I have a startup in energy, and one thing that I think entrepreneurs outside of energy don't understand is just how ridiculously high the ceiling is in this space.<p>In our lifetimes (~40yrs), we will have to replace the 87% of the energy sources that are adding carbon to the carbon cycle[1]. That's ~450 Quadrillion BTUs (QBTU) per year[2]. No matter what, this will happen.<p>Do you know how much solar the US installed in 2012? 30 Gigawatts[3], which equals ~0.9 QBTU/yr. Even if solar eventually only amounts to 20% of the total fuel replacement (~90 QBTU/yr), that's a 100x growth in 40 years for an already huge industry. That's Internet revolution scale growth.<p>And that's only one industry. What about energy efficiency? There's so much opportunity for tech disruption there, and the ceiling is just as high as solar.<p>Why the hell are entrepreneurs (and investors) trying to make the next big app when the ceiling is so much higher in cleantech? The next Google will be an energy company.<p>[1] - <a href="http://www.eia.gov/todayinenergy/detail.cfm?id=11951" rel="nofollow">http://www.eia.gov/todayinenergy/detail.cfm?id=11951</a><p>[2] - <a href="http://www.eia.gov/cfapps/ipdbproject/IEDIndex3.cfm?tid=44&pid=44&aid=2" rel="nofollow">http://www.eia.gov/cfapps/ipdbproject/IEDIndex3.cfm?tid=44&p...</a><p>[3] - <a href="http://cleantechnica.com/2013/12/24/npd-solarbuzz-predict-massive-49-gw-solar-pv-demand-2014/" rel="nofollow">http://cleantechnica.com/2013/12/24/npd-solarbuzz-predict-ma...</a>