The Growth of Solar Power

Solar and Moore’s Law

by Charlie Cook


Solar power will grow at an exponential rate through the 21st century. This prediction has been made by the futurist and Director of Engineering at Google, Ray Kurzweil, on many occasions.

In line with the lesson from his essay, The Law of Accelerating Returns, Ray believes that 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.”

Moore's Law

source: Intel

Of course, this is a very exciting idea. In 2011 solar PV 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 (let’s put the storage issue aside for a moment).

So, four years later at the end of 2015, is solar PV still seeing a consistently exponential growth?


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 just 2014.

Cumulative solar

Source (years 2000–2013): Global Market Outlook for Photovoltaics 2014-2018 (EPIA, 2014), Source (year 2014): Global Market Outlook for Solar Power 2015-2019 (SSE, 2014), *based on prediction by Mercom

For the next seven years, from 2000 to 2007, the world saw gradual but impressive double-digit year-on-year growth of between 20%-40% year-on-year (YOY).

It is fair to say that the years 2008 to 2012 saw a boom in the global solar PV market as the rate of new installations almost doubled to between 50% and 75% YOY.

This was followed by a cooling off to previous growth rates during the years 2013 to 2014. Now, coming to the end of 2015, it is estimated that 57.4GW has been added to global PV capacity, bringing the global total to 237.3GW.

YOY growth of PV


Where has the growth been coming from?

Official statistics for solar installations in 2015 are not yet available country by country. However, the growth up until 2014 is all we need to see where the action has been happening. It is good news that the 178GW of installed solar built since 2000 was been deployed all around the world.

Germany has been the largest contributor, increasing its capacity from 114MW to an enormous 38GW. Following closely is China which, although being one of the most coal hungry countries, has seen an incredible growth in solar since 2011. A similarly steep increase has been achieved in Japan, in particular since 2012 when a generous feed-in-tariff was introduced.

The USA and Italy are the 4th largest markets, both with around 18.4GW of installed capacity. Considering their relative size, this is a great achievement for Italy. However, new installations have become almost none existent in the past couple of years after cuts to the financial incentives.

The remainder of the top 10 is made up of France, the UK, Australia, Belgium and India, all with between 2.5GW to 5.5GW of installed capacity.

Growth of PV country by country

From these figures, it would seem as though Germany, China, Japan, Italy and the USA have been driving the global trend of solar PV growth. In the boom years of 2008-2011, Germany and Italy were responsible for 72% of all growth. Whilst, where Germany and Italy have been slowing in the past few years, China, Japan and the USA have been picking up the slack.


So how has solar compared to Moore’s Law?

To measure the growth of solar over fifteen years, the compound annual growth rate (CAGR) can be used, 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 has been 42.13%.

So, 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…