You may or may not have heard of electrolysis. Simply put, it’s the process by which good old H2O (water) is split into its constituent parts, hydrogen, and oxygen. Perhaps most importantly, seawater can be used in the process, and this matters as we have an almost endless supply of it.
How the electrolysis process may be able to provide future generations with clean air, energy, and clean, untainted drinking water requires a little more explanation. Before we dive into the science, let’s look at why clean drinking water (potable water) is so important to us and why access to it poses the greatest risk to our continued existence as a species.
The elixir of life
We cannot survive without water. Generally, three dry days is the average human limit, and the hotter the climate, the quicker the onset of dehydration. During an average day in a temperate climate such as the United Kingdom, a person’s body loses approximately 2.5litres of water.
This can be through the lungs as water vapor, through the skin as sweat, or through the kidneys as urine. Some water (a less significant amount, in the absence of diarrhea) is also lost through the bowels.
During vigorous exercise or in a hot environment, it is easy to lose several times this amount. Heavy exercise in high temperatures could cause the loss of over 2.5 liters of fluid per hour, which exceeds the body’s absorptive capacity.
So we must have clean drinking water which is becoming a rapidly diminishing natural resource. Consuming contaminated or dirty drinking dirty water dramatically increases your risk of contracting diarrhea, cholera, and a host of other water-borne parasites and diseases.
A catastrophe in the making
2.2 billion people (that’s 3 in 10) globally do not have access to potable water. Each year this figure rises and there are a number of factors that affect these figures.
- A lack of infrastructure in poor and developing nations
- Pollution of existing rivers, lakes, and underground freshwater reservoirs
- Climate change which can affect rainfall in hot arid regions
- Unchecked population growth, which places unsustainable demands on limited resources
- Melting mountain glaciers provide many rivers with their annual supply of water. Many of these glaciers are now shrinking or have entirely disappeared, thanks to global warming
It is therefore essential that we start looking for alternatives to produce potable water in sustainable quantities. It is THE challenge facing our growing global population and many companies are now turning their attention to potential solutions. Understandably, most focus on seawater, which accounts for around 98% of the water on our planet.
The manufacture of potable water
The obvious solution is often the only solution and producing potable water from seawater is the starting point of most companies looking to provide solutions. Take the researchers from the Korean Institute of Civil Engineering and Building Technology (KICT). They have created what they call a coaxial electrospun nanofiber membrane, which is essentially a filter.
We already desalinate seawater (the process of removing the salt from the seawater) on a large scale. America is no exception and its desalination plants rely on a process called membrane desalination, which works by using pressure to force water through membranes (filters).
One of the main drawbacks to this method is that membranes rapidly become too wet and ineffective, meaning they have to be replaced frequently. KICT’s new fancy-named membrane solves this issue by dramatically extending the periods between filter changes.
Rather than changing the older membranes every 50 hours as is currently the industry practice, KICT’s membrane only needs to be changed once a month. That’s a massive saving in terms of cost per liter and also increases the operational output of a plant.
There is however another process that needs to be seriously explored and at first glance, it seems counterintuitive as it doesn’t produce drinking water, not immediately anyway.
The process of electrolysis
Imagine a process that could provide us with an abundant source of clean energy (hydrogen) and as a byproduct of the manufacturing and subsequent consumption of that energy, leaves us with oxygen and potable water. Sounds like an eco-dream doesn’t it? Particularly given the dire climate warnings sounding across the globe.
The reality is this process already exists and has for years. We can, by passing an electric current through seawater, separate it into its constituent parts, namely hydrogen, and oxygen. The process is called electrolysis.
How the entire cycle fits together
Let’s start with the hydrogen and oxygen that are produced from the electrolysis process. The oxygen is a no-brainer and can be used in medical settings or simply vented into an atmosphere that is arguably in very dire need of it. The hydrogen that is produced is the element we’re really interested in.
Hydrogen is potentially a serious energy solution for the future. It is a clean, incredibly efficient, and flexible energy carrier. It is the simplest and most abundant element on earth — it consists of only one proton and one electron. Hydrogen can store and deliver usable energy, but it doesn’t typically exist by itself in nature and must be produced from compounds that contain it, like water.
Hydrogen is an energy carrier, not an energy source, and can deliver or store a tremendous amount of energy. Hydrogen can be used in fuel cells to generate electricity, or power, and heat. Today, hydrogen is most commonly used in petroleum refining and fertilizer production, while transportation and utilities are emerging markets.
Using Hydrogen
Hydrogen is a clean fuel that, when consumed in a fuel cell, produces only water, electricity, and heat. Hydrogen and fuel cells can play an important role in our global energy strategy, with the potential for use in a broad range of applications, across virtually all sectors — transportation, commercial, industrial, residential, and portable.
