One of the largest and most complicated systems goes unnoticed by most of us. Have you ever stopped to think about how magical electricity is? In most developed countries around the world, electricity is super reliable… When you flip that switch, turn on the oven, or heating, or plug in your phone to charge, there’s an extremely high chance that it’s going to work. 

It’s the simple things in life that tend to have the most complexity hiding just underneath the covers. 😉

Our electrical grid is a modern marvel, but it’s impressive due to its scale and reliability, not its technical innovations. Sadly, if Thomas Edison were alive today, he would not only be able to understand everything within our current electrical grid, but he probably could run it for us

That’s about to change… Renewable energy and new ways of storing energy are paving the way for a future that Edison would struggle to wrap his head around. 

This week’s wandering is an extension of the Climate Change path I’m wandering down and it’s about renewable energy storage, specifically the “storage problem” (more on this later). If you don’t think Climate Change is an issue go here to learn more. If that doesn’t convince you, I’m not sure what will. 

Renewables Kryptonite

With Climate Change becoming more of an urgent problem companies, governments, research institutions, and non-profits are scattering to uncover any and all solutions to combat this beast. Luckily, there’s a  long list of solutions that can be used simultaneously. These solutions come in many flavors (more here) and this week we’re going to narrow in on a problem with one of the most popular… Renewable energy, but more specifically wind and solar. 

An analogy often used in the space of renewables is… 

“The sun doesn’t always shine and the wind doesn’t always blow” 

This quote basically means that we humans need energy 24/7 even when it’s night or winter, but solar panels and wind turbines can only provide energy when the climate wants to play nice (e.g. windy or sunny). If we want to live in a 100% decarbonized world, then figuring out how to store this energy for a rainy day is pretty important (unless we supplement this with Nuclear & we’ll dive into this in a future post). There’s a graph called the “duck curve” showing this problem in all its glory (see below). 

The important thing to notice here is that when solar and wind are at their max energy generation, no one is home to use this energy, but when they’re at their weakest everyone needs energy… This simple duck is at the heart of our “Storage Problem”

There is a silver lining here. The storage problem has become more popular over the past couple of years because solar and wind have drastically improved their ability to generate energy and the cost for both have drastically fallen (see below). 

The “storage problem” is a good one to have… It means renewables are becoming more prominent in our world. 🙂

Choosing your flavor of storage

When you think of energy storage, I’m sure the first thing that comes to mind is a battery. Something like this… 

But battery storage is just one of many tools we have in our toolbelt. 

Some other popular ways we’re storing renewable energy are… 

  • Pumped Hydro – This is when you have two bodies of water, one at a higher elevation than the other. Once energy is needed the water at a higher elevation is released to the lower area creating energy by running through a turbine (e.g. big mechanical propeller). This water is then pumped back up to the higher elevation for later use. 
  • Compressed Air – Basically people are pumping air into underground caves or deep water tanks to be stored, then releasing this air when energy is needed. 
  • Lithium-ion batteries (most popular battery) – We’ll dive deeper into batteries a bit later, so for now just think of batteries magical mix of chemicals that create electricity. 
  • Molten Salt – Imagine two big tanks, one holding cold molten salt and the other hot molten salt, with a solar panel farm in between them. As the solar farm is creating energy from the sun, this molten salt flows through tubs above the solar farm getting heated and transferred from the cold to hot tank. This hot salt is stored, then used to heat water creating steam to turn a traditional steam turbine for electricity when the sun not shining. 
  • And many more…

With so many different renewable storage options there are really two useful ways I’ve found to think about this. Either the length of time something can hold energy or how the energy is physically stored. 

  • Time – There are two separate groups, short-term (minutes, hours, & days) and long-term (days, weeks, months, & even years) storage. Batteries currently fall into the short-term camp, while “Pumped hydro” and “compressed air” fall into the long-term camp. 
  • Type of Storage (see below) – Energy can be stored in many forms… The big five are – electromagnetic, thermal, electrochemical, mechanical, and chemical. 

The battery wave

If you spend 5 minutes googling renewable energy storage, you’ll quickly realize the majority of R&D, startups, and investors are focused on batteries. There are many reasons for this, but the most obvious are the cost of manufacturing (thanks to Tesla) and general advancements in tech. 

There are many kinds of batteries, but the most popular battery at the moment is Lithium-ion.

So what is a lithium-ion battery and how does it work

To explain battery science in gory detail is not my goal here, so if you’re interested in that I would recommend heading here, here, and here

Instead of boring you with the terminology, we’re going to stay high-level. If you can understand how the “pumped hydro” (mentioned above) works, then you can intuitively understand lithium-ion batteries. 

Similar to pumped hydro, lithium-ion batteries move stuff back and forth to create electricity, but instead of moving water, batteries move lithium ions. As these lithium ions move from one side of the battery to the other electrons are released as a byproduct, creating electricity. 

Within every battery, there’s a special mix of ingredients and the majority of battery science revolves around getting that mix just right to increase the longevity, speed of charging, safety, power, and other things. 

Side rant:

This might upset a few storage geeks, but to me, it seems like Tesla is one of the key drivers (pun intended) behind this battery movement. The interest and adoption of electric vehicles (EV) are both lowering battery costs and increasing quality… And it’s hard to see a world where this happens sooner without Tesla helping with battery cost and quality. They’ve created an EV better than every fossil fuel vehicle out there, which rapidly increased the adoption of EVs. More importantly, they’re building out the largest battery factories on the planet and that’s lowering the cost of manufacturing, as well as improving quality

The beauty of batteries is their ability to quickly respond when power is needed… Instead of waiting on water to run down a mountain turn a turbine to create energy (e.g. pumped hydro).

There are many other benefits to lithium-ion batteries, but the two big negatives people point out are the base materials they’re made from (cobalt, nickel, and lithium) and the limited amount of time they store energy (4ish hours). O… And of course safety… Remember all the Galaxy Note 9 phones exploding, that’s thanks to overheating lithium-ion batteries. 

If batteries are going to be the main way we store renewable energy without supplementing (e.g. nuclear energy), then we need batteries that store energy for long periods of time (days or weeks), made from materials that are cheap. 

Luckily, there are many smart people tackling both of these problems. One possible solution could be “solid-state” batteries, which I’ll leave for a future post, but if you’re interested here’s a quick video

The many-headed hydra

There’s a common theme I’m discovering while wandering down this path of Climate Change, which is “problem stacks” (or hydras). Every problem and sub-problem seems to have multiple problems hidden inside of it. 

For example, with renewable energy storage, we need tech advancements in basic battery science, new policies to level the playing field for competition in the utility energy industry, and big investments to help scale new storage solutions. 

Like Climate Change, energy storage can seem intimidating or even impossible with the current timelines we have to transition to a 100% decarbonized world. But as Marie Curie says…

“Nothing in life is to be feared. It is only to be understood.”

Outside of playing with radiation of course. 🙂

The more we understand the problems and possible solutions, the faster we’ll move towards a more sustainable and advanced society.

Until next time my fellow “wanderers”!