Exhibit 99.1

CMS ENERGY ANNOUNCES THIRD QUARTER EARNINGS OF $0.53 PER SHARE; RAISES LOW END OF ADJUSTED EARNINGS GUIDANCE TO $1.87 TO $1.89 PER SHARE

JACKSON, Mich., October 29, 2015 — CMS Energy announced today reported net income of $148 million, or $0.53 per share, for the third quarter of 2015 and $417 million, or $1.51 per share, for the first nine months of the year. Adjusted earnings per share for the third quarter and first nine months were the same as reported amounts.

CMS Energy raised the low end of its 2015 adjusted earnings per share guidance by a penny from $1.86-$1.89 to $1.87-$1.89, consistent with performance at the high end of its long-term plan to grow earnings per share at 5% to 7%.

For the first nine months of 2015, CMS Energy achieved high marks for customer satisfaction as it focused on reinvestments in its electric and natural gas operations, affordability and transitioning to cleaner energy sources.

“We are transitioning to a cleaner energy portfolio, which benefits our customers and Michigan as it develops a compliance strategy for the federal Clean Power Plan,” said John Russell, president and chief executive officer for CMS Energy and its principal subsidiary, Consumers Energy.

“We’ll be buying competitively priced renewable energy from a new 100 megawatt wind park in Huron County, allowing us to exceed the renewable energy requirements in Michigan’s current law. We’re building two new community solar gardens, the largest program in the state, in collaboration with Grand Valley State University and Western Michigan University,” said Russell. “We’re also adding the clean-burning Jackson Gas Plant to our generating portfolio in the next few months as we retire our seven oldest coal plants by the second quarter of 2016 in April.”

The Company’s work to lower industrial electric rates and keep residential bills low is helping to stimulate job growth and economic development in Michigan. In part due to the Company’s efforts, Chilean-based Arauco announced during the quarter a new particle board manufacturing facility in Grayling, creating 250 jobs. Separately, General Motors announced upgrade and expansion plans for its manufacturing facilities in Flint and Grand Rapids, adding 300 jobs.

These expansions are in addition to recent announcements of new facilities in Michigan by Italian-based Brembo, and Dicastal, a Chinese company. Meanwhile, Michigan’s

economy continues to make progress as the state’s unemployment rate fell below the U.S. average for the first time since 2000.

On the natural gas side of the business, Consumers Energy reduced fuel costs to the lowest level since 2001, due to abundant supplies and the Company’s investment of more than $400 million over the last five years in its gas delivery and storage system. The lower costs are driving a 15 percent expected reduction this winter in heating costs for an average residential customer, along with savings for business customers.

The Company expects to double investments in its gas business over the next decade. Those investments include expansion of its pipeline and storage system, adding new customers who formerly used higher-cost propane, and strengthening pipeline integrity in a multi-year line replacement program.

The Company maintained its focus on sustainability as Consumers Energy was ranked as a “Top 2015 Environmental Champion” by MSI Cogent Reports in the Midwest Combination category.

CMS Energy (NYSE: CMS) is a Michigan-based company that has an electric and natural gas utility, Consumers Energy, as its primary business and also owns and operates independent power generation businesses.

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CMS Energy will hold a webcast to discuss its 2015 third quarter results and provide a business and financial outlook on October 29 at 9:00 AM (EDT).  To participate in the Webcast, go to CMS Energy’s home page (www.cmsenergy.com) and select “Investor Meeting.”

Investors and others should note that CMS Energy routinely posts important information on its website and considers the Investor Relations section, www.cmsenergy.com/investor-relations, a channel of distribution.

This news release contains non-Generally Accepted Accounting Principles (non-GAAP) measures, such as adjusted earnings. Management views adjusted earnings as a key measure of the company’s present operating financial performance, unaffected by discontinued operations, asset sales, impairments, regulatory items from prior years, or other items detailed in the attached summary financial statements. These items have the potential to impact, favorably or unfavorably, the company’s reported earnings.

This news release contains “forward-looking statements.” The forward-looking statements are subject to risks and uncertainties that could cause CMS Energy’s and Consumers Energy’s results to differ materially. All forward-looking statements should be considered in the context of the risk and other factors detailed from time to time in CMS Energy’s and Consumers Energy’s Securities and Exchange Commission filings.

For more information on CMS Energy, please visit our web site at: www.cmsenergy.com

Media Contacts: Dan Bishop, 517/788-2395 or Brian Wheeler, 517/788-2394

Investment Analyst Contact: CMS Energy Investor Relations, 517/788-2590

CMS Energy Corporation

SUMMARIZED CONSOLIDATED STATEMENTS OF INCOME

(In Millions, Except Per Share Amounts)

1

CMS Energy Corporation

SUMMARIZED CONSOLIDATED BALANCE SHEETS

(In Millions)

(*) Current and long-term

CMS Energy Corporation

SUMMARIZED STATEMENTS OF CASH FLOWS

(In Millions)

2

CMS Energy Corporation

SUMMARY OF CONSOLIDATED EARNINGS

Reconciliations of GAAP Net Income to Non-GAAP Adjusted Net Income

(In Millions, Except Per Share Amounts)

* Less than $500 thousand or $0.01 per share.

3