It may not seem obvious in our daily lives, but the world is rapidly becoming a harsher place to live.
Food production is at risk, and some are starting to look at the ocean for a solution.
If the future of humanity is something you’re interested in, this is an article you can’t afford to miss.
Contents
Drought is coming 🏜️
Droughts in arid regions are becoming more extreme and less predictable due to climate change, affecting the total water supply available to the public and industry.
At the same time, this water supply is under stress due to human consumption, compounding the pressure on this finite resource..
Neither the amount of water available nor human consumption is bound to change anytime soon, meaning there will be less water available in the future.
This water scarcity will primarily affect the agricultural sector as it is entirely reliant on this freshwater supply.
And this effect is skewed towards arid areas that are prone to long-term drought, particularly those in developing countries that don’t have the capacity to implement any necessary measures.
The potential of the desert 🌞
Considering this proneness to drought, arid regions are complicated places to launch an agricultural endeavour.
Some arid regions like Israel do agriculture out of an existential necessity, while the Peruvian desert valleys are beginning to struggle with brackish groundwater.
Yet most arid areas have a key ingredient that other more favourable agricultural regions don’t have: bountiful sunlight.
As an investor in a desertic region, an intuitive plan is to forget about agriculture and deploy a solar energy business to produce electricity.
For example, a colossal solar energy project in the Sahara has long been discussed as a potential solution for Europe’s green energy future.
However, the fact of the matter is that there may be better ways of adding value to land in arid regions besides producing raw electrons. Something that would also bring benefit to local communities through agriculture.
Desert greenhouses 🍅
Greenhouses are a water-efficient method of agriculture in arid regions.
You may have heard of the greenhouses in Southern Spain, that produce a large proportion of Europe’s cucumbers, watermelons, eggplants, zucchinis, peaches, peppers and most of all tomatoes.
In fact, Spain is the second largest tomato producer in the EU thanks to these desert greenhouses 👇.
Greenhouses allow plants to receive ample sunlight for photosynthesis while minimising water loss through evaporation as they provide physical barriers for the water to escape.
Yet this is only possible because SOME water is available in the first place, as the greenhouses are located downstream of the Sierra Nevada mountains, a source of ample fresh water.
But what will happen when this water runs out or starts turning brackish? Almeria’s wells are certainly drying up over time, despite some government efforts to improve freshwater management.
Solar desalination 🌞🧂
Another source of water that still remains mostly untapped is the ocean, which contains a virtually infinite amount of freshwater.
Actually, many arid regions with agriculture like the Atacama desert in South America and the Namibian desert in Africa are ironically coastal deserts.
They have direct access to seawater (or brackish groundwater) which can be turned into distilled water through desalination in order to water plants.
The issue is that modern industrial-scale desalination is an energy-intensive process, that has until recently required fossil fuels for electricity.
As the world seeks to decarbonise, fossil fuels are being replaced by solar farms that can leverage the abundant sunlight of arid regions for carbon-neutral desalination.
A large deployment of solar photovoltaics often comes to mind, being the cheap and versatile solar alternative to produce the electricity required for common desalination processes such as Reverse Osmosis.
This is a valid hypothesis, yet there is another way of using solar energy for desalination. Using the sun’s ability to produce heat instead of its ability to excite electrons.
Concentrated Solar Energy📡
Concentrated thermal solar uses a vast array of mirrors to focus sunlight into a single point to concentrate the energy to produce thousands of degrees of heat, not electricity.
This heat can be used to heat a large distillation still filled with salt of brackish water in a process regularly referred to as solar thermal desalination, which is much simpler than Reverse Osmosis and doesn’t require a complex electrical system.
The only potential issue is that without electricity, it is difficult to run any temperature regulation equipment that is needed in the desert as the large temperature variations can easily kill most crops, except that this actually has a very easy fix…
Seawater for cooling🌊
Like any water, salt water can regulate the ambient temperature simply by existing. In fact, ancient arab cultures have been using water for this purpose for hundreds of years, circulating it in canals within buildings to keep them cool during the day, and warm during the night.
Sub-tropical deserts can have some of the most extreme climates on Earth, with very hot temperatures during the day that descend into freezing at night.
In an agricultural context, this spells certain death for most crops unless this simple trick is leveraged without the need for any complex technology.
Sundrop Farms 🌊 🧂 🍅 🌞
Using the seemingly unrelated components we have introduced (i.e. concentrated solar, greenhouses, seawater, thermal desalination), a seemingly unusable arid plot next to the sea was turned into one of Australia’s horticulture powerhouses.
Sundrop Farms in Port Augusta (South Australia) finished their 20-hectare seawater greenhouse facility in 2016 and have since then consistently provided 15% of Australia’s national tomato production 🤯, without the need for fossil fuels.
Not only does the area receive more solar energy than anywhere in Europe and has an infinite seawater resource, but it is located within reach of most of the Australian consumers concentrated on the South-West coast of Australia.
The Sundrop System ♻️
The facility has a unique system of doing seawater agriculture, with the concentrated solar infrastructure being at the core of all processes (except the cooling of the greenhouse by the seawater).
Flowchart of the Sundrop system of growing crops in a coastal desert. (Credit: Sundrop Farms)
The hydroponic greenhouse🌴
The farm can produce 16,000 tons of tomatoes all year round without the need for genetically modified varieties because of the facility’s saltwater temperature regulation capabilities and ubiquitous sunlight.
Additionally, the greenhouse acts as a physical barrier to pests and diseases that could ravage the entirety of the crop (as it is typical of monoculture), which prevents this from being an issue.
The system requires no soil as it is entirely hydroponic. In other words, it adds nutrients to distilled seawater which can be endlessly re-utilised in a close, efficient system.
The solar system🪐
As many as 24,000 automated mirrors (heliostats) re-orient themselves throughout the day to point sunlight at the tower’s 127m-high receiver, producing 20,000 MWh of heat to drive thermal desalination.
The Solar Thermal Distillation (STD) system can desalinate 1,000,000 litres of water per day, which is enough to fill an Olympic swimming pool every three days.
Any leftover heat is used to run a steam turbine that typically produces 1,700 MWh of electricity per year, enough to power the facility. For reference, it is equivalent to producing power for nearly 200 typical U.S. homes yearly.
Seawater Greenhouses 💧
Sundrop Farm is the first seawater horticulture project operating at a commercial scale. This is a big deal, as new concepts often don’t make it past the prototype stage, and doing so for 6 years proves that seawater horticulture is a financially viable business.
Other similar projects by Seawater Greenhouse Ltd (which was initially involved in Sundrop Farms) have been operating at a small scale since the 1990s in Tenerife, UAE, Oman, Somalia and other coastal arid locations.
The most notorious is the Sahara Forest Project which is regularly featured in the COP conferences as the future of clean agriculture for areas with a high risk of extreme drought.
Their pilot project in Jordan has been in development for years, making it frustratingly obvious how slow development is when there is no clear commercial incentive to get it done.
However, it is reassuring to know that these developments in agriculture using clean energy and an infinite water resource are possible, as we’re likely going to be needing them very soon.
External Resources
