Energy Storage Dispatch for Demand Charge Reduction
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Solution Overview
Problem
Photovoltaic systems face challenges in effectively dispatching stored electrical energy to reduce demand charges, which are influenced by time of use and peak demand periods, with limited solutions available for optimizing energy distribution across extended periods.
Innovation Solution
A method and system that monitor facility load demand, compare it against demand caps, and strategically discharge or charge energy storage systems to manage peak demand periods, using a control system to optimize energy dispatch and recharge based on forecasted demand and available energy storage capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If photovoltaic systems store electrical energy for later use, then energy availability is extended, but the ability to reduce demand charges during peak periods is limited
Solution Approach 1:
The system performs preliminary actions by charging the energy storage system during off-peak periods when demand charges are low, and then discharges the stored energy during peak periods when demand charges are high. This advance preparation allows the system to effectively reduce demand charges while extending energy availability across different time periods.
Solution Approach 2:
The control system dynamically adjusts the charging and discharging operations of the energy storage system based on real-time monitoring of facility load demand, forecasted demand, and current energy storage capacity. This dynamic operation optimizes the timing and amount of energy discharge to maximize demand charge reduction while maintaining extended energy availability.
2Loss of energy
If energy storage systems discharge at high power during peak demand, then demand charges are reduced, but the duration of energy availability decreases
Solution Approach 1:
The control system implements partial action by discharging the energy storage system at power levels that are optimized rather than maximum. It determines the precise amount of power needed to reduce demand charges and discharges only that necessary amount, preserving remaining energy for extended availability while still achieving demand charge reduction objectives.
Solution Approach 2:
The system continuously monitors facility load demand, compares actual demand against forecasted demand, and adjusts discharge power levels in real-time based on feedback from these measurements. This feedback mechanism ensures that the energy storage system discharges at optimal power levels to reduce demand charges while maintaining sufficient energy for extended availability.
3Loss of energy
If the control system monitors and adjusts energy dispatch in real-time, then demand charge reduction is optimized, but system complexity increases
Solution Approach 1:
The control system is designed to perform multiple functions: monitoring facility load demand, forecasting future demand, determining optimal discharge power levels, controlling energy storage charging/discharging, and tracking energy storage capacity. By consolidating these diverse functions into a single multi-functional control system, the patent manages complexity while achieving optimized demand charge reduction.
Solution Approach 2:
The control system autonomously monitors facility load demand, forecasts future demand, determines optimal discharge strategies, and executes control decisions without requiring constant external intervention. This self-service capability simplifies the overall system architecture by making the control system self-sufficient while maintaining optimized demand charge reduction performance.
Data Source
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AI summary
Demand of a facility load for electrical energy is monitored (201) and compared to a demand cap (202) for a demand period. A demand cap may be set for peak periods, another demand cap may be set for part-peak periods, and yet another demand cap may be set for off-peak periods. Dispatch of electrical energy from the energy storage system is based on the demand of the facility load relative to the demand cap (204).