Bio Fuel
In theory, generating electricity or power generation from bio fuels seems to be very attractive especially as one can easily see a huge savings in a waste to wealth scenario where what used to be considered waste (still remains waste anyway) is being used to generate electricity (which happens to be a cheaper source).
However, not everything that sounds nice is easy to get so a lot of work will still need to be done to achieve a simple and workable template for any interested person to replicate for personal use.
If the content above doesn't make sense just ignore it but the point is that bio fuel must be easy to understand and setup for the technology to make sense in a practical way.
There are many wide scale implementation of bio fuel anyway to the extent that even city wide transportation in Brazil makes good use of this technology.
Many would argue that bio fuel may not be all that good because it leads to increase in the cost of food items like sugar canes so it may ultimately boil down to opportunity cost.