MWh Of Electricity Research Articles

The use of photovoltaics and electric vehicles for electricity peak shaving in office buildings

The use of electric vehicles and photovoltaics is perceived as a viable option to reduce the human impact on the natural environment. This paper investigates the opportunity of managing a fleet of EVs along with PV installation in such a manner that shaves the peak load in an office building. The simulation used hourly load data representative for a small office building located in Cracow (Poland). For the same location hourly irradiation data was obtained. A deterministic model was created and implemented in MS Excel software. The study showed that 30 kW installed capacity in photovoltaics can reduce the observed peak load by 36% (from 19.8 kW to 14.52 kW) in a building consuming on an annual basis 54.7 MWh of electricity. Additionally, an appropriate management of the charging process of electric vehicles can increase the energy from photovoltaics self-consumption and level the observed energy demand in normal office building operating hours.

Material-flow analysis, energy analysis, and partial environmental-LCA of a district-heating combined heat and power plant in Sweden

Combined heat and power (CHP) plants are a great improvement over waste-to-energy incineration plants supplying only heat, and power plants supplying only electricity. The primary purpose of a functioning CHP plant however, may be to provide district heating services, and thereby its main output will be heat energy. This paper is a case study commissioned by Karlskoga Energi och Miljö AB (KEMAB in short; Karlskoga Energy and Environment) in the Värmland State of south-central Sweden, and focuses on the functioning of the CHP plant owned and operated by the company. The life-cycles of the fuels used by the CHP – household/industrial waste, bio-oil, light fuel oil, wood waste, wood chips, a slaughterhouse-waste-derived product and peat to generate 202,222 MWh of heat, 119,234 MWh of steam and 28,220 MWh of electricity have been studied, and the carbon footprint calculated for year-2016. Using two sets of emissions factors for the combustion stage of the life-cycle, as part of a data uncertainty analysis, the total emissions were 44,000 tonnes carbon dioxide equivalents (CO2-eq) and 58,000 tonnes CO2-eq respectively. A quasi-realistic scenario analysis in which plastics are not available for incineration and have to be substituted with alternatives has also been carried out, and while wood waste has been suggested as the best alternative with regard to greenhouse gas (GHG) emissions, availability permitting, a combination of alternatives has been mooted as the practical option.

The Effect of Feeding Frequency and Organic Loading Rate on the Anaerobic Digestion of Chinese Rice Straw

Abstract China produces over 200 tonnes of rice straw (RS) a year. This is an underutilized energy source that is often burned in the fields causing pollution and health problems for populations near and far. Anaerobic digestion (AD) can produce methane (CH 4 ) rich biogas (45-55%) from waste RS as an alternative to burning whilst being affordable. Five 2L reactors were used to test the effect of feeding frequency (FF) and organic loading rates (OLR) on the anaerobic digestion of rice straw with input rates of between 5 feeds per week and one feed every 3 weeks. Two OLRs were used: 1gVS/L/d (OLR1) for 56 days and 2gVS/L/d (OLR2) for 83 days. At the lower OLR1, the best average biogas yield was 300 ml/L of reactor/d at 50% CH 4 and at OLR2 the best reactor achieved a mean biogas yield of 447 ml/L/d at 52%CH 4 . The best performing FF at OLR1 was 1/21 day whilst at OLR2 the 5/7 day FF produced the highest volume and quality of biogas. Results confirm that biogas from rice straw anaerobic digestion could be used with combined heat and power (CHP) technology to potentially produce 0.5-0.8MWh of electricity per day per tonne of rice straw.

Environmental costs resulting from the use of hard coal to electricity generation in Poland

In the world's fuel mix used for generating electricity, the most common fossil fuel is coal. In the EU, coal combustion and electricity generation entail the need to purchase emission allowances (EUA) whose purchase costs affect the costs of electricity generation significantly. The research described in the article shows how current market conditions shape the profitability of generating electricity from coal and how Clean Dark Spread (CDS) changes as a function of changes in energy and coal prices at the assumed levels of emission and prices of EUA allowances. The article compares the results of CDS calculations in two variants. Areas have been highlighted where prices of both coal and EUA allowances cause CDS to assume values at which the prices of generated electricity do not cover the costs of fuel (i) and CO2 emission allowances, cover all costs (ii), or constitute positive prices (iii), but still do not cover all fixed costs. With higher power plant efficiency, CO2 emissions are lower (0.722 t/MWh). The costs of purchasing fuel required to generate 1 MWh of electricity are also lower. In such case—even with relatively high prices of coal—a power plant can achieve profitability of electricity generation.

