Commercial Solar Photovoltaic (PV) Installations

Myriad can design and Install your PV system

This page will help you understand the pros and cons of PV systems for generating electricity. We've covered the costs, sizing approach, install process and practical questions around selecting, funding and installing a photovoltaic system.

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How much roof space will you need?

What are the minimum requirements?

What is the cost?

What are the savings?

Additional info we'll need to provide a firm quote

Or jump straight to our FAQs

By simply installing Solar PV panels, you can utilise your roof space on your commercial premises (eg. agricultural buildings, factories, warehouses, hospitals, schools etc) to generate electricity that is free to be used on site.

How Much Roof Space Do I Need For PV Panels?

The panels provide approx 180-230W/m2

Approximate roof areas are below:

  • 25kW - 125m2
  • 50kW - 250m2
  • 75kW - 375m2
  • 100kW - 500m2
  • 200kW - 1,000m2

Minimum Requirements for a Good Return on your PV Installation

These indicators will ensure your PV system provides a good financial return:

  • 3 phase supply to the building
  • Roof area > 100m2
  • Electrical demand > 50,000 kWh/yr
  • Roof pitch angle < 25deg, although a flat roof and even ground areas can be utilised with panel frames to generate the panel angle, 
  • Roof is facing SE, S or SW facing, although E/W is also often OK
  • Electrical cost > 12p/kWh

If you meet this criteria, call us today and we will help you realise the financial gains available from a PV installation.



There are several benefits to be had from investing in solar for commercial purposes:



Solar panels generate free electricity for use on site. This, in turn, will reduce the electricity consumption during daylight hours and can significantly bring down the cost of your electricity bill.


We will ideally match the size of installation to cover typical electricity consumption, however, any surplus electricity can be sold to the grid to provide an additional income stream.


Over the last 10 years energy prices have consistently increased, and forecast predict for this to continue. By generating your own electricity, you can protect yourself from energy price rises.


Solar PV is a proven and reliable technology with very little maintenance costs. It is a safe investment that provides returns exceeding those of other low risk financial products. A well-designed Solar PV system can deliver payback on initial investment in as little as 2.5 years.


The UK is committed to hitting carbon-zero by 2050 and every business in the UK is going to have to meet carbon reduction targets. Generating electricity from solar as a renewable energy source significantly reduce your carbon footprint and adds to your corporate responsibility message.

Why Myriad?

  • We are an award winning renewable energy company.
  • We deliver Solar PV projects from 20kW to 5MW and we have installed many megawatts of PV projects across the UK.
  • We calculate PV system size based on clients’ actual energy usage and then design bespoke PV systems that will deliver the highest possible returns. 
  • We will guide clients through the whole PV process from DNO application (allowing connection to the grid) to commissioning of the PV system.
  • Our professional installation teams will keep on-site disruption to a bare minimum and we only install the highest quality equipment.
  • We provide monitoring and maintenance solutions, to make sure your PV system continues to produce the highest levels of generation.
  • We can also assist with asset finance and power purchase agreements (PPA’s). Many PV projects can easily be financed or can be installed with no costs upfront.
  • We also provide in-house planning services for renewable energy projects.
  • We work with many clients to help them hit carbon reduction targets.
  • We work with clients to identify the right renewable energy solution(s) for them. Technologies include; Solar PV, Battery Storage, Biomass, Combined Heat & Power (Gas CHP) and Heat-Pumps (air & ground).
  • We work with high energy usage clients, across a variety of sectors, including; manufacturing, automotive, chemical, food/drink, plastics, printing, and agriculture.

How much does the Installation of a Commercial Solar PV System Cost?

For roof mounted solar PV systems the capital cost of a fully installed system is typically between £650/kW and £900/kW giving a typical pay back between 2-5 years.

System Information
  • PV system size
  • Typical installation price
  • 25kW
  • £20k - £25k
  • 50kW
  • £35k - £45k
  • 100kW
  • £70k - £95k
  • 200kW
  • £140k - £190k
Technical Information

How Much Will A Commercial Solar PV System Save?

1kW of solar panel will typically yield between 700 and 900kWh of electricity per year, depending upon the panel efficiency, orientation, angle to the horizontal and geographical location. Taking the middle figure of 800kWh, for each 1kW installed a saving of approx. £224 is made each year*

Typical system sizes, their saving potential and their approx. installation process are shown in the table below

*assumes an electricity cost of 28p/kWh.

System Information
  • PV system size
  • Typical installation price
  • Typical annual saving on electricity bill
  • Typical payback
  • 25kW
  • £20k - £25k
  • £5,600
  • 3-4 years
  • 50kW
  • £35k - £40k
  • £11,200
  • 3-4 years
  • 100kW
  • £70k - £95k
  • £22,400
  • 3-4 years
  • 200kW
  • £140k - £190k
  • £44,800
  • 2-4 years

How Are PV Systems Sized?

There are many factors that determine how best to size a PV system but the main three are:

  • Capacity approval from the DNO
  • Size to match your electricity consumption
  • Available roof area

District Network Operator (DNO) Approval

    • Before any PV system over 11kW can be installed, DNO approval must be obtained.
    • Myriad can undertake this process for you.
    • Your district network operator (DNO) for your region will tell you what the maximum installation capacity (kW) you can have at your site. This is dependent upon other generators in your region or even if you already have solar or wind on your site. You cannot go above this figure.
    • The DNO will also confirm how much electricity you can export to the grid and whether any upgrade work is required.

Sized To Match Your Site Electricity Consumption

In order to ensure that you get maximum benefit from your PV system you need to size it carefully.A solar PV system will deliver the majority of its generation between April and October, so an over-sized PV system will be exporting quite a lot of energy to the grid in the summer. Although you can now get a decent export rate it is more benefical economically if you use the PV generated rather than export it. If you can obtain the half-hourly import data from your supplier, we can be very precise in our system design and make sure your PV system delivers the best ROI possible.


