Exhibit 99.1

Hannon Armstrong Announces Q1 2017 GAAP Earnings per Share of $0.14 and Core Earnings per Share of $0.32

ANNAPOLIS, Md., May 2, 2017 /PRNewswire/ — Hannon Armstrong Sustainable Infrastructure Capital, Inc. (“Hannon Armstrong,” “we,” “our” or the “Company”) (NYSE: HASI), a leading investor in sustainable infrastructure, including energy efficiency and renewable energy, today reported earnings as shown in the table below:

“Another strong quarter of putting capital to work in long-duration, high credit quality assets has taken our balance sheet over the $2 billion mark, creating long term recurring revenue streams,” said Hannon Armstrong President & CEO, Jeffrey Eckel. “Looking forward, we see a strong, diversified pipeline in each of our efficiency, wind and solar markets, as well as sustainable infrastructure.”

Highlights

Portfolio

Our Portfolio totaled approximately $1.9 billion as of March 31, 2017, and included approximately $0.6 billion of energy efficiency and other sustainable infrastructure investments and approximately $1.3 billion of renewable energy (wind and solar) transactions. The following is an analysis of our Portfolio by type of obligor and credit quality as of March 31, 2017:

First Quarter Financial Results

Revenue grew by over $3 million, or 16%, in the quarter as compared to last year. Increases were primarily driven by growth in the Portfolio to $1.9 billion as of March 31, 2017 from $1.4 billion as of March 31, 2016 offset by approximately $1 million of lower gain on sale and fee income. GAAP equity method income grew by approximately $4 million over the same quarter last year primarily due to new renewable energy equity investments.

The growth in both revenue and income from the equity method investments was offset by an approximately $3 million increase in interest expense for the three months ended March 31, 2017, as compared to the same period the previous year. This increase was primarily the result of higher average levels of debt outstanding in the first quarter of 2017 as compared to 2016.

Other expenses (compensation and benefits and general and administrative expenses) increased by $1 million for the three months ended March 31, 2017, as compared to the same period in 2016.

Core Earnings grew by $3 million over the same quarter last year as a result of the above factors.

A reconciliation of our GAAP Net Income to Core Earnings is included in this press release.

An analysis of our fixed-rate debt and leverage ratios is shown in the chart below.

“We added approximately $100 million of additional fixed rate debt and approximately $100 million of additional floating rate debt in the quarter, resulting in a slight decline in our fixed rate debt as a percentage due to an increase in total debt levels. Over the next several quarters, we expect to add additional fixed rate debt as we work towards our increased fixed rate debt target,” said Chief Financial Officer Brendan Herron.

Conference Call and Webcast Information

Hannon Armstrong will host an investor conference call today, May 2, 2017, at 5:00 pm eastern time. The conference call can be accessed live over the phone by dialing 1-800-211-3767, or for international callers, 1-719-457-2617. A replay will be available beginning two hours after the call and can be accessed by dialing 1-844-512-2921, or for international callers, 1-412-317-6671. The passcode for the live call and the replay is 9706420. The replay will be available until May 9, 2017.

A webcast of the conference call will also be available through the Investor Relations section of our website, at www.hannonarmstrong.com. A copy of this press release is also available on our website.

About Hannon Armstrong

Hannon Armstrong (NYSE: HASI) invests in the sustainable infrastructure markets, including energy efficiency and renewable energy. We focus on providing preferred or senior level capital to established sponsors and high credit quality obligors for assets that generate long-term, recurring, and predictable cash flows. We are based in Annapolis, Maryland.

Forward-Looking Statements

Some of the information contained in this press release is forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended that are subject to risks and uncertainties. For these statements, we claim the protections of the safe harbor for forward-looking statements contained in such Sections. These forward-looking statements include information about possible or assumed future results of our business, financial condition, liquidity, results of operations, plans and objectives. When used in this press release, the words such as “believe,” “expect,” “anticipate,” “estimate,” “plan,” “continue,” “intend,” “should,” “may,” “target,” or similar expressions, are intended to identify such forward-looking statements. Forward-looking statements are subject to significant risks and uncertainties. Investors are cautioned against placing undue reliance on such statements. Actual results may differ materially from those set forth in the forward-looking statements. Factors that could cause actual results to differ materially from those described in the forward-looking statements include those discussed under the caption “Risk Factors” included in our most recent Annual Report on Form 10-K filed with the U.S. Securities and Exchange Commission, as well as in other reports that we file with the SEC. Statements regarding the following subjects, among others, may be forward-looking:

Forward-looking statements are based on beliefs, assumptions and expectations as of the date of this press release. Any forward-looking statement speaks only as of the date on which it is made. New risks and uncertainties arise over time, and it is not possible for us to predict those events or how they may affect us. Except as required by law, we are not obligated to, and do not intend to, update or revise any forward-looking statements after the date of this earnings release, whether as a result of new information, future events or otherwise.

