It's rarely great news when an area gets blanketed in volcanic ash – but University of Barcelona researchers have discovered it has a rare combination of useful properties, which make it remarkably useful as an energy storage medium.

We've written a number of times about super-cheap thermal energy storage, and a number of other times about highly efficient heat batteries operating at super-high temperatures. The cheapest of these 'brick toasters' use the most abundant of materials, and the most efficient can handle extraordinarily high temperatures using materials like liquid tin and carbon materials – but volcanic ash, as it turns out, might offer a kind of goldilocks proposition in the middle for certain applications.

The key application at the heart of a new study published in the Journal of Energy Storageis concentrated solar power. So, not photovoltaic panels – we're talking those towers out in the desert with huge rows of parabolic mirrors all around them designed to precision-track the Sun and reflect its light toward a single point.