Estimation of Environmental Damage Costs from CO<sub>2</sub>e Emissions in Libya and the Revenue from Carbon Tax Implementation

This paper addresses the GHG emissions from oil and gas extraction, production and combustion and other emissions sources in Libya. In general, this research deals with the primary energy tracing from well to wheel leading to inventor of pollutants emitted through this path. This study presents the first work conducted in the estimation of costs of the environmental damages caused by GHG emissions from Libyans activities, we involved not only the energy or industrial facilities but also the waste and livestock in this process. For Libyan market, we adopted a cost of CO2e is 44 LD/ton CO2e (which equivalents to 32 US$ or 29 �, the present study reveals that the prices of all fusel fuel must be increased by 79%, 138%, 19% and 80% for Gasoline, Diesel, Air-jet fuel and LPG respectively, and by 8%, 143%, 6%, 3% and 14% for air traveling tickets, MWh of electricity, ton of steel, ton of cement, kg of red meat and ton of garbage, respectively. The total revenue as a result of the implementation of carbon tax is 4.4 billion LD which equivalent to 10% of the Libyan GDP in 2015. The followed procedure enables to investigate the effect of each type of energy, production or service on the environment individually. This research paved the road for more intensive researches to account all pollutants in the social-economical-environmental system.

Urban Scale Application of Solar PV to Improve Sustainability in the Building and the Energy Sectors of KSA

The Kingdom of Saudi Arabia (KSA) is the largest country in the Gulf Cooperation Council (GCC) region in terms of population, geographic area, economy, and construction and utility infrastructure. The rapid growth of the building sector in general and residential buildings in particular is creating huge energy and environmental challenges for the country. To address these problems and reduce its reliance on an oil-based energy infrastructure, the country aims to install 9.5 GW of renewable energy by 2030. Traditionally the emphasis has been on large-scale renewable projects. Globally, the recent success of solar energy has been significantly contributed by the application of photovoltaics (PV) in buildings. This is an area that has been overlooked in KSA. This study investigates the prospects of application of PV in buildings to improve the sustainability standards in the building and energy sectors of the country by considering the King Fahd University of Petroleum and Minerals (KFUPM) as a case study. PVsyst and RetScreen software programs have been used to model the application of PV on building rooftops in KFUPM. The study also discusses the concerned policy. It is found that the rooftop application of PV can annually produce 37,746 MWh of electricity, meeting over 16% of the KFUPM’s total energy requirements.

Implications of a US electricity standard for final energy demand

This paper analyzes the emissions impact of an emissions intensity standard (metric tons of CO2 per MWh of electricity) for the US power sector on US final energy demand — i.e. the manufacturing, residential, commercial, and transportation sectors. An emissions intensity standard, although geared towards the power sector, will have implications for these other sectors of the economy through its effect on economy-wide energy prices. Using a hybrid energy-economy simulation model (CIMS), we find the effect on aggregate emissions from final demand to mostly be small. However, after disaggregating final demand, we find significant changes in CO2e emissions for several of sub-sectors. Given that emissions reductions in final energy demand are needed alongside power sector reductions for the US to achieve deep emissions cuts, our findings provide needed insight as to whether these eventual reductions will be helped or hindered by a US electricity standard.

CO2 Emission Trading Effect on Baltic Electricity Market

This paper investigates the CO2 cost pass-through to electricity prices of the Baltic market, as well as CO2 prices effect on merit order of generation sources and consequently marginal changes of CO2 emissions in response to changes in electricity demand. Authors use multiple regression analysis to demonstrate that a 1 EUR change in the price of CO2 emissions would increase the price of the Nordic power market by 0.55 EUR and in the Baltic countries by 0.67 EUR. Additionally, it has been shown that CO2 prices significantly impact merit order of electricity generators and consequently marginal emissions of CO2 due to reduction of electricity consumption in case of energy efficiency measures. Based on analysis, it can be concluded that, in the low price scenario (7.5 EUR per ton of CO2), combined heat and power plants are marginal generators emitting 0.25 tons of CO2 per 1MWh in cogeneration mode. If CO2 prices are above 20 EUR, the marginal emitter will become oil shale power plants that emit around 1 ton of CO2 per 1 MWh of electricity.

