Power Ledger is "The Power Ledger Ecosystem supports a growing number of energy trading applications. Some of the key classes of applications are listed below while the full list is available in our white paper, with some already operational, and others in advanced conceptual design or in development."
source :
https://bitcointalk.org/index.php?topic=2003922.0and you can buy Power Ledger in :
1 Binance
2 Huobi
3 Bittrex
4 Upbit
5 BX Thailand
6 LATOKEN
7 Bancor Network
8 Kucoin
9 Cryptopia
10 EtherDelta
11 IDEX
12 Gate.io
13 TDAX
14 Lykke Exchange
15 BigONE