On-grid or grid-tie solar systems are by far the most common and widely used by homes and businesses. These systems do not need batteries and use either solar inverters or micro-inverters and are connected to the public electricity grid. Any excess solar power that you generate is exported to the electricity grid and you usually get paid a feed-in-tariff (FiT) or credits for the energy you export.

Unlike hybrid systems, on-grid solar systems are not able to function or generate electricity during a blackout due to safety reasons. Since blackouts usually occur when the electricity grid is damaged; If the solar inverter was still feeding electricity into a damaged grid it would risk the safety of the people repairing the fault/s in the network. Most hybrid solar systems with battery storage are able to automatically isolate from the grid (known as islanding) and continue to supply some power during a blackout.

Batteries are able to be added to on-grid systems at a later stage if required. The Tesla Powerwall 2 is a popular AC battery system which can be added to an existing solar system.

What it can offer you

This simple system can be a very wise investment offering reduction in outgoings and bringing you an income:

  • Reduce your electricity consumption and your bills by 30% to 40%
  • Systems can pay for themselves in as little as 4 years and continue offering benefits for at least next 25 years.
  • 100% Clean Energy production and reduced carbon foot print impact on our Environment
  • No Operating and maintaining cost for solar PV systems as far as only PV modules cleaning
  • Add on-grid batteries solutions in case power cut off or self-consumption. Grid Connect System with Battery Storage.
  • Get paid for allthe electricity you export to grid via the Net Metering in Pakistani by new regulation approved by NEPRA

What’s in the system

As an example here is a list of components in a typical grid connected solar system (from the roof down):

  1. Solar PV panels
  2. Special DC solar cable & connectors
  3. DC isolator
  4. Solar PV inverter
  5. AC isolator
  6. Normal AC cable
  7. kWh generation meter
  8. MCB in distribution board

Adding Storage to Grid Connected PV Systems

A large portion of the energy generated by a typical PV system will be exported to the grid and there is increasing demand for solutions to enable better use of this energy through the use of energy storage.

Adding battery storage enables this excess generation to be stored for use later when consumption is higher than generation. As electricity prices rise this sort of battery storage system will become more and more cost effective. Systems can also provide backup power in the event of grid failure.

We offer several Energy Storage Solutions to suit different budgets and requirements.

See: On-Grid Solar PV Battery Storage Solutions

For kits see: On-Grid Battery Storage Kits & Commercial Battery Storage Kits

Types of Energy Storage Systems

These can be broadly described as one of three types with the following features:

  1. a) AC Coupled Energy Storage
  • Here the battery is connected on the AC side of the solar inverter
  • An additional battery inverter/charger is required to convert battery power to 230 Vac and vice versa
  • There is no effect on the PV Net metering tariff
  • Possible to charge the battery from cheap rate electricity
  • Back-up may be possible with additional switchgear in the event of grid failure
  1. b) AC Coupled Energy Storage with Back-up
  • Allows operation in event of a power cut / grid failure
  • Extra protection relays are required to enable AC loads to be run either from grid or from the battery and to provide a new neutral earth connection
  • These can be included in inverter/charger
  1. c) DC Coupled Energy Storage
  • Here the battery is connected on the PV side of the solar inverter
  • A high voltage battery (to match PV voltage) is used to store the energy when it’s generated for when it’s needed
  • There is some (slight) reduction in the PV feed in tariff due to energy used in battery charge/discharge process
  • No requirement to inform the DNO about changes to the system connected to the grid
  • Not possible to charge the battery from cheap rate electricity
  • Usually no operation in the event of a power cut

Not all installers are familiar with the issues and benefits of energy storage. We run regular training courses for installers on this topic and can provide recommendations, feel free to contact us.