Before we talk about the emerging microgrid with solar, let’s talk about the traditional energy grid, first. An electrical grid is an interconnected network for electricity delivery from producers to consumers. Electrical grids vary in size and can cover whole countries or continents. Traditional energy grid has a few stages before the produced electricity reaches the consumers.
The first stage is Generation.
- 70% Fossil Fuel
- 30% Clean Energy
- Scarce Resource
- High Capex
Generation is 60% of your electricity bill. Electricity is most often generated at a power plant by electromechanical generators, primarily driven by heat engines fueled by combustion or nuclear fission but also by other means such as the kinetic energy of flowing water and wind. Other energy sources include solar photovoltaics and geothermal power.
The next stage is Transmission.
Transmission is 7% of your electricity bill. The three-phase power leaves the generator and enters a transmission substation at the power plant. This substation uses large transformers to convert the generator’s voltage (which is at the thousands of volts level) up to extremely high voltages for long-distance transmission on the transmission grid. You can see at the back several three-wire towers leaving the substation. Typical voltages for long distance transmission are in the range of 155,000 to 765,000 volts in order to reduce line losses. A typical maximum transmission distance is about 300 miles (483 km). High-voltage transmission lines are quite obvious when you see them. They are normally made of huge steel towers.
The third stage is Distribution.
The distribution of electricity first begins with distribution substations that use “step-down” transformers, which perform the opposite task of the “step-up” transformer. The voltages of long distance transmission are unsafe for people to handle, so these step-down transformers bring the voltage down to safer levels. The distribution grid then connects these substations to the customers that require electricity, ranging from large industrial buildings to small homes. More substations and smaller transformers help to further lower the voltages, and divide the electricity among subdivisions or residential areas. Then, that is the only time the electricity reaches your homes.
Emerging Microgrid with Solar
Microgrid is a self-sustained electric power generation, and distribution system that provide electricity service to number of small, remote, and isolated areas that remain un-electrified. They can be fully isolated from the main grid or connected to it but able to intentionally isolate themselves. Microgrid supply remote communities which includes residential households, local businesses, as well as public institutions.
Generation is also the first stage for Microgrid.
DC electricity will be converted to AC through solar inverters, then it’s ready for commercial, industrial and residential consumer use. Sunlight and generation is the only cost for microgrid.
