Ray Kurzweil, the futurist and Director of Engineering at Google, predicts that solar power will grow at an exponential rate throughout the 21st century.
In his essay “The Law of Accelerating Returns”, Ray believes the growth of solar will resemble Moore’s Law: the doubling of computer capability every two years.
During an interview in 2011, Ray explained:
“Solar panels are coming down dramatically in cost per watt. And as a result of that, the total amount of solar energy is growing, not linearly, but exponentially. It’s doubling every 2 years and has been for 20 years. And again, it’s a very smooth curve. There’s all these arguments, subsidies and political battles and companies going bankrupt, they’re raising billions of dollars, but behind all that chaos is this very smooth progression.”
RAY KURZWEIL, GOOGLE
Image source: Intel
This is a very exciting idea. In 2011, solar PV (meaning “photovoltaic” – the type of panel used to generate electricity, as opposed to thermal panels that generate heat) generated 60.6TWh or 0.27% of global electricity generation. Based on Ray’s simple number crunching, solar would generate enough energy to meet the entire world’s electrical needs of today by 2029 (putting the storage issue aside for a moment).
So, is solar PV still seeing consistently exponential growth six years on?
Global growth of solar since 2000 – in numbers
At the beginning of the 21st century, global installed solar PV capacity paled in comparison to today’s figures. Estimates put the total installed PV capacity in 2000 at around 1.4GW. To put this figure in perspective, China alone installed ten times this amount of solar PV in 2014.
Data source (years 2000–2013): Global Market Outlook for Photovoltaics 2014-2018 (EPIA, 2014). Data source (year 2014 – 2016): Global Market Outlook for Solar Power 2015-2019 (SSE, 2014), Renewables Global Status Report 2017 (REN21, 2017)
For the next seven years, from 2000 to 2007, the world saw gradual but impressive double-digit growth of between 20%-40% year-on-year (YOY).
It is fair to say that 2008 to 2012 saw a boom in the global solar PV market – the rate of new installations almost doubled to between 50% and 75% YOY.
This was followed by a cooling off to previous growth rates between 2013 and 2014. At the end of 2016, it is estimated that around 74GW has been added to global PV capacity, bringing the global total to 303GW.
Where has the growth been coming from?
Germany was the solar PV leader up until 2014 with 40GW of solar (equal to around 20 coal-fired power stations). Then, the German energy program Energiewende was wound down, allowing China and Japan to overtake Germany, with the USA close behind. Incredibly, China matched Germany’s 40GW in 2015 and then almost doubled this figure again in a single year. The latest figures for the end of 2016 show that China has almost 80GW of solar PV installed. So much for China not pulling their weight on climate action, Donald.
Japan has achieved a steep increase following the introduction of a generous feed-in-tariff in 2012. Japan’s solar market grew almost as fast as China’s, but cooled off slightly between 2015 and 2016.
The USA has also managed to grow at an impressive rate since 2012, adding a record breaking 14.7GW of solar in 2016. Italy’s growth was impressive for a small country but has remained largely flat since financial incentives were removed in 2013.
The remainder of the top 10 is led by the UK, followed by France, Australia, Spain, Belgium and India, all with between 3.5GW to 11.5GW of installed capacity.
Germany and Italy were responsible for 72% of all growth In the boom years of 2008-2012. Today it is very much a story of China, Japan, and the USA. It will be interesting to see how this plays out over the next few years.
How has solar compared to Moore’s Law?
To measure the growth of solar over fifteen years, we can use the compound annual growth rate (CAGR), which is similar to the way you would calculate your average interest on a bank account over a period of time.
For computing capability (or anything, for that matter), to follow Moore’s Law and double every two years, a minimum CAGR of 41.42% is needed. The CAGR of global solar PV installations from 2000-2015 was 42.13%, meaning it almost exactly tracked Moore’s Law. The CAGR has dropped slightly to 39.79% as of the end of 2016.
On average solar has been doubling every two years since the beginning of the 21st century, and so far, Ray Kurzweil’s prediction has been accurate. Let’s hope Ray continues to be right over the next 15 years. Or at least not far off…