Solar power could oust diesel generators used by marines

The US Office of Naval Research (ONR) is to use solar energy in an effort to help marines phase out diesel generators currently used in combat outposts.

The Renewable Sustainable Expeditionary Power (RSEP) programme seeks to create a transportable renewable hybrid system that can provide marines with electricity for a 15-day mission without relying on fuel re-supply convoys.

‘This programme takes on a number of power-related challenges and ultimately will allow the Marine Corps to take a big step toward its goal of using fuel only for mobility purposes by 2025,’ said H Scott Coombe, product manager for RSEP, a collaboration between ONR’s Expeditionary Maneuver Warfare and Combating Terrorism and Sea Warfare and Weapons departments.

‘This is a very interesting multidisciplinary problem we’re trying to solve,’ Coombe said. ‘There are multiple heat-transfer issues, as well as optical, electrical and control/optimisation challenges.’

According to a statement, ONR has enlisted the help of three industry teams — led by Raytheon, Battelle and Emcore — that have developed concepts for hybrid systems that use sunlight, heat and fuel to create electricity.

One option is to combine a Stirling engine with a solar concentrator resembling a satellite dish, while another is to use solar cells to collect sunlight in conjunction with a solid-oxide fuel cell.

These systems must be able to independently switch back and forth from solar when the sun is out to fuel at night or when there is heavy cloud cover. They also have to be compact enough to fit on a small trailer towed by a Humvee so they can be transported to forward positions. So far, solar concentrators are said to have been too large to carry around the battlefield.

‘These systems will be used in forward-deployed locations where we don’t want to have to go to re-supply.’ Coombe said.

Researchers expect a successful product will reduce fuel needs by 40 per cent for expeditionary power systems, with a continual output of 3kW. It also will be much quieter than current systems and have the potential to use biofuels.

RSEP is a five-year Future Naval Capabilities programme. ONR will evaluate the industry teams each year and could keep working with one or more of the industry products or continue to explore other options for renewable power sources.

‘We’re going to learn a lot from all the different approaches and make sure we capitalise on all the successes and lessons learned going forward,’ Coombe said.