I haven’t seen that episode and I unfortunately can’t provide the specific answer you’re looking for but there does seem to be a good amount of of people doing research on using organic materials like peanut shells for energy related project and peanut shells are considered low cost and easy to source. There’s a teen in Zimbabwe who worked on harvesting energy from Peanut shells . Scientists in Canada created a new capacitor from Peanut shells. A a physicist from Cheikh Anta Diop University in Senegal has done work on energy storage using Peanuts. There’s been research into utilizing Peanut shells for solar desalination and a town in Argeinta uses them to keep the power on so I’m sure this is something we’ll be hearing more about in the future