Electric vehicle batteries are often underused, prompting innovations to turn them into effective power storage for homes and solar systems. Regulatory and technical challenges hinder bidirectional charging, but Energy Island Power has developed a solution enabling seamless household energy supply from vehicle batteries. Their devices prevent unintentional grid feed-in and enhance efficiency. While user-friendly, some vehicles’ V2L functionalities may be inconvenient. Energy Island’s products are expected to launch in mid-2025, with pricing yet to be announced.
Maximizing Electric Vehicle Battery Usage
Electric vehicle batteries often remain unused for the majority of the day, with only 10 to 15 percent of their capacity being utilized in daily life. This underutilization has sparked numerous innovative ideas aimed at transforming electric cars into effective power storage solutions for homes, solar energy systems, and even the public electricity grid.
Overcoming Regulatory and Technical Challenges
Despite the potential benefits, existing regulations and technological limitations have posed significant hurdles for electric vehicle owners looking to utilize their cars as a buffer for solar power through bidirectional charging. Many suitable wall boxes are prohibitively expensive and frequently lack approval in Germany. The process of feeding power from the vehicle back into the grid (known as V2G, or ‘Vehicle to Grid’) is often made unattractive due to bureaucratic complexities and an absence of appealing pricing models. However, there are numerous electric vehicles capable of supplying power from their batteries to specific consumers (referred to as V2L, or ‘Vehicle to Load’).
Energy Island Power, a manufacturer based in Lehrte, has developed a groundbreaking solution that allows for seamless and safe use of V2L to power an entire household.
Innovative Power Solutions for Homes
The car’s energy can be redirected through the solar inverter, utilizing simple inverters within the vehicle to produce 230 volts of alternating current. These inverters should never be directly linked to the power grid, as this could result in a short circuit. Energy Island’s ‘Power Unit’ cleverly circumvents this issue by converting the alternating current from the car into direct current, housed in a compact device comparable in size to a first aid kit. It effectively simulates the power output of photovoltaic (PV) modules, allowing for connection to a standard roof PV system’s inverter using conventional PV wiring. The Power Unit boasts a maximum output of 3,000 watts, which can be manually adjusted to 400 watts.
For the solar inverter, the source of the power is irrelevant—it can either charge the system’s battery, supply energy to household consumers, or contribute excess power to the grid. However, feeding energy back into the grid is generally not financially beneficial and is often undesirable. Owners of older solar systems with high feed-in tariffs may perceive profitability differently, but it is crucial to note that only power generated directly from the registered PV system is permitted for feeding into the grid.
Preventing Unwanted Power Feed-In
Energy Island has devised a practical solution to prevent unintentional feeding of power back into the grid. They provide two distinct control units: one for the proprietary Eaton interface of E3DC inverters and another for the open Clever-PV standard, which accommodates a wide range of PV components. These control units can adjust the power draw from the car battery based on the solar storage levels in the home, such as automatically shutting off when the battery level exceeds 70 percent.
Another innovation is Energy Island’s ‘Connect Unit,’ which addresses the issue of limited inputs on solar inverters. This unit divides one input into two branches that are automatically managed, enabling one input to be utilized at night for energy supply from the car battery without the need for unplugging.
Addressing Efficiency and Usability Challenges
Despite the advantages, the process of converting power from generation in PV modules through inverters and wall boxes into the car—and back again—can lead to energy inefficiencies. The constant conversions can result in energy losses of up to one-third of the original output. However, even with these losses, it may still be beneficial to utilize the remaining power rather than selling it back to the grid for minimal feed-in tariffs.
While Energy Island’s technology offers a user-friendly integration with home solar systems, the V2L functionalities within vehicles can be less convenient. Typically, switching between charging and discharging requires either a charging cable or the V2L adapter to be connected to the car’s charging port, necessitating unplugging during transitions. Additionally, some vehicles, like certain models from Chinese manufacturers, only permit V2L operation when the ignition is on. In contrast, the forthcoming bidirectional solution from Renault for the R5 is expected to handle both charging and discharging automatically through a single cable, making the Energy Island approach appear clever yet somewhat cumbersome.
What’s Next for Energy Island?
Energy Island’s products have yet to hit the market, with expectations for a launch in the second quarter of 2025. Pricing details are still under wraps, but updates will be provided as they become available.