How does TNB calculate your bill after you install solar energy system?
After you install on- grid solar energy system, you need to be register under Net Energy Metering (NEM) Scheme. The concept of this scheme is that the energy produced from the installed solar PV system will be consumed first and any excess will be exported to TNB on a "one-on-one" offset basis. This means that every 1 kWh exported to the grid will be offset against 1 kWh consumed from the grid. Under this scheme, your current electric meter will change to NEM meter that calculate your solar generated energy and energy you used from the grid.
For example you have a 8 kW solar PV system installed to your building. In a day, assume that you will generate 28 kWh (8kWp x 3.5 hour = 28 kWh). Assume that, you fully used your generated energy on that day, therefore when the night come you will use energy from energy distributor (TNB or Sabah Electricity).
Another situation is, you did not fully utilised your generated energy on that day. Therefore, the excess energy will be sent to your energy distributor. At the end of the month, your bill consists of the amount of energy you generate from solar and energy you used from the grid. Any excess from solar generation will offset amount you used from the grid.
What if you did not stay in your building for months. You will still generate energy but you did not use energy from solar or energy from grid. The generated energy will still be sent to your energy distributor but you can offset your future bill within 24 month.
Figure 1: How NEM works