Sahara solution: How solar power could energise the world
Kardashev scale: Solar farms in vast desert able to fuel Earth's energy needs
As humanity faces the dual crises of energy shortages and climate change, the sun presents an enormous, untapped resource.
Solar energy, with its virtually limitless supply and eco-friendly characteristics, is emerging as the most viable solution for the planet’s long-term energy needs.
This perspective has cosmic foundations: it aligns with the so-called “Kardashev Scale”, a framework used to classify civilisations based on their energy consumption.
It turns out the transition toward solar energy, especially concepts like the “Sahara Solution” may represent the beginning of our journey to a Type I civilisation, for us Earthlings.
Unmatched power
For perspective, the sun delivers an mind-blowing 173,000 terawatts (TW) of solar energy to Earth continuously, more than 10,000 times the world’s current energy consumption.
This enormous potential dwarfs the capacity of fossil fuels or nuclear power. The challenge, then, lies in capturing and utilising even a small fraction of this potential energy.
By comparison, humanity’s total energy consumption is 410 quintillion joules every year.
Kardashev Scale
Understanding the Kardashev scale shows why solar power is the future.
For one, solar panel cost and efficiency have improved significantly since the 1960s. Driven by technology advancement, economies of scale, and policies supporting renewables, current solar panel efficiency has hit more than 20 per cent, from around 6 per cent in the 1960s (when early solar panels were used main in space applications due to their high cost).
The US National Renewable Energy Laboratory (NREL) shows that improvements in safety and energy density of batteries, shows that innovation battery chemistry is unleashing a "revolution with a revolution".
For example, the next-generation 4680 batteries made by Panasonic, given its 30 years of know-how in the development of cylindrical lithium-ion battery technology, promises up to 500 per cent more power density. Even if it lives up to only half (250 per cent) of its promised improvement, that will significantly revolutionise the energy sector, in ways that legacy industries would fear.
The Chinese and South Korean battery makers including CATL, BYD, CALB, LG Chem and Samsung, have also contributed to this raft of innovations. Even if Panasonic's 4680 battery efficiency gains only prove to be half (250 per cent) of what it claimes, that's still a significant jump enough to continue reshaping the global energy sector.
The Kardashev Scale, proposed by Russian astrophysicist Nikolai Kardashev, classifies civilisations based on their ability to harness energy:
- Type I: Uses all available energy on its home planet.
- Type II: Harnesses energy from its star.
- Type III: Utilises the energy of its entire galaxy.
Currently, based on this scale, humanity is on the cusp of becoming a Type I civilisation, i.e. using all available energy on planet Earth.
It's clear that solar power is the way forward, as harnessing the sun’s energy would allow us to meet our energy needs in a sustainable and clean manner.
Solar potential on Earth
The United States, with an annual electricity demand of around 4,000 terawatt-hours (TWh), provides a case study in solar feasibility.
Solar panels typically convert 15 per cent to 20 per cent of incoming sunlight into electricity. Even at this relatively low level of efficiency, solar panels could easily meet this demand using a (surprisingly) small land area.
According to the National Renewable Energy Laboratory (NREL), covering just 10,000 square miles of land with solar panels in the sun-drenched regions of Texas or New Mexico could generate enough power for the entire country.
To put this into perspective, a 60W light bulb uses 60 joules every second, while a 1-horsepower air conditioner (AC, rated at 745.7 Watts) consumes 745.7 joules per second.
The Sahara: A solar powerhouse
On a global scale, the “Sahara Solution” represents one of the most ambitious concepts for large-scale solar power generation.
The vast Sahara receives about 2,500 kilowatt-hours (kWh) of solar irradiance per square metre annually, making it one of the sunniest regions on the planet.
Covering just 1.2 per cent of the Sahara with solar panels could generate enough electricity to power the entire world.
Studies suggest that concentrated solar power (CSP) and photovoltaic (PV) technologies in North Africa could not only meet local demand but also provide surplus electricity (and food!) to Europe and Africa.
Drop in cost
The cost of solar panels has dropped dramatically, thanks to scaling of production, innovations in materials and improvements in supply chains.
- 1960s: In the 1960s, solar energy was prohibitively expensive. According to a study from the Energy Information Administration (EIA), the cost of solar cells in the early 1960s was around $300 per watt (W). This high cost limited their use primarily to niche markets like space exploration.
- 1970s: By 1977, the cost of solar panels had dropped to about $76 per watt due to early efforts to commercialize the technology. Since then, solar panel costs have decreased by over 99%:
- 2010: The cost of solar panels was around $2 per watt.
