Several different devices are available if you need to store electricity in your home for later consumption.

One of the most common solutions is the Battery Energy Storage Systems (BESS), which are essentially rechargeable batteries. Typically, they are lithium-ion or lead-acid. What makes the modern BESS system special is the ability to control it through in-home computer software, which in turn makes the administration of charging and discharging cycles much easier.

A cheaper alternative to BESS are the smaller flow batteries for home use, but they are chiefly intended to help during short blackouts.

Why have energy storage at home?

Energy storage when energy is generated on-site

When energy is generated on-site from intermittent sources, e.g. through solar panels or a private windmill, it can be beneficial to have the ability to store electricity during high-yield hours and use it during low-yield or no-yield times. Solar panels will not produce electricity in darkness, windmills do not produce electricity without wind, and so on.

Batteries can be used for both smoothing and shifting.

• Smoothing is when a battery connected to the home system turns the (inherently variable) power output from solar or wind into a smooth, uniform source of electricity. Modern systems are available that can monitor the output of the intermittent source and respond by allowing the battery to release more energy or absorb excess energy, as needed.
• Shifting is when a battery is used to store the excess energy produced during peak-production hours and release it during hours of peak demand. This is especially helpful for solar systems since peak demand in a household doesn´t necessarily coordinate with peak production from solar panels.

Short och semi-long grid losses

The transmission of electricity from power plants to individual homes can be interrupted for many different reasons, including everything from inclement weather to technical failures and terrorist attacks. Therefore, many homeowners want to keep a backup solution to run the most essential electrical devices during a blackout.

What is an UltraBattery?

UltaBattery is a type of hybrid energy storage device invented by Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO). It combined ultracapacitor technology with lead-acid battery technology in a single cell with a common electrolyte.

The UltraBattery can be used for many different energy storage needs, including storing energy generated from solar panels and windmills at home, thereby smoothing out the electric supply from such intermittent energy sources. The UltraBattery can also be used as an emergency backup in case of sudden power outages, used in electric vehicles, etcetera.

Compared to conventional VRLA batteries, the UltraBattery is more efficient, has a longer lifetime and has better charge acceptance in partial state of charge (pSoC) conditions. Conventional batteries are typically designed for high SOC use, i.e. when the battery is close to fully charged, and conventional VRLA batteries tends to deteriorate quickly when operated in pSoC conditions.

The basics

The negative battery electrode is made from lead, while the negative ultracapacitor electrode is made from carbon. A lead grid with lead oxide is included in the positive plate. The electrolyte solution consists of sulfuric acid and water.

The UltraBattery in microgrids

The UltraBattery has become a popular choice for microgrids, where these batteries are used to smooth and shift the electrical capacity from sources such as sun and wind. With batteries included in the microgrid, the electrical energy supply become more uniform and reliable. Energy can be stored during high-yield & low-use periods, and then drawn from the battery during low-yield & high-use hours.