Excess Electricity Generation Research Articles

Towards sustainable development in the MENA region: Analysing the feasibility of a 100% renewable electricity system in 2030

This research explores the feasibility of 100% renewable energy (RE) systems for the Middle East and North Africa (MENA) region for assumptions of the year 2030. The demand for three sectors are taken into account: power, non-energetic industrial gas and seawater desalination. Three strategical scenarios are discussed, namely Region, Area and Integrated, mainly differing in level of regional grid interconnection and sector coupling. Solar photovoltaics (PV) and wind energy are found to be the most cost-competitive RE sources with the highest potential in the region covering more than 90% of the generation capacity in all the considered scenarios. The variability of RE is solved via energy storage, surplus electricity generation and electricity grids. The estimated overall levelised cost of electricity (LCOE) lies between 40.3 and 52.8 €/MWh, depending on the scenarios. The total LCOE decreased by 17% as a result of sector coupling compared to the interconnected power sector alone. Power-to-gas technology not only functions as a seasonal storage by storing surplus electricity produced mainly from wind power and partially from solar PV, but provides also the required gas for the non-energetic industrial gas sector. Battery storage complements solar PV as a diurnal storage to meet the electricity demand during the evening and night time. Seawater reverse osmosis desalination powered by renewables could potentially be a proper solution to overcome the water challenges in the MENA region at affordable cost of 1.4 €/m3. A comparison with a BAU strategy shows that a 100% renewable energy-based power system is 55–69% cheaper than a BAU strategy without and with greenhouse gas emission costs.

Hybrid SOLAR / DIESEL Low Power Generation Performance System for Local House in Baghdad City

The national electrical energy situation report study today in Iraq represents that the value of the conventional electrical energy power is increasing day after day with increasing more demand on the electricity source in all sectors of life in Iraq. To avoid energy supply shortage, today should be using renewable energy sources with rise required management. A hybrid electrical energy system usually consists of two or more renewable energy sources used together with conventional electrical energy sources to extend increased system efficiency, but the design of hybrid power involves uneconomic and excessive capacities results in excess electric generation with increasing the initial costs. In this study, we find the optimization the best time required of sharing alternative between both of solar-diesel generator hybrid power system for 24 hours. The PV peak power was 1.3kW and diesel power 2.4kW with using both of theoretical calculation. The HOMER software was used to improve a simulation model for one day in Baghdad city in Iraq. The HOMER software is used to implement the optimization. The master objective is to optimize hybrid system component sizes, minimizing excess electricity generation, and set electric load and implement cost analysis based on life cycle price. Inputs data used for simulation consist of real solar radiation data (Averaged to monthly values), taken from the local weather station installed at Baghdad city. Based on maximum load, hybrid system parameters sizes considered and many simulation results are acquired.

Electricity Access, Community Healthcare Service Delivery, and Rural Development Nexus: Analysis of 3 Solar Electrified CHPS in Off-Grid Communities in Ghana

Over 600 million people living in sub-Saharan Africa do not have access to electricity. Modern healthcare services, including vaccine refrigeration, which require electricity are therefore lacking in such energy-deprived communities. In this work, analysis has been conducted on how electricity access can help improve healthcare service delivery and rural development, with a case study on 3 different off-grid solar photovoltaic (PV) systems in community-based health planning and services (CHPS) in Ghana. Analysis from this study showed that for the 3.0 kWp solar PV systems installed at the various sites, the in-house electricity consumptions are between 4.30 and 7.58 kWh per day. It was found out that excess electricity generation of 148–304 kWh per month is available and can be used to provide other economic services including phone charging, torchlight battery charging, and small-sized cold storage services to generate income for the maintenance of the systems, which is critical for sustainability of solar PV installations in rural poor communities. The study results also showed that electrified health facilities which are able to provide basic healthcare services have potential impact on community health outcomes and rural development. Assessment conducted at the CHPS compounds revealed that, generally, there is improvement in healthcare service delivery resulting in time savings of 15-43 hours per month for the inhabitants which can potentially be used for productive work. The time savings were more significant in females and children than in males. In many rural agro-based communities in developing countries, female and children are usually the workforce engaged in various farming activities. This paper concludes that access to electricity in CHPS compounds helps to improve community health outcomes and increases time availability for women to engage in productive work that can potentially result in significant socioeconomic activities and rural development.

