Electricity Exports Research Articles

Mechanical-biological treatment of municipal solid waste: Case study of 100 TPD Goa plant, India

A long-term feasibility analysis of a 100 ton per day mechanical biological treatment (MBT) plant for municipal solid waste (MSW) valorization and material and energy recovery was carried out. It involves the material recovery and segregation stage (MRSS), organic extraction (pulping), thermophilic anaerobic digestion (AD), composting, effluent treatment plant (ETP), and biogas genset stages producing: 11.90% recyclables, 33% refused derived fuel (RDF), 5% compost of total waste received, 70 m3/day recyclable water and 0.435 MWh/day electricity. The biogas and methane yield were 0.535 and 0.350 m3/kg VSadded (avg.), respectively, with 40% VS removal (avg total solids (TS) 10%). Less than 3% (inert) of total waste received was subjected to landfill disposal. The MBT plant's revenue generation is 995 US$ per day/148 tons ($ 6.72/ton) waste processed. The gross OPEX is 24 US$/ton making the net OPEX of 17 US$/ton (minus revenue), which could be considered as the excellent OPEX for MSW based MBT plants as per global benchmarks. Further, local usage of RDF can significantly reduce the OPEX to 14 US$/ton, as almost 16% of the OPEX goes towards RDF disposal to cement companies located at a distance of 200–500 km from the MBT plant site. As per LCA study, the total GHG emissions have been calculated to be −25.68 tons CO2 eq./100 tons MSW. The negative emissions result from the export of electricity, compost, and RDF as well as recycling of paper and plastic products. Our study presents a cutting-edge scenario of all-inclusive recycling, recovery, and reuse loop of MSW direly required for accomplishing a circular economy.

Stationary, Second Use Battery Energy Storage Systems and Their Applications: A Research Review

The global demand for electricity is rising due to the increased electrification of multiple sectors of economic activity and an increased focus on sustainable consumption. Simultaneously, the share of cleaner electricity generated by transient, renewable sources such as wind and solar energy is increasing. This has made additional buffer capacities for electrical grids necessary. Battery energy storage systems have been investigated as storage solutions due to their responsiveness, efficiency, and scalability. Storage systems based on the second use of discarded electric vehicle batteries have been identified as cost-efficient and sustainable alternatives to first use battery storage systems. Large quantities of such batteries with a variety of capacities and chemistries are expected to be available in the future, as electric vehicles are more widely adopted. These batteries usually still possess about 80% of their initial capacity and can be used in storage solutions for high-energy as well as high-power applications, and even hybrid solutions encompassing both. There is, however, no holistic review of current research on this topic. This paper first identifies the potential applications for second use battery energy storage systems making use of decommissioned electric vehicle batteries and the resulting sustainability gains. Subsequently, it reviews ongoing research on second use battery energy storage systems within Europe and compares it to similar activities outside Europe. This review indicates that research in Europe focuses mostly on “behind-the-meter” applications such as minimising the export of self-generated electricity. Asian countries, especially China, use spent batteries for stationary as well as for mobile applications. In developing countries, off-grid applications dominate. Furthermore, the paper identifies economic, environmental, technological, and regulatory obstacles to the incorporation of repurposed batteries in second use battery energy storage systems and lists the developments needed to allow their future uptake. This review thus outlines the technological state-of-the-art and identifies areas of future research on second use battery energy storage systems.

Generation and transmission expansion planning for bulk renewable energy export considering transmission service cost allocation

This paper proposes a bulk renewable generation and transmission expansion planning (GTEP) applied to the Iran power system. The objective is to minimize the cost of investors who intend to invest in renewable power plants for electricity exports in high-potential countries. The costs include the generation and transmission investment cost (CAPEX), operation cost (OPEX), and transmission service cost (TSC). In this paper, three TSC allocation methods are proposed to be used, including methods based on annual MWh of consumption or generation, based on the peak value of consumption or generation, and based on the power flow of lines. The proposed optimization-based GTEP is examined through various cases. The effects of different parameters including the location of the neighbors to whom the power is exported, the location of the candidate buses for installing power plants, the neighbor's load shape, and the type of renewable power plant are discussed on the GTEP results.

