Malta — Using molten salt to store renewable energy
“The climate crisis has already been solved. We already have the facts and the solutions. All we have to do is wake up and change.” - Greta Thumberg
Our world has been facing the problem of climate change for quite some time and the impacts from climate change are happening now. These impacts extend well beyond an increase in temperature, affecting ecosystems and communities in Canada and around the world. Things that we depend upon and value — water, energy, transportation, wildlife, agriculture, ecosystems, and human health — are experiencing the effects of a changing climate.
As a society we already know the things we have to do to reverse or slow the effects. Things like retrofitting buildings to make them more energy efficient, adopting renewable energy sources like solar, wind and small hydro, helping cities develop more sustainable transport such as bus rapid transit, electric vehicles, and biofuels etc. But why is this still not enough? It’s because our solutions are actually not sustainable.
Renewable energy is said to be the thing thats saves us all from the horrendous effects of climate change, kind of like our “saving grace”. It’s one of the solutions that we are relying most on to help save our planet. It’s abundant, clean, and increasingly inexpensive but there are still some major potholes that we need to fix to make renewable energy a long term solution.
Why our status quo isn’t going to be enough
The problem is that our current renewable energy it’s not always available when the demand is greatest. Right now when wind and solar farms generate more electricity than the electric grid needs, all of the excess energy is wasted. In March alone, 223,195 MWh of wind and solar energy went to waste. Worse, if energy demand increases when the sun isn’t shining or the wind isn’t blowing, utilities will often turn on “peaker plants” to rapidly get additional power online. Those “peaker plants” aren’t actually as green as they sound. They are usually powered by fossil fuels and emit huge amounts of CO2, defeating the entire purpose of the solar panels itself.
Where Malta comes in…
What Malta is doing is taking electricity, converting it and storing that electricity as heat, and then converting it back to electricity to be redistributed on the electric grid. In “charge” mode, the system operates as a heat pump, storing electricity as heat in molten salt. In discharge mode, the system operates as a heat engine, using the stored heat to produce electricity. When the energy demand is high, their device will discharge electricity back to the grid, basically “time shifting” energy from when it is generated to when it is most required.
Malta’s tech is based on a theoretical system designed by Stanford physicist and Nobel Prize winner Robert Laughlin, who showed that electricity could be, in theory, stored for days — or even weeks — as heat in molten salt and as cold in antifreeze.
Malta’s solution is making it much more viable from both an environmental and cost perspective. This is all because their raw materials are inexpensive as so much of the system uses conventional and easy-to-produce tech like steel tanks, air, and cooling liquids. One of their main components — the salt is really easily extracted from the earth and can store heat with minimal degradation or toxic byproducts. The salt tanks can also be re-charged many thousands of times, for possibly up to 40 years which is at least three times longer than other current storage options 🤯.
How do they work exactly?
Although their system sounds a bit complicated, we can break it down into 5 steps.
- Collecting: Electrical energy is collected from grid-connected wind, solar, or fossil generators and sent to Malta’s energy storage system.
- Converting: The electricity powers a heat pump, which converts electrical energy into thermal energy by creating a temperature difference.
- Storing: All the heat is then stored in the molten salt, where as the cold is stored in a chilled liquid.
- Reconverting: This is where it can get a bit confusing, basically what we are doing in this step is converting the temperature difference back to electrical energy with a heat engine.
- Distributing: Finally, the electricity that was converted is sent back to the grid when it is needed.
Where Malta is now
Malta Inc. is now an independent company. They are planning to build and sell industrial-grade, grid-scale energy storage solutions that can be located anywhere in the world. Those storage solutions will collect and store large quantities of energy to dispatch quickly as electricity on demand. Their team is hoping to develop a megawatt-scale pilot plant to prove the technology at commercial scale!
Key Takeaways 🔑:
- Our world has been facing the problem of climate change for quite some time and the impacts from climate change are happening now.
- There are many major potholes that we need to fix to make renewable energy a long term solution.
- Malta is planning on fixing those potholes with their solution of storing our renewable energy in molten salt
- They are now an independent company and are planning to build and sell industrial-grade, grid-scale energy storage solutions that can be located anywhere in the world.
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