It started with hot water, washing machines and computers; now the next big revolution for the modern home will be the battery allowing for energy independence.

Dating back to the late 1800s, we see the home become the predominant place for adopting new technologies that are simply designed to make our lives easier, cleaner and more enjoyable. These technological advances have always been focused on improving life at home and many of them have stuck around for multiple decades. Homes have seen a transformation in the way energy has been utilised throughout the last century, from burning coal to harvesting solar radiation, this rise in consumption has kept pace with the rapid industrialisation of our planet. While having instant hot water on hand and a machine to prevent dishes from piling up in the sink, has certainly made an impact within our own four walls, few technologies have been implemented to tackle external factors.

Combating climate change

As we neared the end of the 20th century, a radical new shift towards combating climate change became more mainstream day by day. The way we view energy, technology and our own social responsibilities has evolved to become a worldwide commitment to preserving our planet and avoiding catastrophe for the Human race. We began to see the emergence of Wind and Solar PV power on a small residential scale, as well as the introduction of Solar Thermal and Air/Ground Source Heat Pumps to provide domestic hot water.

The two worlds of zero-emission energy production and the electrification of heating, both play pivotal roles in providing the core for the energy transition needed to improve the sustainability of domestic homes. In parallel, we have also seen some slightly less newsworthy, but equally as important, advancements: the Smart Meter rollout, improvements in home insulation, higher efficiency electrical loads and Electric Vehicles. All of these developments aid us in transitioning away from carbon-heavy sources of energy and towards the ultimate goal of a zero-carbon future.

By reading this, I’m sure it sounds like we should start planning the “We Saved Earth” parade and cracking out the Waitrose Prosecco next week. But unfortunately, we still have an excruciatingly long way to go in order to achieve our targets of clean energy mass adoption. Also, not everything is perfect with those aforementioned technologies because the reality is the wind does not always blow and the sun is not always shining. We need a solution that can act as the glue for all of the different technologies in our homes, and ensure that energy can flow between them in an efficient and cost effective manner. We need the perfect home battery.

Batteries

Batteries, in their most basic definition, are vessels which allow energy to be stored in the form of Chemical Energy so that it can be discharged at a later time for a specific purpose. We are all familiar with the lithium ion batteries (mostly lithium-cobalt) that are found in the devices used to read articles like this one on the internet. These batteries can be charged and discharged multiple times over a set lifespan (number of cycles) and allow our devices to operate independently from the grid. Batteries operate differently depending on their temperature, state of charge (SoC) and the conditions at which they are charged (Amperage which roughly equates to the speed).

All of these topics are what battery engineers explore when they design larger batteries that are utilised for powering entire homes. There is already a thriving market for residential battery storage which is designed to be paired with or without a Solar PV system. Most of these batteries deploy a Lithium Iron Phosphate (LiFePO4) battery cell chemistry; which is mainly advantageous for its lower cost, longer lifespan and higher safety when compared to the Lithium-Cobalt batteries normally found in smart phones and EVs.

The bathtub analogy

When thinking about batteries, I always use the bathtub analogy: the size of the bathtub can be measured in Litres (KiloWattHours or kWh in electrical terms). While the tap that fills the tub can supply water at a set speed which can be written as Litres/Hour (or KiloWatts which is the current multiplied by the voltage). So, a 75L tub that can be filled from a tap which supplies 7.4L/hour will take around 10 hours to fill. This equation is identical for the battery of an Electric Vehicle which has a 75kWh battery and if you use a standard 7.4kW home charger.

Now, home batteries on the market today are much smaller than EV batteries and the power demands from a typical UK home are also much lower. We normally see the average UK three bedroom house consuming around 8 to 10kWh a day and most residential battery systems range from 2.4kWh up to 13kWh. Again, it’s important to note that as homes move away from natural gas fired combi boilers and begin driving Electric Vehicles, these figures will increase.

Creating an energy independent home

With a base understanding of batteries, we can now explore how this revolutionary technology will shift our homes from traditional energy consumers towards flexible and agile energy producers. By incorporating even 5kWh of storage in a typical house, we can begin to unleash the vast amount of potential of distributed energy storage. A battery of this size could provide hours of uninterrupted power to appliances during times of grid blackouts, high energy costs or when the grid is supplied by carbon intensive energy sources.

Interesting concepts such as Vehicle to Everything (V2X) charging allows homeowners to utilise their EVs as “batteries on wheels” and use that stored energy to supply power back into the home. This is the holy grail for an energy independent home. Imagine coming home from work, where you charged your EV all day, and connect your car to your house at 5:30 right when the energy costs are at their peak. Then, your EV supplies the power to your appliances and charges up your home battery from 60% to 95%, because your Solar PV array was underperforming due to all day cloud cover. This eliminates any draw from the grid while the costs and carbon emissions are at their peak. After midnight, your EV begins charging from the grid again once the cheaper electricity becomes available and by the morning, both batteries are full and ready to be used.

This ideology centres around the home battery and its ability to connect everything in the house together into one mesh network of energy self reliance. This is why I truly believe that the battery will become the next essential home appliance in our lifetime. It will become integrated into our lives just like the washing machine, refrigerator and toaster. As more and more homes incorporate Solar PV, Air Source Heat Pumps and battery storage, we will see the advantage of the Smart Grids come to light. Entire neighbourhoods and towns can work together to share energy production and storage between one another which will reduce the demand on carbon intensive energy sources on our grid networks. While ushering in the new age of renewable energy sources at residential and industrial scales.

The home energy jigsaw puzzle

As things stand, all of these technologies exist in the market but there is no all-encompassing ecosystem of products that can achieve that high level of interoperability required. The final piece of this energy jigsaw puzzle is a missing software/hardware combination that enables all the different technologies to communicate with one another. Once this Home Energy Management System product becomes available to the market, we will see a tipping point where mass adoption will ensue. This system will act as the brains of the home and will unlock new levels of cost savings and emission reductions for homeowners.

Energy storage will be the at the heart of the energy revolution for domestic properties and the Home EMS will allow that technology to reach it full potential in the combat against climate change. We are living in exciting times and I feel that there are a handful of manufacturers who are close to solving this full ecosystem dilemma. Once they do, you will see this become the next big thing for homeowners to incorporate into their lives.