Lowest Levelized Cost Of Electricity Research Articles

Sensitivities of Power-to-gas Within an Optimised Energy System

The storage of fluctuating energy production is a major challenge on the pathway to a fully renewable electricity supply. This paper investigates the role of Power-to-Gas (PtG) as a key storage technology in the fulfilment of the Energiewende. This study describesthe optimal composition and application of energy supply technologies using a detailed cost optimisation model based on data from an existing system in an actual German region. The region's electricity demand can be covered with 100% renewables at a levelised cost of electricity (LCOE) of 11 ct/kWhel. We found that the PtG capital expenditures (CAPEX) do not significantly affect the optimal system in terms of the installed capacity of PtG. Due to the high storage capacity of the existing gas grid, the use of PtG results in lower LCOE than the use of batteries. Alteration of system components towards greaterfluctuating energy production increases the need forlong-term energy storage, especially PtG, and results inhigher total costs. In summary, this investigation demonstrates the significance of Power-to-Gas.

Modeling and optimization of batteryless hybrid PV (photovoltaic)/Diesel systems for off-grid applications

This paper presents a new model and optimization procedure for off-grid hybrid PV (photovoltaic)/Diesel systems operating without battery storage.The proposed technico-economic model takes into account the variability of both the solar irradiation and the electrical loads. It allows optimizing the design and the operation of the hybrid systems by searching their lowest LCOE (Levelized Cost of Electricity). Two cases have been investigated: identical Diesel generators and Diesel generators with different sizes, and both are compared to conventional standalone Diesel generator systems. For the same load profile, the optimization results show that the LCOE of the optimized batteryless hybrid solar PV/Diesel (0.289 €/kWh for the hybrid system with identical Diesel generators and 0.284 €/kWh for the hybrid system with different sizes of Diesel generators) is lower than the LCOE obtained with standalone Diesel generators (0.32 €/kWh for the both cases). The obtained results are then confirmed by HOMER (Hybrid Optimization Model for Electric Renewables) software.

Assessment of Different PCM Storage Configurations in a 50 MWel CSP Plant with Screw Heat Exchangers in a Combined Sensible and Latent Storage – Simulation Results

Abstract Effective and economic storage solutions have an important role to enable Solar Thermal Electricity plants (STE) to generate dispatchable power. A thermal storage can increase the value of STE by providing firm electricity in times of peak load or ancillary services. Latent storages are suited optimally for direct steam generating STE systems: due to the isothermal behavior of the phase change materials (PCM) during melting /crystallization, exergy losses during storage charging/discharging are minimized. Up to now latent heat storages are, due to technical and economic issues, not used commercially in STE systems. The PCM have a very low heat conductivity – therefore a sophisticated heat exchanger design is needed to build such storages with sufficient charging/discharging power. An innovative storage concept, uses a screw heat exchanger to transport the PCM from a cold to a hot tank or vice versa during phase change. This concept separates heat exchange and storage tanks.Existing concepts do not have this ability. In annual yield calculations the use of this heat exchanger as part of a thermal storage in a 50 MW el direct steam generating solar thermal power plant has been assessed. After setting up of a cost structure, the respective levelised cost of electricity (LCOE) have been used as comparison criterion for two storage systems with different designs. It can be shown, that a storage system with three storage tanks yields lower LCOE than one with two storage tanks. There is further potential for cost reductions, such as the optimization of the heat exchanger area and the temperature difference between the heat transfer fluid and the PCM.

Biomass and central receiver system (CRS) hybridization: Integration of syngas/biogas on the atmospheric air volumetric CRS heat recovery steam generator duct burner

Central receiver systems (CRS) are a promising concentrated solar power (CSP) technology for dispatchable electricity generation. The CRS levelized cost of electricity (LCOE) is usually increased by low power-block capacity factors or by high thermal storage costs. The economical turnover is still positive for the Portuguese case but depends on the bonus feed-in tariffs. On the other hand, with biomass existing feed-in tariffs and raising prices, the viability of current biomass power plants is at risk. To address these issues, several base case power plants and hybrid biomass/CSP options are analyzed: wood gasification, refuse-derived fuel pellets, biogas from a wastewater anaerobic digester, biogas from a landfill and natural gas.The solution with lower LCOE was obtained for the hybridization of a 4 MWe CRS using an atmospheric volumetric receiver with biogas from an anaerobic digester using sludge from a wastewater treatment plant (WWTP). Different results would be obtained for the hybrid systems if different CRS technologies are used. The hybrid CRS/anaerobic digester power plant LCOE is 0.15 €/kWh, returning the investment in 13 years (assuming sludge collection and transport without cost) with the best net present value (15 million euro) and internal rate of return of all the hybrid options.

