Commercial rooftop solar PPA costs for businesses

Commercial rooftop solar is a highly effective way of reducing energy costs for your organisation, or business over the lifetime of the solar - some 25 + years. 

Reduce your cost of electricity down to 5 p/kWh (self-financing) - 14 p/kWh for the complete term.  This is with zero indexation. 

These prices are low because MaxGen works with businesses to self finance, or finance with zero indexation, and a fixed interest rate for the life of the PPA. 

Ball-park roof-top solar costs:

  • £700 per kW for 1 - 2 MWs commercial shed
  • £800 per kW for a 200 kW tiled roof 
  • £850 per kW for 50 kW roof


However, there are numerous limiting factors that need to be assessed. 

Is the roof suitable?

  • Legal status of roof - is it owned by the business, will the landlord provide permission?
  • Does the roof have at least 25 years of life?  It is best for the roof to be redone if there are just a few years of life.  The roof could be redone once the solar is installed, however this would add cost.
  • For flat roofs, the solar can cover the complete roof - this would then be a ballast system
  • For pitched roofs - this would be connected to the southerly facing roofs
  • Skylights (daylight is more valuable than solar), chimneys and shaded areas are all to be avoided
  • Is the roof and supporting structures structurally sound - are there any recent structural reports?

Sizing of solar array

  • What is the minimum hourly load of the business during daylight hours?  The daylight generation per hour should not be substantially more than the load in the summer months of May, June, and July.  This is when the solar will be most effective.  However if all the generation is not utilised within the business, it will be spilled to the grid for a very low 5 p/kWh.  Therefore at weekends and other times when the demand is low, generation will be spilled to the grid for a minimal return.  A battery can be installed, however this will add substantial costs, unless there is a large differential or excellent requirement due to brownouts/blackouts etc.

Planning for solar

  • If the rooftop solar array is under a MW, then it is permitted development in the UK, with no planning.   If over a MW, then planning is required.

Commercial rooftop solar