Image credit: Inhabitat
Half the news reports we read today seem to be about solar power. It is as if the entire world will soon be running on solar power.
Well, that kind of pops up the question: Can the entire world indeed run on solar power alone, if not now, sometime in the future?
Well, wait, hang on.
I will change the Yes to Maybe.
I will first explain why it could be Yes.
Before that, when I talk solar here, I am talking about Solar Photovoltaic (PV) which is by far the dominant solar power generation system today, worldwide (the much-smaller cousin is solar thermal based power generation).
Solar has the potential to power a large portion of global power needs because:
Proven technology – Solar photovoltaic based solar power (the solar panels you see all around) is a proven and mature technology, with over 200 GW of solar power plants operating worldwide.
Land is available – There is enough land available worldwide to generate enough solar power to satisfy all of the world’s electricity requirements. Some thumb rule estimates suggest that the total area needed for solar panels to power the entire world will just be the area of Spain. (We have a simple calculator running at Solar Mango to estimate area required for rooftop solar power plants. You can check that out here).
Costs are coming down – The cost of solar power is also falling so rapidly that by 2020, it is quite possible that solar power will cost less than the cost of power generated from coal.
The above imply that it is, or soon will be, economically feasible for solar power to replace fossil fuels completely. The basic infrastructure, land and stuff, is not going to be a problem either – well, at least for a good number of countries.
But…there is a catch.
All this power is generated only during day time for a particular region. How then will the region be powered at night? For this, you need to have power storage systems, typically batteries.
Without storage, solar power cannot completely (or even to a large extent) replace power from conventional fuels. Imagine a world powered by solar power alone, without storage. What will you have at night?
So, storage is a must for solar power (or for that matter, wind power) to satisfy a majority of our electricity consumption.
But battery based power storage, the predominant way of storing solar power currently, is not fully there when it comes to storing vast amounts of power generated from large solar farms. In many other posts (here, here and here), I have explained where battery based storage technology is, currently. Just to illustrate, while there are millions of small rooftop solar power plants using small amounts of battery storage, as of 2016, there is no large-scale, commercial solar farm using battery based storage.
Now, you will hear here and there that there are large-scale solar farms running with battery back-up, but go deep in, and you will realize that these are either not really large-scale, or not really using batteries on a large scale, or are operating just pilot facilities, or are working under special incentives that offset the cost of storage.
Essentially, don’t believe folks who claim they are profitably running large-scale solar PV power plants with significant battery storage without any external subsidies and artificial incentives!
The summary: Battery is an expensive way of storing electricity, and its use for storing large scale solar power is economically infeasible for the foreseeable future.
Thankfully, at the hectic pace of technology advancement, the horizon of definition for foreseeable future has come crashing down from perhaps 25 years to 5 years! All the same, while in theory solar can power the entire world, in practice, we just might have to wait a few more years in the very least for it to be really feasible. And the key for this to happen will be breakthroughs in batteries, or in any other form of electricity storage (see here for other forms of energy storage).
How much is solar power contributing right now?
Just for those who are curious: As of 2016, solar power contributes only slightly more than 1% to the world’s total electricity consumption! And, even by 2040, solar power is likely to contribute only about half the power generated by coal.
But let that not take away the credit from solar, because right now, solar generates only slightly more than 2% (1/50th) of electricity that coal generates. From 1/50th, contribution from solar will rise to about half that of coal by 2040 – a remarkable growth by any metric.