Desalination could be bigger than you’ve ever imagined

You might have caught the recent announcement of a breakthrough in desalination technology, which uses graphene. If your brain filed that as “interesting but irrelevant”, allow me to dispel that notion.

Graphene desalination could change the world. Today, we’ll explore how.

This new technology is so efficient, desalination energy costs could be reduced by nearly half. You might think that’s a niche application – something unlikely to make much difference to the economy (and to your investments). But desalination could actually be one of the biggest growth stories of this century.

I’ll put a personal slant on how I came to understand the significance of this issue.

It might seem strange to say, but in Britain we are spoiled. That’s something I only really appreciated when I visited Denver, Colorado. It’s a beautiful area – but arid. On arrival, I was immediately struck by a nagging discomfort. I wanted to leave, and that feeling didn’t depart for my entire visit.

You can go for miles around Denver and see little or no farming in the countryside, as it’s far too dry. My instinctive aversion to this landscape was something that astonished me. It was only in the middle of a large public park, irrigated with unsustainable groundwater, where I felt truly relaxed.

Next time you fly over the US, take a look at its circular fields. These giant green discs are the results of irrigation. In drier regions, the choice is stark: no irrigation, no crops.

What’s all this got to do with investment?

Currently, the world faces a multifaceted problem. On the one hand, the world’s population is increasing. Growth is slowing, but we are still set for a peak of around ten billion. Our irrigation and potable water systems need to expand, just to accommodate this growth.

But it gets worse. The world is developing and urbanising. We’re also eating far more luxury foods, especially meat. The result is a massively increased demand for water – notably, for irrigated agriculture. Meanwhile, our aquifers are running out – depleted, principally, by the demands of irrigation.

In Exponential Investor, we’ve already covered this challenge. Today, we’re going to be looking at the impact of desalination. It’s a magical technology, giving a completely scalable supply of fresh water. No matter how much water we desalinate, it always ends up back in the sea. Unlike oil, it can’t ever run out.

But how does desalination work?

There are two principal technologies. On the one hand, water can be distilled. You keep the condensed steam and throw the concentrated brine away. The alternative technique is called reverse osmosis, and the new graphene technology falls into this second category.

Reverse osmosis works by squeezing water through a membrane with tiny holes in. The water molecules pass through the holes, but the dissolved salt ions can’t. If a bit of pressure is applied to the salty side, the water gets shoved through – but the salt gets filtered out. This means that brackish water, or even seawater, can be made safe to drink.

The new desalination technology is based on a modified form of graphene, called graphene oxide. You might be familiar with graphene as an atom-thick layer of carbon. Here, however, it’s used not as individual sheets. Instead it’s packed like corrugated cardboard, giving it the crucial holes.

What’s the catch?

Overall, desalination sounds good.

Current desalination technology is expensive. It gives unlimited water, but only if you have unlimited energy.

Desalination is already perfectly reasonable for drinking water as each person drinks only a few litres of water per day. However, it’s much less realistic for general domestic use. A single toilet flush is about as much water as you’d drink in three days. Therefore, only industrialised countries can really afford to get their domestic water supply from desalination. The costs, both financial and environmental, remain controversial.

The amount of water used in irrigation dwarfs domestic use. We tend to forget this, due to living in the ever-damp UK. In much of the rest of the world, agricultural water is a precious commodity, which needs to be managed carefully. My trip to Denver brought that to my attention.

Much of the food that we enjoy eating is thirsty to produce – everything from beef to lettuce. However, it’s unlikely that widespread use of current desalination technology is going to be realistic for agriculture. But this could all change, removing a key constraint on the worldwide spread of a Western diet.

As well as the potential cost savings from graphene, we are fast approaching an era where energy is set to become far cheaper. This is one of the primary impacts of the reliably-falling cost of solar electricity.

Obviously, solar energy is generated in abundance at noon. However, demand does not conveniently follow the sun. As a result, there needs to be a glut of generation capacity to meet peak demand. That’s called “overbuilding”, and it could result in a lot of wasted energy.

Could we find a use for this surplus solar?

Industries which can use energy flexibly can expect a significant economic boost. One we’ve covered before is hydrogen production. As you might have guessed, desalination is another. Water can be very cheaply stored in reservoirs and tanks, meaning that intermittent desalination isn’t problematic.

In fact, using excess energy in this way can actually reduce energy costs. In some locations, notably Germany and Australia, we’ve briefly seen negative electricity prices. Taking surplus energy off the grid helps to stabilise it – and that’s a service worth paying for.

Desalination plants that can use this surplus electricity on demand will open up a new way to obtain abundant freshwater, at a potentially attractive price.

As groundwater becomes scarcer, it’s not hard to see how a world of rapidly-falling energy prices will lead to an enormous boom in desalination. This could be far beyond what we might expect, if only potable water was considered. It looks like the graphene research at the University of Manchester could be a really big part of that story.

At Exponential Investor, we pride ourselves on picking up big economic changes that the mainstream media overlooks. Desalination is one you really need to watch.

What do you think of solar desalination? Please do let us know –


Andrew Lockley
Exponential Investor

Category: Energy

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