Waves, Carbon Lego Blocks, and Making Concrete Greener
Get Inspired by the Cutting-Edge Solutions in Renewable Energy Storage and Carbon Capture
Welcome to the second edition of the Green Innovations Newsletter, where we bring you the latest updates and insights into the world of sustainable technology. In this edition, we focus on the cutting-edge solutions that are being developed to address the challenges of renewable energy storage, carbon capture, and the use of environmentally-friendly materials.
We'll explore how waves are being harnessed to generate electricity, how carbon blocks, bricks and rocks are being used to store energy, and how carbon is being captured and stored in concrete.
Sit back, relax, and get ready to dive into the world of green innovations.
Riding Waves to Green Energy
Hydropower isn’t new. But it often involves building a dam or rerouting water in some form or another, tunneling the water through a waterwheel or turbine. We’ve also had buoys use their up and down motion to generate power themselves. Later, buoys also started to power pistons that use the up and down movement to generate more power. But the output was limited to 50-300kW, and most importantly, they are difficult to install, as you need to fix them to the seabed. However, better options are emerging.
For one, Oscilla Power is developing a set of wave energy converters (WEC) called Tritons, which uses all six types of motions (heave, pitch, surge, roll, and yaws - up, down, left, right, tilting; everything), instead of just up and down.
Installation seems to be relatively straightforward. The Triton has a ring at the bottom with cables that get lowered when it’s been towed to where it needs to be. Once underwater, the ring stabilizes, while the top piece’s movement generates power. There are drivetrains inside the top that hold the cables to the ring, and the drivetrains are the moving parts, generating electricity. Here’s a detailed video of how it’s deployed and works.
There’s a 1-megawatt unit (~650 homes) that is designed to deliver to a major energy grid. It’s relatively small at 10 meters (32ft) wide and 7.5 meters (24ft) long. There’s also a smaller 100kW unit meant for small rural areas with little access to power and may be reliant on fossil fuel generators, like Alaska. They’re also developing a micro-unit of 50kW for power on the ocean itself, like research stations or when Waterworld happens.
While all of this is still under development, Oscilla Power is estimating the Tritons will provide energy between $0.10 and $0.15 per kWh, which could be great for the scalability of this.
By the way, I’ve focused on Oscilla Power here, but wave energy converters development is a big area. Here are some other companies to check out: Eco Wave Power, CalWave, and C-Power
How Carbon-Based Thermal Energy Storage Could Change the Game
There’s an exciting new wave of alternative energy storage solutions coming up. We all know what batteries are, from the phone in your pocket to your car. Traditional batteries use chemical reactions to store energy and disperse energy. Another way to store energy is with heat, known as thermal energy storage (TES). Heat something, keep it at temperature, then transfer the heat to generators or other applications. But using heat for storage has its challenges; heat leaks into the surrounding air, and we’ve not had efficient material to hold heat, so you’d have to spend a lot of energy keeping the “batteries” hot.
But now, there's a new and exciting way to store energy using something called phase change material (PCM). This material can absorb and release a lot of heat energy when it changes, for example from a solid to a liquid, which makes it great for thermal energy storage. Examples of this are salt, steel, aluminum, and carbon.
It turns out that carbon can hold extreme temperatures of about 3000°C / 5500°F without changing form. It also has a massive energy density of around 1500kWh per cubic meter. The density helps bring down the price to about $1 per kWh, claimed by Antora Energy. That’s 150 times cheaper than lithium-ion batteries. 🤯
I’ll zoom into a specific solution to give you a better view of how this works.
Antora Energy is a California-based startup that uses incoming power from solar, wind, and, if needed, power from the grid, and heats big blocks of carbon that continuously disperse their heat to power industry. They’re primarily focused on industry because industry uses heat for their manufacturing.
The great thing about thermal energy storage is that it's easy to make it bigger or smaller; literally, add more or less (lego) blocks to the solution. This makes it a good solution for all kinds of renewable energy systems, from residential to large-scale utility projects.