Long term electricity storage by oxygen liquefaction and LNG oxy-combustion

The paper proposes an innovative scheme exploiting oxygen liquefaction as a means for storing excess electricity generation from renewable sources. Liquid oxygen is then used in an oxy-combustion process with LNG to generate electricity when renewable energy generation is below the demand. An equivalent round trip efficiency is defined to make it possible comparing the system performances with hybrid plants including conventional generation and storage. The proposed scheme exhibits very high equivalent round trip efficiency, giving the system operators the opportunity to integrate more and more renewable energy generation inside power systems. Liquefied carbon dioxide and water are byproducts of the process. The size of the plant and of the storage tanks needed for a 4 TWh yearly demand with a peak around 800 MW is compatible with state-of-the-art systems used for LNG storage in similar size gas power plants.

A Novel Peer-To-Peer Energy Sharing Business Model for the Portuguese Energy Market

The co-evolution of techno-economic, societal, environmental and political-institutional systems towards sustainable energy transitions is largely influencing the disruptive reconfiguration of the energy sector across the globe. At the heart of this disruption is the peer-to-peer energy sharing concept. Nonetheless, peer-to-peer energy sharing business models are yet very little put into practice due to the rigid energy market structures and lagging regulatory frameworks across the globe. In view of this, this paper presents a novel peer-to-peer energy sharing business model developed specifically for the context of the Portuguese energy market, which was successfully trialed in three pilot projects in Portugal under real market conditions. All things considered, the novelty of this paper lies on an innovative approach for the collaborative use of the surplus electricity generation from photovoltaic systems between end-users under the same low voltage/medium voltage transformer substation, which resulted in direct financial benefits to them. While absent deregulation obstructs the implementation of effective peer-to-peer energy sharing markets in Portugal, such demonstration projects are essential to challenge restrictive regulatory frameworks that do not keep pace with techno-economic and societal innovations, thus helping to build the emerging consumer-centric energy regime and disrupt the old one.

Development and analysis of a novel biomass-based integrated system for multigeneration with hydrogen production

Energy and exergy analyses of an integrated system based on anaerobic digestion (AD) of sewage sludge from wastewater treatment plant (WWTP) for multi-generation are investigated in this study. The multigeneration system is operated by the biogas produced from digestion process. The useful outputs of this system are power, freshwater, heat, and hydrogen while there are some heat recoveries within the system for improving efficiency. An open-air Brayton cycle, as well as organic Rankine cycle (ORC) with R-245fa as working fluid, are employed for power generation. Also, desalination is performed using the waste heat of power generation unit through a parallel/cross multi-effect desalination (MED) system for water purification. Moreover, a proton exchange membrane (PEM) electrolyzer is used for electrochemical hydrogen production option in the case of excess electricity generation. The heating process is performed via the rejected heat of the ORC's working fluid. The production rates for products including the power, freshwater, hydrogen, and hot water are obtained as 1102 kW, 0.94 kg/s, 0.347 kg/h, and 1.82 kg/s, respectively, in the base case conditions. Besides, the overall energy and exergy efficiencies of 63.6% and 40% are obtained for the developed system, respectively.

Industrial Data-Based Life Cycle Assessment of Architecturally Integrated Glass-Glass Photovoltaics

Worldwide, an increasing number of new buildings have photovoltaics (PV) integrated in the building envelope. In Switzerland, the use of coloured PV façades has become popular due to improved visual acceptance. At the same time, life cycle assessment of buildings becomes increasingly important. While a life cycle inventory for conventional glass-film PV laminates is available, this is not the case for glass-glass laminates, and in particular, coloured front glasses. Only conventional glass-film PV laminates are considered in databases, some of which are partly outdated. Our paper addresses this disparity, by presenting life cycle inventory data gathered from industries producing coloured front glass by digital ceramic printing and manufacturing glass-glass PV laminates. In addition, we applied this data to a hypothetical façade made of multi-coloured glass-glass laminates and its electricity generation in terms of Swiss eco-points, global warming potential, and cumulative energy demand as impact indicators. The results of the latter show that the effect of the digital ceramic printing is negligible (increase of 0.1%), but the additional glass (4% increase) and reduction of electricity yield (20%) are significant in eco-points. The energy pay-back time for a multi-coloured PV façade is 8.1 years, which decreases by 35% to 5.3 years when replacing the glass rain cladding in an existing façade, leaving 25 years for surplus electricity generation.

