When most people talk about
green energy being "clean", they probably mean that it leads to fewer carbon emissions and less consumption of natural resources.
However, researchers at Boston University have been looking into the physical cleanliness of green energy infrastructure - in particular large-scale solar power installations.
In use, solar panels can become dusty - especially if they are installed in hot, dry, windswept desert areas where the sun's power is at its highest.
Meanwhile, water may not be available at low cost due to the environmental conditions, compounding the problem.
Now the Boston University researchers are looking further afield for inspiration on how to combat the problem - with their gaze resting on an entirely different planet.
Mars is known for its red dusty surface and, in recent years, missions to the planet have included technology designed to keep equipment clean while working in its environment.
In the space of two minutes, solar panels fitted to Martian explorer vehicles can be cleaned with an effectiveness of 90 per cent.
This is achieved by detecting when the panels have become dusty and sending a wave of
electricity across their surface, repelling the particles.
Using the same technology on renewable energy installations on Earth could help to overcome the dust problems encountered here too.
Study leader Dr Malay K Mazumder says: "To our knowledge, this is the only technology for automatic dust cleaning that doesn't require water or mechanical movement."
The researcher's areas of special interest include solar technology, along with powder and particle technology, electrostatic processes and surface science.
He also looks into issues relating to material engineering and respiratory drug delivery, a discipline in which powdered steroidal formulations are often administered to help combat breathing difficulties.
