4kWp solar systems: Pricing, output, and returns for the UK

4kWp solar systems: Pricing, output, and returns

by James Martin II on September 21, 2012

A 4kWp solar system is probably the most popular size for solar systems for homes and small businesses across the UK, and with solar power system prices falling, solar PV systems of all sizes are becoming a more and more attractive investment for homes and business-owners. This article is an overview of the typical price ranges, power yields (in kWh), and financial benefits that a home or business should anticipate with a well-installed 4kW solar PV system.

Solar Selections can provide Solar Quotes from the most competitive Solar Installers in the UK. Request a free Solar Quote Comparison by filling out the form to the right of this page or call 020 7205 2267 for more information.

4kWp solar system prices in the UK – Starting at around £5,240

Solar panel system prices have plummeted in the UK in the past few years for a number of reasons, including massive increases in solar panel and inverter production from China, and falling incentives in the UK that have lead to fiercer competition between solar installation companies.

In the UK, the average price of a solar PV system is about £1.31 per watt. This means that at the time of writing, the average cost of a 4kWp solar system of decent quality is less than £5,2400, which is less than half of what it would have been 12 months ago.

Of course, as with any type of electrical equipment, there is a wide range of quality levels to choose from–low-end products tend to be cheaper, whilst higher-end products are generally dearer.

4kWp solar systems: Output

The actual power output of a 4kWp solar system is influenced by a number of things, including:

-Geographical location of the system and the expected daily and annual solar irradiation and cloud cover levels.

-Orientation and tilt angle of the solar panel array.

-Whether there is any shade cast on the panels.

-Operating temperature of the panels (higher temperatures can negatively impact panel output).

-Whether the solar panel array is properly sized to match the inverter capacity.

-The quality of the components used in the installation–i.e. the panels and the inverter.

Depending on the location, a system will receive different amounts of sunlight throughout the day, season, and even year. The amount of sunshine falling on a solar system’s solar panels directly affects the system’s output. As an average figure a solar panel system should produce 2.35 kWh per kWp per day.

Therefore, an average 4kWp system will yield approximately:
- 2.35 x 4 = 9.4kWh on an average day.
OR
- 9.4kWh x 365 = 3,431kWh per annum.

Having said this even for systems in the north of England, a Solar Selections 4kWp customer has produced over 4,120kWh per annum.

Indicative financial returns from a 4kWp solar system

The financial returns from a 4kWp solar PV installation are mainly dependent on the Solar Feed-in Tariff rate available to the owner/operator of the system. The UK’s Solar Feed-in Tariff scheme pays solar system owners a premium for each kWh (unit) of power that they generate. Financial payback accordingly depends not only on the total output of the system, but also how that power is utilised–i.e. how much is being exported to the grid vs how much is being ‘self-consumed’.

Download a 4kWp solar power system ROI Calculator*

How to use the calculator:

1. Download the Solar Selections 4kWp solar system ROI calculator (Excel spreadsheet file)

2. Request a Solar Quote Comparison of the solar system installers in your area to obtain system prices,

3. Alter the variables in the light blue boxes in the spreadsheet (system size, system price, etc) in column B to reflect your situation and calculate system Return on Investment (ROI).

(You may also open the file in Google Docs if you have a Google account.)

*Calculator outputs are indicative only–please keep in mind that electricity rates and Feed-in Tariff rates may change over time.

© 2012 Solar Selections Ltd

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