Economic and performance investigation of hybrid PV/wind/battery energy system for isolated Andaman and Nicobar islands, India

ABSTRACT This study presents an economic and performance investigation of stand-alone photovoltaic (PV), wind and PV–wind hybrid energy system for isolated Andaman and Nicobar islands, India. The optimal location is obtained from the highest solar insolation and wind speed data available from island geographic coordinates. The analysis is carried out by considering a typical seasonal load profile for the isolated single household. The cost of energy obtained from simulation results is found to be 0.583 US$/kWh (for stand-alone PV system), 0.394 US$/kWh (for stand-alone wind system) and 0.434 US$/kWh (for hybrid PV–wind system) with a capacity shortage of 5.6%, 10.3% and 1.2%, respectively. Besides the monthly average electricity generation, excess electricity generation, unmet electrical load, capacity shortage, converter output, battery state of charge, battery input/output power are also compared. The obtained results show that the implementation of stand-alone PV–wind hybrid system is a viable option in the aforementioned region.

An economic analysis of residential photovoltaic systems with lithium ion battery storage in the United States

Residential photovoltaic systems can reduce reliance on grid electricity, which may be desirable for numerous reasons. However, the economic viability of such systems is dependent on effective use of excess electricity generation, most often through net or bi-directional metering. With recent cost reductions in residential-scale lithium ion battery storage systems, these may be a practical alternative. In this work, we model the lifetime performance and economics of residential photovoltaics with lithium ion batteries across all 50 states in the U.S. We investigate in detail how photovoltaic size and battery capacity affect performance and cost metrics in California, Georgia, and Massachusetts. We find that with appropriate sizing, photovoltaic-battery systems can be more affordable than photovoltaics alone. We demonstrate that these systems may be competitive with grid prices when the federal investment tax credit and favorable financing terms are used, and we calculate the sell-back price required for bi-directional metering to reach cost parity with photovoltaic-battery systems in every state.

Tailoring large-scale electricity production from variable renewable energy sources to accommodate baseload generation in europe

Abstract This work investigates the possibility of combining large-scale penetration (around 50% of annual demand) of variable electricity production (wind and solar power) with baseload generation of electricity (e.g., via nuclear power or coal burning). A new methodology is developed that focuses on renewable resource and variation management in combination with transmission expansion and curtailment of excess electricity generation. Using the Conditional Value-at-Risk (CVaR) measure in the objective function, the optimization model targets the residual load and tailors it to fit the baseload generation. Using Europe as an example, the results show that it is possible to tailor the residual load to fit the baseload with only a small sacrifice (∼1%) of output of generation from variable renewable energy sources (VRES). Expansion of the electricity transmission system is an important factor in accommodating baseload generation in systems with a high penetration level of VRES, whereby, for example, 50 GW of transmission capacity opens the way for baseload generation to increase from 20% to 32% of annual demand. The results show that wind power is the main contributor to VRES production, even in the case of exceptionally low future costs for solar PV.

Utilisation of excess electricity in different Power-to-Transport chains and their environmental assessment

Future energy systems with dominating shares of non-dispatchable renewable energy sources will be confronted with excess electricity generation. Power-to-Transport applications for passenger cars are a promising flexible consumer for utilisation of excess electricity instead of its curtailment.Goal of this article is to design and assess future Power-to-Transport chains with regard to their substitution potential of conventional passenger cars and accompanying environmental impacts. This analysis focuses on Germany in the year 2050 as one example for a future renewable dominated energy system. As technologies battery and fuel cell electric vehicles as well as synthetic natural gas vehicles with internal combustion engines are analysed. To guarantee fuel supply, energy storage options are taken into account.Results show that excess electricity input enables highest travelling distances for the battery electric vehicle. This trend continues in the results of the environmental performance of the Power-to-Transport chains. With the lowest environmental impacts in eleven out of 13 categories battery electric vehicles show the best environmental performance. Furthermore, a detailed assessment of contributions from individual stages of the Power-to-Transport chains to entire results revealed that the vehicle construction dominates the majority of impact categories.

