With power generation, grids and networks constantly expanding, the need for additional efficient and environmentally friendly power has never been greater. Technologies based on direct current (DC) power can dramatically improve efficiency in many applications. ABB was a pioneer in DC power and continues to innovate its applications to help improve the way the world uses electricity.
Eric Schreiber from ABB Marine spoke with us this morning and gives insight into the power systems on board vessels at sea:
“Some maritime industry enthusiasts and seasoned seafarers might remember when DC power was the prevailing source of electricity on board ships. Due to the simplicity of AC power, it eventually overtook DC electricity on board ships. ABB’s recent developments in DC power technology, called “Onboard DCgrid,” are reviving the usage of DC power on board ships because it is simply more efficient.
The Onboard DC Grid is a new philosophy in optimized propulsion and an integration of multiple DC links as used in current propulsion and thruster drives designs. Onboard DC Grid enables ship designers to combine the benefits of AC components with the advantages of a new smart DC distribution. Just as variable speed drives allow the electric propulsion motors to be run at their optimum working point, Onboard DC Grid allows the diesel engines to run at variable speed for top fuel efficiency at each load level. And, the Onboard DC Grid enables full flexibility in combining energy sources, including renewables.
Studies based on Onboard DC Grid estimate higher efficiency levels up to 20% in addition to the advantages of smaller equipment footprint and reduced weight.
The efficiency improvement is mainly achieved from the system no longer being locked at a specific frequency (usually 60Hz on ships), even though a 60Hz power source can also be connected to the grid. This new freedom of being able to control each power source totally independently opens up numerous ways of optimizing fuel consumption. The additional benefits of size provides more cargo space while the weight reduction contribute to a more functional layout. The reduced weight and footprint of the installed electrical equipment will vary depending on the ship type and application. One comparison using the Onboard DC Grid instead of the traditional AC system for a Platform Supply Vessel (PSV), reduced the weight of the electrical system components from 115,520 kilograms (254,700 lb) to 85,360 kilograms (188,200 lb).”