 h backup capacities with and without current U.S. subsidies. TES increased the annual capacity factor from around 30% with no backup to up to 55% with 12 h of storage when the solar field area was selected to provide the lowest levelized cost of energy (LCOE). Using TES instead of a natural gas-fired heat transfer fluid heater (NG) increased total plant capital costs but decreased annual operation and maintenance costs. These three effects led to an increase in the LCOE for PT plants with TES and NG backup compared with no backup. LCOE increased with increasing backup capacity for plants with TES and NG backup. For small backup capacities (1–4 h), plants with TES had slightly lower LCOE values than plants with NG backup. For larger backup capacities (5–12 h), plants with TES had slightly higher LCOE values than plants with NG backup. At these costs, current U.S. federal tax incentives were not sufficient to make PT profitable in a market with variable electricity pricing. Current U.S. incentives combined with a fixed electricity price of $200/MWh made PT plants with larger backup capacities more profitable than PT plants with no backup or with smaller backup capacities. In the absence of incentives, a carbon price of $100–$160/tonne CO_2eq would be required for these PT plants to compete with new coal-fired power plants in the U.S. If the long-term goal is to increase renewable base load electricity generation, additional incentives are needed to encourage new CSP plants to use thermal energy storage in the U.S.     

Viability of a concentrated solar power system in a low sun belt prefecture

Concentrating solar power (CSP) is considered as a comparatively economical, more efficient, and large capacity type of renewable energy technology. However, CSP generation is found restricted only to high solar radiation belt and installed where high direct normal irradiance is available. This paper examines the viability of the adoption of the CSP system in a low sun belt region with a lower direct normal irradiance (DNI). Various critical analyses and plant economics have been evaluated with a lesser DNI state. The obtained results out of the designed system, subjected to low DNI are not found below par, but comparable to some extent with the performance results of such CSP plants at a higher DNI. The analysis indicates that incorporation of the thermal energy storage reduces the levelized cost of energy (LCOE) and augments the plant capacity factor. The capacity factor, the plant efficiency, and the LCOE are found to be 32.50%, 17.56%, and 0.1952 $/kWh, respectively.     

Solar multiple optimization for a solar-only thermal power plant, using oil as heat transfer fluid in the parabolic trough collectors

Usual size of parabolic trough solar thermal plants being built at present is approximately 50 MW_e. Most of these plants do not have a thermal storage system for maintaining the power block performance at nominal conditions during long non-insolation periods. Because of that, a proper solar field size, with respect to the electric nominal power, is a fundamental choice. A too large field will be partially useless under high solar irradiance values whereas a small field will mainly make the power block to work at part-load conditions.This paper presents an economic optimization of the solar multiple for a solar-only parabolic trough plant, using neither hybridization nor thermal storage. Five parabolic trough plants have been considered, with the same parameters in the power block but different solar field sizes. Thermal performance for each solar power plant has been featured, both at nominal and part-load conditions. This characterization has been applied to perform a simulation in order to calculate the annual electricity produced by each of these plants. Once annual electric energy generation is known, levelized cost of energy (LCOE) for each plant is calculated, yielding a minimum LCOE value for a certain solar multiple value within the range considered.     

Preliminary feasibility evaluation of solar thermal power generation in India

Results of a preliminary techno-economic appraisal of solar thermal power generation at three locations in India are presented. The study uses System Advisor Model developed by NREL, USA. The results of the study provide useful insight into (a) selecting appropriate reference direct normal irradiance for design of solar thermal power plants, (b) identifying suitable combinations of solar multiple and hours of thermal energy storage and (c) cost reduction potential. The parabolic trough technology is used for exemplifying the procedure for this purpose. The estimated levelised unit cost of electricity is in the range of Rs (US$1=Indian rupees 51.66 on 5 October 2012) 16–21 per kWh for the most likely range of input parameters. The results also indicate possibility of about 30% reduction in unit cost of electricity by year 2021.     