Take this example:

  • Manor Farm site consumes 200,000kWh of electricity each year during daylight hours at a cost of 14p/kWh
  • The owner of Manor Farm installs a PV system that can generate 400,000 kWh in a year. (This is over sized).
  • Therefore, 50% of the electricity will be used on site and 50% will be exported into the grid.
  • Manor Farm electricity supply company offer them 5p/kWh for all the electricity they export to the grid:
  • Electricity cost saving: 200,000kWh x 14p = £28,000
  • Export tariff income: 200,000kWh x 5p = £10,000

As you can see, the benefit of oversizing the panels is small compared to the saving you can make by consuming what you generate.

“Remember, you can always add panels later.

Under sizing is also undesirable as it means there are savings potential savings that you are not making. Remember, you can always add panels later.

It is for this reason that the panels should be sized to match the load as accurately as possible and not oversized or undersized. Available roof area

Solar PV panels are often mounted on the roofs instead of on the ground because the cost is slightly lower and also there is less risk of shading from surrounding buildings. It is possible to mount the panels on frames on the ground if you have the space and shading from surrounding buildings isn't an issue.

Detailed Steps

Dno Authorisation And G99 Application

Myriad will send you a standard letter of authority which for you to sign and return. Once we have this we can contact your DNO and apply for the G99 connection. This will allow us to establish the maximum installation capacity (kW) for your site.

Analysis Of Your Consumption

Myriad will ask you for your bill and also your half hourly data. Once we have this, we can size a PV system that is optimised for your specific site needs. Myriad will size the optimum PV system size (kW) based on the DNO response, analysis of your electricity consumption, and Google Earth images of your roofs.

Budget Quotation

Myriad will provide a budget quotation based on the selected system size (kW). Once this budget is accepted, we will proceed to a detailed site survey.

Site Survey

During the site survey we will establish exactly where the electrical connection points are and ensure the roof structure is adequate for the number of panels quoted. This information allows us to firm up the quotation.

Firm Quotation

Myriad will provide a fixed price turnkey quotation for the PV installation at your site. Once approved we will agree project time frame to completion.

Installation And Signoff

Myriad will provide all equipment, wiring, scaffolding, labour and a handover document pack. We will commission the system in conjunction with the DNO. The time this takes is dependent upon the system size but it generally takes around 1 week to install a 50kW system.



Is Planning Permission Needed For A Solar Pv System?

Generally not as they are covered by ‘permitted development’ allowances, unless your building is in an Area of Outstanding Beauty (AONB), a National Park, Conservation area or your building is listed in any way. We would recommend contacting your local planning office to be 100% sure.

What Is The Lifetime Of A Pv Panel?

Panels do degrade very slowly over time, around 1% each year. Quality suppliers will provide a power output warranty such that the panel will produce 80% of the rated power after 20 or 25 years. They will, however, typically maintain quite high efficiencies for well over 30 years.

How Much Carbon Will A Pv System Save?

PV panels will save carbon as the site will be importing less electricity form the grid. The actual amount of carbon is dependent upon the carbon intensity of the grid (which changes all the time, depends how much big win, PV and nuclear is generating at any one time.

A rule of thumb, however, is that for every 2kW of PV installed 1T of carbon is saved each year.

Are There Grants Available For A Pv System?

There may be grants available locally for low carbon solutions such as solar PV but they are often challenging to apply for and can take a long time before you are accredited. Our customers find that the paybacks on solar PV are good enough without grants at the moment, so our customers tend to prefer to move on with the installation rather than chase the potential for a grant.

Do Pv Systems Need Servicing?

Solar PV systems don't require annual servicing and require very little maintenance as there are no moving parts. They may need cleaning however if they are in a location where dust and debris may collect on the panels. If this happens the shading from the dust etc can affect the output of the whole system quite significantly so you do need to make sure the panels are kept clean. Use warm (not cold) soapy water or ask a PV cleaning company to do this for you.

Every three or four years you should get the system inspected by a qualified installer to check the inverters and panel strings are all working correctly.

Myriad can undertake the cleaning and can also inspect and test any panel and inverter type so please call the office if you need someone to do this for you.

Do I Need A South-Facing Roof?

In northern hemisphere country South facing roofs do experience more sunlight than North, East or West facing roofs. If you have a steep roof pitch then you may need to restrict your panels to the South, East or West facing roofs as there will be times of the day when North facing roofs will be shaded from the sun. East/West panels will typically deliver less energy than a South facing roof, but they are still a viable investment. Myriad can review this during the site survey.

Agricultural buildings tend to have a low pitch so having a South facing roof is less important as even North facing roofs still get sun most of the day for most of the year.

What Is The Installation Process?

Myriad follow the following install process. Each stage is clearly defined so you know where you are at each stage.

  • DNO authorisation and G99 application
  • Analysis of your electricity consumption and sizing of the PV system
  • Budget Quotation
  • Site survey
  • Firm Quotation
  • Installation and signoff

Why Consider Myriad for Your PV Installation?

Why Myriad Service?

  • Established since 2003
  • Nationwide network of accredited engineers
  • All aspects of plant room equipment serviced
  • Repair, service, maintenance and professional services
  • Free equipment and plant room quotations
  • Prompt and efficient service with competitive pricing
  • Professional customer service and technical support
  • 24/7 emergency call-out
  • High quality workmanship backed by guarantees

Additional Information Required For a Firm Quotation

  • Are you in a conservation area or is the building listed?
  • Any taller buildings/trees etc adjacent which will shade the new PV?
  • Photos of the building showing each side
  • Postcode or what.three.words of the site
solar panels and cloudy sky

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