18,839 research outputs found
Emission-aware Energy Storage Scheduling for a Greener Grid
Reducing our reliance on carbon-intensive energy sources is vital for
reducing the carbon footprint of the electric grid. Although the grid is seeing
increasing deployments of clean, renewable sources of energy, a significant
portion of the grid demand is still met using traditional carbon-intensive
energy sources. In this paper, we study the problem of using energy storage
deployed in the grid to reduce the grid's carbon emissions. While energy
storage has previously been used for grid optimizations such as peak shaving
and smoothing intermittent sources, our insight is to use distributed storage
to enable utilities to reduce their reliance on their less efficient and most
carbon-intensive power plants and thereby reduce their overall emission
footprint. We formulate the problem of emission-aware scheduling of distributed
energy storage as an optimization problem, and use a robust optimization
approach that is well-suited for handling the uncertainty in load predictions,
especially in the presence of intermittent renewables such as solar and wind.
We evaluate our approach using a state of the art neural network load
forecasting technique and real load traces from a distribution grid with 1,341
homes. Our results show a reduction of >0.5 million kg in annual carbon
emissions -- equivalent to a drop of 23.3% in our electric grid emissions.Comment: 11 pages, 7 figure, This paper will appear in the Proceedings of the
ACM International Conference on Future Energy Systems (e-Energy 20) June
2020, Australi
Introducing small storage capacity at residential PV installations to prevent overvoltages
Low voltage distribution feeders are designed for
unidirectional energy supply from transformer to consumer. However, the implementation of small-scale PV production units on local utilities may result in bidirectional energy flows. The simultaneous power injection at sunny moments may cause a serious voltage rise along the feeder. These overvoltages may not only damage critical loads but also switches PV inverters off causing loss of green energy at the most productive moments. This paper presents a method to limit the voltage rise by introducing small battery buffers at local production sites. A smart inverter decides whether the PV energy is injected in the grid or buffered in the batteries. The relation between battery buffer size and overvoltage reduction is presented for a typical Belgian residential distribution feeder. The influence of the buffer along the feeder is calculated by working with synthetic load profiles and solar irradiation data
Achieving Very High PV Penetration
This article argues that optimally deployed intermittency solutions could affordably transform solar power generation into the firm power delivery system modern economies require, thereby enabling very high solar penetration and the displacement conventional power generation. The optimal deployment of these high‐penetration enabling solutions imply the existence of a healthy power grid, and therefore imply a central role for utilities and grid operators. This article also argues that a value‐based electricity compensation mechanism, recognizing the multifaceted, penetration‐dependent value and cost of solar energy, and capable of shaping consumption patterns to optimally match resource and demand, would be an effective vehicle to enable high solar penetration and deliver affordable firm power generation
Time-Series Analysis of Photovoltaic Distributed Generation Impacts on a Local Distributed Network
Increasing penetration level of photovoltaic (PV) distributed generation (DG)
into distribution networks will have many impacts on nominal circuit operating
conditions including voltage quality and reverse power flow issues. In U.S.
most studies on PVDG impacts on distribution networks are performed for west
coast and central states. The objective of this paper is to study the impacts
of PVDG integration on local distribution network based on real-world settings
for network parameters and time-series analysis. PVDG penetration level is
considered to find the hosting capacity of the network without having major
issues in terms of voltage quality and reverse power flow. Time-series analyses
show that distributed installation of PVDGs on commercial buses has the maximum
network energy loss reduction and larger penetration ratios for them.
Additionally, the penetration ratio thresholds for which there will be no power
quality and reverse power flow issues and optimal allocation of PVDG and
penetration levels are identified for different installation scenarios.Comment: To be published (Accepted) in: 12th IEEE PES PowerTech Conference,
Manchester, UK, 201
Solar+Storage for Low-and Moderate-Income Communities: A Guide for States and Municipalities
The Clean Energy States Alliance (CESA) has produced a new report for states and municipalities on solar+storage for low- and moderate-income (LMI) communities. The report explains how solar+storage can benefit LMI residents and describes a variety of policy tools for doing so, including grants, rebates, utility procurement standards, financing support, opening markets, and soft cost reduction
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