scholarly journals What Fraction of the Electrical Energy Produced in a Hybrid Solar-Fossil Power Plant Should Qualify as ‘Renewable Electricity’?

Author(s):  
Paolo Iora ◽  
Ahmed F. Ghoniem ◽  
Gian Paolo Beretta

Hybrid power production facilities, based on the integration of renewable resources into conventional fossil-fuel-fired power plants have gained a growing interest during the past decades due to a world-wide continuous increase of shares of the renewable sources into the electricity generation market. In fact, in spite of the variable nature of most of the renewable sources, the hybrid configuration may provide a more economic, sustainable, and reliable use of the renewables in all load-demand conditions compared to renewable single-resource facilities. Nonetheless, the question of what fraction of the electricity produced in such facilities is to be considered as generated from renewables, still remains not fully addressed. This implies that there is space for some arbitrariness in the quantification of the share of the produced electricity to be qualified for the subsidies granted to renewable electricity, as normally prescribed by most of the policies that promote the applications of renewable primary energy resources. To overcome this problem, in this work we first define the classical Single-Resource Separate-Production Reference allocation method (SRSPR) usually considered by the regulators which is based on reference partial primary energy factors that must be chosen by some authority as representative of the performance of the (best available or representative average single-resource) power production technologies that use the same renewable resource and the same fossil fuel as the hybrid facility. Then we propose a Self-Tuned Average-Local-Productions Reference allocation method (STLAPR) whereby the electricity allocation fractions are based on the energy scenario of the local area of interest that includes the hybrid plant itself. We compare the two methods for a case study consisting on the renewable-to-fossil allocation of the power produced in an Solar-Integrated Combined-Cycle System (SICCS) with parabolic trough solar field. It turns out that the differences between the classical SRSPR and the STLAPR method become significant as the hybrid facilities take on a sizable fraction of the production of electricity in the local area.

2021 ◽  
Vol 34 (02) ◽  
pp. 859-871
Author(s):  
Timur B. Temukuyev

An energy method for computing the use of fossil fuel energy has been considered in the article. On the world market, the fuel price depends on supply and demand and involves no energy costs for fuel production. An energy analysis of economic activity was suggested by Charles Hall, an American scientist, who introduced a notion of Energy Returned on Energy Invested, as a ratio between returned and invested energy, into scientific discourse. No account has been taken of invested energy depreciation in this method. All losses are fully incorporated, when the ratio between beneficially used energy in all process flow chains from fuel deposit exploration to energy utilisation, and the considered amount of natural fuel primary energy is taken as the coefficient of beneficial primary energy use (CBPEU). When CBPEU is determined, allowance is made for all potential energy losses; the depreciation degree of energy, contained in the fuel, from its deposit to a consumer, is defined. When energy of renewable sources is utilised, a coefficient of renewable sources energy conversion, defined as the ratio between energy delivered by a power unit throughout the entire operation period, and invested energy taking into account CBPEU over the same period, will represent an objective criterion of power unit efficiency.


2019 ◽  
Vol 17 (1) ◽  
pp. 1185-1197 ◽  
Author(s):  
Ansori Ansori ◽  
Sasmitha Ayu Wibowo ◽  
Heri Septya Kusuma ◽  
Donny Satria Bhuana ◽  
Mahfud Mahfud

AbstractFossil fuel is the main energy resource in Indonesia with oil as the dominant fuel (44.1% of primary energy consumption) in 2017. But fossil fuel is not environmentally friendly and non-renewable. Thus, there is a need for alternative renewable fuels such as biodiesel. Biodiesel from nyamplung (Calophyllum inophyllum L.) oil can provide a promising future as a renewable fuel resource. The used of CaO catalyst from eggshell waste is also profitable, and microwave radiation can help the biodiesel production process run more effectively. Optimization of parameters such as microwave power, catalyst concentration, and transesterification time was performed by using Box-Behnken design. Combinations between biodiesel production from nyamplung oil with CaO catalyst using microwave and treated with Box-Behnken design is considered a new and modern method with optimization of the parameters which affect the transesterification process. The result showed that at a microwave power of 325.24 W, a concentration of catalyst of 3.88%, and a transesterification time of 12.47 min can produce an optimal yield of biodiesel of 98.9079% with the reliability of 92.37%.