Click here to learn more from Antora’s founder, with sooo many awesome nerd details. 😄
Rock, Brick, and Sand Batteries
Speaking of thermal energy storage (TES) batteries, if you think a battery made up of carbon blocks is outlandish, you'd be stoked to know that companies are building batteries using rocks, bricks, and sand. Compared to lithium-ion batteries, these alternatives are not only cheap, but they also use abundant and easily available materials, can last several decades without degradation, and have no environmental impact.
Rondo Energy, a California-based startup, is building batteries out of bricks that can be heated up to 1500°C and hold the heat for several hours or days. The stored heat can be delivered on demand in the form of hot air or steam to various industrial applications, such as cement production, which currently relies on fossil fuels.
Brenmiller Energy, a Tel Aviv-based company, is applying the TES principle to crushed rocks. These batteries can be charged (i.e., heated up) using multiple energy sources besides electricity, such as biomass, excess heat recovered from industrial processes, or even flue gas (industrial exhaust).
Finland-based startup, Polar Night Energy has built sand batteries to store heat, which is then used to power the district heating system to heat homes. With the ability to retain heat for months, the batteries can be charged during the summer and discharged during the winter, meeting the seasonal demand for heat.
Check out these fantastic videos from Matt Ferrel at Undecided for a deeper look at how these brick, rock, and sand batteries work. While at it, subscribe to Matt's content for the latest in sustainable tech.
Making Concrete Greener
Unless you live a gazillion miles away from civilization, it is pretty hard not to notice that concrete is everywhere - buildings, roads, bridges, you name it. At 30 billion tonnes (~100 thousand Burj Khalifas), no wonder it's the second most consumed material after water. Cement, a key ingredient in concrete, is responsible for roughly 10%1 of global CO₂ emissions. To understand why let's look at how cement is manufactured.
Cement is produced by heating limestone and clay in a large oven called a kiln. Limestone (CaCO₃ or calcium carbonate) breaks down into calcium oxide (lime) and CO₂, which is released into the atmosphere. This accounts for 60% of the CO₂ from cement production. What about the other 40%? That comes from burning fossil fuels to heat the kiln.
With 75% of the urban infrastructure that will exist in 2050 yet to be built, we'll need to make concrete greener to achieve net zero emissions by 2050.
Several startups are developing cool (pun intended) ways to reduce the carbon footprint of concrete. Sublime Systems has developed an electrochemical process to extract lime from limestone at ambient temperatures, eliminating the kiln, and with it, 40% of the emissions from cement production. Dive in to this link for details on this process and some equations that will remind you of high school chemistry. Sublime's process can also extract lime from sources that do not release CO₂, like coal ash, which will eliminate the other 60% of the CO₂ emissions.
CarbonCure is taking a different tack by reducing the need for cement in concrete. It injects captured CO₂ into concrete, where it reacts with the calcium to form nano-sized carbonate (CaCO₃) minerals that strengthen the concrete. Thus trapping CO₂ virtually forever; the CO₂ stays trapped even when the structures built with the concrete are destroyed. An average high-rise building constructed with concrete will potentially trap as much CO₂ as a 900-acre forest can absorb. Now isn't that green concrete!
Check this video out for an overview of the technology.
Next Time on Green Innovations Newsletter..
And that's a wrap for this edition of Green Innovations, exploring the latest and greatest advancements in sustainable technology. From waves to carbon lego blocks and greener concrete, we've seen some awesome innovations driving towards a cleaner, more sustainable future.
But the fun doesn't stop here. In next month's edition, we'll be diving into the exciting world of battery technology, exploring some of the weirdest, wackiest, and most awesome battery innovations out there. We'll explore everything from liquid metal batteries to bacteria-powered cells, and everything in between.
So be sure to tune in next month for another dose of Green Innovations, and join us as we continue to explore the cutting-edge of sustainable technology. Until then, stay green!
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Wait isn’t it 8%? Based on data we have from 2021, ~4B tons of cement was produced and each ton of cement produces a ton of CO₂. That’s 4B tons of CO₂. Total CO₂ equivalent emissions in 2021 was ~37B tons. That’s ~10%.