Energy conservation through industrial cogeneration

Combined generation of process steam and electric power in coal-fired industrial power plants is examined, and a rate of return on various investments of this type is estimated. The effect on these rates of return of a 20% investment tax credit is calculated, which appears to be slight. We note that positive incentives such as investment tax credits allow the firm to face lower energy prices and could result in more energy intensive operation at the level of the firm.     

The effects of federal energy tax credit on the solar thermal industry and government revenue

This study shows the impact of the federal energy tax credit (ETC) on the solar thermal industry and on government revenue. The analysis examines investment in solar thermal technologies by limited partnerships. The potential for investment is determined by calculating the investment internal rate of return assuming a 30-year system life. Several scenarios are considered, including state tax credits at both 25 and 0% levels and coverage ratios of 1.2 and 1.4. This analysis indicates that private investment without federal incentives during the early stages of industry development is highly unlikely. Extension of the energy tax credit beyond 1985 is one means to establish a viable solar thermal electric industry before the year 2000. However, as the industry matures, the tax credit can be reduced while federal receipts will increase.     

Thermal-economic analysis of heat-matched industrial cogeneration systems

Recent federal incentives in the U.S. concerning tax credits, fuel-use exemptions, and facilitation of sale of electric power to local electric utilities have greatly stimulated interest in industrial cogeneration. In particular, the ability to sell excess or all cogenerated electric power (i.e. arbitrage) has widened the options available to a potential cogenerator. In the present paper we consider a comparison of alternate cogeneration plants with an existing steam-only plant in terms of energy conservation and engineering economics. The concept of marginal cost of production is applied throughout. The criterion of economic selection is acceptable incremental rate of return on incremental investment based on the challenger-defender test of successively greater capital costs. As an example, coal-fired topping steam turbines as well as natural-gas-fired gas turbines and oil-fired diesels with waste-heat boilers are considered to replace a gas-fired steam-only plant and provide a range of electric power for the same thermal load.     

Solar power generation in the US: Too expensive,or a bargain?

This article identifies the combined value that solar electric power plants deliver to utilities' rate payers and society's tax payers. Benefits that are relevant to utilities and their rate payers include traditional, measures of energy and capacity. Benefits that are tangible to tax payers include environmental, fuel price mitigation, outage risk protection, and long-term economic growth components. Results for the state of New York suggest that solar electric installations deliver between 15 and 40 ¢/kWh to ratepayers and tax payers. These results provide economic justification for the existence of payment structures (often referred to as incentives) that transfer value from those who benefit from solar electric generation to those who invest in solar electric generation.     

Optimisation of hybrid cane-based combined heat and power-concentrating solar thermal power plants of 30 MW

The benchmarking and optimal power extraction from a cane-based combined heat and power (CHP) plant using state-of-the-art processes has been underestimated. This study indicates that the export power potential can be much more than the presently achieved values of 5.8–7.0 MW/1000 tcd (tonnes crushing per day). It can be 11–12 MW/1000 tcd. By integration of cane-based CHP with concentrating solar thermal (CST) – parabolic trough concentrators (PTC) systems of even size, the heat rate (power only) can be decreased from 2984.12 to 2088.89 kcal/kWh and the overall efficiency (power +heat) of 48.59% can be enhanced to 69.41%. The CHP potential of sugar mills will be considerable enhanced to 12 MW/1000 tcd by four elements: (a) integration with solar-concentrating collectors, (b) the use of high-efficiency, high-pressure boilers (>11.0 MPa and 560°C), (c) three-dimensional designed stage optimised steam turbines with high isentropic efficiencies of 92–94+% and (d) minimising in-house steam demand to below 225 kg/t of cane (=9.37 t/h per 1000 tcd) and in-house electric demand to below 22 kWh/t of cane (=0.91 MW/1000 tcd). Auxiliary power must be below 8% of the power export. Matching policy incentives will help in new initiatives and quick take off of new projects. The estimated potential for India for cane-based CHP is around 7 GW without solar systems and is 10 GW for hybrid CST–PTC cane-based systems. This is a zero fossil fuel-consuming technology.     