Prospects of large‐scale photovoltaic‐based power plants in the Kingdom of Saudi Arabia

AbstractThe techno‐economic analyses of 67 MW and 144 MW photovoltaics (PV) power plants are performed and the results are compared with the diesel power plants situated in two cities in the Kingdom of Saudi Arabia. The feasibility analysis is conducted with the aim to show the technical and economic viability of replacing the conventional fossil fuel‐based plants with clean production systems in the country. The production capacity of the proposed PV plants based on the single‐axis tracking configuration is around 35% higher than that of the tilted‐fixed configuration, equivalent to a reduction in the production cost by more than 20% for both the plants. PV plants with a tracking system can produce up to 23% excess electricity than the base‐case diesel plants. Moreover, the production costs at the Bisha plant can be as low as 1.77 ¢/kWh, considering the credit resulting from the reduction of greenhouse gas (GHG) emissions. The feasibility of installing a 144 MW PV plant in six cities in the country is also evaluated. The results indicate that the average cost of electricity production is 2.22 ¢/kWh and the average annual reduction of GHG emissions is 462 tCO2/GWh with the replacement of a diesel power plant of similar capacity. The effects of subsidies, feed‐in tariff rates, and electricity export escalation rates are also evaluated.

Influence of Electrification Pathways in the Electricity Sector of Ethiopia—Policy Implications Linking Spatial Electrification Analysis and Medium to Long-Term Energy Planning

Ethiopia is a low-income country, with low electricity access (45%) and an inefficient power transmission network. The government aims to achieve universal access and become an electricity exporter in the region by 2025. This study provides an invaluable perspective on different aspects of Ethiopia’s energy transition, focusing on achieving universal access and covering the country’s electricity needs during 2015–2065. We co-developed and investigated three scenarios to examine the policy and technology levels available to the government to meet their national priorities. To conduct this analysis, we soft-linked OnSSET, a modelling tool used for geospatial analysis, with OSeMOSYS, a cost-optimization modelling tool used for medium to long-run energy planning. Our results show that the country needs to diversify its power generation system to achieve universal access and cover its future electricity needs by increasing its overall carbon dioxide emissions and fully exploit hydropower. With the aim of achieving universal access by 2025, the newly electrified population is supplied primarily by the grid (65%), followed by stand-alone (32%) technologies. Similarly, until 2065, most of the electrified people by 2025 will continue to be grid-connected (99%). The country’s exports will increase to 17 TWh by 2065, up from 832 GWh in 2015, leading to a cumulative rise in electricity export revenues of 184 billion USD.

PVAnalytX: A MATLAB toolkit for techno-economic analysis and performance evaluation of rooftop PV systems

The adaptation of rooftop solar PV systems has increased significantly in recent years. Batteries have become an essential part of the rooftop solar PV systems, which ensures maximum utilisation of solar energy. With a view to present a clear insight to benefits of a rooftop solar PV system, considering both the technical and economic benefits, a MATLAB based PVAnalytX software toolkit has been presented in this paper. The end users can evaluate both the technical and economic benefits of a rooftop solar PV system considering solar generation and electricity demand variability, as well the battery performance degradation over the course of its usage. In addition, the mechanism to generate forecasted solar power generation and electricity demand data is also included as a feature in the proposed software toolkit. Furthermore, the toolkit considers actual electricity imports and export tariffs that allow the end consumers to know their financial expenditures for electricity consumption and income generated through the export of access rooftop PV energy to the grid. A thorough validation of the proposed toolkit has been presented through two case studies using actual dataset of rooftop PV systems located at CBD region of Sydney, Australia.

