Homeowner Blog

Solar PV Battery Storage: Marks out of 10 for the Powerwall 2

Erica Charles · 08 Sep 2017

In the past 12 months, Tesla has generated unprecedented interest in home battery storage, and in particular solar PV battery storage, both in the US and in the UK. Its latest product, Powerwall 2, has spearheaded a 50% drop in the cost per kWh of storage capacity, while achieving an aesthetic that wouldn’t look out of place at Apple Inc.

Many of us hear mention of the word 'Tesla' and, as with Apple's iPhone, like kids in a candy store we want one... a Tesla car, Tesla solar tiles, Tesla battery storage for solar panels... but, are we right to 'want one'? More specifically, are you right to want one?

We'll let Jeremy Clarkson speak for the Tesla car, and while the Tesla solar tiles look fantastic, they are not yet available in the UK, so we can't really speak for them either. But we have fully road tested the Tesla Powerwall 2.  As accredited Powerwall installers, we have installed several systems and designed even more, each with their own idiosyncrasies, some of them requiring backup, others with 3 phase electricity. And we have spent hours modelling the Powerwall 2, not only to provide battery storage for solar panels, but also to enable homeowners to take advantage of Economy 7 tariffs, by 'buying cheap' at night and 'using peak' in the day. We have modelled the Powerwall2 and other solar PV battery storage systems under many different load and solar output scenarios.

We have published the results of our road-test in our guide "Is Tesla Powerwall 2 Right for Me?"

Is Tesla Powerwall 2         Right for Me? Tesla battery solar Download now

The contents of the guide are summarised below. What's the conclusion?

A big fat 9 we think

In a nutshell, all credit to Elon Musk for having the vision to create a great product for residential storage, and for rolling out production at an unprecedented scale such that the price is affordable.

The lifetime cost of electricity from residential solar storage is around 12p -15p per kWh - well below the average domestic cost of grid electricity (15-16p per kWh). What's more the payback time for the Tesla solar battery is now around 9-10 years - well below the payback time competitor systems.

And that's with a 10 year warranty, beautiful design etc etc...

Why not a big fat 10?

You'll have to read the guide... you can download it for free by clicking on the link on the right. If you're thinking about battery storage, we promise you it will be 15 minutes well spent.

Here's a summary of the contents:

Is Tesla Powerwall2 right for me?

Summary of contents

In-depth guide to the functionality of the Tesla Powerwall 2, with a head-to-head comparison between the Tesla solar battery and other residential solar storage systems. The guide covers:

  • Powerwall 2 functionality: what's here already, what's coming;
  • specification of Powerwall 2 versus other comparable battery chemistries and systems;
  • economic analysis for typical and large residential properties for Powerwall 2 and competitor systems - how much can you save by installing a Tesla solar battery, or any other residential solar storage system?

Topics: Battery storage, Tesla Powerwall