Investing in greentech innovation: patience, piles of cash, tons, and years

Two particular articles in today's NYT provide a nice comparison between investing for innovation in greentech versus internet startups.  

One article, G.E. Goes With What It Knows: Making Stuff, provides a description of GE's new strategy of investing in manufacturing.  A nice return to reality, CEO Jeffrey Immelt seems to imply, and away from making and selling "knowledge work."  Immelt also offers his perspective on where greentech innovation will come from, describing GE's strategy as focusing on "heavyweight products that take patience and piles of cash to develop, weigh tons and last for years — next-generation jet engines, power turbines, locomotives, nuclear plants, water-treatment systems, medical-imaging equipment, solar panels and windmills." Of the eight big-ticket items in his list, six are central technologies in the greentech landscape.  

Patience, piles of cash, weigh tons and last for years are a good description of most greentech—and as Immelt goes on to note, the cost of a good-sized solar-panel plant, about $70 million, is more than twice the total investment in Google in the six years before it went public in 2004.  Greentech doesn't scale quite the way internet companies do, which means greentech investing is not the same game as traditional (and current) Silicon Valley investing.

Compare this, for example, to an adjacent article, A Silicon Bubble Shows Signs of Reinflating, which describes the current state of investing in traditional internet-style startups, "all younger than seven years and all worth billions." Twitter is now worth roughly $4 billion, gamemaker Zynga is worth more than $5 billion, and of course Groupon has supposedly just walked away from a $6 billion offer by Google (after being value at $1.35 billion just 8 months ago).

When investing in greentech startups, should we really be using the same assumptions and the same strategies that we see succeeding in Silicon Valley? Or should we be thinking differently about how to bring to market tings that take patience, piles of cash to develop, weigh tons, and last for years?