Measuring accuracy and computational capacity trade-offs in an hourly integrated energy system model

• We use a national hourly energy system model with a linear programming approach. • Reducing transitional scope drastically decreases the computational time. • Neglecting hourly electricity trade overestimates electricity prices by ~40%. • Neglecting flexibility options increase the sub-optimality up to 31%. • Neglecting Inter-sectoral flexibility options can increase system costs by ~20%. Improving energy system modeling capabilities can directly affect the quality of applied studies. However, some modeling trade-offs are necessary as the computational capacity and data availability are constrained. In this paper, we demonstrate modeling trade-offs resulting from the modification in the resolution of four modeling capabilities, namely, transitional scope, European electricity interconnection, hourly demand-side flexibility description, and infrastructure representation. We measure the cost of increasing resolution in each capability in terms of computational time and several energy system modeling indicators, notably, system costs, emission prices, and electricity import and export levels. The analyses are performed in a national-level integrated energy system model with a linear programming approach that includes the hourly electricity dispatch with European nodes. We determined that reducing the transitional scope from seven to two periods can reduce the computational time by 75% while underestimating the objective function by only 4.6%. Modelers can assume a single European Union node that dispatches electricity at an aggregated level, which underestimates the objective function by 1% while halving the computational time. Furthermore, the absence of shedding and storage flexibility options can increase the curtailed electricity by 25% and 8%, respectively. Although neglecting flexibility options can drastically decrease the computational time, it can increase the sub-optimality by 31%. We conclude that an increased resolution in modeling flexibility options can significantly improve the results. While reducing the computational time by half, the lack of electricity and gas infrastructure representation can underestimate the objective function by 4% and 6%, respectively.

Optimising renewable energy integration in new housing developments with low carbon technologies

Since buildings account for more than one-third of final energy use, it is important to integrate renewable energy sources for new housing developments to reduce demand for grid energy and carbon emissions. This research investigates the potential of solar PV, energy storage, and electric vehicles in new housing developments and their associated grid impacts by taking the UK’s Cambridge, Milton Keynes, Oxford arc as a case study. Using published data on electrical loads for different types of dwellings, energy demands for new housing developments with and without renewable and low carbon technologies are analysed using techno-economic modelling frameworks. Technical analysis includes sizing and optimisation of PV and storage while economic analysis covers cost-benefit analyses, by considering a range of existing and future tariffs and subsidy schemes including Standard, Economy 7 (cheaper electricity for 7 h at night), Feed-in tariff, and the Smart Export Guarantee. Results show that installing PV panels and storage systems not only reduces the dwellings’ grid energy demand by 31% in January but also helps the dwellings to become net exporters of green electricity to the grid in July and hence saves a substantial amount of money by taking advantage of Feed-in and Economy 7 tariffs.

Implications to the electricity system of Paraguay of different demand scenarios and export prices to Brazil

Paraguay's power system is based entirely on hydropower. It serves as the largest net electricity exporter in Latin America. Nonetheless, the country´s electricity consumption per capita is one of the lowest in the world and the transmission and distribution network has one of the highest losses in Latin America. This paper presents an electricity expansion investment outlook (2018–2040) for Paraguay using OSeMOSYS, analyzing three electricity demand scenarios under different electricity export prices to Brazil. The study identifies the least-cost power generation mix, future investments and the financial requirements to meet the needs of different demand scenarios. We find that Paraguay will need to invest in hydropower plants, by mainly expanding the capacity of Yacyreta to cover its electricity needs and sustain national electricity exports levels. In the High demand scenario, where the electricity demand could approximately double by 2040, the country's overall electricity exports decrease by 50% compared to the Reference scenario. Based on the different scenarios examined, the government spends approximately 18.3–31.2 billion USD on power plant investments for the period 2018–2040 to cover future electricity demand. The findings could be useful in supporting decision-making concerning socio-economic development pathways in the country.

