In recent years, growth in the solar energy industry has been massive.

As I reported last week, just since 2008, U.S. wind and solar capacity have tripled. And the story continues: On Tuesday, Apple announced it was investing a dramatic $848 million to partner with First Solar on a huge California solar farm – Apple’s slice of the farm will be 1,300 acres.

new report from IHS, a global business research firm, gives a glimpse at how big, in revenue terms, one key portion of the solar industry is. The report examined 20 top global companies who are suppliers of solar photovoltaic modules (what we often tend to think of as a “panel”; see an example from First Solar here). It found that in the fourth quarter of last year, these companies – a group that includes such names as First Solar, SunPower, Trina Solar and Yingli Green Energy — brought in $5.9 billion in combined revenue from module sales. (The number excludes “process servicing revenue.”)

The growth is impressive: This is a 12 percent increase compared with the last quarter of 2013, according to IHS.

Still, it’s important to keep this in perspective. One single oil company, Exxon Mobil, reported a profit last quarter that is larger than this revenue total across the 20 solar companies. Exxon reported a profit of $6.6 billion for the quarter. Total revenue, meanwhile, was a staggering $87.3 billion.

And the fourth quarter of 2014 wasn’t even a particularly good one for Exxon, due to the oil price plunge. In the last quarter of 2012, the company reported earnings of $9.95 billion, and in the fourth quarter of 2013, $8.35 billion. (Exxon Mobil’s quarterly earnings can be found here.)

Other oil majors reported similar results, if not quite as big as Exxon. Shell reported earnings of $4.2 billion last quarter. Chevron reported $3.5 billion. Both are also, of course, pulling in significantly less because the price of a barrel of oil has tumbled in the past three months or so.

And don’t even get started on the magnitude of other parts of the global oil industry. OPEC’s countries, according to the Energy Information Administration, brought in an estimated $826 billion in revenue from exporting oil in 2013.

In fairness, there is more to the total solar industry than these 20 companies — they accounted for 68 percent of all photovoltaic module demand last quarter, according to IHS. And that says nothing of other parts of the industry — the designers and installers of home systems like SolarCity, for instance.

Nonetheless, these numbers serve to indicate that despite dramatic strides — and growth that is slated to continue, according to IHS — solar remains a fairly new and small industry, compared with other energy players. In 2013, it provided less than a percent of total U.S. electricity, versus 67 percent for fossil fuels. Solar has grown rapidly in just the last year alone — but based on a new report by Bloomberg New Energy Finance, it still remains under 1 percent of electricity — for now.

So yes, our energy systems are changing. But we’re still in a relatively early phase of transitioning out of the old world, and into the new.

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