There’s a company that everyone is talking about in the domestic energy space and it isn’t one of the ‘big 6’. Everyone is talking about Tesla, about their cars and about their home energy storage system. So is it as ground-breaking as we’re led to believe and what does it mean for the Inspirit Charger?


The basic principle here is that battery storage can be used to store energy in much the same way as a traditional car stores energy in its petrol tank. So long as you can store enough electricity to take the car a reasonable distance then it starts to become interesting, particularly when you take into account zero local emissions and virtually silent operation. What makes Tesla so interesting is the amount of electrical energy they have been able to squeeze into a car, which gives it a long enough range to make it a practical alternative and also gives it industry-leading performance in terms of acceleration. To do this they use a battery set with a 90kWh capacity plus super-capacitors for near instant delivery of power to an electric motor which responds almost immediately.


This impacts on domestic energy usage in two ways. Firstly recharging a 90kWh Tesla battery, even from a 50% charge, is a lot of electricity. Given that a Tesla Model S should travel 300 miles on a full charge then 50% equates to 150 miles. Most of us drive much less than 55,000 miles per year so let’s assume 45 miles per day on average, equating to a 15% daily recharge. The average domestic property with gas heating uses 3,300 kWh of electricity, per Ofgem figures. That equates to around 9kWh per day. A 15% Tesla charge every day would need 14kWh per day, i.e. a 150% increase in daily electricity use. If the average electricity bill is around £450 per year, then our hypothetical Tesla owner doing a 15% charge every night could be facing a bill of around £1,125 per year, depending on miles travelled, of course. The electricity cost for the Tesla is around one third of the cost of petrol, even at today’s pump prices, but maybe even more can be done?


The Inspirit Charger generates electricity at the same time as heat. The overall efficiency is in excess of 90%. This means that the cost of the electricity, assuming all the heat is used, is only around 10% more than the cost of gas. Given that gas can be purchased domestically now for as little as 2.25p/kWh, this means that the cost of electricity produced by the Inspirit Charger is just 2.5p/kWh in terms of gas use, more than four times cheaper than electricity from the grid. Once installed, it makes perfect sense to ‘refuel’ a Tesla with an Inspirit Charger, particularly since the Inspirit Charger can run overnight, which is just when the Tesla is likely to be charging.


So far, so good. A Tesla owner with an Inspirit Charger will spend around four times less per mile than a Tesla owner without an Inspirit Charger and around twelve times less than a traditional car owner buying petrol. So what else?


Let’s go back to that 90kWh battery pack in the Tesla. For the average UK home with a gas boiler that equates to 10 days of electricity use. For homes which have lost power as a result of the floods and storms over the last couple of years, this could be very important. Today’s regulations mean that you need special wiring as well as on-site generation and a battery pack to keep your lights on when everyone else’s go off. Without the special wiring and battery pack, the on-site generation is forced to switch off by safety regulations. If you include an Inspirit Charger, special wiring and the Tesla’s battery pack then you could keep the lights on, the heating on and the Tesla charged, all independently of the electricity grid and for an indefinite period. How does that sound?


If buying a Tesla car is not an option for you, for whatever reason, then Tesla has created the Powerwall. This is a home battery pack for just the type of scenario described above. The drawback with the Powerwall is that it has a much smaller capacity, at just 6.4kWh, around 70% of the Ofgem average household’s daily demand. To keep the lights on and everything working with your Inspirit Charger topping up and heating the house, then you would probably want two or three of these, depending on your normal usage. Indeed, home battery storage is a new emerging product market and Tesla is not alone in developing such products.


Even if you haven’t yet experienced a blackout caused by extreme weather conditions, you may have noticed a recent announcement by the Department for Energy and Climate Change saying that variable pricing by the half hour for electricity should be enabled in 2017 (DECC’s Single Departmental Plan 2015-2020). The actual text states: “To make the most of the opportunities provided by smart meters, by early 2017 Ofgem will enable “half hourly settlement”. This will enable energy suppliers to offer new time of use tariffs so households can reduce their bills by adjusting their energy use depending on the price of electricity.” For every off-peak reduction there will be a peak time increase, so the ability to keep the lights on without electricity from the grid at peak times may suddenly become a lot more financially attractive, whatever the weather.