The interconnection option of a renewable energy system (e.g. photovoltaic system) is known as “Grid-tied” (Interconnected). Being “interconnected” to the electrical network of a utility company means that during the day, while receiving sunlight, it will be generating electricity from 100% solar energy and whatever is not consumed will be exported back to the utility company. During the night, or when the photovoltaic modules are not exposed to solar energy (rainy or cloudy day), you will be consuming 100% electricity from the utility company. There are two types of “Grid-tied” systems:
- “Grid-tied” (without batteries): In this type of interconnection, if sunlight is not received, electricity is consumed from the utility. If the utility is out of service, the customer can’t have electricity unless it has an electric generator or some other source of “back up”.
- “Grid-tied” (with batteries): In this type of interconnection, if sunlight is not received, electrical energy from the utility is consumed. If the utility is out of service, the customer will have electricity by consuming the energy stored in the photovoltaic batteries. The price for this option is higher than the previous option due to the cost of the additional battery (storage) components.
- Net consumption at the end of the month = Excess of kWh consumed: If the amount of electrical energy consumed at the end of the month is GREATER than the electrical energy exported to the utility, the difference between what is consumed and exported (net amount) results in a charge amount greater than the minimum established by the utility. Maybe in that particular month, it rained constantly or was cloudy most of the time. If you have accumulated kWh’s of credit in your account, it will automatically be used to pay the excess kWh on your bill. Otherwise, the customer would pay an amount greater than the minimum established, in that specific month.