- 2020: The cost had fallen to $0.20 to $0.30 per watt for commercial-scale solar projects.
Source: International Renewable Energy Agency (IRENA)
Alongside this steep decline is the scaling up of production, particularly in China, while improvements in manufacturing technologies such as thinner wafers, better production methods and material usage have dramatically improved.
‘Swanson law’
Alongside this steep decline is the scaling up of production, particularly in China, while improvements in manufacturing technologies such as thinner wafers, better production methods and material usage have dramatically improved.
The cost reduction in solar panels follows what is known as ‘Swanson’s Law’: the observation that the price of solar PV modules tends by drop 20 per cent for every doubling of cumulative shipped volume.
At present rates, costs go down 75 per cent about every 10 years.
A study by Bloomberg New Energy Finance (BNEF) confirms this trend, showing that the price of solar PV modules has dropped nearly 90 per cent over the past decade.
• Thin-Film technology: Thin-film solar panels, which use materials like cadmium telluride (CdTe) and copper indium gallium selenide (CIGS), offered a lower-cost alternative to silicon-based panels in the 2000s. Although they are generally less efficient, their low cost made them viable for large-scale projects.
• Perovskite Solar Cells: More recently, perovskite solar cells have emerged as a promising technology, with the potential to offer high efficiency at a lower cost than traditional silicon cells. Studies by the Royal Society of Chemistry report that perovskite cells have achieved efficiencies exceeding 25 per cent in lab settings.
• Tandem cells: Tandem solar cells, which combine different types of materials (e.g., silicon and perovskite), have reached record efficiencies of over 30 per cent in laboratory conditions, representing the future of high-efficiency solar technology.
Energy capture
One of the most efficient methods of solar energy capture, particularly in areas like the Sahara, is CSP. This technology uses mirrors or lenses to focus sunlight, converting it into heat, which then drives turbines to generate electricity.
With the Sahara’s high direct sunlight and minimal cloud cover, CSP is particularly effective.
Solar energy: The future of power generation
When the math on solar energy, the conclusion is inescapable: solar power could meet the world’s energy needs.
The Sahara Solution, along with other large-scale solar initiatives, could revolutionise global energy systems, reducing reliance on fossil fuels and cutting greenhouse gas emissions. With the proper infrastructure, the Sahara alone could theoretically power the entire world.
Powering the world: A breakdown
If a CSP plant covering 143,253 square kilometers (a square of 380 km on each side) were installed in the Sahara, it would generate approximately 23,398 TWh of electricity annually—enough to meet the world’s current electricity consumption.
Why aren’t we there yet?
Despite the overwhelming potential of solar energy, significant hurdles remain. The upfront costs of building “solar farms”, especially on the scale needed for global energy production, are considerable.
Energy storage and transmission infrastructure also pose challenges. However, as solar technology continues to advance and costs drop, these obstacles become less daunting.
A green tomorrow
The shift to solar energy is not just a possibility—it’s inevitable. As humanity faces the escalating impacts of climate change and the limitations of fossil fuels, the sun offers a sustainable and scalable solution.
Realisation of the “Sahara Solution” could provide a glimpse into a future where clean, renewable energy powers the world.
Takeaways:
Covering just 0.3 per cent of the Sahara Desert would generate enough energy to meet Africa's electricity needs.
Expanding this to 1.2 per cent could power the entire globe, showcasing the vast potential of large-scale solar power projects.
The potential for solar power is staggering, and the Sahara Solution demonstrates that a solar-powered future is within our grasp.
Harnessing this clean and abundant energy source could help us achieve a sustainable future and bring us closer to a type of civilisation that makes both mathematical and scientific sense.
This requires utmost cooperation and creativity on the part of humanity as a whole.
Powering the world
If we were to install a CSP plant with an area of 143,253 square km (square of 380 km by 380 km (236 mi by 236 mi), the energy produced will be enough to cover the annual consumption of the world – 23,398 TWh.
To break it down for specific regions:
- Africa (722 TWh) – 4,420 km2 (square 66 km by 66 km)
- Asia Pacific (11,614 TWh) – 71,106 km2 (square 267 km by 267 km)
- Central & South America (1,103 TWh) – 6,753 km2 (square 82 km by 82)
- Eurasia (1,237 TWh) – 7,573 km2 (square 87 km by 87 km)
- Europe (3,886 TWh) – 23,792 km2 (square 154 km by 154 km)
- Middle East (1,023 TWh) – 6,263 km2 (square 79 km by 79 km)
- North America (5,151 TWh) – 31,537 km2 (square 178 km by 178 km )
These numbers showcase the immense potential of solar energy in powering our world sustainably.