Novel concept of enhancing the performance of sloped solar collector by using natural anabatic winds

A solar updraft power plant (SUPP) also called a solar chimney power plant is a kind of promising power generation device that operates naturally under the indoor air buoyancy at the cost of low operation and maintenance cost without use of fuel and cooling water and without need of refuse disposal. To date this SUPP technology, the feasibility of which was verified by the Manzanares prototype built and operated in 1980s, has not been commercialized mainly due to high investment per MWh of electricity. In this paper, a novel concept of extracting power from natural valley–mountain anabatic wind aided by an SUPP collector is proposed. In the system, the solar collector is built on the upper mountain slope so as to use both the heat from the solar radiation received by the collector and the extra heat from the solar radiation received by the lower bare mountain slope. In comparison with that of the conventional sloped-collector SUPP, the performance of this novel SUPP is studied based on the mathematical model developed. Results show that with an increase in the lower bare mountain slope area from 0 to 5 times the collector area, the plant efficiency increases by 183%, and the levelised electricity cost (LEC) decrease by 64.7%. This implies that the proposed power extraction from natural valley–mountain anabatic wind aided by SUPP collector is a very effective measure to enhance the performance and cost effectiveness of SUPP. This paper lays a solid foundation for studies and commercialization of SUPPs in future.

Exergetic, economic, and environmental evaluations and multi-objective optimization of an internal-reforming SOFC-gas turbine cycle coupled with a Rankine cycle

In the present study, a detailed thermodynamic model for an internal-reforming solid oxide fuel cell-gas turbine (SOFC-GT) hybrid system integrated with a Rankine (steam) cycle is developed, and exergetic, economic and environmental analyses have been carried out on the plant. Considering the exergetic efficiency and the total cost rate of the system as conflicting objectives, a multi-objective optimization of the system is conducted to determine the optimal design point of the plant. A set of optimal solutions (Pareto front) is achieved, each of which is a trade-off between the chosen objectives. Finally, TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution) decision-making method is used to choose the final optimal design parameters. The results demonstrate that the final optimal design of the proposed plant leads to an exergetic efficiency of 65.11% and total cost rate of 0.13745€/s. Furthermore, the optimization results reveal that the integration of the Rankine cycle with the SOFC-GT system has led to an 8.84% improvement in the total exergetic efficiency of the plant, producing additional 8439.2MWh of electricity and avoiding ∼5900 metric tons of carbon dioxide emissions annually.

Exergoenvironomic modelling and performance assessment of selected gas turbine power plants

Purpose This study aims to use an environomics method to assess the environmental impacts of selected gas turbine power plants in Nigeria. Design/methodology/approach In this study, exergoenvironomic analysis has been carried out to investigate the environmental impact of selected gas turbine power plants in Nigeria from an exergetic point of view. Findings The exergy analysis reveals that the combustion chamber is the most exergy destructive component compared to other cycle components. The exergy destruction of this component can be reduced by increasing gas turbine inlet temperature (GTIT). The results of the study show that thermodynamic inefficiency is responsible for the environmental impact associated with gas turbine components. The study further shows that CO2 emissions and cost of environmental impact decrease with increasing GTIT. Originality/value The exergo-environomic parameters computed in this study are CO2 emission in kg per MWh of electricity generated, depletion number, sustainability index, cost flow rate of environmental impacts (Ċenv) in $/h and total cost rates of products (ĊTot) in $/hr. For the period considered, the CO2 emissions for the selected plants vary from 100.18 to 408.78 kgCO2/MWhm, while cost flow rate of environmental impacts varies from $40.18 /h to $276.97 /h and the total cost rates of products vary from $2935.69/h to $12,232.84/h. The depletion number and sustainability index vary from 0.69 to 0.84 and 1.20 to 1.44, respectively.

Exergetic analysis and dynamic simulation of a solar-wind power plant with electricity storage and hydrogen generation

The ambitious vision of off-grid renewable energy autonomy of remote regions has yet to come to fruition. The development of comprehensive energy production systems would be needed to achieve such a goal. This study consists of the simulation and exergetic evaluation of a novel hybrid power plant for stand-alone operation aiming to provide electricity autonomy of a Mediterranean island. The considered power plant is simulated dynamically over an annual cycle and accounts for both energy input fluctuations and electricity surplus. The plant combines a photovoltaic array with wind turbines for energy input, coupled with electricity storage and a hydrogen generation facility to stabilize the power output of the plant. Unlike other similar studies, the energy system presented here relies on real-case weather and demand data of a relatively large remote community and is optimized to ensure continuous operation – even under extreme conditions. It is seen that this stand-alone hybrid power plant constitutes a robust and secure alternative to the current conventional energy situation; the combined renewable technologies succeed in complementing each other and offer stable performance throughout the year without the requirement of additional support by fossil fuels. The mean annual exergetic efficiency of the plant is found to be 17.9%, producing approximately 25,000 MWh of electricity per year, along with a secondary product (hydrogen) produced in the electrolyzer of the plant. Although this additional product is associated with additional investment cost, it offers the possibility to stabilize the power plant's performance and can be used as an additional source of financial income for the community.

