It is one of the greatest three-word phrases ever. It was most memorably uttered by Woodward & Bernstein's mysterious Watergate source Deep Throat, and repeated by many, including the teacher of a graduate journalism course I took at Boston University in 1985, as the first rule of business reporting: "Follow the money."

As 2011 nears its halfway point and the world economy continues its slow recovery, a lot of big money is leading directly to clean tech. In the second quarter alone, three big deals in particular tell us a lot about this current trend, and I believe, point toward a future of energy transformation. It’s an impressive trio:

  • French oil and energy giant Total SA, the world’s 14th largest corporation, offered to take a 60 percent stake in San Jose-based solar PV stalwart SunPower, for $1.38 billion.
  • Japanese computer/electronics icon Toshiba said it will acquire Swiss electricity meter manufacturer Landis & Gyr, an increasingly influential player in smart meters and other smart-grid technology, for $2.3 billion.
  • Home improvement retailer Lowe’s, a Fortune 50 company with nearly $50 billion in revenue, took an undisclosed minority stake in fast-growing solar installer/lessor Sungevity. Lowe’s plans to offer fast rooftop solar price estimates, at kiosks with Sungevity’s iQuote software application, to its in-store customers in the eight states where Sungevity operates.

Although the Lowe’s-Sungevity hookup doesn’t compare to the other two deals in terms of dollar amount, it’s a similar example of a very large corporate player, not primarily in the clean-tech business itself, seeing the business potential in this sector. Sungevity’s rival installers SolarCity and SunRun have a similar arrangement with Home Depot, though without the equity stake.

We follow the money because money follows opportunity. And right now, with corporate pursestrings starting to loosen up more than they have since the 2008 financial meltdown, large companies across the globe – from a variety of industry sectors – are looking to clean tech for new business opportunities.

At Clean Edge, this does not surprise us. We have written about the inevitability of the global transition to a clean-energy economy for the past decade. It is a not smooth or even transition and there have been plenty of setbacks, most glaringly the lack of a comprehensive federal energy policy in the U.S. to help manage and spur that transition. As we all know, in any fundamental long-range shift in history, entrenched interests can take a very long time to shift. But sometimes, change can happen very quickly – just ask the former rulers of Egypt and Tunisia.

Another potential game-changer for the global future of energy, clearly fueling this trend, is the Fukushima nuclear disaster in Japan. Its shock waves are starting to play out in energy circles around the world; in recent weeks, both Germany and Switzerland announced that they intend to phase out all nuclear power in roughly the next two decades and Japan, while not planning to shutter all of its plants, has announced the end of new nuclear power plant construction in favor of renewables, smart grid, conservation, and other clean-energy options. France-based Areva, the world’s leading builder of nuclear plants, recently said its projects will be delayed six to nine months to assess additional safety measures, and one Areva plant in Finland, already delayed before Fukushima, is over budget by an estimated €2.7 billion ($3.85 billion). Areva itself has put big money into clean energy too, acquiring U.S. concentrating solar company Ausra and German wind turbine maker Multibrid in the past year.

With the business potential of nuclear power considerably dimmed, companies are seeking alternate paths, and seeing opportunities in smart grid and efficiency as well as clean-energy generation. Toshiba’s Landis & Gyr acquisition, reported Reuters, “comes as Toshiba's hopes of growing profits in its nuclear power division are being overshadowed by the crisis at Japan's tsunami-hit Fukushima reactor, and utilities around the world focus on smart grids as a means of saving energy and cutting carbon emissions.”

As for solar – why exactly is Total, the third-largest oil company in Europe, laying out more than $1 billion for a stake in SunPower? There are many reasons, but one simple one, again, is Follow the Money – specifically, pricing trends. Petroleum prices are rising, leading to more fuel-efficient car sales from General Motors and others, while solar prices are falling dramatically, sparking record growth in PV installations around the world. Anyone want to bet against those trends continuing? I thought not.

Total apparently doesn’t want to, either. Nor does General Electric, whose global research director Mark Little predicted in an interview with Bloomberg that solar PV may reach grid parity with fossil and nuclear power in three to five years. Little knows energy; he ran GE’s power generation business for eight years. GE (no stranger to clean tech) opened the pocketbook in the second quarter too, announcing $600 million in new solar investments, including the remaining shares of PrimeStar Solar, an Arvada, Colorado-based PV panel maker in which GE owned a majority stake.

What about coal? It’s clearly still growing in China and India, but in the past four years, more than 100 of the proposed 151 new coal-fired power plants in the U.S. have been cancelled, abandoned, or placed on hold. That doesn’t sound like a good growth market to me.

Returning to oil – over the Memorial Day weekend, we heard what may turn out to be the quote of the year in the energy world. Showing uncommon candor, Prince Al-Waleed bin Talal, grandson of the Saudi Arabian king, told CNN’s Fareed Zakaria, "We don't want the West to go and find alternatives, because, clearly, the higher the price of oil goes, the more they have incentives to go and find alternatives.”

Well, true words. The real incentives for business are future profits, and from Total’s corporate boardrooms in Courbevoie, France, to Toshiba’s in Tokyo, and Lowe’s in Mooresville, North Carolina, there’s a growing belief that solar and other sectors of clean tech are the path to reach them. That’s the current trend of smart business investment around the globe, and it’s not hard to spot – just follow the money.

Wilder is Clean Edge's senior editor, co-author of The Clean Tech Revolution, and a blogger about clean-tech issues for the Green section of The Huffington Post. E-mail him at wilder@cleanedge.com and follow him on Twitter at @Clint_Wilder.