The cuts affect call centre staff at four sites
The redundancies will take place over the next 18 months at its customer service centres in Bradford, Sheffield, Swindon and Worcester.
Innogy said the "streamlining" was unavoidable in an increasingly competitive marketplace.
The company needs to save £35 m after the acquistion of Yorkshire Power in a £1.8 bn deal.
Redundancy package
Innogy, part of the former National Power group, is better known by its Npower and Yorkshire Electricity brands.
The job cuts mean the closure of four of Innogy's seven customer service centres.
But they also bring 900 new jobs at two of the remaining sites, at Stoke and Peterlee.
Staff are being offered the option of transferring with their work on existing terms and conditions or accepting a redundancy package.
Unison are currently in talks with management.
Innogy's Chief Executive, Brian Count, said: "We will work closely with the unions and staff representatives to ensure that staff receive help and support during this difficult period of change."
He said the firm had to remain focused on how it delivers good service and value.
"We have moved from a background as a regional utility to a future as an efficient national service business offering a growing range of products.
"We need to deliver high quality service for customers and best cost performance for the business.
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Essential services like power are best provided and adminstered locally
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John Cafferty, Unison
"That means building on our customer service management expertise.
"It also means developing flexible systems and processes with the capability to offer customers a service personalised to their particular needs."
But Unison's senior regional officer in Yorkshire, John Cafferty, said cutting staff would not improve customer service.
"As with all such wholesale cuts of staff, customers will ultimately suffer," he said.
"We will strenuously argue that the company should live up to the commitment it made to the people of Yorkshire to maintain a significant presence in the region.
"Essential services like power are best provided and adminstered locally because they are more responsive to customers' needs and expectations.
"There is going to be a lot of hard bargaining on this and Unison will ensure our members' interests are at the top of the agenda."