Energy Cost Estimation of Small Wind Power Systems—An Integrated Approach

Small wind power systems (SWPSs) of 100 kW or below are critical in addressing increasing global energy consumption and pressing greenhouse gas emission issues. Energy cost, i.e., cost of generating 1 kWh or MWh of electricity is an important consideration for design, development, and operation of SWPSs. Various methods for energy cost estimation have been reported, but they typically consider only some aspects of the wind power systems. This paper presents a novel energy cost evaluation methodology for SWPSs, integrating wind turbine energy production, system component efficiency, cost, and reliability together into a single comprehensive model. Monte Carlo simulation is applied to produce random functional intervals or failure intervals, considering the statistical nature of reliability. As compared with previous methods with the segregated and deterministic approaches, the new method comprehensively analyzes the energy costs of SWPSs through an integrated and stochastic approach. The proposed methodology is applied to studies of various SWPS configurations at a typical 30-kW level for both fixed-speed and variable-speed operations. The simulation results present an overview of the investment required for an SWPS over its installed lifetime, reveal cost effectiveness of different configuration options, and provide a benchmark for energy cost evaluation of wind power systems.

Performance and profitability perspectives of a CO2 based district energy network in Geneva's City Centre

A new type of district energy network providing simultaneously heating and cooling services is being investigated. It is based on the use of CO2 as a heat transfer fluid by taking advantage of the latent heat of vaporization, to store and transfer heat across the network. The goal of the present study is to determine the performance of a CO2 network when applied to a real urban area. It focuses first on determining the requirements for the various thermal energy services for a part of Geneva's City Centre. The final energy consumption is first computed for the energy conversion technologies now in place in this area – namely heating oil boilers and air cooled compression chillers. Then the new final energy consumption is computed considering that a CO2 network is used instead of boilers and air cooled compression chillers. For the area considered the CO2 network's variant leads to a final energy consumption of 10,968 MWh of electricity. It represents a reduction of 84.4% when compared to the boilers and chillers case. A comparative profitability analysis of the two cases is also presented. The analysis takes into account investment, heating oil and/or electricity, equipment replacement, operation, and maintenance costs, as well as the sales of energy services.For an interest rate of 6%, a price of the delivered heating/cooling services at 0.108 € kW h−1 and a lifetime of 40 years, the conventional technology does not reach profitability while the CO2 network achieves a profit in present value of 69.59 million € and the break-even point is reached after 5.5 years of operation.

Technical mapping of solar PV for ISM‐an approach toward green campus

AbstractThis paper aims toward the first step for green campus approach for Indian School of Mines (ISM) campus. Comparative study of the performances for nine different commercialized solar panels made of Maxeon Cell Technology, HIT (Heterojunction with Intrinsic Thin layer), monocrystalline silicon (Mono C‐Si), polycrystalline silicon (Poly C‐Si), Micromorph, SCHOTT, amorphous silicon (a‐Si), CIGS, CdTe technologies in the environmental condition of ISM are presented in this paper. This system suggests to supply the daytime electricity demand of ISM campus as well as efficient use of the huge roof areas of different buildings to setting up the photovoltaic plant. This system ensures a daily mean reduction of 8 MWh electricity consumption from grid. The outcome of this study is that a superior performance is noted for modules made of amorphous silicon technology under the typical temperature variant and dry environmental condition of ISM campus.

Thermo-economic comparative analysis of gas turbine GT10 integrated with air and steam bottoming cycle

Abstract A thermodynamic and economic analysis of a GT10 gas turbine integrated with the air bottoming cycle is presented. The results are compared to commercially available combined cycle power plants based on the same gas turbine. The systems under analysis have a better chance of competing with steam bottoming cycle configurations in a small range of the power output capacity. The aim of the calculations is to determine the final cost of electricity generated by the gas turbine air bottoming cycle based on a 25 MW GT10 gas turbine with the exhaust gas mass flow rate of about 80 kg/s. The article shows the results of thermodynamic optimization of the selection of the technological structure of gas turbine air bottoming cycle and of a comparative economic analysis. Quantities are determined that have a decisive impact on the considered units profitability and competitiveness compared to the popular technology based on the steam bottoming cycle. The ultimate quantity that can be compared in the calculations is the cost of 1 MWh of electricity. It should be noted that the systems analyzed herein are power plants where electricity is the only generated product. The performed calculations do not take account of any other (potential) revenues from the sale of energy origin certificates. Keywords: Gas turbine air bottoming cycle, Air bottoming cycle, Gas turbine, GT10