Balancing Ukraine’s energy system: challenges under high renewable energy penetration and the COVID-19 pandemic

The paper deals with the problems of balancing the United Energy System of Ukraine caused by high renewable energy penetration and the impact of the COVID-19 pandemic on the energy sector. The paper analyses the trends in renewable energy development, the dynamics and structure of electricity consumption and export in pre-epidemic and epidemic periods and identifies the main challenges to operational security of the United Energy System of Ukraine. The methodical approach to improve the methodology for estimation of country’s energy security level by considering the index of developing capacities for balancing the United Energy System of Ukraine is suggested. In addition, proposals have been made to reduce threats to the stable work of the United Energy System of Ukraine by putting into operation of energy storage capacities, promoting the development of мaneuvering renewable energy capacities, and implementation of other appropriate measures in this field.

Asymmetry and hysteresis in the Russian gasoline market: the rationale for green energy exports

Using monthly data of 79 Russian regions from 2003 to 2017, we study the long-run relationship of the retail gasoline prices with the crude oil price and the nominal exchange rate. We find that models that were successfully applied to deal with asymmetries in other countries are not suitable for Russia without taking structural breaks into account. Once breaks are allowed, we find that there is no asymmetry in the long-run elasticities between the gasoline prices and the crude oil price, and no significant hysteresis. However, there is an asymmetric relation between the gasoline price and the exchange rate that has decreased over time. These results also hold after several robustness checks. The evidence reported in this work shows that the effects of the exchange rate on gasoline prices are much more difficult to control than the oil price, and they require a larger set of policy measures: the recent development of a plan to decrease the importance of hydrocarbons exports by producing clean hydrogen using electrolysis and pyrolysis and the potential future export of electricity generated using nuclear power and onshore wind farms may help to diversify the local economy and to shield it from new sanctions.

Educational evaluation of renewable energy projects based on RETScreen software

In the design of renewable energy projects, a present problem is the techno-economic evaluation of them, regularly different methods and models are used to do it, in this work it is proposed to innovate in the degree of Engineering in Renewable Energies (LIER) of the UNAM in the National School of Superior Studies Juriquilla campus the way to evaluate projects using the software RETScreen. This paper presents a methodology to evaluate a wind energy project in the state of Queretaro Mexico. The project contemplates a wind turbine brand VESTAS V44 - 40m of 600 kW capacity of 40 m height in the state of Querétaro in the center of the country of Mexico. The initial costs of this wind turbine are 1,283 $/kW or 770,000 USD, with a rate of 80 $/kW. The electricity exported to the grid is 1,703 MWh and the income from electricity exports is 136,235.52 USD. With this wind turbine you can save 1,318.2 tCO2 per year or 566,414 liters of unused gasoline.

Ecuador as an Exporter of Electricity

In this article, an analysis is made on the sale of the electrical energy made by Ecuador to other countries, also mentioning the beginnings of the electricity market in the country. The hydroelectric projects built in the last decade are described, which are the ones that will guarantee the export of the energy resource. There is talk of the amount of energy that is exported in MWh, to the countries of Colombia and Peru, as well as the limitations that have arisen in the infrastructure when sending the energy. There is also talk of the benefit that the sale of electrical energy brings to Ecuador and the profit that this implies. The objective of this article is to make known how the sale of electrical energy from Ecuador to other countries is carried out, and how much it enters the country as a profit for it, in addition to analyzing the current situation as energy exporters and looking for possible solutions in case of find difficulties or deficiencies.

Assessment of renewable energy transition in Moroccan electricity sector using a system dynamics approach

AbstractMorocco is one of the major importers of conventional fuels in the MENA region. In fact, ensuring energy security in the western kingdom is placing a heavy burden on economic balances, while generating many environmental impacts and social discrepancies. The local government has been striving to reduce its GHG emissions coming mainly from activities related to the field of energy harvesting. The current research work aims to evaluate technical, economic, social, and environmental impacts of the ongoing transition toward renewable energy (RE) deployment in Morocco. We used the system dynamics approach in order to study different interactions of the components of the Moroccan electricity sector and their behaviors on this complex system under various scenarios. The results showed that 35 MtCO2 of avoided emissions can be ensured up to 2030 if renewable installed capacity reaches 15.72 GW by the same year. On the other hand, demand is estimated to be reduced by almost 30 TWh if robust measures were taken turning the country into an electricity exporter of up to 8.67 TWh by 2030. Finally, while research and development activities are expected to decrease RE plants construction costs by almost 700 million USD, nearly 448.986 renewable jobs can be created by 2030.

