How to use Thunderbolt display (with MBP lid closed) without connecting MBP to power cable

Whenever i disconnect the power cable with my MBP lid closed, i loose my external display. And there is no way to turn it back on unless i open my MBP and start it and connect to power cable. Is there a way to get around this issue?

PS: I have the option of "Wake my MBP using bluetooth devices" enabled.

- Kaushik