Decarbonising heat presents a huge challenge, which could be addressed by a technology that stores electricity as thermal energy in molten silicon blocks.

 

1414 Degrees based in Adelaide, Australia, is installing the first customer pilot of its thermal energy storage system (TESS)  at a water treatment plant, which will be commissioned in February 2019.

Silicon’s high melting point of 1414°C makes it an ideal thermal storage material. A tonne of silicon can hold half a megawatt of energy. 1414 Degrees has engineered a modular storage system that provides both electricity as well as high temperature heat.

The system is applicable for behind and front of meter deployments, though the company is targeting the former category first where many processing industries, from food and drink, to chemicals, to packaging, need heat, steam or both.

According to the International Energy Agency (IEA), more than half of the world’s energy consumption goes on heating, for use in buildings and for industrial processes.

Because heat is mostly produced by burning fossil fuels – primarily natural gas – to first generate electricity, its production accounts for 39% of global energy-related carbon dioxide emissions.

Australian utility SA Water approached 1414 Degrees over two years ago to discuss using the company’s technology within its operations.

 

Making use of surplus gas

The utility’s Glenelg wastewater treatment plant is already 80% energy self-sufficient. Installing the thermal energy storage system (TESS) within its operations will allow SA Water to burn the biogas created through sewage treatment processes that would otherwise be flared off, to generate electricity through reciprocating gas engines, which can be converted to thermal energy and stored.

Credit: 1414 Degrees

The pilot TESS with a capacity of up to 30MWh will enable SA Water to achieve its aim of operating electricity cost-neutral waste water sites, even allowing it to sell energy at times of high demand. The 10MWh modules can store latent heat in molten silicon that can release 250kW of electricity for six hours, as well as heat which is returned to the plant’s digesters.

According to 1414 Degrees chairman Kevin Moriarty, the company is seeing global interest from utilities and operators of facilities where electricity generated from surplus gas can be stored.

Next year 1414 Degrees will deliver a second system, with a 10MWh capacity, for installation at Austcor Packaging’s corrugated packaging plant in New South Wales. The packaging producer also plans to install a solar PV array. Excess electricity produced on site will divert to the TESS and energy will be used to generate steam required for the corrugating process.

 

Large-scale demonstrator

1414 Degrees also has plans for a larger version of its TESS involving renewables.

Initially the TESS was promoted as a means to support integration of renewables in the grid. Moriarty says: “We approached wind farm operators on the south coast of Australia with the concept. In that region a lot of wind blows early in the morning when there isn’t as much demand, so potentially it could be stored. However, the industry didn’t have much incentive to work with us.”

So 1414 Degrees is taking a more proactive approach. “In Australia there are older wind farms, which can be acquired so we are looking at the possibility of purchasing one where we can build our grid-scale demonstrator,” says Moriarty.

Credit: 1414 Degrees

This will be a 200MWh device, able to supply a baseload of 10MW of electricity plus heat over eight hours. Several of the 200MWh devices can be connected up providing the building blocks for a 1GWh plant. The cost of building the first 200MWh TESS is in the region of AUS$20-30 million.

One potential site is a wind farm close to a paper factory, which could use the heat for its processes, but the company is also exploring other possibilities.