BTC/USD is falling to a fresh low under $51000 after the news out of Tesla earlier:
The basis of Musk’s expressed concern over BTC is its mining and transaction environmental cost (electricity usage, power most often generated by the use of fossil fuels). Musk said he’d support less energy intensive coins instead.
As an example, Ripple (XRP) uses less power.
Musk nominated <1% of Bitcoin’s energy/transaction as a baseline for use. XRP fulfills this criteria apparently.