Why TATA OR other car maker try to make bio-energy driven car to combine solar energy vis-vis-cng?

Question

Why TATA OR other car maker try to make bio-energy driven car to combine solar energy vis-vis-cng?

Answer 1

perhaps they are, the most economical designs are the ones that will be marketed first

Answer 2

Part of being a successful company is finding new markets.  There is a perceived demand for alternative fueled vehicles so theya re exploring different methods to gain market share and thus, profits.  ZPlus, it looks good to be researching these things publicity wise.  It's a form of greenwashing.

Answer 3

Fossil fuel availability is getting difficult. Expensive and polluting the environment resulting in Global Warming.

For now the solar energy or other alternative energy is not proving practically effective.  They are not on par with the fossil fuel powered vehicles, in terms of performance and refuel etc., It is still under Research! Sooner the Better.