No shortage of this type of energy

A cow produces 120 pounds of manure a day and for centuries manure and dung has been used as a source of energy but now with scientific advancement it is a more popular form of generating environmentally friendly energy all over the world. 

It can be used to generate biogas. Many countries use this gas for their cooking which then avoids cutting down trees to fuel their fires and ovens or the gas can be used to generate electricity.

In many places anaerobic digesters have been installed into which is poured large quantities of dung collected on the same farm. The resulting methane is piped to a generator and it can not only provide the farm with all its energy needs but also to neighbouring households by feeding it back to the grid. 

However in smaller farms the dung collected can be transferred into a large container and left and it will produce biogas which can be piped into the house for cooking. 

1kg of cow poo can produce 375 kilowatts of electricity and after it has been digested it does not smell and has no dangerous bacteria. 

Any solid waste can be retained and used as fertiliser thus no waste.

There are also projects using human waste to generate gas and electricity. 

Interesting though this is I don't think ERA will be including it in its current plans!