Author(s):  
Miao Wang ◽  
M. A. Khan ◽  
Imtinan Mohsin ◽  
Joshua Wicks ◽  
Alexander H. Ip ◽  
...  

As renewable electricity prices continue to diminish, interest grows in alternative routes for the synthesis of sustainable fuels and chemicals, including ammonia. Considering demand for fertilizers, as well as for...


2020 ◽  
Vol 12 (21) ◽  
pp. 9300
Author(s):  
David Alfonso-Solar ◽  
Carlos Vargas-Salgado ◽  
Carlos Sánchez-Díaz ◽  
Elías Hurtado-Pérez

Applications of renewable electricity in cities are mostly limited to photovoltaics, and they need other renewable sources, batteries, and the grid to guarantee reliability. This paper proposes a hybrid system, combining biomass and photovoltaics, to supply electricity to educational buildings. This system is reliable and provides at least 50% of electricity based on renewable sources. Buildings with small (<500 kW) installed power based on renewables, mainly biomass, are usually expensive. Besides, in urban areas, photovoltaic capacity is limited due to roof availability. This paper analyzes different configurations, meeting these constraints to obtain an economically feasible solution based on photovoltaic-biomass modelling of small size hybrid systems. The technology used for biomass energy valorization is a fluidized bed gasification power plant, which has been modelled with real data obtained from experimental tests and previous research projects. Thereby, real costs and electric efficiency are included in the model. The techno-economic feasibility analysis using HOMER software with metered real load curves from an educational building has been modelled. The results of the model show that hybrid renewable systems are very feasible in the scenario of 50% of electricity contribution, however, higher contribution (>70%) implies high electricity costs.


2011 ◽  
Vol 133 (01) ◽  
pp. 24-29 ◽  
Author(s):  
John Reilly ◽  
Allison Crimmins

This article predicts future global energy demand under a business-as-usual scenario. According to the MIT projections, conventional technology supported by fossil fuels will continue to dominate under a business-as-usual scenario. In fact, in the absence of climate policies that would impact energy prices, fossil fuels will supply nearly 80% of global primary energy demand in 2100. Alternative energy technologies will expand rapidly. Non-fossil fuel use will grow from 13% to 20% by 2100, with renewable electricity production expanding nearly tenfold and nuclear energy increasing by a factor of 8.5. However, those sources currently provide such a small share of the world's energy that even rapid growth is not enough to significantly displace fossil fuels. In spite of the growth in renewables, the projections indicate that coal will remain among the least expensive fuel sources. Non-fossil fuel alternatives, such as renewable energy and nuclear energy, will be between 40% and 80% more expensive than coal.


Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4938
Author(s):  
Hellinton H. Takada ◽  
Celma O. Ribeiro ◽  
Oswaldo L. V. Costa ◽  
Julio M. Stern

Primary energy consumption is one of the key drivers of global CO2 emissions that, in turn, heavily depends on the efficiency of involved technologies. Either improvement in technology efficiency or the expansion of non-fossil fuel consumption requires large investments. The planning and financing of such investments by global policy makers or global energy firms require, in turn, reliable measures of associated global spread and their evolution in time, at least from the point of view of the principles for responsible investment (PRI). In this paper, our main contribution is the introduction of index measures for accessing global spread (that is, measures of inequality or inhomogeneity in the statistical distribution of a related quantity of interest) of technology efficiency and CO2 emission in primary energy consumption. These indexes are based on the Gini index, as used in economical sciences, and generalized entropy measures. Regarding primary energy sources, we consider petroleum, coal, natural gas, and non-fossil fuels. Between our findings, we attest some stable relations in the evolution of global spreads of technology efficiency and CO2 emission and a positive relation between changes in global spread of technology efficiency and use of non-fossil fuel.


Science ◽  
2019 ◽  
Vol 364 (6438) ◽  
pp. eaav3506 ◽  
Author(s):  
Phil De Luna ◽  
Christopher Hahn ◽  
Drew Higgins ◽  
Shaffiq A. Jaffer ◽  
Thomas F. Jaramillo ◽  
...  

