The scheme strongly favors the largest pool since it will win most preselections. The next to largest pool will win less, therefore it's clients will have less profits per invested mining capital. Yes, there would be some savings with the energy costs, but not proportional to the revenue drop since capital costs are paramount in mining. The miners will therefore switch to the largest pool where they are able to compete on an equal footing with other miners; this pool will quickly control 100% of the hashing power and employ it 100% of the time. We have achieved centralization without any energy savings.