One battery to rule them all?

After the Tesla Powerwall launch, there is reason to think lithium-ion batteries could become the overwhelming technology of choice for battery storage. Photo: Tesla Gigafactory

After the Tesla Powerwall launch, there is reason to think lithium-ion batteries could become the overwhelming technology of choice for battery storage. Photo: possible Tesla Gigafactory design.

By Jason Deign

The Tesla Powerwall launch three weeks ago focused attention on energy storage but may also have been a nail in the coffin for non-lithium-ion (Li-ion) technologies.

In drastically reducing prices, Tesla removed one of the remaining barriers to adoption of Li-ion as the standard for battery storage.

Currently other technologies are vying for supremacy on the basis of cost, safety, performance and bankability.

However, the launch of a residential battery system for USD$3,500 helped lay to rest the idea that Li-ion is automatically more expensive than other chemistries.

Even Tesla’s grid-scale Li-ion offering, the Powerpack, looks competitive with the most cost-effective battery technologies out there.

Costing just $0.05/kWh

An analysis by Zachary Shahan of Cleantechnica, for example, shows the Tesla product costing just $0.05/kWh over a 5,000-cycle lifespan.

That’s cheaper than an Imergy vanadium flow battery could achieve with a 15-year lifespan at current prices.

The Eos Aurora battery system, which uses a rechargeable zinc hybrid cathode battery technology, beats Tesla at $0.02/kWh. But it will not be available until next year.

Importantly, too, it seems practically all of Tesla’s price cut is down to economies of scale that look likely to be achieved after the company reported an estimated $800 million worth of orders in a fortnight.

In the meantime, though, other companies are scrambling to make the underlying technology even cheaper.

Non-toxic production processes

Electrovaya, for example, is looking to cut Li-ion costs by incorporating a non-toxic production process into battery manufacturing. Such advances could also help to address another of Li-ion’s perceived shortfalls: safety.

Li-ion batteries have traditionally been seen as a fire hazard, a problem that has led project developers such as Demand Energy to resort to lead-acid technology in risk-conscious markets such as New York State.

However, manufacturers such as Electrovaya and Tesla are increasingly working to dispel Li-ion’s dirty, dangerous image.

Unveiling the Powerwall, Tesla’s boss Elon Musk said: “It gives you safety, security, and it gives you a complete, affordable, solution.”

What of performance, though?

Energy delivered up to four hours

Right now, says Roger Lin, director of product marketing at NEC Energy Solutions, many utilities are happy with the performance of Li-ion for short-term storage, where energy is delivered for up to four hours.

With a growing need for longer-term storage applications, however, utilities are keen to explore the potential for using other product categories, such as lead-acid, molten sodium and flow batteries.

But the reason for overlooking Li-ion in these applications is usually down to cost. If Li-ion product prices continue to plummet, it is hard to see why project developers should choose anything else.

And it is the matter of choice that could be the clincher for Li-ion.

When two competing technologies are roughly equal in terms of price, safety and performance, it is natural for developers and owners to choose the one that is most established and bankable. Here, Li-ion wins hands down.

Widespread use in other applications

“The one thing that lithium has that a lot of other [battery technologies] don’t have is widespread use in other applications, and the manufacturing infrastructure to support it,” Lin told Energy Storage Report.

“Lithium-ion batteries are used in almost every portable electronic device in the world, they are used more and more in vehicles, so you’ve got this diversity of markets and applications that lithium-ion enjoys.”

This, plus the fact that Li-ion batteries are produced by major, diversified manufacturers with healthy balance sheets, means the technology is a natural choice for utilities wanting to reduce risk in energy storage projects.

“For the utility industry it’s going to be more the mature technologies that make it in early on, in the next five years or so,” said Lin. “I see Li-ion taking most of the applications, most of the projects that will be put into commercial service.”

It is important to note that Lin is not a Li-ion evangelist. As a project developer, NEC Energy Solutions is technology agnostic. “Look at the guys at Aquion Energy,” Lin said. “They have got this new aqueous hybrid ion battery.

A breakthrough chemistry

“Maybe that is a breakthrough chemistry. That could be the ideal one for stationary, large-scale energy storage and nothing else competes on a levelised cost of energy basis.”

But companies such as Aquion have the odds stacked against them as utilities automatically favour Li-ion products from big manufacturers, and those manufacturers continue to pour research into improving their products.

“If we see Li-ion getting down into the very aggressive numbers that you might expect to be viable for the stationary side of the business, because of Li-ion’s energy density you are probably going to see some advantages there,” Lin said.

The issue of which technologies are most suited to stationary energy storage will be front and centre in discussions at Energy Storage USA 2015, where Lin is speaking.

However, another speaker, SunEdison’s director of advanced energy solutions Faisal El Azzouzi, has already told Energy Storage Report of concerns over adopting non-mainstream products that are not backed by a reputable brand.

“In solar, the buzzword was bankability,” El Azzouzi said. “Same thing here.”

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