Green technology companies are already feeling a pinch from the world credit crisis, but, if history is any guide, the problem will get worse three years from now. That's the word from Richard MacKellar, managing director at Chrysalix, an early-stage energy venture fund and one of the first VCs to invest in clean tech. (MacKellar will speak at Greentech Innovations: End to End Electricity on November 17.) The problem is that VCs operate on a different timeline than the rest of the economy. A large number of firms already raised a significant amount of capital in 2006, 2007 and the first half of 2008. They now have to place this money somewhere. As a result, startups will continue to receive funding. The money spigot may not be turned up on high anymore, but VC millions will still find their way to the market. But three years from now, new startups and those who are emerging now will need another infusion of capital. By then, a good portion of these existing funds will have been used and limited partners may still feel conservative. Thus, getting cash will be tougher. A similar phenomenon happened in the first part of the decade, MacKellar said. The stock market cratered in mid-April 2000. (I remember that Friday well -- the open period for options at my old company was slated to begin the coming Monday). Still, VCs invested $105 billion that year, according to the National Venture Capital Association. In 2001, when employees at Web companies were getting squishy balls and T-shirts in lieu of actual money as severance pay, VC investment came to $40.6 million. It plummeted further to $22 million in 2002, but it didn't hit rock bottom until dropping to $19.7 million in 2003, which, if you recall, was the year the overall recovery began. Similar patterns can be found in previous decades, he said. Several factors could mitigate or change the pattern. Unlike the dotcom crash, many energy startups are being propelled by government regulation and subsidies. If several jurisdictions impose carbon caps or green building codes, those companies like Integrity Block or Serious Materials that make building products will likely get funding. The government never stepped in and mandated consumer deliver of pet foods and chew toys, which could have helped the oft-maligned Pets.com. Then again, the plummeting price of oil may dampen the enthusiasm for biofuels -- it has happened before. Ergo, some investment categories may decline and not rebound. The Chrysalix portfolio, by the way, is always an interesting one to check out every once in a while. They tend to place some long bets on technologies, like nuclear fusion (General Fusion) and hydrogen.