Examining interconnection and net metering policy for distributed generation in the United States

Following requirements of the Energy Policy Act of 2005, most U.S. states require utility companies to adopt interconnection and net metering policies, allowing customers to become prosumers who both consume and produce electricity, generating electricity using distributed renewable energy technologies, connecting to the existing electric utility grid and receiving compensation for excess electricity generation. This paper reviews existing interconnection and net metering policies instituted by investor owned utilities (IOUs) across the U.S., specifically focused on policies regulating installations of small scale, residential or Tier 1 (a term used to indicate policies applicable to smaller scale rather than larger scale, although the size at which DG systems are classified as either Tier 1 or higher tiers varies by utility). Publicly available data from each IOU reveal inconsistencies in interconnection and net metering policies, within states and even within individual companies. In addition, accurate information is often unavailable to consumers. Perhaps most importantly, results suggest that compensation for excess distributed generation often lacks transparent articulation in utility policy. The results of this study provide important insight into interconnection and net metering policies for distributed renewable energy generation, as states and utilities continue to modify interconnection and net metering policies in response to increased adoption of distributed renewable energy systems.

Model-based investigation of residual load smoothing through dynamic electricity purchase: The case of wastewater treatment plants in Germany

Energy systems with a high share of renewable electricity generation face a challenge associated with surplus electricity generation. Flexibility options may help to integrate renewable electricity and reduce the need for electricity from fossil fuels. Load shifting is one of the flexibility options that lead to residual load smoothing in energy systems. In this paper, the effects of load shifting by dynamic electricity purchase on future residual load smoothing was assessed using wastewater treatment plants (WWTPs) in Germany as a case study. As dynamic electricity purchase is motivated economically, a consumer’s demand for supplying flexibility options needs a price signal. Therefore, electricity wholesale prices on an hourly basis were modeled for 2030 using a merit order simulation for two scenarios. Relevant data for WWTPs was obtained from primary data suppliers, which was then aggregated. The effects on residual load smoothing were assessed by optimizing WWTPs electricity purchase costs on a daily basis. Our results show that German WWTPs have a potential to integrate 120MWel of surplus electric power. The developed methodology has a high potential to be applied to other potential load shifting actors when assessing the potential of residual load smoothing and renewable electricity integration. This can be achieved by adapting boundary constraints to other electricity consumers.

Optimized Hybrid Wind-Diesel Energy System with Feasibility Analysis

The enormous percentage of people in the world; particularly in the developing countries; are living mostly in decentralized, rural and remote areas, those are geographically secluded from the main grid connection. The power distribution and continuous fuel transportation to generate electricity for these areas pretenses a very big challenge. By proper utilization of renewable energy resources in off grid hybrid energy systems will be an efficient solution of this crisis. Moreover, the high cost of renewable energy systems has led to its slow adoption in many developing countries. Hence, it is very important to find an appropriate size of system in order to reduce the energy cost and excess electricity generation as well as to maximize the available resources. Therefore, a hybrid energy system has been designed and simulated to support a small community considering an average load demand of 85 kWh/d with a peak load of 8.7 kW. The simulation and optimization of the system have been performed by the HOMER software using real time field data of solar radiation, wind speed and biomass of that particular area. The simulation results confirm that the system is suitably feasible with respect to the net present cost (NPC) and CO2 emission reduction purpose. The simulation results also confirm that the NPC and CO2 emission can be reduced about 32.45% and 29 tons per year respectively compared to the conventional power plants. The NPC of the optimized system has been found about USD $160,626 having per unit Cost of Energy (COE) about USD $0.431/kWh and the operating cost USD $10,779/yr.

