Saving energy and recycling energy wastes are the first steps toward sustainable colliders. But only limited gain can be expected because, as often mentioned in the previous chapters, extensive past efforts have been maturing the technology, not always to reduce the energy consumption but very often so. Going further requires implementing renewable energies in the complex ILC infrastructure. This is certainly the most challenging endeavor, but also the most rewarding to ILC and to any further HEP infrastructure project. Moreover, it is essentially here that ILC will contribute the most to developing solutions to the energy crisis. Any progress will be directly transposable to societal applications.

1. Which, among the many available sustainable energy sources, are the most suitable for the ILC in the Kitakami region?
2. What is the best mix for a 24/7 consumption need?
3. How to manage the energy sources during short and long shutdown?
4. Building pilot plants and connecting renewable energies to ILC