Residential PV capacity estimation and power disaggregation using net metering measurements

As the intermittency and uncertainty of photovoltaic(PV)power generation poses considerable challenges to the power system operation,accurate PV generation estimates are critical for the distribution operation,maintenance,and demand response program implementation because of the increasing usage of distributed PVs.Currently,most residential PVs are installed behind the meter,with only the net load available to the utilities.Therefore,a method for disaggregating the residential PV generation from the net load data is needed to enhance the grid-edge observability.In this study,an unsupervised PV capacity estimation method based on net metering data is proposed,for estimating the PV capacity in the customer’s premise based on the distribution characteristics of nocturnal and diurnal net load extremes.Then,the PV generation disaggregation method is presented.Based on the analysis of the correlation between the nocturnal and diurnal actual loads and the correlation between the PV capacity and their actual PV generation,the PV generation of customers is estimated by applying linear fitting of multiple typical solar exemplars and then disaggregating them into hourly-resolution power profiles.Finally,the anomalies of disaggregated PV power are calibrated and corrected using the estimated capacity.Experiment results on a real-world hourly dataset involving 260 customers show that the proposed PV capacity estimation method achieves good accuracy because of the advantages of robustness and low complexity.Compared with the state-of-the-art PV disaggregation algorithm,the proposed method exhibits a reduction of over 15%for the mean absolute percentage error and over 20%for the root mean square error.

Water, Air Emissions, and Cost Impacts of Air-Cooled Microturbines for Combined Cooling, Heating, and Power Systems： A Case Study in the Atlanta Region

The increasing pace of urbanization means that cities and global organizations are looking for ways to increase energy efficiency and reduce emissions. Combined cooling, heating, and power （CCHP） systems have the potential to improve the energy generation efficiency of a city or urban region by providing energy for heating, cooling, and electricity simultaneously. The purpose of this study is to estimate the water consumption for energy generation use, carbon dioxide （CO2） and NOx emissions, and economic impact of implementing CCHP systems for five generic building types within the Atlanta metropolitan region, under various operational scenarios following the building thermal （heating and cooling） demands. Operating the CCHP system to follow the hourly thermal demand reduces CO2 emissions for most building types both with and without net metering. The system can be economically beneficial for all building types depending on the price of natural gas, the implementation of net metering, and the cost structure assumed for the CCHP system. The greatest reduction in water consumption for energy production and NOx emissions occurs when there is net metering and when the system is operated to meet the maximum yearly thermal demand, although this scenario also results in an increase in greenhouse gas emissions and, in some cases, cost. CCHP systems are more economical for medium office, large office, and multifamilv residential buildings.

Optimal Day-ahead Dynamic Pricing of Grid-connected Residential Renewable Energy Resources Under Different Metering Mechanisms

Nowadays,grid-connected renewable energy resources have widespread applications in the electricity market.However,providing household consumers with photovoltaic(PV)systems requires bilateral interfaces to exchange energy and data.In addition,residential consumers’contribution requires guaranteed privacy and secured data exchange.Dayahead dynamic pricing is one of the incentive-based demand response methods that has substantial effects on the integration of renewable energy resources with smart grids and social welfare.Different metering mechanisms of renewable energy resources such as feed-in tariffs,net metering,and net purchase and sale are important issues in power grid operation planning.In this paper,optimal condition decomposition method is used for dayahead dynamic pricing of grid-connected residential renewable energy resources under different metering mechanisms:feed-intariffs,net metering,and net purchase and sale in conjunction with carbon emission taxes.According to the stochastic nature of consumers’load and PV system products,uncertainties are considered in a two-stage decision-making process.The results demonstrate that the net metering with the satisfaction average of 68%for consumers and 32%for the investigated electric company leads to 28%total load reduction.For the case of net purchase and sale mechanism,a satisfaction average of 15%for consumers and 85%for the electric company results in 11%total load reduction.In feed-in-tariff mechanism,in spite of increased social welfare,load reduction does not take place.

FEASIBILITY OF AN OFF-GRID RENEWABLE ENERGY SOURCE FOR THE MERCANTILE SECTOR

Increased CO_(2),a Greenhouse Gas(GhG),emission and its accumulation in the atmosphere is a major climatic con­cern,creating an urgent need to control its rate of growth with the goal to reduce or reverse the growth.Reduction is being attempted at macro scales(large GhG producers but relatively small in number),at mezzo levels(mercantile stores which are large in numbers and relatively large consumers in scale)and at micro scales(individual dwell­ing units which are very large in number but relatively small on a GhG producer scale).This research identifies the strategies and challenges of adopting an off-grid renewable energy source for the mercantile sector(retail)at the mezzo level.A theoretical model for an off-grid renewable energy source considering a parking lot of a retail outlet was developed.In future work,a proposed physical model should be able to test the assumptions and hypothesis of the theoretical model presented.The proposed hybrid system uses two or more alternative renewable energy sources.In the proposed system,solar energy is integrated with a local bio gas plant,which treats waste to produce electricity.The excess energy can be sold to grid using net metering or dual metering or sold to charge plug-in vehicles to earn revenue.The renewable energy produced reduces the grid load on public utilities,thereby reducing the amount of CO_(2)emissions from the grid pro­viders,thus bridging the current grid dependent system and a grid-independent(off grid,or net zero)goal.

Wind and Solar Power in the United States:Status and Prospects

The United States has committed to reduce its greenhouse gas emissions by 26%–28%by 2025 and by 83%by 2050 relative to 2005.Meeting these objectives will require major investments in renewable energy options,particularly wind and solar.These investments are promoted at the federal level by a variety of tax credits,and at the state level by requirements for utilities to include specific fractions of renewable energy in their portfolios(Renewable Portfolio Standards)and by opportunities for rooftop PV systems to transfer excess power to utilities through net metering,allowing meters to operate in reverse.The paper discusses the current status of these incentives.