Stationary storage systems are batteries designed to store excess power from the grid, including from renewable sources, for use during expensive peak demand periods.

They include residential and industrial ‘behind the meter’ systems — but today we’re just talking about the big ones.

Like the 129MWh lithium-ion Hornsdale power reserve in South Australia, also known as ‘Tesla’s big battery’.

At present, most stationary storage is lithium-ion, with vanadium flow (VRFB) uptake – a better alternative for grid style storage in many respects – hindered by high vanadium prices.

By 2040, BNEF reckons the global energy storage market will grow to a cumulative 942GW worth about $US620 billion in investment over the next 22 years.

But is thermal storage poised to snatch market share from the main players?

Private South Australian company CCT Energy Storage, which has commercialised the world’s first thermal battery, certainly thinks so.

The TED (Thermal Energy Device) battery is a “game changer”, it says, smashing lithium-ion and VRFBs out of the park by a number of key metrics.

TED works by heating and melting the phase change material (PCM), silicon, to store electrical energy as thermal energy.

This PCM has almost five times the energy density of lithium-ion and more than 800 times that of vanadium flow. Energy density refers to the amount of energy that can be stored in a given mass.

TED is low maintenance, has a life of over 20 years, and is fully recyclable. “Not one element” is harmful to the environment, CCT says.

But what about cost? CCT chief executive Serge Bondarenko says thermal storage isn’t just better – it’s cheaper.

CCT’s Serge Bondarenko with the TED thermal battery.

“Cost against lithium-ion is significantly less, and longevity and performance is much greater depending on the application,” Mr Bondarenko told Stockhead.

“With respect to vanadium flow batteries we have not done the cost comparison, but it appears that longevity matches ours with performance not near as good as based on energy density.”

TED is also scalable, useful for smaller 5kW set ups through to larger 100MW-plus applications, CCT says.

It could be an affordable alternative power source for remote communities, commercial businesses, telecommunications networks, and transport systems.

CCT already has plans to supply at least 10 TED units to commercial customers this year, with production expected to ramp up to more than 200 units by 2020.

European energy partner MIBA Group will also manufacture and distribute TED to Denmark, Sweden and the Netherlands.

The EU has quickly recognised the downside of non-environmentally friendly storage solutions, Mr Bondarenko says.

“Europe is fast going through a change toward renewable energy and is looking at battery storage solutions that provide longevity, [and are] effective, environmentally friendly and reliable,” he says.

“We believe our technology provides exactly that on a viable scale.”

“It is a significant shift in the way renewable energy solutions are being thought of.”

1414: Thermal storage on steroids

Fellow Adelaideans 1414 Degrees (ASX:14D) are developing their own thermal energy storage system, called TESS.

Unlike TED, which is being commercialised, TESS is currently going through large-scale pilot testing.

Yet 1414’s numbers also support thermal storage as a strong alternative to lithium-ion and VRFB.

1414 reckons TESS could be 10 times cheaper than lithium ion. Unit costs fall as it scales up to GWh capacity, “unlike batteries whose storage unit cost remains fairly constant with scale”, the company says.

And it scales pretty easily, the company says, which means 1414 can aim big.

Remember Hornsdale? It’s currently the largest battery in the world (although not for much longer)  with a capacity of 129MwH.

This is 1414’s concept for a 1GwH grid-integrated TESS energy storage facility, connected to a renewable energy farm:

Big TESS could provide base load power for long periods, but also go head-to-head with Hornsdale-type batteries by providing stability services to the National Electricity Market (NEM).

“The device would  earn revenue from NEM fees for grid stability because its turbine has spinning inertia like a gas or coal power plant, and it could provide fast frequency response (FFR) to grid variations by near instantaneous switching of its charging connection,” 1414 told investors in a January update.

1414 chairman Dr Kevin Moriarty was in Washington DC, speaking at the Global Energy Solutions Summit on the latest trends in energy storage.

He says the electrically charged TESS is infinitely scalable, with 1414’s current focus on 10MWh to 1GWh iterations which will be able to distribute power over an eight to 16 hour period.

“Given the low economic and environmental cost of silicon – both in acquiring and disposing, the long indefinite lifetime of the TESS with minimal O&M and the compact nature due to the density of silicon, we are aiming for a capital cost of US$50,000 per MWh,” he told Stockhead.

“However this capital cost is only one proposition – the majority of customers coming to us value the lower operating cost of the TESS plus flexibility and function of what our technology can do in terms of delivering heat which solves a range of other economic and environmental challenges for them.”

In December, 1414 kicked off a commercial pilot of its  biogas thermal energy storage system GAS-TESS at South Australia’s Glenelg Wastewater Treatment Plant, which is testing the system’s ability to integrate energy storage and the provision of both heat and power for industrial users.

READ: Cheaper, better battery storage will underpin the global modern energy system