First: Dealing with renewable terawatts on Terra
Cheap mass storage of grid-level energy has been the conundrum of the expanding renewables market. It is all good and well to have energy when the wind blows and the sun shines, but very often the production window does not match the hours when demand is high.
Equally, our electricity grids are created for stable base power supply and cannot handle power surges well. The more intermittent energy sources we add to the grid, the less reliable it becomes and the more we need to spend on extra infrastructure to add reliable flexibility. The result is that, even if the production cost of renewables is now at parity with traditional coal power production plants, when we include infrastructure upgrades, the cost to the nation as a whole is higher.
However, if we could store large amounts of energy locally, where they are produced or used, say at the base of a windmill/solar park, or at the level of a park for heavy industry, the suburban neighbourhood, the county or municipality; and furthermore transferred or distributed at the most appropriate time, then existing infrastructure might suffice and the necessity of spending a high cost to upgrade it might lower or sometimes vanish. Adding the distributed battery system would still add cost, but the equation would already look much better.
Nevertheless, till recently the required power storage systems would be either too bulky and costly for many applications. So is there no compact economical solution?
Down under, the South Australian company CCT Energy Storage might have cracked the code. Both in power density, compactness and operational cost, the system seems to turn the heads of professional analysts. Understandably, the developers are proud of their baby:
“TED is the first battery of its kind and will be a game changer in the renewables space, with the ability to significantly reduce power costs while providing versatile and long-lasting energy with little to no environmental effect,” says CCT Chief Executive Serge Bondarenko.
TED stands for Thermal electric battery. TED stores electrical energy as thermal energy by heating and melting a unique phase change material. The energy is stored at more than 12 times the density of a lead acid battery, before being extracted by a thermic generator to provide electricity when, and where it’s needed.
That phase change material is the non-toxic silicon, which we find, among other places, in beach sand. The secret is that with its high melting point of 1414 °C (and a boiling point of 3265 °C) it takes a lot of energy to heat and cool. This explains why it can store so much energy for later use. After oxygen, silicon is the second most abundant element, with 90% of the Earth crust or 28% of its weight, composed of it in the form of silicate minerals (and in beach sand). With a silicon density of 2,329 kg/m3 the system does not lend itself for mobile applications like electric cars or trucks, but in stationery modules, the technology shines.
And the system is not limited to small trickles of power either:
“TED’s scalability means it can be used in small-scale 5kW applications to large-scale applications of hundreds of megawatts of instantaneous power,” Mr Bondarenko states in a press release. A standard TED box holds 1.2 megawatt-hours of energy, with all input and output electronics on board, and fits easily into a 6-m container.
“And unlike some renewable energy sources, TED can manage input variations, produce base load output and charge and discharge simultaneously – minimizing energy wastage and making it applicable to numerous commercial industries.”
The Lonsdale-based business will supply at least 10 TED units to commercial customers this year, with production expected to increase to more than 200 units by 2020.
While serving the Australian home market, CCT energy storage is already expanding its commercialization to other parts of the world, with European energy partner MIBA Group to exclusively manufacture and distribute TED to Denmark, Sweden, and the Netherlands.
The Martian connection
It is not an application the creators might have in mind but thermal battery storage might have a future off-world as well.
Combined with a viable source of energy which on Mars can be nuclear (such as a 10kW nuclear NASA reactor), solar or aeolian in nature, just as on Earth, storing the produced energy for later use will be an essential piece of any off-world power infrastructure.
In our application, a Martian power grid, the advantage of using a TED comes from the fact that only the well-insulated chamber would require transport. Mars has roughly the same fractions of silicon by weight. Elemental composition maps show that the largest mass in the TED module is easily accessible on the surface of Mars and does not have to be sourced from Earth.
Admittedly, the production and purification of the silicon is a challenge in itself, but there is nothing stopping one of the In Situ Research Utilisation startups, to adapt terrestrial technology to the Martian environment.
Since it can release large amounts of power in bursts while being able to be fed with even wimpy sources of power, this well-managed power dense battery could serve to run energy-intensive industrial production processes, such as conversion of chemicals, the creation of plastics, running a swarm of 3D printers.
Slowly but surely all the required infrastructure elements to inhabit Mars are coming together.
Author: JORIS LUYPAERT