1) BitcoinZ can already handle 8x more transactions per second than Bitcoin.

2) BitcoinZ is scalable so by reducing just its block time to 30secs can have instantly  40x more transactions per second in comparison with BTC (& so on...)

3) The BITCOINZ network is based on the ASIC Resistant algorithm for all these years. So it discourages people to use mining equipment.

The idea is to base its network mostly on PCs that are used even for many other things in parallel since their PCs for mining use only the GPU. Most PCs are used at the same time for web apps, office suites, communication, social media etc Not all people use mining rigs.

4) Even its algo is far less power-hungry in comparison with Ethash or other algos.
 A card with just 120w can have a temp below 60 Celsius offering 80 Sols.

5) There is no POS change chance for BitcoinZ because the PoW is the only original cryptocurrency model that ensures decentralized coin distribution to the community.

Most PoS projects have 100% pre-mined supply which was allocated to their founders' wallets.
Or those who change to PoS wish to distribute the rest of the supply to the existing holders, they don't do it for a "green effect".

6) It is hypocritical to say that you are troubled with the environmental effect of the PoW nature of BitcoinZ.
Even if BitcoinZ had much more transactions & miners, the energy that it would burn would be much less than the power that an average single bank uses for its network. (Simply because its algo is super less power hungry, most devices that mine are used for many other things as well and its transactions can be scaled easily to 40x than BTC or even more).

& last but not least, offering a real alternative network, 100% Decentralized, ideal for borderless, almost zero fee transactions is a noble cause that deserves this minimal amount of energy.