Bidirectional EV Battery Load Leveling for Building Peak Demand
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Demand charges in electric service billing penalize peak energy demands, which can be inefficient due to the high cost of battery storage solutions, and existing technologies do not effectively utilize electric vehicles (EVs) for load leveling without affecting their range or utility.
Innovation Solution
Electric vehicles are connected to buildings via a bidirectional electrical connection to supply energy to intermittent loads, using their batteries to level demand by providing DC power directly or indirectly, eliminating the need for an inverter and minimizing costs by leveraging existing EV charging infrastructure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If battery storage solutions are used to level demand and reduce peak loads, then demand charges are reduced, but the cost of implementing battery storage is high
Solution Approach 1:
The electric vehicle battery is utilized for dual purposes: (1) providing propulsion energy for vehicle operation, and (2) serving as a stationary energy storage system for demand charge management. The bidirectional charging system enables the vehicle battery to discharge power to level building demand peaks while still being recharged from the grid during off-peak periods, eliminating the need for dedicated battery storage infrastructure.
Solution Approach 2:
The electric vehicle itself provides the energy storage service it would otherwise need to purchase separately. By utilizing the vehicle's existing battery capacity and bidirectional charging capability, the system turns the vehicle into a self-sufficient demand response resource that can reduce its own energy costs while providing service to the building.
2Loss of energy
If electric vehicles are used for load leveling, then demand charges are reduced, but the vehicle's range or utility may be affected
Solution Approach 1:
The vehicle battery operates in periodic charge-discharge cycles that are strategically timed to match building demand patterns. The vehicle charges from the grid during off-peak periods when building demand is low, and discharges during peak demand periods when the building requires power. This periodic operation allows the battery to provide demand response services without depleting its charge during normal vehicle operation.
Solution Approach 2:
The system dynamically manages the vehicle battery's state of charge based on real-time conditions including vehicle range requirements, building demand patterns, and grid pricing signals. The bidirectional charging system can adjust charge/discharge rates and timing to ensure the vehicle maintains sufficient charge for its transportation needs while maximizing demand charge reductions.
3Adaptability or versatility
If an inverter is used to convert DC to AC for powering loads, then AC loads can be supplied, but system complexity and cost increase
Solution Approach 1:
Instead of converting all vehicle battery power to AC through an inverter, the system identifies and directly powers DC-compatible loads (such as LED lighting, DC-powered appliances, and electronic equipment with DC input) from the vehicle's DC battery output. This localized DC power delivery eliminates the need for inversion for these loads, reducing system complexity and improving efficiency.
Solution Approach 2:
The system extracts and utilizes the DC power component from the vehicle battery independently, bypassing the AC inversion process for DC-compatible loads. By separating the power delivery paths and directly connecting DC loads to the DC battery output, the system eliminates the inverter component from the power architecture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces demand charges by averaging peak loads, utilizing the vehicle's battery storage capacity to lower energy costs without impacting the EV's range or utility, providing a cost-effective solution for load management.
Implementation Method 1
supplying electric energy to intermittent loads from the batteries of parked electric vehicles
Data Source
AI summary
This invention has as its objective provision of a method and apparatus to enable the batteries of Electric Vehicles (EV)s to level the electric demand in buildings to reduce demand charges based on instantaneous demand for electric power. This load leveling is done by connecting the EV to the building electrical system by its conventional Alternating Current (AC) recharging connection, and by an additional Direct Current (DC) path supporting intermittent loads. In this way the EV battery stands between the AC energy source and the intermittent load and reduces the electric power drawn from the grid to a constant minimum level, thereby minimizing demand charges.