[Vvector]

It is due to orbit in L2, in eternal shade of earth. So no solar power

[gadnuk]

No, that's not true. It will be orbiting around L2 and not stay at L2, so it will have access to sunlight, which powers the solar array that faces the sun. The actual observatory and the mirror are shielded by the sunshield.

Here is Dr. John Mather explaining it: https://youtu.be/4P8fKd0IVOs?t=1321