Water Evaporation: A New Weapon In The Fight Against Climate Change?
Climate change sucks.
Nowadays, it seems like we hear that a lot. So much so that the actual meaning behind it has started to diminish. While it's true that we've made extensive progress in the last few decades, our world is still far from perfect.
Today, about 1.2 billion people worldwide are living with little to no electricity. However, for those with access to energy, nearly 84% comes from non-renewable sources such as coal, oil and natural gas.
Well, what about renewable energy?
In efforts to switch to a greener world, we've seen tons of hype around alternative energy sources like solar panels, wind farms and geothermal power plants. But it turns out we are a LONG way from reaching the UN's net-zero emissions by 2050 goal. In the US alone, renewable energy sources only make up 12–15% of the annual energy production, despite being one of the wealthiest countries. It makes you wonder if these energy sources work so well; why do they play such a minor role in total energy production?
Although several factors underline why we don't use more renewable energy, three central aspects are driving us away from them.
1) Inconsistency
Currently, renewables are too inconsistent; the sun doesn't always shine, the wind doesn't always blow, you get the point. These fluctuations make them unsuitable for many environments, which renders them to become supplementary energy sources since there's no guarantee you'll have the same power generated between two days. Even if we were to overcome these issues, geography and seasonal variations would make it extremely difficult to apply these technologies globally at scale.
For some additional clarity, here's the energy generation of a wind power plant in contrast to the energy demands of a city:
2) Resource Intensity
When people think of renewables, one of their first thoughts is that these sources are environmentally friendly, which is a bit misleading. While they may not produce direct emissions, they require significantly more minerals and resources than other energy production methods. Especially today, with the global chip shortage, manufacturing and mass-producing "green" technologies like electric vehicles and solar panels are not only problematic but highly resource-intensive. Worse yet, most of these materials will become debris after their 20-year lifespan.
3) High Land Usage
The most flawed part about renewables is their inferior power density, which is about 1000x less than natural gas. In other words, we would need to build 1000 solar farms to produce the SAME amount of energy as ONE natural gas plant. This results in more deforestation, local community displacement, extinctions, and less land available to feed an ever-growing population. Just think about it; our earth is 30% land and 70% water, yet we continue using more and more land.
At this point, it’s clear that we need a new form of renewable energy. One that can provide a consistent amount of power, isn't very resource-intensive, and doesn't require much land usage. Most importantly, we need it NOW.
As ridiculous as this might sound, there may be a new way to generate energy while sidestepping the previous flaws. A unique energy source that has the potential to generate 365GW of energy per hour or fulfill over 70% of the US energy consumption.
I'm talking about evaporation.
How It Works
You’re probably a little confused, and that’s okay. How could we possibly harness the water cycle for energy? Well, it's a bit more complex than that. But before we get into the specifics, let's briefly go over evaporation.
In the water cycle, evaporation occurs when sun rays warm the surface of the water. The heat from the sun forces the water molecules to vibrate faster and faster until they move so quickly that they escape as a gas (or vapour). Once in the atmosphere, the vapour condenses to form clouds and eventually precipitates back to the ground in the form of rain or snow.
But now, let's imagine that the vapour, for whatever reason, built up and was unable to leave the surface.
That's essentially what we want to try to accomplish with large-scale evaporation engines.
In a 2015 paper issued by a team of scientists at Columbia University, they reported using microscale devices that could generate small amounts of electricity using moisture. In these devices, bacterial spores are grown on films and positioned underneath shutter-like structures. The spores swell, and shutters open as humidity increases, allowing moisture to escape. As a result, the spores dry out and contract, allowing the shutters to close. A generator can then convert the force produced from the shutters' repeated opening/closing into electricity.
In other words, when water molecules are turned into vapour, we want to contain them beneath these shutters instead of going directly into the atmosphere. Combined with a particular type of bacterial spore, we have a machine that generates power simply through changes in humidity levels.
In the prototype above, a yellow layer of tape stretches across the length of the shutters. These tapes contain millions of spores called Bacillus subtilis, which can exist in a dormant state for hundreds of years. What makes them unique, however, is their ability to expand and contract, just like a muscle. Bacillus subtilis spores can continue to perform the necessary mechanical motion even when dead or dormant, which makes them an invaluable component of the device.
When the shutters of the evaporation engine are closed, it creates a humid environment that Bacillus subtilis spores require for expansion. Once expanded, the shutters open, which allows the vapour to escape. This forms a less humid atmosphere allowing these spores to contract again and, as a result, close the shutters. This continuous cycle of growing and shrinking bacterial spores that open and close the shutters are connected to an electromagnetic generator that produces a constant energy supply.
The power produced by the generator will be transported to the grid using similar infrastructure to floating solar farms, but it will eliminate the single most expensive thing that floating solar farms require; energy storage. The average US energy storage price is a staggering $625/kWh. Since evaporation is a continuous process, the energy generated is consistent; hence, we can eliminate the storage cost altogether.
Now that you understand the technical aspect of the device, you might be wondering what the downside is. If it were flawless, why hasn’t it been implemented yet?