槽式太阳能热发电在浑善达克沙地的应用可行性分析

使用太阳能发电模拟软件SAM3.0.3.0对在浑善达克沙地建造50MW槽式太阳能热发电站进行可行性分析。对该热电站在不同系统组合条件下的运行状况进行模拟。分析了太阳能辐射强度、地理位置、蓄热设备容量、冷却方式和辅助能源等因素对该类型电站经济性的影响。模拟结果表明:在浑善达克沙地建立50MW槽式热发电站(6h蓄热,水冷,天然气辅助热源)的上网电价可达到0.727$/kWh,另外,单位集热面积每年可减排CO2307kg。     

A theoretical study of molten carbonate fuel cell combined with a solar power plant and Cu–Cl thermochemical cycle based on techno-economic analysis

A novel power and hydrogen coproduction system is designed and analyzed from energetic and economic point of view. Power is simultaneously produced from parabolic trough collector power plant and molten carbonate fuel cell whereas hydrogen is generated in a three-steps Cu–Cl thermochemical cycle. The key component of the system is the molten carbonate fuel cell that provides heat to others (Cu–Cl thermochemical cycle and steam accumulator). A mathematic model is developed for energetic and economic analyses. A parametric study is performed to assess the impact of some parameters on the system performance. From calculations, it is deduced that electric energy from fuel cell, solar plant and output hydrogen mass are respectively 578 GWh, 25 GWh and 306 tons. The overall energy efficiency of the proposed plants is 46.80 % and its LCOE is 7.64 c€/kWh. The use of MCFC waste heat allows increasing the solar power plant efficiency by 2.15 % and reducing the annual hydrogen consumption by 3 %. Parametric analysis shows that the amount of heat recovery impacts the energy efficiency of fuel cell and Cu–Cl cycle. Also, current density is a key parameter that influences the system efficiency.     

新能源项目LCOE度电成本与IRR内部收益率的等效性分析

[目的]随着国内新能源发电行业的发展,补贴退坡和资源竞争配置等政策的实施,全生命周期平准化发电成本(LCOE)越来越被大家关注和使用,但行业内对LCOE的计算标准不一,文章主要为了解析其与内部收益率(IRR)的关系,来提高大家对LCOE度电的认识以及规范LCOE度电成本的使用。[方法]文章先对两者的特点和应用场景做了分析,然后通过两者计算公式的简化和转换,分析固定IRR反算电价和LCOE度电成本在模型上的差异和联系。最后通过某海上风电的实例分析,计算两者结果的实际差距,并分析造成这些差异的因素及敏感性。[结果]从结果来看,简化条件后两者的计算模型十分接近,两者差异仅为所得税。通过实例分析,造成IRR反算电价和LCOE度电成本差异的因素有建设期增值税抵扣、增值税和所得税的税后优惠、附加税、融资情况,且这些因素的影响方向和程度都不同。可以认为,IRR内部收益率反算电价与LCOE度电成本在原理上是近似的,但受到国内财税制度的影响,输入参数、边界条件的增加使得两者出现了差异。[结论]建议通过主管部门、行业协会等对LCOE进行适当的本地化修正,并结合环境影响成本和电力系统影响成本,使其可以横向比...     

Alternative energy development in the USA The effectiveness of state government incentives

This paper presents a rationale for government incentives to alternative energy development in the USA. The effectiveness of the major incentives now in use by state governments is tested empirically by using active solar residential hot water installations data for the USA. The results suggest that state income tax credits and increases in conventional fuel (ie natural gas) prices through taxation or other means appear to be having the expected effect of increasing the number of solar collectors installed. From these data, property tax exemptions do not appear to be effective in promoting alternative energy development. The data on sales tax exemptions and grant or loan programmes are inconclusive. Untested incentives, including direct regulation, and saved-energy and non-targeted incentives, provide opportunities for further research.     

Assessment and prospects for energy resources in kuwait

Kuwait's only resources of primary energy are oil and natural gas. The country produces 1 million barrels of oil per day of which 15% are used locally. The surplus of oil is exported. Due to rapid development, the per capita consumption of electricity increased from 1473 kWh in 1960 to 9255 kWh in 1985. If this situation continues, Kuwait will be forced either to increase oil production or reduce exports. Reduction of exports will affect the standard of living in Kuwait. We assess the energy in Kuwait and discuss other alternative resources that are available, e.g., nuclear, wind, and solar energy. We also introduce the concept of coupling a large solar pond to a 150 MWe power plant as a measure to reduce dependence on oil. A detailed economic analysis is carried out comparing hybrid, conventional, and ORC engine power plants.     