Identifying High-Potential Work Areas in Engineering for Global Development: Linking Industry Sectors to the Human Development Index

AbstractThose working in Engineering for Global Development seek to improve the conditions in developing countries. A common metric for understanding the development state of a given country is the Human Development Index (HDI), which focuses on three dimensions: health, education, and income. An engineer’s expertise does not always align with any of those dimensions directly, while they still hope to perform impactful work for human development. To discover other areas of expertise that are highly associated with the HDI, correlations and variable selection were performed between all World Development Indicators and the HDI. The resultant associations are presented according to industry sector for a straightforward connection to engineering expertise. The associated areas of expertise can be used during opportunity development as surrogates for focusing on the HDI dimensions themselves. The data analysis shows that work related to “Trade, Transportation, and Utilities,” such as electricity distribution, and exports or imports, “Natural Resources and Mining,” such as energy resources, agriculture, or access to clean water, and “Manufacturing,” in general, are most commonly associated with improvements in the HDI in developing countries. Also, because the associations were discovered at country-level, they direct where geographically particular areas of expertise have been historically associated with improving HDI.

Regional disparities in emissions reduction and net trade from renewables

Operational constraints of the power system and inter-regional trade of electricity make it challenging to predetermine the reduction in emissions from the integration of solar and wind power. Using spatially resolved historical data for solar and wind generation, fossil fuel-based generation, emissions and exports, we isolate the impacts of renewable integration for multiple regions spanning the United States. Here we show regional differences for the reduction of carbon dioxide, sulfur dioxide and nitrogen oxides emissions, with a wider range of outcomes for regional wind power. Given the heterogeneity in transmission infrastructure, some regions have limited capacity to increase electricity exports to neighbouring regions. For both solar and wind generation, we identify the regions that retain nearly all of the emissions reductions locally and those that increase net exports, reducing emissions in neighbouring regions. Our results show lower rates of emissions mitigation than previous studies that relied on less-contemporary data or utilized simulated renewable generation. These differences may reflect the longer-term trends in power-sector emissions reductions and the importance of utilizing observed renewable generation data. An analysis of spatially explicit historical data shows notable regional differences in the benefits in reduced emissions from integrating renewable energy across the United States.

Technical feasibility evaluation of a solar PV based off-grid domestic energy system with battery and hydrogen energy storage in northern climates

Self-sustaining off-grid energy systems may require both short-term and seasonal energy storage for year-around operation, especially in northern climates where the intermittency in both solar irradiation and energy consumption throughout the year is extreme. This paper examines the technical feasibility of an off-grid energy system with short-term battery storage and seasonal hydrogen storage, comprising a water electrolyzer and a fuel cell. The study is based on data from a currently grid-connected residential single-family house in Finland with an existing 21 kWp photovoltaic (PV) installation and a ground source heat pump based heating system. Energy system performance is simulated using real PV power generation data as well as data on grid electricity import and export from the house over a three-year period to find the minimum combination of battery and hydrogen storage system capacities capable of year-round off-grid operation. It is concluded that technically feasible solutions are available for the proposed setup. The most significant factor affecting the system dimensioning is found to be high peak electric power demand during times of low PV power generation, indicating a need for smart power control. Demand for battery storage capacity is found to be significant only to about 20 kWh. Fuel cell and electrolyzer nominal powers of at least 4 kW and 5 kW to 7 kW, respectively, were found to be sufficient for off-grid operation with the studied system. The storage capacity demand for 170–190 kg of hydrogen annually is, however, impractically large for residential houses.

Structural and technological determinants of carbon intensity reduction of China's electricity generation.