The risks included here are not exhaustive. Our 2016 Form 10-K or other regulatory filings may include additional factors that could adversely affect our business and financial performance. Moreover, we operate in a very competitive and rapidly changing environment. New risk factors emerge from time to time and it is not possible for management to predict all such risk factors, nor can it assess the impact of all such risk factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements. Given these risks and uncertainties, investors should not place undue reliance on forward-looking statements as a prediction of actual results.

Investor Relations

410-571-6189

investors@hannonarmstrong.com

EXPLANATORY NOTES

Non-GAAP Financial Measures

Core Earnings

We calculate Core Earnings as U.S. GAAP Net Income excluding non-cash equity compensation expense, non-cash provision for credit losses, amortization of intangibles, one-time acquisition related costs, if any, any non-cash tax charges and add back earnings attributable to our non-controlling interest. We also make an adjustment to account for our equity method investments in the renewable energy projects as described below. In the future, Core Earnings may also exclude one-time events pursuant to changes in U.S. GAAP and certain other non-cash charges as approved by a majority of our independent directors.

Certain of our equity method investments in the renewable energy projects are structured using typical partnership “flip” structures where we, along with other institutional investors, if any, receive a pre-negotiated preferred return consisting of priority distributions from the project cash flows, in many cases, along with tax attributes. Once this preferred return is achieved, the partnership flips and the renewable energy company, which operates the project, receives more of the cash flows through its equity interests with the institutional investors retaining an ongoing residual interest. The cash flows in renewable energy projects are often significantly different from the net income due to high levels of depreciation and other non-cash expense and the agreed upon allocation of cash flow in a project with these preferred returns may be different than the profit and loss allocation.

Under U.S. GAAP, we account for these investments utilizing the hypothetical liquidation at book value method (“HLBV”). Under this method, we recognize income or loss based on the change in the amount each partner would receive, typically based on the profit and loss allocation, if the assets were liquidated at book value, after adjusting for any distributions or contributions made during such quarter. Given the structure of the investments, we negotiated the purchase prices of our renewable energy investments based on our assessment of the expected cash flows we will receive from each investment discounted back to net present value based on a discount rate that represented an expected yield on the investment. This is similar to how we value the expected cash flows in financing receivables. In an attempt to treat these investments in a manner similar to our other investments and our initial valuation and because we are entitled to receive a preferred return of cash flows on our investments independent of how profits and losses are allocated, in calculating Core Earnings for the below periods, we include as Core Earnings the distributions received from these investments less an estimated return of capital. Generally, under this methodology, we reflect our initial capital investment as being amortized over the life of the project using a constant yield. The initial constant yield we selected is equal to the discount rates we determined when making our investment decisions. On at least a quarterly basis, we will review and, if appropriate, adjust the discount rates and the expected amortization for purposes of calculating Core Earnings in future periods, as necessary, to reflect changes in both actual cash flows received and our estimates of the future cash flows from the projects. Our allocation of profits and losses in certain of our equity investment transactions is projected to change in 2019, which is expected to result in an increase of the amount of HLBV profits or losses allocated to us.

For the three months ended March 31, 2017, we collected cash distributions from our equity investments of approximately $17 million. We recognized $4 million under GAAP for our equity investments and an additional $5 million for our Core Earnings adjustment based upon the constant yield methodology discussed above.

We believe that Core Earnings provides an additional measure of our core operating performance by eliminating the impact of certain non-cash expenses and facilitating a comparison of our financial results to those of other comparable REITs with fewer or no non-cash charges and comparison of our own operating results from period to period. Our management uses Core Earnings in this way. We believe that our investors also use Core Earnings, or a comparable supplemental performance measure, to evaluate and compare our performance to that of our peers, and as such, we believe that the disclosure of Core Earnings is useful to (and expected by) our investors.

However, Core Earnings does not represent cash generated from operating activities in accordance with U.S. GAAP and should not be considered as an alternative to net income (determined in accordance with U.S. GAAP), or an indication of our cash flow from operating activities (determined in accordance with U.S. GAAP), a measure of our liquidity, or an indication of funds available to fund our cash needs, including our ability to make cash distributions. In addition, our methodology for calculating Core Earnings may differ from the methodologies employed by other REITs to calculate the same or similar supplemental performance measures, and accordingly, our reported Core Earnings may not be comparable to the core earnings reported by other REITs.

Reconciliation of our GAAP Net Income to Core Earnings

We have calculated our Core Earnings and provided a reconciliation of our GAAP Net Income to Core Earnings for the three months ended March 31, 2017 and 2016 in the tables below:

The table below provides a reconciliation of the Other Core Adjustments:

The table below provides a reconciliation of the GAAP SG&A Expenses to Core SG&A Expenses:

HANNON ARMSTRONG SUSTAINABLE INFRASTRUCTURE CAPITAL, INC.

CONSOLIDATED STATEMENTS OF OPERATIONS

($ IN THOUSANDS, EXCEPT PER SHARE DATA)

(UNAUDITED)

HANNON ARMSTRONG SUSTAINABLE INFRASTRUCTURE CAPITAL, INC.

CONSOLIDATED BALANCE SHEET

($ IN THOUSANDS, EXCEPT PER SHARE DATA)