The Energy Dice – exploring efficient transformation, transport, storage and application of thermal energy

The world faces a ‘global energy trilemma’ – affordability, low carbon and security – and the race is on to find innovative solutions to radically transform how energy is supplied and used, and to make future systems more efficient and reliable.

In fact, the best single solution to all these problems may already have been invented – by Professor Yulong Ding, the University’s founding Chamberlain Chair of Energy Storage, and one of the world’s most influential researchers.

Called liquid air energy storage (LAES), this is an emerging technology that has the potential to drive the development of variable renewable energy sources, such as wind and solar power, due to its ability to convert excess/off-peak electricity into multi megawatts of stored energy.

The off-peak, renewable electricity is used to compress and liquefy ambient air, which is then stored in tanks at the cryogenic temperature of -196C, where it can be kept for extended periods of time without significant losses. When energy is required – at peak times – the stored liquid air is drawn from the tanks, pumped to high pressure and heated, expanding by more than 700 times in the process, and used to drive a turbine to generate electricity.

LAES has already been commercialised, by Highview Power Storage, the UK-based developer of large-scale long duration LAES systems, and Yulong is confident it is the way forward in addressing the world’s energy challenges.

‘My work is about addressing the energy trilemma challenges facing the world today,’ he explains. 'My part in this is to use science to develop energy storage technologies, in particular heat and cold energy storage. My work has been and is still focused on the efficient conversion, storage and utilisation of heat and cold. We develop novel formulations and associated advanced manufacturing technologies for micro-structured composite materials, new thermodynamic cycles and processes, and integration and optimisation methods for efficient heat and cold energy harvesting and storage.'

Chinese-born Yulong arrived at Birmingham nearly two years ago (for the third time – he did his PhD here and, later, his post-doc) to head up the Birmingham Centre for Cryogenic Energy Storage (BCCES), the world’s first research centre for cryogenic energy storage, set up with the aid of a £12.3m EPSRC grant. To support Yulong’s work, Highview relocated its 350kW/2.5MWh LAES pilot plant to Birmingham.

The energy challenges the world faces include not only the mismatch in energy supply and demand and the need to cut carbon emissions, but also the amount of industrial heat waste. LAES can significantly improve the efficiency of diesel generators, routinely used as reserve capacity for the National Grid. LAES can integrate waste heat or cold from industrial processes to increase the system’s overall efficiency to more than 70 per cent.

'Waste is a key issue and by addressing it, we can enhance efficiency,’ says Yulong. 'Our power stations only use about 50 per cent of their capacity, because they are designed and built to deal with peak demand (for electricity), and peak demand only occurs at a certain period. By using off-peak energy, we reduce the need for the building of more power plants, thereby saving a lot of money and allowing the power plants we already have to work a lot more efficiently.'

When Yulong started working on energy 30 years ago, initially as a thermophysicist, it wasn’t the hot topic it is today. ‘We were ahead of our time, although we didn’t realise it. Initially it was curiosity-driven, with some sort of idea of application, but the problem wasn’t as severe as it is now.

‘Storing energy is not particularly new; in the past few decades, people have been focusing on batteries, which are useful, but very little emphasis has been placed on hidden cold storage, which turns out to be more important.’

Yulong, who recently delivered his Inaugural Lecture, entitled ‘The energy dice – exploring efficient transformation, transport, storage and application of thermal energy’, is recognised as a globally influential scientist: In 2014, he was one of four academics from the University to be named as Highly Cited Researchers in a list of the world’s leading scientific minds, published by Thomson Reuters.

Having filed 13 patents and published more than 400 academic papers, Yulong thinks his place on the list reflects his determination ‘continue something you believe in’ and that most of his work has clear, real-life applications.

What gives him most satisfaction is that his work solves more than one energy problem. ‘The technologies we have developed actually address the trilemma of affordability, clean energy and security; in other words, we are killing many birds with one stone.’