Examining Interconnection and Net Metering Policy for Distributed Generation in the United States

Following requirements of the Energy Policy Act of 2005, most U.S. states require utility companies to adopt interconnection and net metering policies, allowing customers to become prosumers who both consume and produce electricity, generating electricity using distributed renewable energy technologies, connecting to the existing electric utility grid and receiving compensation for excess electricity generation. This paper reviews existing interconnection and net metering policies instituted by investor owned utilities (IOUs) across the U.S., specifically focused on policies regulating installations of small scale, residential or Tier 1 (a term used to indicate policies applicable to smaller scale rather than larger scale, although the size at which DG systems are classified as either Tier 1 or higher tiers varies by utility). Publicly available data from each IOU reveal inconsistencies in interconnection and net metering policies, within states and even within individual companies. In addition, accurate information is often unavailable to consumers. Perhaps most importantly, results suggest that compensation for excess distributed generation often lacks transparent articulation in utility policy. The results of this study provide important insight into interconnection and net metering policies for distributed renewable energy generation, as states and utilities continue to modify interconnection and net metering policies in response to increased adoption of distributed renewable energy systems.

Lab-scale experimental studies of Fischer–Tropsch kinetics in a three-phase slurry reactor under transient reaction conditions

Fluctuating electricity can be converted into hydrocarbon fuels via hydrogen as intermediate, thus replacing fossil fuels and possibly be attractive as a long-term storage in excess electricity generation situations. In this context, flexible operation of the chemical synthesis reactor may be motivated by the possibility of reducing the size of the hydrogen storage and the investment needed. The present study has the aim to identify general aspects and limitations of flexible Fischer–Tropsch reactor operation considering catalyst behavior and reactor operation in a three-phase system. In this contribution, methodology and first results of lab-scale experiments with a stirred slurry reactor are presented. Results of step-change experiments can be described by a mathematical model of the lab-scale setup, using steady-state kinetics determined in separate experiments. During periodic-change experiments, average rates of CO consumption and CH4 formation are not affected by period length. In contrast, analysis of periodic-change experiments with emphasis on hydrocarbon product distribution indicate that long chain hydrocarbon molar flows cannot follow forced oscillation as fast as methane molar flow.

Getting to Net Zero on a Budget

Only a few homes in the US have demonstrated net zero energy performance over a full year. Of the successful net zero energy projects for detached single-family homes, most have been newly constructed, rather than retrofits. A cost-effective retrofit strategy for single-family homes could expand net zero options to a broader segment of the housing stock, a segment with a relatively high energy consumption per household. Also, most net zero energy projects are limited to the structures on the property, and are focused on energy, rather than greenhouse gas (GHG), primarily carbon dioxide (CO2) emissions. Expanding the scope to incorporate not only energy from structures, but also a household's CO2 emissions from structures and vehicles would enable the evaluation of strategies to reduce all Scope 1 and 2 emissions. These are the emissions that a household has direct control over, namely the direct combustion or emission of CO2 and the emissions caused by the household's use of electricity.One family's net zero project in Washington, DC, aims to demonstrate cost-effective attainment of annual zero net CO2 emissions not only from the retrofitted home itself, but from the household's two vehicles. In this way, the household will lower its net Scope 1 and 2 emissions to zero. The project's house-related energy reduction investments to date consist of a ground source heat pump, solar hot water, spray foam insulation, lighting upgrades, new windows, programmable thermostats, and other energy efficiency retrofits. These investments and activities have resulted in 65% reduced energy consumption and 32% reduction in house-related CO2 emissions (before taking into account on-site solar generation). Over the course of a year, the total house-related energy consumption of 33 million British thermal units (MMBtu) (mostly electricity with some natural gas for cooking) was lower than the 36 MMBtu electricity generated by the 9.8 kW of roof-mounted solar photovoltaic (PV) panels.To reduce the household's net Scope 1 and 2 GHG emissions to zero, vehicle-related CO2 emissions also were addressed in the project. Excess electricity generation from the PV panels is used to offset electricity required to power an electric vehicle for daily commuting requirements (up to 8,000 miles annually). A second vehicle is primarily fueled by biodiesel and used for longer trips.By August 2014, four years after the project began, the project had demonstrated that for certain markets, commercially available energy technologies can enable a suburban single-family detached house to be cost-effectively retrofitted and operated to achieve net positive GHG emissions. The household achieved a year of net zero house-related electricity, energy, and emissions in October, 2013, possibly becoming the first home to achieve that distinction in the District of Columbia. For the 12 months to September, 2014, combined net building and vehicle (Scope 1 and 2) CO2 emissions of 1.9 MT was 86% less than annual building and vehicle emissions prior to the project of approximately 13.6 MT CO2. The household is expected to have demonstrated 12 months of net zero emissions for the home and two vehicles (Scope 1 and 2) in 2015.The project also demonstrates a process for determining a combination of energy saving technologies with potential to reduce emissions sharply, possibly up to net zero overall household emissions, at a relatively low cost and impact to occupants.The family that carried out the project funded the project at its own expense, without any sponsorship or support other than government incentives available to the general public. Total energy related investments after state and federal incentives are approximately $85,000. The family expect to see a complete return on these energy investments in 10 years.

