From Under the Hood to Over Your Roof: Powerwall, Tesla's Solar Solution

According to Elon Musk, your home’s sustainable energy solutions shouldn’t be limited to a wood burning stove and candlelight. Imagine instead a rechargeable battery that draws power from sunlight during the day and provides that electricity throughout the night and into the next morning. Then, as sun rises anew, the cell recharges, and the cycle continues for as long as the cell is maintained. Musk described this innovative battery system at the unveiling of “Tesla Energy,” a new Tesla initiative which plans to address the immediate and global need for cleaner power.

Called the “Powerwall,” it is a commercially viable battery that can power a sustainable home or business. For most people, one unobtrusive wall-mounted battery module in the garage isn’t going to be enough. But according to the Tesla power website, one Powerwall can deliver 2 kW of continuous power and nine can work in parallel, which means you might need one for each computer or toaster you own – but the Powerwall still has your power demands covered. Furthermore, each home with a Powerwall energy cell cuts from fossil fuel generated electricity on the grid, which with wider adoption can eventually turn down the fossil fuel infrastructure completely.

The Powerwall is presented as an intermediary solution to a constant problem: how can we get clean electricity when the wind isn’t blowing or the sun isn’t shining? To eliminate our worldwide dependence on fossil fuels, such as coal, oil, and even natural gas, we need to improve on existing sustainable solutions. A battery solves this problem by storing energy for later use, but battery technologies typically suffer from a number of logistical and technical limitations. Lead-acid batteries are good at holding a charge but the materials are toxic and they don’t charge quickly. You could use a sophisticated lithium ion battery, but they are expensive and the power load must be regulated to maintain battery integrity. For these and lesser known battery types (e.g. NiCd, molten salt), other problems arise over a battery’s working lifetime that are usually only known to electrical engineers and technicians, such as electric load capacities, the memory effect, overheating, and voltage regulation. For all of these reasons, a green energy home usually requires a specialist to install and service your batteries to support your green energy appliances for years to come.

Tesla’s Powerwall is an affordable lithium ion battery that handles these details for you and “just works” out of the box. For example, the Powerwall has a liquid cooling system that can prevent overheating in ambient temperatures from -20C (-4F) to 43C (110F), a problem normally addressed with a much more costly custom cooling system. Tesla also considers their computer regulated load balancer good enough to support a ten year warranty, ensuring a long life for relatively little cost.

Like most of Tesla’s innovations, changing how people think about energy is essential to their success. This goes for other electrical components manufacturers as well, and the list of power inverters that integrate with the Powerwall is growing as Tesla tackles new strategic partnerships across the industry. These components are essential for another of Tesla Energy’s projects, the all solar-powered Tesla Gigafactory, so you can expect a lot of cross-industry support for their energy products going forward.

In these ways, the Powerwall is a genuine realization of what a home power cell solution should be and offers a compelling vision of distributed power solutions that shall propel us into a green energy future. The question is no longer how, but when these technologies will reach full adoption and we dismantle the last combustion power plant forever.