Jun 3, 2019 - 5min read
Photovoltaic solar panels are an extremely powerful tool in the clean energy revolution, but they really come into their own when they’re coupled with a home battery. It can be hard, though, to visualise just how big a difference this combination of renewable tech can truly make.
In light of that, we thought there’s no better way to showcase the benefits of battery storage working in harmony with solar panels than putting the tech to the test ourselves.
Matt Morgan is one of the founders of renewable installation experts (and our sister company) The Phoenix Works, so it should come as no surprise that he has 4kW of photovoltaic solar panels installed on his roof; some facing south, some facing west.
It should also come as no surprise that his tech expertise and enthusiasm meant he was one of the very first people to install a Tesla Powerwall in his home - the same market-leading battery that is now available for purchase and installation through Tonik Energy. So just how much of a game-changer is it?
Matt’s home without battery storage
Matt lives in a semi-detached, three-bedroom home in Leeds with his wife and two boys; a 3-year-old, and a 5-month-old. Their house uses around 4,600kWh of electricity per year, which is a little higher than the national average.
“We’ve had a solar PV system on our family home since 2011,” says Matt, “and we were so impressed with the amount of power generated and savings on our electricity bill that we upgraded to an even bigger solar system in 2015.”
In the area of the UK that Matt lives, he could expect his panels to generate around 3,800kWh a year - which, for context, is approximately the figure the Department for Business, Energy and Industrial Strategy uses as the average yearly electricity consumption of a UK household.1
Obviously, solar generation will vary throughout the year as some days are brighter than others, but on a particular sunny day - 24th June 2018, in this case - Matt’s solar panels can generate as much as 29kWh of energy in 24 hours.
For that specific day, 29kWh was considerably more energy than was needed - Matt’s home only used 12.5kWh of electricity on 24th June (for comparison, the national average for daily consumption is around 10.4kWh). The purple line on the graph below shows Matt’s family’s consumption plotted against when their solar panels were generating energy.
Without a battery installed, Matt’s home would be able to use the energy from his solar panels as it was being generated, but not store any of the ‘excess’ power. So, during the night - when the solar panels weren’t generating - Matt bought 3.6kWh of electricity from the grid. During the day, Matt’s home was powered with 8.9kWh of electricity generated by his solar panels, meaning he didn’t have to buy from the grid while the sun was out.
So without a battery, 20.1kWh of the energy generated by his solar panels would not have been used in his home, and would instead have been exported back to the grid - a significant loss of potential savings!
Matt’s home with battery storage
Fortunately, Matt’s home has a 13.5kWh Tesla Powerwall installed, and this changes his situation considerably. “We decided to add a battery to our home last year,” says Matt. “Both my wife and I work during the day, meaning that a lot of the electricity our solar panels are generating isn’t actually being used by us. So we decided that the ability to store that energy for use when we get home would be the logical thing to do.”
Because the Powerwall is able to store the ‘excess’ energy generated by his solar panels, Matt is able to store up his renewable electricity for use at a later time - when the sun isn’t shining, or when his household demand is particularly high. The green shaded areas on the graph below show where Matt’s home was using the electricity stored in his battery rather than electricity bought from the grid.
During the periods when his solar panels weren’t generating and when his household usage peaked during the day, Matt was able to use the electricity stored in his Tesla Powerwall rather than buying electricity from the grid.
So just how much electricity did Matt buy from the grid? None! Well, almost none - a mere 0.01kWh. Essentially, Matt’s home was entirely energy independent on June 24th 2018.
Now, this was a particularly sunny day, and on a more typically cloudy and drizzly British summer day, we might not have seen such a high level of performance from the solar panels. However, across the five months from May to September, with solar panels and a Tesla Powerwall installed, the amount of energy Matt’s household imported from the grid fell from 1619kWh to just 18kWh. That’s less than two days’ worth of average energy consumption - spread across five entire months!
“Since having the Tesla Powerwall installed, our electricity savings have risen from around 30% to around 80%,” says Matt. “On sunny days we are able to power our home 100% from our solar and battery system, meaning that some days we don’t buy any electricity from the grid at all. It’s a great feeling!
“The ability to generate and use our own dedicated renewable electricity gives us a sense of independence and pride that we’re doing our bit to help the shift away from fossil fuels - especially when we know the small amount of grid electricity we do use comes Tonik and is 100% renewable.”
So not only has Matt’s solar and battery system resulted in a dramatically reduced carbon footprint from generating and storing his own renewable energy, his increased independence from the grid means he is saving a huge amount on his bills as well.
To find out more information visit our Tesla Powerwall page, or to book your Tesla Powerwall installation, call The Phoenix Works on 0113 815 5366.