Case Studies

Reflections upon installing solar panels.

I had been thinking about installing solar panels for some time and having tracked the work Jill Bruce had been doing with Essex County Council in developing a local Community Energy Project I was nudged into action. The one thing that gave me confidence was using a firm which ECC had introduced to the project, i.e. no cowboy operators.

There were three main motives for installing solar panels:

(1) Doing my bit for the environment by generating green power myself using my unused roof space rather than seeing panels covering productive farm fields. 

(2) Insulating myself against future spikes in energy prices. Given the geopolitical tensions around the global right now the risks for future spikes in prices is high in my view.

(3) The investment in solar panels had to make sound commercial sense.

Installing solar panels clearly ticks boxes (1) and (2), but what about (3), the economic case?

Simcott Renewables undertook a survey of my property and designed a solar array with an 8.2kwh storage battery system. Their quote came with a financial model to forecast the payback. I use about 3,500kwh of electricity a year and the 14-panel array is expected to generate 4,813kwh of electricity annually, producing a surplus in summer which is sold to the grid and a shortfall in winter. Payback on my investment is expected to be 8 ½ years using a discount rate of 6% (which is significantly higher than you can get in a deposit account). The big variable in the financial model is future electricity prices, if prices rise above future forecasts, then my payback shortens and if lower then my payback lengthens.

The three main pieces of kit are:

(1) the solar panels which come with a 25 years product and 30 years performance warrantee,

(2) the inverter which has a 12 years warrantee and

(3) the storage battery which has a 12 years warrantee.

All warrantees being materially longer than the forecast payback.

Based on this information I proceeded with the investment. Simcott Renewables took about 3 days for the installation. Most of the work is up on the roof so there was limited disruption in our house. The work done was neat and tidy, rubbish was removed and the work appeared to be well planned. The only inconveniences were scaffolding around the house and being without power for a couple of hours as they connected the solar system to the house’s existing electrical system.

The system is configured as follows:

Solar power first flows to the house and any surplus is used to charge the battery.

Once the battery is fully charged any surplus is sold to the grid.

When solar power is not being generated power is taken first from the battery and only once this has been exhausted will it draw electricity from the grid. In the winter months I can also configure the battery so that it can be topped up during night time off peak tariff rates and released to the house during the day when tariff rates are higher. As off-peak rates are approximately 50% of daytime rates this should further shorten my investment payback period.

Whilst it’s only been 6 weeks since the install, so far there have been no issues and the system is performing as forecast.

Am I content with my investment decision so far – Yes.

Would I recommend others to consider solar power – Yes!

Howard Walkden - February 2024