Hi
Thanks for your positive Feedback! I share your concerns about electricity consumption of PoW blockchains therefore I looked for ways to improve it without compromising the safety.
In fact, the electricity consumption of Freechain will be much smaller compared to traditional PoW blockchains with speculative tokens whilst providing a similar safety. This is because in normal operation, most users only mine with a small fraction of their computing power (so called non-profit-mining). Only if the client detects that there is a 51% attack, the mining effort is ramped up to the maximum available computing power until the attack is over.
As you can imagine, this will make it much harder for an attacker to estimate the hash power needed to pull off a 51% attack as he can never be sure how ready the network is to fight back. This should further discourage attackers and provide additional safety.