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Case Study 1: Mr & Mrs Moseley, Malvern 

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Richard and his wife, Jane, installed 12 solar panels on their house in the autumn of 2015. 

Each of the panels is rated at 280W with an estimated output of 2.8kW, although in full sun summers this can be exceeded. Richard says, The total cost including installation was about £6,400 and the estimated payback period was 8 years. If you add the value of electricity generated and the annual Feed-in Tariffs, the breakeven was actually about six years for us considering the energy cost increases.”

Five years later, he added another four panels to his workshop rated at 310W each with a 1,500W grid tie inverter. Giving him a maximum output of around 1,100W in full sun during the summer. 
 
Richard was eligible for a Feed-in Tariff rate on the original 12 panels of 12.92p/kWh for generating electricity to use within his own home. And another 4.85p/kWh for exporting electricity, assuming that he exports 50% of what he generates. These are fixed rates for 20 years since 2015. 
 
His current electricity costs are 27.86p/kWh, which is a recent hike from his pre-April 2022 prices of 20.59p.

To put it into context, this is Mr and Mrs Moseley’s useage 

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All of the above data is recorded by his Smart Meter. At the moment Mr Moseley has chosen not to purchase batteries: “If we could store the solar energy which we currently export to the grid, and use it in the evenings, it would be worth approximately £226 at the current rates. If we were to install a battery storage system, a 3kWh system would cost around £2,000. The breakeven time on this would be about nine years, but this would clearly reduce when electricity prices go up, as they are bound to.”

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Solar iBoost 

 
“We also have a Solar iBoost controller which diverts excess energy which would be exported, to heat water in our hot water tank. On a good day, we may store about 3kWh this way, providing enough hot water for showers in the evening. 
 
“The Everhot uses about 11kWh per 24 hour cycle, which equates to about 4,000kWh per year. We have our Everhot set to enter ECO mode from 7pm to 6am. And in addition, we have recently installed a drying rack above the Everhot to take advantage of the residual heat in the evening and reduce the us of our tumble dryer. This is very effective.”
 
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Everhot useage 
 
Mr Moseley estimates that his current annual import cost for electricity will be about £2,150. Without solar panels that would increase to £2,970. Over the last 12 months they have received approximately £406 in Feed-in Tariff payments, effectively reducing his annual electricity bill to £1,745. “The solar generation and FIT payments easily fund the running cost of the Everhot, which is about £1,115 per year at our current rates.

Mr Moseley was able to provide this data thanks to a logging system called Emoncms. He says: "There is a very informative website for anyone who may be interested. The main data logging unit is based on a Raspberry Pi with special add ones to allow measurement of the power consumed in various circuits of the home. It is typically installed near the consumer unit, and uses easily fitted 'current clamps' around the wires to measure the current and the power used. Normally it would measure incoming feed from the grid and solar, but additional circuits can be monitored like our Everhot and the water heater to give more insight."