Thermo-economic analysis of a direct supercritical CO2 electric power generation system using geothermal heat

A comprehensive thermo-economic model combining a geothermal heat mining system and a direct supercritical CO₂ turbine expansion electric power generation system was proposed in this paper. Assisted by this integrated model, thermo-economic and optimization analyses for the key design parameters of the whole system including the geothermal well pattern and operational conditions were performed to obtain a minimal levelized cost of electricity (LCOE). Specifically, in geothermal heat extraction simulation, an integrated wellbore-reservoir system model (T2Well/ECO2N) was used to generate a database for creating a fast, predictive, and compatible geothermal heat mining model by employing a response surface methodology. A parametric study was conducted to demonstrate the impact of turbine discharge pressure, injection and production well distance, CO₂ injection flowrate, CO₂ injection temperature, and monitored production well bottom pressure on LCOE, system thermal efficiency, and capital cost. It was found that for a 100 MW_e power plant, a minimal LCOE of $0.177/kWh was achieved for a 20-year steady operation without considering CO₂ sequestration credit. In addition, when CO₂ sequestration credit is $1.00/t, an LCOE breakeven point compared to a conventional geothermal power plant is achieved and a breakpoint for generating electric power generation at no cost was achieved for a sequestration credit of $2.05/t.     

Modelling of solar/diesel/battery hybrid power systems for far-north Cameroon

Solar/diesel/battery hybrid power systems have been modelled for the electrification of typical rural households and schools in remote areas of the far north province of Cameroon. The hourly solar radiation received by latitude-titled and south-facing modules was computed from hourly global horizontal solar radiation of Garoua using Hay's anisotropic model. Using the solar radiation computed for latitude-tilted and south-facing modules, the average daytime temperatures for Garoua and parameters of selected solar modules, the monthly energy production of the solar modules was computed. It was found that BP solar modules with rated power in the range 50–180 Wp produced energy in the range 78.5–315.2 kWh/yr. The energy produced by the solar modules was used to model solar/diesel/battery hybrid power systems that could meet the energy demand of typical rural households in the range 70–300 kWh/yr. It was also found that a solar/diesel/battery hybrid power system comprising a 1440 Wp solar array and a 5 kW single-phase generator operating at a load factor of 70%, required only 136 generator h/yr to supply 2585 kWh/yr or 7 kWh/day to a typical secondary school. The renewable energy fraction obtained in all the systems evaluated was in the range 83–100%. These results show that there is a possibility to increase the access rate to electricity in the far north province without recourse to grid extension or more thermal plants in the northern grid or more independent diesel plants supplying power to remote areas of the province.     

Summary of the Closing Session

Plausible costs of photovoltaic power plants of concentration are presented. Costs are based as much as possible on the recent experience of solar thermal plants. Efficiencies, on the existing world experience of PV power plants. The result is that the costs of concentrating photovoltaic plants should be of 0.08 ECUs/ kWh, about 1/3 of that of flat module plants, and of the same order of magnitude, even lower, than those attributed to solar thermal plants of present technology.

For the future, high concentration systems based on Si or tandem cells seem to be the most promising, also in the range of costs of the advanced solar thermal plants.     

Effect of financial and fiscal incentives on the effective capital cost of solar energy technologies to the user

Development and dissemination of solar energy technologies in India has been aided by a variety of policy and support measures. One of the promotional measures is the provision of financial and fiscal incentives such as capital subsidy, low interest loan and accelerated depreciation related income tax benefits to the users on the purchase of solar energy technologies. In this study an attempt has been made to determine the effective capital cost of solar energy technologies to the user with the provision of financial and/or fiscal incentives. Results of exemplifying calculations for a domestic and an industrial solar water heating system, a solar home lighting system and a solar drying system have been presented and discussed.