It starts as DC…
At present, most on-site renewable energy systems produce direct current (DC) electricity which is then inverted to alternating current (AC) and fed into the utility grid.
It ends as DC…
The AC power from the utility grid has to be converted to DC within the building to power the modern electrical loads such as fluorescent and LED lighting, IT equipment, energy efficient motors and pumps, etc.
Connecting on-site generation to building loads directly on DC power
makes systems more reliable and efficient.
Conventional AC System
Challenges with existing AC systems
- On-Site generation must utilize DC-AC power conversion to be connected
- Power conversion devices have considerable efficiency losses and are the first devices to fail
- On-site generation is separated by the AC grid from the building loads
- Electrical loads need AC to DC convertor to use grid energy
- Power conversion electronics create maintenance and reliability problems
- On-site renewable generation cannot be easily used for back-up without including expensive equipment