Enabling solar electricity with electric vehicles smart charging

It has been shown that a long term sustainable energy system based on a high penetration of solar photovoltaics requires massive deployment of day charging electric vehicles to make use of the excess solar electricity generation at sun peak hours. In this paper the synergy between these technologies is further explored, determining the minimum penetration levels that allow fulfilling the climate and energy targets. Simulations for a case study of Portugal in 2050 using an electric vehicles smart charging approach show that a 100% renewable energy based electricity supply is possible with certain photovoltaics and electric vehicles combinations and that the environmental targets to reduce carbon dioxide emissions are just reachable with significant electric vehicles market share. The notion that vehicle charging will have to take place during working hours to maximize petroleum displacement is reinforced.

Cost-optimal design of a simplified, highly renewable pan-European electricity system

Based on a data-intensive weather-driven modelling approach, technically and economically optimal designs are derived for a simplified, highly renewable pan-European electricity system, which minimise the need for backup energy, backup capacity, transmission capacity and the levelised system cost of delivered electricity. The overall cost-optimal design, based on standard cost assumptions, relies on synchronised backup across the transmission grid and comes with a renewable penetration of 50% with a rather high wind fraction of 94%. Given the current European electricity consumption, this corresponds to 600 GW rated wind power capacities, 60 GW installed solar power capacities, 320 GW conventional backup power capacity, and about five times today's installed transmission capacities. A sensitivity analysis reveals that the design and cost of the optimal system depend mostly on the assumed cost of wind capacity and fuel for backup energy. Lower costs for wind capacity, higher costs for backup energy and usage of otherwise curtailed excess electricity generation lead to a strong increase of the optimal renewable penetration. The sensitivity analysis is also used to find that a CO2 tax of over 100 €/ton would be needed for the economic viability of carbon capture and sequestration.

Economic perspective of hybrid wind-diesel technology for commercial loads of Dhahran Saudi Arabia: A step towards sustainable future

The governments world-wide are deliberating to promote renewable energy sources such as wind to mitigate increasing demand of energy and to overcome effects of pollution due to to use of fossil fuels. Integration of wind turbine generators (WTG) with the diesel plants is pursued widely to reduce dependence on fossil-fuels and to reduce carbon emissions. Literature indicates that commercial/residential buildings in the Kingdom of Saudi Arabia (K.S.A) consume an estimated 10 - 40% of the total electric energy generated. The aim of this study is to analyze wind-speed data of Dhahran (East-Coast, K.S.A.) to assess the economic feasibility of utilizing hybrid wind-diesel power systems to meet the load requirements of a typical commercial building (with annual electrical energy demand of 620,000 kWh). The monthly average wind speeds range from 3.3 to 5.6 m/s. The hybrid systems simulated consist of different combinations of 100 kW commercial WTG supplemented with diesel generators. NREL?s (HOMER Energy?s) HOMER software has been employed to perform the techno-economic analysis. The simulation results indicate that for a hybrid system comprising of 100 kW wind capacity together with 175 kW diesel system, the wind penetration (at 37 m hub-height, with 0% annual capacity shortage) is 25%. The cost of generating energy (COE, $/kWh) from this hybrid wind-diesel system has been found to be 0.121 $/kWh (assuming diesel fuel price of 0.1$/liter). The study exhibits that for a given hybrid configuration, the number of operational hours of diesel gensets decreases with increase in wind farm capacity. Emphasis has also been placed on wind penetration, un-met load, energy production and COE, excess electricity generation, percentage fuel savings and reduction in carbon emissions (relative to diesel-only situation) of different hybrid systems, cost break-down of wind-diesel systems, COE of different hybrid systems, etc.