Duplication/dilution should be avoided if possible, but failure to start is MUCH worse than suboptimal allocation.
There's so much variance, and so many unknown factors, that making this based on high-level industry-wide generalities is bound to be wrong. Details matter more than you think. WHAT very specific thing would your startup do? Why isn't someone already doing it that you can join/contribute to? What is your chance of success in a new startup vs in an existing company (even if it's not perfectly aligned with your vision)? How much "wasted" effort will you have in random business overhead for a startup or in random coworker disagreements if you join others (note: I'd argue neither of these is waste).
All that said, the general algorithm everyone actually uses for this kind of decision is to make a pro/con list with scores and weights, carefully consider all the pros and cons and distribution of outcomes, and then do what they wanted to do in the first place. Fortunately, you're young and resilient - there's no wrong answer as long as you're trying something.
I second @Dagon's advice. I've done a lot of landscaping and tech due diligence consulting projects for investors, corporates,and governments interested in various types of cleantech. It's true that there's a lot of undifferentiated companies that probably shouldn't have been founded. They may attract some money, maybe make some progress, maybe even attract a lot of money, then fail, with nothing to show for it. There's also some that, in principle, should be able to have amazing impact, but for some reason just can't. Often those inspire a 2nd generation a decade later that does better. And there's a few that seem ridiculous but nevertheless go on to actually do well.
I'd add that the field has a lot more people interested in funding the cheap early stages than the expensive late stages. The valley of death is a hard filter. If you think your plan eventually needs a $200M FOAK plant to make money, that's very different than if you expect you'll be able to start generating commercial revenue or have a positive acquisition after a $20M series B. This is especially true if you're looking for funding from non-US sources.
I would suggest that, compared to the average startup, you should spend more time on the econ part of technoeconomic analysis than you think, at the very beginning before you can possibly know the details of what you're going to build and how you're going to sell it. Otherwise you're likely to spend years optimizing the wrong thing. Try to talk to actual experts with high level industry experience, if you can, to find out what the real KPIs and bottlenecks and hard steps are going to be.
Can't really say much more without some info on what you're thinking of doing. Happy to talk more if you want to PM me.
For context, I’m a student trying to choose a career where they can have maximum impact. One path I’m considering is founding a cleantech startup.
However, I’m worried that even if I found a startup, I might not actually increase the total amount of socially impactful work being done in the world.
Here’s my reasoning: suppose, very crudely, that the total social benefit produced by the cleantech sector scales with the number of cleantech startups that get funded. Also suppose there are more "viable" startups (i.e. startups that could plausibly become profitable if adequately financed) seeking funding than there are funding opportunities. If so, funding my company may simply displace capital from another viable startup. I would change which company gets funded, but not how many get funded, and therefore have little to no counterfactual impact.
I’ve considered a few possible counterarguments:
i) My startup could be more socially valuable than the one it displaces. But in areas like cleantech, many founders are already working on important problems, so I’m not sure I should expect mine to be better on average.
ii) My startup could be uniquely suited to my skills. But uniqueness alone doesn’t imply greater value; the displaced startup may also make a different but similarly valuable contribution.
iii) Exceptional companies can attract additional capital, so capital may cease to be the bottleneck for a sufficiently compelling startup. But founding an exceptional company is extremely rare / difficult, and I’m not sure it makes sense to base a career decision on that outcome.
iv) My underlying assumption may simply be wrong: perhaps there are actually more funding opportunities than “viable” cleantech startups. However, everything I’ve found so far suggests the opposite: there seem to be far more viable projects seeking funding than there are opportunities to fund them.
TL;DR: if I found a company in a sector where many other founders are already doing useful work, why should I expect my entry to increase the total amount of socially valuable work that gets done, rather than mostly reshuffling scarce capital?
I’ve been thinking about this for three weeks and haven’t found a satisfying answer. If anybody has any counterarguments, would really appreciate it...