BlogTotal Money Required to Power the World with Solar Energy Alone
I recently came across a very interesting post:
Total Surface Area Required to Fuel the World With Solar
Since solar power is one the most abundant form of renewable energy available to us, it is certainly a legitimate effort to study the feasibility of powering the world solely on solar power. The article produces some very good estimates as to what the total world energy demand is in one year (199,721 TWh), and given some legitimate estimates of solar panels conversion efficiency (200W/m2) and hours of sunshine per year (2000hrs/year) concluded that the surface area required to fuel the world using exclusively solar energy, in a sort of World Solar System, is 496,804,500,000 m2. This, as the author concludes, is roughly the area or Spain.
I have been involved for a while with solar energy projects here in Thailand. Here we get that powerful 1,000W/m2 radiation in its full glory, but are afflicted by a long rainy season and short days. This means that we get less of that 1000W/m2 of potential solar power and we also get less overall hours per year. Overall however, solar evergy seems to have some potential in Thailand.
Solar definitely does have perfect conditions to work in the areas that the author recommends: southern California, the Sahara region of Africa, Australia, and Saudi Arabia among others.
However in my experience one of the big hurdles is not space itself. Think of all the people who have an empty roof, hence available space, but have not installed solar panels. Even more meaningful, like the author shows, we have large deserts that are vastly unusable land with the perfect conditions for solar energy generation, yet we haven’t installed a significant capacity of solar panels there yet.
The problem is money
Since I am now facing the very same problem of finding financing for building several solar power plants in Thailand, I though I would calculate “How much would it cost to power the whole world using solar panels?”
Thanks to the article that identifies the required output and area we can calculate this very easily.
Cost of solar panels systems
The cost per kW of a solar system must include not only the the panels themselves but and also inverters to convert from DC to AC current and other accessories.
According to the latest Global Benchmark Price Indices published in September 2009 by SolarBuzz.com the cost per Watt of a solar system is:
$8.50 per Watt for a 2kW Home Solar System
$6.40 per Watt for a 50kW Commercial Solar System
$4.63 per Watt for a 500kW Industrial Solar System
Of course if we decided to use solar exclusively to power the world demand would rise substantially and if supply could keep up the price per Watt of solar panels would decline further. However also the opposite is possible that if demand was to grow faster than supply then the price of a solar system could actually go as there would be a shortage of solar panels.
For the purpose of this analysis I will therefore use an installed cost of $3.90 per Watt, which is what I get quoted these days here in Thailand for a large 100 MW solar plant.
Calculations
We need to buy panels to cover an area of 496,804,500,000 m2 to power the world by solar panels for a total of 198,721,800,000,000 kWh over 2000 hours per year. This means that the total installed capacity has to be at least 99,360,900,000 kWh.
At $3.90 per Watt it would cost $387,507,510,000,000 to install these solar panels, DC-AC inverters, and accessories. That’s 387 trillion dollars.
Of course if the price per installed Watt decreased to $3 it would take ~$300 trillions or if it decreased by 50% to $2 per Watt it would still take ~$200 trillion.
Comparison to the Gross World Product (GWP)
To put these $200 to $300 trillion in perspective, according to the CIA World Factbook entry for the World as a whole, the Gross World Product was $69.62 trillion (2008 est.)
This means that it would take 5.6 years of GWP equivelent to pay for all the solar panels to power the world on solar power alone.
We must also consider that solar panels have an expected life of just 20 to 25 years before they have to be substituted, therefore there is not much room for extending the depreciation period of the World Solar System so that it becomes a significantly smaller percentage of GWP.
Comparison to fossil fuel consumption
Fossil fuels daily production during 2006 was:
from: Wikipedia
- Oil: 84 million barrels per day (13 million m³)[15]
- Gas: 104,435 billion cubic feet (2,960 billion m³)[16], 19 million barrels oil equivalent per day (MBOED)
- Coal: 18,476,127 short tons (16,761,260 tonnes)[17], 52 MBOED
Which at $100 per barrel totals approximately $6 trillion per year of money spent on oil, natural gas, and coal combined. This is 64 years the cost of a 25-year useful life World Solar System. And we still would have not powered our cars, planes, and any other off-grid system.
The renewable energy challenge ahead
This certainly is just a back of the napkin assessment, but what I wanted to show was the magnitude of the investment that lies ahead for us in order to switch from fossil fuels to renewable energy as the primary form of energy source. Certainly there are many factors that have to be taken into account to make a similar calculation. But of course mine is as much as possible a fair analysis as it is a provocation to stir a discussion.
I would like to thank the author of the original article on the total area needed to power the world on solar energy alone. It gave me the inspiration to write this follow up and it is definitely required reading as I have also kept his assumptions unchanged in writing this blog post.
Please feel free to leave you comments so we can get the discussion going.