Electrocatalytic transformation of carbon dioxide (CO2) and water into chemical feedstocks offers the potential to reduce carbon emissions by shifting the chemical industry away from fossil fuel dependence. We provide a technoeconomic and carbon emission analysis of possible products, offering targets that would need to be met for economically compelling industrial implementation to be achieved. We also provide a comparison of the projected costs and CO2 emissions across electrocatalytic, biocatalytic, and fossil fuel–derived production of chemical feedstocks. We find that for electrosynthesis to become competitive with fossil fuel–derived feedstocks, electrical-to-chemical conversion efficiencies need to reach at least 60%, and renewable electricity prices need to fall below 4 cents per kilowatt-hour. We discuss the possibility of combining electro- and biocatalytic processes, using sequential upgrading of CO2 as a representative case. We describe the technical challenges and economic barriers to marketable electrosynthesized chemicals.Science, this issue p. eaav3506


2016 ◽  
Vol 19 (1) ◽  
pp. 59-74 ◽  
Author(s):  
Olabanji Benjamin Awodumi ◽  
Adebowale Musefiu Adeleke

Abstract This study adopted two-stage DEA to estimate the technical efficiency scores and assess the impact of the two most important components of fossil fuel associated with oil production on macroeconomic efficiency of Seven oil producing African countries during 2005-2012. Our results showed that increasing the consumption of natural gas would improve technical efficiency. Furthermore, increasing the share of fossil fuel in total energy consumption has negative effect on the efficiency of the economies of the top African oil producers. Also, we found that increasing the consumption of primary energy improves efficiency in these economies. We therefore, recommend that governments and other stakeholders in the energy industry should adopt inclusive strategies that will promote the use of natural gas in the short term. However, in the long-run, efforts should be geared towards increasing the use of primary energy, thereby reducing the percentage share of fossil fuel in total energy consumption.


2020 ◽  
Author(s):  
Andreas Wagner ◽  
Benjamin Fersch ◽  
Peng Yuan ◽  
Harald Kunstmann

&lt;p&gt;The assimilation of observations in local area models (LAMs) assures that the states of meteorological variables are as close to reality as possible. Water vapor is an important constituent in terms of cloud and precipitation formation. Its highly variable nature in space and time is often insufficiently represented in models.&lt;/p&gt;&lt;p&gt;The aim of our work is to improve the simulation of water vapour in the Weather Research and Forecasting model WRF by assimilation of different observations. At the current stage, temperature, relative humidity, and surface pressure derived from climate stations are applied as well as zenith total delay (ZTD) data from global navigation satellite system (GNSS) stations. We try to identify the best setup of assimilation parameters which all of them directly or indirectly influence water vapour simulations. We will show case studies of high-resolution WRF simulations (2.1 km) between 2016 and 2018 for different seasons in southwest Germany. The impact of assimilation (3D-VAR) of different variables, combinations of variables, background error option as well as the temporal resolution of assimilation is evaluated. We look at column values and also at profiles derived from radiosondes. Our results show a positive impact when assimilating measured data, but deteriorations are also possible. A distinct influence of assimilation is only apparent for a few time steps. If the temporal resolution of the assimilated variables is too coarse and there is no assimilation close to these time steps, the positive effect vanishes.&lt;/p&gt;


Author(s):  
Yin Hang ◽  
Ming Qu

Buildings are responsible for 41% of the primary energy use in the United States. Due to the negative environmental impact from fossil fuel, people are trying to use renewable energy resources to provide energy to the buildings. Integrated solar absorption cooling and heating (SACH) technology can be one of the promising solutions to this issue. Due to the nature of solar energy, integrated SACH has many drawbacks, such as discontinuity of generation, thus backup system driven by fossil fuel should be included to the system configuration as well. Therefore, optimization is highly required during the design stage. This paper presents the development of a method to optimize an integrated SACH system. Regression analysis is used to identify the relationship between the life cycle primary energy savings (PES) and the system factors according to the data provided by experiments. In order to obtain an accurate model to estimate the problem using small number of experimental trials, the method of central composite design (CCD) from design of experiments (DE) is used as a key technique. The experimental trials are conducted in TRaNsient SYstems Simulation (TRNSYS). Finally, the optimization problem is formulated and solved by including the model as the objective function and the physical constraints of the system factors. A case study was conducted to apply this optimization method to the design of an integrated SACH system installed in a medium-sized office building in Los Angeles.


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