Gst on reimbursement

read rule 33 of CGST Rules 2017

you can satisfy the conditions of pure agent and then issue invoices.

From above it seems you are availing consulting services from a companh with whom you have a contract to even reimburse the charges like electricity charges etc.

As per provisions of GST, reimbursement in nature of Pure agent is only not laible for tax otherwise it would be taxable at rate applicable on service provided.

In your case, the reimbursement doesnt fall under pure agent and hence GST is applicable.

However you xan avail input credit of same.