For many applications, there is an electric option and a fuel-based option. For example, there are electric cars and cars which burn fuels. There are electric water heaters and gas water heaters (and also, of course, solar water heaters). Depending on how renewable electricity and renewable fuels evolve and depending on how the technologies that use or can use those energy options evolve, electricity or fuel may come to dominate a particular application.
However there are some applications for which electricity is unlikely to become a realistic option in the foreseeable future. Commercial air travel is an example.
Therefore we need to explore renewable fuels.
Producing biofuels from food scraps and the otherwise unusable parts of agricultural crops is a good idea. However dedicating agricultural land to the production of biofuels is problematic. Not only is agricultural land required for food production, but the second and third biggest biofuel producers are Brazil and Indonesia, both countries with a track record for forest fires, deforestation and for turning the deforested land into agricultural land.
What this means is that biofuels are probably only a good option for specialised applications such as aviation and not for general transport fuel. According to an article by the International Energy Agency, 15 Million litres of aviation fuels were produced in 2018. This was less than 0.1% of aviation fuel consumption, but it is enough to prove the concept. More widespread adoption would bring the cost down which is what the article also suggests.
Hydrogen is already commercially produced for various applications. It is also used as a fuel. Hydrogen powered cars are already sold commercially overseas. Here is an interesting article by Shell on this topic. Hydrogen powered cars will likely be on sale in Australia in 2020. See article by Car Advice
Currently hydrogen is mostly obtained in a process called steam methane reforming which converts methane (a component of natural gas) and water to hydrogen and carbon dioxide.
One carbon neutral way to obtain hydrogen is electrolysis (splitting water into hydrogen and oxygen using electricity) for fuel. Obviously the electricity would have to come from renewable sources. This method of obtaining hydrogen is little more expensive but becoming increasingly competitive. See this EnergyPost article
It is also possible to use methane from plant sources or from waste for steam methane reforming.
It is possible that new technologies will emerge that are not yet well known.
I am particularly intrigued by technology for making liquid hydrocarbon fuels from carbon dioxide extracted from air and hydrogen (see section above). There is an interesting article in the National Geographic Magazine. This technology works. It will be interesting to see if it turns out to be competitive against other renewable fuels.