Especially as a solar energy medium.
Biomass energy will eat up too much land and agriculture will generate too much pollution with a poor ratio of Energy Return On Energy Invested (EROEI). Synthetically created photovoltaic materials will convert sunlight to energy far more efficiently than plants can manage. This fact might one day enable nanobots to outcompete DNA-based life. But for the foreseeable future the use of photovoltaics instead of biomass energy will protect nature.
Once we figure out a way to cart the energy for our electric motors with us – something that works better and weighs less than batteries – lots of interesting possibilites open up. I’ve ridden in a prototype of one (and will beg my coworker for a ride when he gets his) and even aircraft could get in on the fun.
In any case, biomass fuels, especially ethanol from corn, are a massively stupid idea (unless you happen to raise corn). Already this idiocy is playing havoc with the economy of Mexico. Even if it didn’t cost more oil to produce ethanol than the oil that’s replaced by it it would be dumb.