Edge of Innovation

Living off the grid: how solar batteries like Tesla’s Powerwall change everything

 

When Elon Musk announced the Tesla Powerwall and Powerpack, wall-mounted consumer batteries for solar energy storage in homes and businesses, the world sat up and took notice. After all, this is the man who dreams of a 760 mph hyperloop transport system, future missions to Mars and affordable electric cars. Disrupting age-old business monopolies is par for the course.

A Tesla home battery should have energy providers worried.

Why? Because the combination of roof-mounted solar panels and large residential energy storage could ultimately allow you to stop buying electricity from the big power companies and start living “off the grid”.

Instead of selling the excess electricity you generate from a solar installation, why not store and use that electricity when you need it – e.g. when your house is not actively generating power?

Cheap solar batteries boost the advantages of solar energy installations

Available in 10kWh ($3,500) and 7kWh ($3,000) versions, the good-looking Powerwall is a lithium-ion battery pack that can “help you keep the lights on and fridge cold in a power outage or natural disaster while potentially saving you even more on your monthly utility bills.” It also offers a scalable storage solution – pair two 10kWh Powerwalls for 20kWh of capacity.

Savings can potentially be made using the system by charging the battery during cheaper, off-peak periods and drawing on that stored power when energy costs are at their most expensive. In the UK, for example, the peak period is typically between 4pm and 8pm. It’s not quite full “living off the grid” independence, but it’s a step in the right direction.

Tesla car with superchargers
Tesla’s work to optimise lithium ion battery cells for electric cars will have huge benefits for domestic energy storage.

Of course, while Musk’s product will raise the profile of solar batteries, the technology isn’t entirely new and SolarCity isn’t the first solar company to offer them. In Japan, Panasonic, Kyocera and NEC have all developed their own domestic energy storage systems, while Toshiba sells a 6.6kWh eneGoon lithium-ion battery can power select devices in a home for 12 hours on a full charge.

In the UK, companies like Energy Gain and the Save Energy Group both offer energy storage solutions that boost the advantages of solar energy installations. The Save Energy Group calls these first solar storage battery systems “the biggest breakthrough in the UK solar energy market for 20 years” and says that its lead-acid batteries can be retrofitted to existing solar systems of 2.5kW and above.

Domestic energy storage could allow us to start living off the grid

According to a recent report by the Department of Energy & Climate Change, solar power in the UK almost doubled in 2014. “Overall UK solar PV capacity at the end of December 2014 stood at 4,979 MW, across 650,195 installations,” the report revealed. That’s almost 5 gigawatts (GW) of renewable energy. It’s a small bite out of overall UK power requirements, which hit a high of 52.54 gigawatts during the cold snap in January 2015, but it’s a promising start.

And it can only get better as the costs of solar continue to fall and the efficiency of PV panels improves. Crucially, Tesla’s work with electric cars has focused heavily on battery improvements and its Roadster 3.0 now has a range of over 400 miles thanks to the development of what the Tesla Motors team says is a “new cell that has 31% more energy than the original Roadster cell.”

With Tesla constructing a vast “gigafactory” for large-scale battery production in Nevada, future lithium ion cells could give us the capacity to power our homes and our cars, while saving money and reducing pollution.

Tesla Energy storage utility
Infinitely scalable, the Tesla Powerpack will enable Gigawatt-class utilities that can store solar energy. Image: Tesla.

Of course, Musk dreams bigger. He’d like to transition the whole world to sustainable energy. Instead of pollution-belching coal and gas power stations, imagine acres of Tesla-built, industry-class 100kWh Powerpacks clustered together in Gigawatt installations. Ten thousand could power a small city, 160 million could power the US, 900 million could transition the world to run on stored sunshine.

In his announcement, Musk said that existing batteries ‘suck’. They are expensive and unreliable, they typically are difficult to integrate into the home, have a poor lifetime, low efficiency and they are not scalable.

Better battery technology is key to much of the gadgetry that we rely on in the 21st century. Clean energy generation and energy management is perhaps our biggest challenge. – Dean Evans

 

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