Why Grids Need Diamond To Be Their Best Friend

by Gareth Taylor CEO

A couple of weeks ago I was invited to give a talk on innovation to a group of people from the distribution system end of the electrical utilities sector. It was an interesting opportunity to discuss the subject in an industry that is famed for its conservatism, where the word “innovation” is usually tempered with only so long as the technology/service/practice is already well proven so that the prime directive (“keep the lights on”) is not compromised.

In preparing my talk I was reminded of how my own sojourn into diamond began 18 years ago, not in a lab but from strategy development for the international electrical substations manufacturer I worked for at the time. My brief was to look at how electricity transmission and distribution networks might evolve over the next few decades and to present this to the main board. The outcome was the creation of three scenarios, for which a strategy was developed for each one. These are summarised in the figure below, which highlights the general flow of electricity through the network.

Energy Scenarios

The first scenario was called “Status Quo” – the core assumption being that we would continue to build large gigawatt scale power stations and use the transmission networks as the main conduit for shipping energy to where it was needed. The strategy resulting from this pretty much aligned with where the business was focused, so a happy board – although not for long. The second scenario was called “The Age of Sustainability” – the core assumption here being that other fuel vectors e.g. gas are actually cheaper and more efficient to transport than electricity and growth of renewable generation plant would lead to more distributed generation at the tens to low hundreds of MW level closer to the point of use. The final scenario was called “The User Rebellion” – a scenario where domestic and commercial users, possibly due to worsening quality of supply, took matters into their own hands and installed high levels of embedded generation most of at significantly below the 1MW level.

In the latter two cases this meant that the challenges (and hence new business opportunities) were all going to stem at the distribution network level on systems that were never designed to cope with large amounts of bidirectional power flow or contribute to the national security of the electricity system. The recommendation to the board was that of the three scenarios put forward, Status Quo was the one least likely to happen. Despite acknowledging the validity of this assertion the board choose to subscribe to the Titanic school of management and ignore the impending the threat to its primary business. The outcome? Subsumed as part of a bigger global concern 12 years ago.

With the benefit of hindsight, those scenarios weren’t all that bad. Only today when you look at the energy mix the outcome is that we have a melange of some of the principles that drove The Age of Sustainability and The User Rebellion. And while we correctly predicted that what have become known as Smart Grids would be necessary, what we failed to anticipate was the degree of burden that international government policies towards renewables would further place on already distressed distribution networks. The simple fact is that the intermittency of renewables has yet to be properly addressed.

Going back to the talk I gave, one of my themes was therefore that change and the rapidity of change is becoming something that utilities cannot just react to or engage in programmes that start when the production roll-out of that technology/service/practice is at completion. In fact there are some enabling pieces in the jigsaw that are so fundamental that they enable and drive profound change across a whole swathe of how you might operate electricity networks, boiling down to a handful of enabling component technologies. These I term “horseshoe nail technologies” – for those familiar with the proverb.

So cue Elon Musk’s recent announcement of Tesla’s Powerwall domestic energy storage system highlighting that certainly the The User Rebellion is very much alive– even though he acknowledged it is currently twice the cost that could seen as sustainable. All serving to re-open the vexed question of just who should pay for energy storage – despite the fact that it is recognised as one of the horseshoe nails necessary to cope with the intermittency of all that solar and wind we’re being encouraged to embrace. Ask a renewables developer, ask a grid operator, neither wants to take on the responsibility of energy storage.

While the Powerwall undoubtedly uses some very clever battery technology, actually what makes it really work is the power electronic system that interfaces the battery to the grid and controls the charge and discharge of the battery. Going back to those strategy scenarios what I recognised was that power electronics would play a massively increased role in energy systems not only for energy storage, but the way we connect generators to the grid, the way we control the flow of electricity and the way we use that energy – especially at the utility distribution voltage level. Like energy storage, power electronics continues to be twice the cost that many would see as sustainable. Unlike energy storage, power electronics does justify its cost in many scenarios, so much so that 120GW of power electronic systems designed to control >1MW of energy are manufactured per annum (for comparison UK electrical plant capacity is around 60GW).

The cost of power electronics is not going to come down until a replacement for the silicon transistors that lie at the heart of these systems is found. Only then can large swathes of costs to be taken of power electronic systems. Gallium Nitride and Silicon Carbide continue to make slow but steady advances, albeit at the sub 1800V level. However the real energy challenge lies at the 11kV to 33kV that most distribution networks operate at and this requires devices able to switch at those sorts of voltages. Only then can power electronic systems come to the fore, permitting fully dynamic stabilisation of the grid. And this is where diamond comes in. All those many years ago there was a nagging feel that GaN and Sic would struggle to deliver clear blue water over silicon and so it has, so far, proven to be.

Of all the electronic materials, diamond offers the most compelling case as the material most able to enable and deliver the power electronics needed to make a truly smart power grid. The past 18 years have been a long and necessarily intermittent journey, but with major advances in the materials technology, the recognition that carbon is likely to be to the 21st century what silicon was to the 20th, the technology we are now starting to demonstrate at Evince is truly a breakthrough in bringing fully synthetic diamond based electronics into the mainstream.

And my final message in that talk to the utilities? Most things you may get away with on a purely reactive strategy, but when it comes to those horseshoe nails it may be better to embrace and nurture them from an early stage rather than act in denial until its too late. As Elon Musk is showing, one exceptionally wealthy man can rewrite the rules, think what a few more joining in could do.

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