One of the technologies mentioned in my smart cities course that I ended up going and doing more research on was the idea of using bio luminescence to light cities at night instead of conventional electric lighting. This idea has already been worked on to some extent, and even trialled in some places. Basically, there are two possible ideas here, both involving trees, which improve the air quality and life quality in cities very significantly.
1. The trees are coated with bio luminescent algae, much like an invisible coat of paint. This algae lights up in darkness to an extent that it creates a glow around the tree- enough to see by.
2. The trees themselves are genetically altered with DNA from bioluminescent algae which causes them to glow.
There are some possible downsides that I’ve wondered about, particularly the possibility of cross-pollination in both trees or algae. However, glow-in-the-dark plants already exist and can be purchased, so perhaps this has already been solved.
In The Not So Distant Future, Glow-In-The-Dark Trees Could Replace Street Lights http://www.huffingtonpost.com/2014/03/30/daan-roosegaarde_n_5044578.html
Glowing trees could be used “instead of street lighting” says Daan Roosegaarde http://www.dezeen.com/2014/03/24/movie-sxsw-daan-roosegarde-glow-in-dark-trees/
Glow in the dark plants (funded via Kickstarter) http://www.glowingplant.com