A Study of Techno-Economic Feasibility Analysis of Solar Photovoltaic (PV) Power Generation in the Province of Adana in Turkey

In this study, the examination of techno-economic feasibility analysis of a solar photovoltaic (PV) power generation were carried out by taken into account a PV power plant that has the capacity of 100 kWe as an example, in the province of Adana, Turkey. For this purpose, the technical characteristics of the PV array, the amount of electricity production, the cost of electricity production, investment and operating costs, payback periods and the amount of CO2 emissions reduction were determined for the solar PV plant. By using the total area of 653.4 m2 PV cell, total 135,403 MWh of electricity was produced in the power plant. To this end, total 5 units of PV arrays were required with the surface area of 130.7 m2 each. In this case, the system efficiency was determined as 12.2%, the annual specific efficiency of the system was 1,352 kWh/kW and the amount of CO2 emissions reduction was obtained as 119,830 Mg/year. The payback period of the system was 7.8 years and the electricity production cost was 0.1400 TL (Turkish Liras)/kWh, respectively.

Diagnostic of electricity consumption, its cost and greenhouse gas emission in the wastewater treatment sector of Algeria

Wastewater treatment sector, in Algeria, uses exclusively two processes: the activated sludge applied in the north and the lagooning in the highlands and the south. In the operating balance of the National Sanitation Office (ONA), the activated sludge wastewater treatment plants are characterized by a high electricity consumption which induced high cost and greenhouse gas (GHG) emission. In 2010, about 104.32 million m3 of wastewater was treated. This operation consumed 30,900 MWh of electricity which cost 1.04 million Euros (€) and emitted 18,761 tons of CO2-equivalent. In 2013, the treated wastewater increased by 35.2% and the electricity consumption by 45.8%. To establish an exhaustive diagnostic, this study evaluated the electricity consumed during 2009/2010 in an activated sludge wastewater treatment plant of 70,000 population equivalents (PE) (i.e. Unit of a pollution load produced daily per person, fixed at 60 grams of DBO5, which is used for the sizing of the wastewater treatment plants). Three areas were investigated: (1) the treatment process which consumed 89.63% of electricity; (2) the management department and the laboratory with 4.60%; and (3) the outdoor lighting with 5.77%. The biological treatment was the intensive-energy part of the treatment which consumed 70.05% of electricity. The aim of this diagnostic was to evaluate the performance level of the activated sludge wastewater treatment process relatively to the energy, financial and environmental factors in order to optimize the process and, then, to evaluate the benefit that could be provided by the integration of renewable energy in a sustainable wastewater treatment context.

Solar Tower-biomass Hybrid Plants – Maximizing Plant Performance

Concentrating solar power (CSP)-biomass hybrids plants are becoming increasingly interesting as a low cost option to provide dispatchable renewable energy since the first reference plant commenced operation late 2012, 22.5MWe Termosolar Borges in Spain. The development of such project is a complex task with not only one but two energy sources required to make the project successful. The availability of several studies but only one reference plant worldwide is proof of that.This paper investigates the hybridisation of a biomass power plant with a molten salt solar tower system. The benefit of this combination is a high cycle efficiency as both the steam generators can provide steam at 525°C and 120bar to the steam turbine. A case study approach is used to provide technical, economic and environmental benefits of a 30MWe CSP-biomass plant with 3h thermal storage in Griffith, New South Wales. At this site such a plant could provide annually 160,300MWh of electricity with an annual average electricity price of AU$155/MWh. Compared to a standalone CSP plant with 15h of thermal storage the hybrid plant investment is 43% lower, providing a possibility to fast-track CSP implementation in countries where CSP is struggling to enter the market due to low wholesale electricity prices, such as Australia.

Thermodynamic analysis and life cycle assessment of the heating strategies in historical buildings: a case study

This paper presents the thermodynamic analysis and life cycle assessment (LCA) of the heating strategies in historical buildings. We evaluated two main systems used in historical buildings to provide heat: a central heating system, which is based on a method of heating the whole air volume within the building, and a localised heating system, which is based on a method of supplying the desired amount of heat to the individual occupants. After evaluating both systems in a historic mosque, we found that using a modern localised heating system like the carbon film heating, a comfortable temperature can be maintained while saving 22.4 MWh of electricity annually, compared with a conventional central heating system. Moreover, the carbon film heating system can reduce stress on the environment by 60% when compared with the conventional heat pump system.