Electricity generation is the largest sector with decarbonization potential for China and the world. Based on the new emission factors, this paper aims to identify the structural and technological determinants of provincial carbon intensity in the electricity generation sector (CIE) using the multiplicative LMDI-II method. Results demonstrate that (1) China's overall CIE decreases by 7.3% in 2001-2015, and the research period can be divided into four stages according to CIE changes (i.e., rapid growth, rapid decline, slow growth, and transition). The CIE in the 12th FYP estimated in this paper, 24.9% lower than that using the emission factors from IPCC, is closer to China's actual situation. (2) There exists huge heterogeneity in the determinants of provincial CIE changes in four stages. CIE growth in the Northwest and Northeast is caused by the coal-dominated energy structure. CIE growth in the Southwest is attributed to the electricity structure effect, while that of the Coast region is caused by the geographic distribution effect. The electricity efficiency effect is attributed to the CIE growth for these regions and the Southwest should also place focus on the electricity trade effect. The impact of electricity trade-related factors depends on the region being a net exporter or importer of electricity. (3) To achieve carbon intensity reduction targets, 30 provinces are categorized into four types based on various combinations of structural and technological determinants. The findings provide insights into capturing future emission-mitigating focus as well as defining the emission-mitigating responsibilities between electricity exporters and importers in China.

Unlocking the potential of pulp and paper industry to achieve carbon-negative emissions via calcium looping retrofit

Pulp and paper is considered to be the fourth most energy-intensive industry (EII) worldwide. However, as most of the CO2 emissions are of biomass origin, this sector has the potential to become a carbon-negative industry. This study proposes a new concept for conversion of the pulp and paper industry to carbon negative that relies on the inherent CO2 capture capability of the Kraft process. The techno-economic performance of the proposed carbon-negative system, based on calcium looping (CaL) retrofitted to a pulp and paper plant, was evaluated. The effect of CaL design specifications and cost assumptions on the thermodynamic and economic performance were evaluated. Under the initial design assumptions, the reference pulp and paper plant was shown to turn from electricity importer to electricity exporter with the cost of CO2 avoided equal to 39.0 €/tCO2. The parametric study showed that an increase in the fresh limestone make-up rate resulted in a linear increase of the specific primary energy consumption for CO2 avoided (SPECCA) and a reduction in the amount of electricity exported to the electric grid. This translates into an increase in the price of pulp and newsprint, and the cost of CO2 avoided. This study has also demonstrated that the pulp and paper industry has high potential to become carbon negative. It has been shown that carbon capture and storage would become economically viable in this industry if the negative CO2 emissions are recognised and a negative CO2 emissions credit of at least 41.8 €/tCO2 is implemented.

Impact of One- and Two-axis Solar Tracking on Techno-Economic Viability of On-Grid PV Systems: Case of Burnoye-1, Kazakhstan

Kazakhstan is currently committed to develop its renewable energy resources. In 2012, the government introduced a low-carbon energy strategy to reduce the production of air pollutants, including anthropogenic CO2e, and to increase the share of clean energy up to 50% of total consumption by 2050. As a contribution to this strategy, this paper presents a comparison in techno-economic performance of three scenarios. The differentiation will be between currently implemented fixed-slope on-grid PV power plants in Kazakhstan and proxy similar solar parks using one- or two-axis solar tracking systems. This paper aims to determine to what extent the more effective, but more expensive tracking systems might be a suitable standard in future PV power stations in the country. For this purpose, the existent fixed-slope 50 MWp Burnoye-1 commercial solar power plant located in Jambyl region, Kazakhstan, is used as a benchmark. As expected, solar panels with tracking systems produce more electricity year-round compared to those with fixed slopes. In comparison, one- and two-axis tracking systems led almost to the same amount of electricity export to the grid. Furthermore, despite the proxy PV power stations with one- and two-axis tracking technology could reduce around 10 ktCO2e emissions per year. This 25 to 29% and 33 to 33% ratio of extra-cost to extra-energy production, respectively, made both tracking scenarios not economically competitive compared to fixed panels. Nevertheless, if a tracking system has to be considered to further reduce GHG emissions and add extra annual electricity generation using current installed capacity of Burnoye-I, our results demonstrated that one-axis tracking should be preferred above two-axis system.