As expected, there are still a few obstacles preventing us from bringing this technology to a larger scale. So, let's take a closer glimpse at how these devices could be implemented and what barriers remain in our way.
Looking Into Implementation
The initial step in bringing this concept to reality is assembling evaporation engines on a larger scale. Based on the manufacturing process for solar panels, along with materials like the base, shutters, films, and bacterial spores, I estimate a cost of $512 USD/m². At first glance, this may seem a little steep. However, it is crucial to note that solar panels typically cost ≈$400 USD/m², and when factoring in their energy storage aspect, they are actually less economical than evaporation engines.
Once past the research and developing phase, we can begin to look at launching and eventually expanding the device. The process should pilot in the United States, where they can be built on three different coastlines between 2025 to 2027.
Starting in 2025, evaporation engines should be deployed on the northern coast. Following the project's success, it would make economic sense to expand to the southern coast in 2026 and start a new project on the west coast by 2027. Suppose the pilot in the US has been a success and the devices can generate extensive sums of energy. In that case, we could expand the concept globally and bring energy to the hands of those in need.
In case you're wondering what costs will look like, here is a rough breakdown of the implementation expenses:
Although the immediate costs will be high, we can focus on instantaneously generating revenue as the evaporation engines are operational. To pay for the initial cost of the devices, we can make PPAs (Power Purchasing Agreements) with energy suppliers and sell the electricity at a flat price of $0.2 per kilowatt.
As of now, I have only talked about the advantages and benefits of this technology. Yet, if all of this were already possible, the notion of an evaporation-driven world would likely be a reality and not just an idea, which is why there are a few things we need to figure out before we see this device utilized on a macro scale.
What's Holding Us Back
1) Altering Weather Patterns
The most important thing to understand before installing these devices is their influence on a region's climate. It's difficult to precisely determine what shifts would occur in the water cycle if these devices were to be deployed on a large scale. That being said, to generate the bulk of the country's electricity, these engines would need to be installed on every inland body of water in the US, which is both ecologically and physically impossible. Nevertheless, shifting the project to the coastlines poses a similar risk regarding precipitation. Since the engines involve retaining vapour underneath the shutters, it's tough to infer the amount of vapour lost when the shutters eventually open and how that will affect rainfall patterns.
But this isn't all terrible news, either. When we focus on one of the most significant problems associated with climate change, increased precipitation, things become interesting. In most regions, a reduction in water evaporation is beneficial to us since it minimizes excessive rainfall. In other words, as climate change worsens, technology becomes more powerful, and vice versa.
2) Device Durability
Another factor to consider when looking at large-scale evaporation engines is their longevity. One of its most significant advantages is that it can be manufactured from cheap biological materials that are easier to dispose of than solar panels. However, the combination of these biodegradable and cheap materials comes at an expense: durability. If these devices were placed on coastal waters, there's always a chance that a storm could ruin the devices and leave the area toppled. With this in mind, the ideal engine would have to be made to withstand numerous unpredictable weather conditions while keeping costs relatively low.
It's crucial to note that water itself doesn't affect bacterial spores and their ability to function, especially since these spores retain their muscle-like property even when dead, which means that unless wholly demolished, the devices will continue to operate.
3) Cost
The ultimate hurdle preventing us from seeing this technology on a large scale is, unsurprisingly, cost. Although the proof of concept and technical aspects of an evaporation engine exist, much more research and development are required to make it a reality. We aren't moving forward with this device because of the lack of ambiguity and risk, but as more money is poured into development, we may see the first practical trials running within the next year or two.
Final Thoughts
Climate change remains one of our greatest threats. From fires to famine, the consequences are beyond real. Even with such a complex dilemma, the solution is straightforward: we need cheaper energy.
Without energy, our world wouldn't be the same. It’s why despite understanding the dire consequences, our society is still heavily reliant on fossil fuels; it’s no longer an option but a necessity. Until we find a cheaper and more sustainable source of energy, things aren’t going to improve as fast as we want them to.
On the bright side, innovation in alternative energy space has never been better, and evaporation engines are just another example. Even though the future of this technology is uncertain, I believe it is a promising step toward promoting change in the alternative energy sector and safeguarding our future.
Key Takeaways
- While many of us worry about minimizing our carbon footprint, there are people in our world who don't have access to power at all.
- Current renewables don't play a significant enough role in total energy generation.
- We need a new form of renewable energy that provides consistent power, isn't resource-intensive, and doesn't require much land usage.
- Using evaporation engines, we could harness the evaporation process to generate consistent power for up to 70% of the US.
- These devices work by trapping moisture beneath the machine, allowing bacterial spores to expand and contract. The repeated expanding and contracting causes shutters to generate a mechanical force (through the constant opening/closing) which can be converted to energy.
- These engines have three conceivable drawbacks: altering weather conditions, durability and large-scale development costs. However, as more time and money are invested into this technology, it won't be long before we see it used in real-world trials.
- This technology holds so much promise for resolving the current energy crisis and developing an entirely new method of generating renewable energy that is cheaper, efficient, and reliable.
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