Hydrogen and fuel cells can provide energy for use in diverse applications, including distributed or combined-heat-and-power; backup power; systems for storing and enabling renewable energy; portable power; auxiliary power for trucks, aircraft, rail, and ships; specialty vehicles such as forklifts; and passenger and freight vehicles including cars, trucks, and buses.
Elon, are you listening?
Due to their high efficiency and zero or near-zero emissions operation, hydrogen and fuel cells have the potential to reduce greenhouse gas emissions in many applications. Analysis has shown that hydrogen and fuel cells have the potential to achieve the following reductions in emissions:
- Light-duty highway vehicles: more than 50% to more than 90% reduction in emissions over today’s gasoline vehicles.
- Specialty vehicles: more than 35% reduction in emissions over current diesel and battery-powered lift trucks.
- Transit buses: demonstrated fuel economies of approximately 1.5 times greater than diesel internal combustion engine (ICE) buses and approximately 2 times higher than natural gas ICE buses.
- Auxiliary power units (APUs): more than 60% reduction in emissions compared to truck engine idling.
- Combined heat and power (CHP) systems: 35% to more than 50% reduction in emissions over conventional heat and power sources (with much greater reductions — more than 80% — if biogas or hydrogen from low- or zero-carbon sources is used in the fuel cell)
It’s one thing discovering the next big thing in energy solutions, quite another converting it into a commercial reality, ask any cold fusion scientists and hydrogen suffers from this problem. Currently, costs for producing hydrogen commercially via electrolysis are prohibitively high and that’s directly linked to scale. That could all be about to change.
Potable water from hydrogen fuel cells
Water is a by-product of the processes of hydrogen fuel cells. In a future hydrogen economy, harvesting water from H2 fuel cells and other devices should be considered one of the driving factors for scaling up hydrogen production.
The water quality produced by modern fuel cells is higher than typical tap waters and complies with US Environmental Protection Agency (USEPA) regulations. Research has already been done on the quality of water produced by this means.
To investigate the yield of water from a hydrogen fuel cell (FC), water to energy production ratios were modeled in the study. With 85% capture of exhaust water, an FC operating to meet the daily energy consumption needs of a typical US household would produce around 16 L of water.
This is nearly the volume of internal human consumption of water, but far less than the average 410 L/capita/d of total potable water demand which accounts for all uses of water, however for the purposes of this article we are concerned only with potable water.
In terms of scale, in an American nationwide hydrogen economy, where all energy consumed comes from hydrogen, over 4.9 billion m3 of high-quality water per year would be produced as by-products of hydrogen usage. That’s a lot of water, but is it enough to provide drinking water for the US population?
The answer to that is a definitive yes. To see just how much water the US uses annually, this article provides an interesting perspective. Keep in mind the figures quoted refer to total water consumption, for agriculture, industry, and home consumption. We drink far less water, the average person consuming between 2–4 liters a day.
Where’s the catch?
There isn’t one, quite literally. Again, for this to work, scale matters. More importantly, the mindset has to be present, to change from a fossil-fuel-based economy to one that is powered by hydrogen and fuel cells, and therein lies the catch.
Hydrogen doesn’t have billions of dollars at its disposal to close down the petrochemical industry. Companies harvesting and selling fossil fuels have unlimited funds to bribe, coerce and lobby politicians to continue down a road of no return. A path that favors fossil fuels over all else.
Sadly, a glaring fact is becoming apparent as time progresses. Fossil fuels will outlive humanity. We cannot use them up before the effects of using them kill us, and the potential future awaiting us is going to be a dry and thirsty one.
By limiting the exploration and commercialization of alternate energy solutions, fossil fuel companies like Royal Dutch Shell, Exxon Mobil Corp, China Petroleum & Chemical Corp. (SNP), and others are denying the world a final opportunity to salvage ourselves. They are denying solutions like hydrogen the opportunity to scale up. Solutions that could undo decades of damage.
Footnote for science buffs
I mentioned oxygen briefly. Here’s an interesting fact about electrolysis and the oxygen produced for the science buffs. What total volume (in L ) of O2 and H2 are produced at STP when a current of 30 A is passed through a K2SO4(aq) solution for 193 minutes?
On passing 3.6 Faradays of electricity through the water 3.6 moles of Hydrogen and 1.8 moles of Oxygen will be formed. So the volume of Hydrogen produced at STP is 80.64 liters. The volume of oxygen produced at STP is 40.32 liters.
That’s a lot of fresh air.
