Renewable energy courses graduates may gain advantages from military investment, after one organisation claimed spending in this area is set to increase.

Pike Research revealed military agencies from across the world are set to boost spending significantly in environmentally-friendly technologies over the next 20 years.

Figures from the company estimated expenditure to reach $26.8 billion a year by 2030, jumping $25 billion from 2010 data.

President of the company Clint Wheelock said military sources may be able to bridge the gap between research and development activities and "full commercialisation" of new technologies.

"As such, the myriad of military initiatives focused on fostering cleantech is anticipated to have a substantial impact on the development of the industry as a whole," he added.

This news comes after Europe's first solar-powered rail tunnel was opened near Antwerp in Belgium, with the structure using 16,000 solar panels to generate electricity for trains passing by.

Want to know more about renewable energy courses