Solar Installations on Farm Sites - 10kW - 50kW Power Generation

solar farm installationYou may be missing an excellent opportunity to generate a residual income from your property
The case study below shows how an initial investment of £60,000 to install a 50kW solar array generates over £12,000 a year in income. There are few business opportunities right now that can match this level of return.

The best returns come from sites where there are occupied commercial buildings so that the generated electricity can be sold directly to the businesses leasing the property. Your installation supplies power during the day when it is generating and the grid takes over at night. This is ideal for commercial properties as they consume mainly during the working day. You will be earning 12p -16p per unit directly from the consumer rather than the 4.5p per unit paid by your local supplier when you export the same power to the grid. That said, the export model still generates good returns.


A solar PV installation just sits there and generates power. You have nothing to do except claim your feed-in-tariff payments every 6 months and invoice any on-site consumers. Ideally you should be looking to install a 50kW system as this is where the returns are highest. See the section below for more information.

Cost Benefit Calculator - 10kW - 50kW Solar Arrays

Roof Direction

Roof Slope Angle

Roof Shading


(20 - 60%)



How Much Power
Used On Site

What You Pay For
Electricity Now

Select the size
with the slider

Size (KWatts)
Power Generated
Price (incl. VAT)
Annual Return
Income Year 1
Feed In Tariff
Electricity Savings
Exported Power
Income After 10 Years
Feed In Tariff
Electricity Savings
Exported Power
Income After 25 Years
Feed In Tariff
Electricity Savings
Exported Power
This installation will pay back within
Carbon emission savings Kg each year


Case Study - 50 KWatt Solar PV System


solar 50KW system200 x HJ Solar 250W Panels with 3 SMA Sunny Tripower 17000TL inverters


Loss Factor

System Size

Annual Irradiance

Shade Factor

Annual Energy Output

  0.8      x

  50000 kW       x

  913     x

    1         =

 36,520 kWh/yr


The investment should increase as energy prices rise. At the moment, this price increase is around 7% to 9% each year (according to DECC). Feed-in tariff payments are guaranteed by the Government to increase in line with inflation.

The following table shows the accumulated earnings over the next 1, 5, 10 and 25 years.



Feed In Tariff

Fuel Savings

Export Income

Total Benefit

Carbon Savings








£ 4,759

£ 5,736

£  822






£ 5,215

















50kWatt Solar PV Systems


50 kWatts is a watershed size for solar array for a number of reasons:

  1. The feed in tariff above for systems larger than 50kW drops from 13.5p/kWh  to 11.5p/kWh for the entire array, so a 50kW solar array will earn the same tariff as a 58kW array
  2. Solar arrays of 50kW and under do not need an export meter.  For these size arrays, the export rate is estimated at 50% which is paid at 4.5p/kWh.  In the case of large daytime commercial use, the use of the generated power is close to 100% so this is extra revenue.
  3. Provided that the peak generation from the solar array is not more than the daily power usage, especially iin teh summer then 100% of the generated power is consumed, reducing energy costs at the current supplier rate which (anything from 12p to 18p per kWh).

The production of electricity over the year is not evenly distributed as it relies on the sun.  Any generation of power over the amount directly used is wasted as it is not saving on any costs.  This has to be balanced by the extra generation in winter months. As a general rule, for systems of this size, the extra cost of installation is not offset by winter usage if the summer peak is more than 20% of the usage. 

A 50kW system is a very good fit, getting close to the maximum return available on installation costs for a system of this size.


percent of annual output by month


The G59 Engineering Standard - DNO Application

Before we can confirm any installation over 4kW in size we will need to seek permission from the Distribution Network operator (DNO).  This should be a formality but there are costs involved. We try to anticipate these but occasionally they can be high and could prohibit the installation if the local transmission network needs extensive upgrading. This will require some preliminary documentation to test the feasibility of the installation with the DNO.

Farm properties and comeercial sites are usually set up for at least 100Amps per phase but we will not know the state of the transformer between your property and the local transmission network until we have submitted the G59 application.

The DNO may allow the installation with the existing transformers, which is what we would expect.

The DNO may allow the installation but require that the local transformer is replaced or upgraded This will carry an additional cost.  Transformers of this kind tend to be in the £3,500 range but the size of the installation costs are at the discretion of the DNO.  We would of course present any  additional cost before commencing any contract.

Before any final agreement we will carry out an extensive survey of the properties including the electrical systems and construction materials to ensure that the installations comply with all building regulations and health & safety standards.