The clean tech boom that led to the clean tech bust, the dark years that followed, and today's bull market that has transformed climate tech into one of the hottest sectors in the venture world have all been witnessed by Dan Goldman.

Goldman told us about how to prepare for next year and what he thought about the current market.

He said that they want them to be very careful with cash. The reasons why that is the case are not the same as they were a decade or so ago.

Goldman has been investing for a long time. He has experience in financing large-scale energy and power generation projects. He co-found the Cambridge, Massachusetts-based Clean Energy Venture Group in 2006 after moving to clean energy. He co-founded a company to make investments in early-stage companies. Over 100 has been made since the firm was founded.

Early-stage companies that have received grant money or angel investments but haven't raised a venture round can be invested by Clean Energy. The firm helps guide its investments in things like team development, intellectual property strategy and marketing strategy by leading the first institutional round of investing. It participates in follow-on financing as well.

The firm is focused. There is an energy component involved in everything from materials recycling to hydrogen production and software. Goldman said Clean Energy Ventures does extensive lifecycle analysis for each of its investments to help ensure that they fit the firm's "mandate"

We see the potential for them to grow to really large businesses if they are able to do that. His optimism is dependent on the data. The general venture markets have fallen over 20% in the first nine months. Climate tech is up 50%.

Advice to founders

Goldman has some cautionary advice for those who want to get there. It is not based on whether climate tech is headed in the right direction but on how much money has been flowing to companies from investors not traditionally involved at earlier stages.