In this answer I'm going to assume you live in a rent-controlled apartment. In that case, the landlord can't increase your rent, which includes all "housing services", except by the pre-approved amount yearly after giving you a 30 day written notice. Therefore, the landlord would have to pay for the electric going forward. However, the landlord would be entitled to raise the rent an additional 1% per year because he pays the electricity.
If you are not in a rent-controlled apartment, the landlord can simply give you a written 30 day notice of change in terms of tenancy PROVIDED that the lease has already expired, and you're now month-to-month. If the lease is still in effect, the landlord still has to pay for the utilities.