The U.S. Navy wants to improve its ability to store, generate and surge electricity on ships to accommodate exponentially increasing demand for power, service officials said.
The rise is driven in a large part by the advent of lasers, electromagnetic rail guns and computing technologies on vessels today.
Naval Sea Systems Command recently released a planning document, “Naval Power Systems Technology Development Roadmap,” which calls for new research to identify ways to generate and store power on ships, according to Dr. Timothy McCoy, director of the Electric Ships Office.
McCoy and other Navy experts examined the evolution of the need for electrical power at sea, comparing it to the growth of ship size, or “displacement,” over the past century. They found exponential growth in the level of ship-borne and generated electricity.
“If you go back to the very first destroyer, we were putting electric plants on that which were 3 to 4 kilowatts in rating,” McCoy said in an interview with Military.com. “Today, our DDGs have 9,000 kilowatts on board and the DDG 1000 has 78,000 kilowatts on board. The rating of the power plant has grown exponentially, and the size of the ships has also grown. However, the percentage of the ship that is electric power producing or involved in electric power distribution is growing in relation to everything else. Electric power is getting more and more important on ships.”
On-board power and electricity is needed to support systems such as communications devices, lighting, sonar, radar and weapons, McCoy said. Electric motors are also a key component of alternative propulsion technologies such as the hybrid-electric drive auxiliary propulsion system — which powers several Navy ships such as the USS Makin Island Amphibious Assault Ship and others in development such as the USS America and USS Tripoli.
The so-called road map is intended to inspire collaboration within academia, the Defense Department and the Navy, and to identify some of the methods needed to better integrate electrical systems onto ships now and into the future, McCoy said.
For instance, while the Navy is already deploying everything from solid-state laser weapons and electromagnetic rail guns to high-tech sensors and radar systems, the service expects more of these technologies will be used in the future.
“The far-term involves additional uncertainty, but it is expected that additional directed-energy weapons requiring even more power will become available as well as higher-powered sensors and rail guns of increasing size and capability,” the document states. “It is likely that Navy platforms will operate these systems simultaneously.”
The paper is designed to establish a common approach to developing and introducing electric power systems across various types of Navy ships, McCoy said.
“Given historical technology development cycles and insertion time periods, now is the time to plan and take action required to support future naval power systems and capabilities to influence technology developments in future ships,” he said.
As a result, the document makes a handful of recommendations designed to address these challenges, including the development of an energy “magazine” technology to provide intense bursts of power when needed for weapons such as lasers and rail guns.
“The idea is to store some energy in electrical form – maybe in capacitors,” McCoy said. “We will have some sort of electrical energy stored on the ship so that when these weapons say, ‘I need to go from zero to a megawatt and I need to do it now,’ we can. When it is done, we need to go back down to zero or almost zero.”
Capacitors are able to store an electric field between two conducting plates with an insulator between them, he said.
A promising technology are high-voltage, high-temperature semi-conductors that use silicon carbide — compounds of silicon and carbide blended together forming a crystalline lattice that is able to operate at higher temperatures and switch electrical charges faster, McCoy said.
“Silicon carbide is a different physical material and it has different physical properties,” he said. “One of those is called wide band gap – that is just the amount of excitation it takes to move an electron from one state to an excited state. These wide band gap materials can operate at higher temperatures.
“Semi-conductors are called semi-conductors for a reason,” he added. “When you put electricity through them you have a fair amount of losses that turn into heat. Wide-band gap materials like silicon carbide are pretty promising. What we see with these is a way to revolutionize the power and electronics industry.”