July 25 (Reuters) - U.S. electric and gas utility DTE

Energy Co ( DTE ) beat second-quarter profit estimates on

Thursday as electricity demand rose during the summer months.

Extreme heat and higher supply rates boosted earnings at the

company's electric unit by 56.7% to $279 million in the June-end

quarter.

Strength in the segment, which serves 2.3 million customers

in Southeast Michigan, helped combat weakness in the company's

natural gas and non-utility units.

"DTE's solid financial performance allows us to keep

investing to improve how we produce and deliver energy for

customers," CFO David Ruud said.

The company plans to invest more than $4 billion this year

to upgrade its electric and gas grids, and has already shelled

out more than $2 billion during the first half of the year.

DTE posted operating earnings of $1.43 per share in the

second quarter, above analysts' average estimate of $1.21,

according to LSEG data.

(Reporting by Mrinalika Roy in Bengaluru)