Alternative Energy Storage for Wind Power: Coal Plants with Amine-based CCS

Abstract This paper analyses the performance of a hybrid system consisting of an existing coal plant with post-combustion amine based CCS with amine storage, and a co-located wind farm. The amine storage system allows storage of the CO 2 -rich amine solution to reduce the energy penalty of the CCS system at times of high electricity prices/high demand. The amine-rich solution can be regenerated at an enhanced rate when electricity prices are relatively low or when wind power output exceeds the transmission capacity of the connector lines: effectively providing ‘storage’ for wind power and a mechanism for muting the variability of wind power output. Using prices and wind data from the eastern region of U.S., we find the optimal configuration and operation, profits, Cost of CO 2 Capture (CoC), and Levelized Cost of Electricity (LCOE) of the hybrid system, with and without constraints on the variability of the net power output. We find that favourable conditions regarding price arbitrage opportunities and wind power output variability -same or lower variability than that observed in ∼70% of sites in the EWITS database- allow the hybrid system to be more cost effective than other alternatives for reducing CO 2 emissions from an existing coal-fired power plant and/or integrating wind power as a component of a base-load plant. For example, hybrid systems with up to 10% of the total installed capacity from the wind farm, can operate as a base-load plant, and still be more profitable and have lower LCOE and CoC values, than a continuously operating coal plant with a CCS retrofit. Using an existing plant as a component of a hybrid system can result in lower CoC than replacing it with a new Natural Gas Combined Cycle power plant -assuming natural gas prices are in the range 6-8 $/MMBtu.

Optimizing the Front Electrode of Silicon-Wafer-Based Solar Cells and Modules

Front electrode optimization is one of the important design considerations that affects the efficiency of a silicon wafer solar cell. The optimization of the front electrode is usually done to maximize cell efficiency at standard test conditions (STC). However, with increasing prices in silver, optimization of the front electrode should be done by taking into account the cost of the silver paste. In this study, optimization of the front electrode is done at the cell level at STC (dollars per watt peak), module level at STC (dollars per watt peak), and under real-world module conditions (dollars per kilowatthour), taking into account the cost of the silver paste. For commercial screen-printed multicrystalline silicon wafer solar cells, it is found that to achieve the most cost-effective cell design at the outdoor module level (dollars per kilowatthour), the number of front metal fingers can be strongly reduced (by more than 20) compared with a conventional cell design, which is maximized for STC cell efficiency. For silver price of $1286/kg, optimization at the cell and module level for lowest cost will yield up to 1% cost savings compared with optimization for maximum efficiency. Optimization for the lowest levelized cost of electricity (LCOE) will yield on average 0.6% lower LCOE compared with optimization for maximum annual energy output.

Can Hybrid Solar-Fossil Power Plants Mitigate CO2 at Lower Cost than PV or CSP?

Fifteen of the United States and several nations require a portion of their electricity come from solar energy. We perform an engineering-economic analysis of hybridizing concentrating solar thermal power with fossil fuel in an Integrated Solar Combined Cycle (ISCC) generator. We construct a thermodynamic model of an ISCC plant in order to examine how much solar and fossil electricity is produced and how such a power plant would operate, given hourly solar resource data and hourly electricity prices. We find that the solar portion of an ISCC power plant has a lower levelized cost of electricity than stand-alone solar power plants given strong solar resource in the US southwest and market conditions that allow the capacity factor of the solar portion of the power plant to be above 21%. From a local government perspective, current federal subsidies distort the levelized cost of electricity such that photovoltaic electricity is slightly less expensive than the solar electricity produced by the ISCC. However, if the cost of variability and additional transmission lines needed for stand-alone solar power plants are taken into account, the solar portion of an ISCC power plant may be more cost-effective.