a2017q3irslidesfinal

Q3 2017 SUPPLEMENTAL INFORMATION OCTOBER 31, 2017

©2017 Ameresco, Inc. All rights reserved. 2 USE OF NON-GAAP FINANCIAL MEASURES Use of Non-GAAP Financial Measures This presentation includes references to adjusted EBITDA, adjusted cash from operations, non-GAAP net income and non-GAAP earnings per share, which are non-GAAP financial measures. For a description of these non-GAAP financial measures, including the reasons management uses these measures, please see the section in the Appendix in this presentation titled “Non-GAAP Financial Measures”. For a reconciliation of these non-GAAP financial measures to the most directly comparable financial measures prepared in accordance with GAAP, please see the tables in the Appendix to this presentation titled “GAAP to Non-GAAP Reconciliation.”

©2017 Ameresco, Inc. All rights reserved. 3 Q3 2017 HIGHLIGHTS $20.8M $8.5M +9% $204.7M +13% Adj. EBITDA Q3 EBITDA driven by greater project revenue EBITDA growth EBITDA up 9% y/y Revenue growth Revenue up 13% y/y Revenue Q3 Revenue driven by an increase in project revenues in our U.S. Federal group Net Income

©2017 Ameresco, Inc. All rights reserved. 4 BACKLOG PROVIDES VISIBILITY FOR 2-4 YEARS OF PROJECT REVENUE BACKLOG UP 15% Total project backlog up 15% y/y to $1.7B, another record high, providing approximately 2-4 years of visibility Contracted Backlog We added $147M in new contracts to our Contracted Backlog in Q3 $628M $1.1B Awarded Backlog We added $230M in new awards to our Awarded Backlog in Q3 $1.7B

©2017 Ameresco, Inc. All rights reserved. 5 SOURCES OF REVENUE Q3 2017 $20.6M $33.3M $150.8M Projects Energy efficiency and renewable energy projects Recurring Energy & incentive revenue from owned solar and renewable gas assets; plus recurring O&M from projects Other Services, software and integrated PV

©2017 Ameresco, Inc. All rights reserved. 6 55% OF PROFIT COMES FROM RECURRING LINE OF BUSINESS Q3 2017 16% Projects 74% Assets 9% O&M 7% Other 10% $204.7M REVENUE Projects 38% Assets 41% O&M 14% Other 7% $20.8M Adjusted EBITDA* 55% * Adjusted EBITDA percentage amounts exclude unallocated corporate expenses. RECURRING

©2017 Ameresco, Inc. All rights reserved. 7 ENERGY ASSET PORTFOLIO – 9/30/2017 183 MWe of Energy Assets. Renewable Gas is 122MWe, Solar is 61MW* Energy Assets 183 MWe 67% Renewable Gas 33% Solar In Development Construction 87 MWe 67% Solar 26% Renewable Gas 87 MWe in development & construction. Renewable Gas is 23 MWe, Solar is 58 MW*, Other is 6 MW. *Numbers may not sum due to rounding

©2017 Ameresco, Inc. All rights reserved. 8 ENERGY ASSET BALANCE SHEET – 9/30/2017 $82M out of the $357M energy assets on our balance sheet are still in development or construction. $146M out of the $202M of total debt on our balance sheet is debt associated with our energy assets. Energy Assets $357M $275M Operating $82M Development/ Construction Total Debt $202M $56M Corporate $146M Energy Debt

APPENDIX

©2017 Ameresco, Inc. All rights reserved. 10 ENERGY ASSET METRICS MWe $ MWe $ Energy Assets: In Operations 183.4 274,679$ 162.0 230,738$ In Construction 87.1 82,476$ 60.0 48,519$ Total Energy Assets 270.5 357,155$ 222.0 279,257$ 2017 2016 2017 2016 Energy Assets Performance: Revenues 18,525$ 17,980$ 51,801$ 48,551$ Adjusted EBITDA 11,589$ 9,585$ 29,691$ 25,079$ 2017 2016 Energy Assets Debt Financing: In Operations 121,557$ 100,619$ In Construction 23,991$ -$ Total Debt Financing 145,548$ 100,619$ Energy Asset Metrics (in thousands, except megawatt equivalents ("MWe")) As of September 30, Three Months Ended September 30, Nine Months Ended September 30, As of September 30, 2017 2016

©2017 Ameresco, Inc. All rights reserved. 11 GAAP TO NON-GAAP RECONCILIATION 2017 2016 2017 2016 (Unaudited) (Unaudited) (Unaudited) (Unaudited) Adjusted EBITDA: Net income attributable to common shareholders 8,493$ 5,715$ 13,680$ 8,763$ Impact of redeemable non-controlling interests 298 95 (673) (149) Plus: Income tax provision 3,881 1,865 4,296 2,872 Plus: Other expenses, net 1,668 2,268 5,232 4,961 Plus: Depreciation and amortization of intangible assets 6,563 6,290 18,835 18,232 Plus: Stock-based compensation 326 328 976 1,086 Plus: Restructuring and other charges 8 2,630 252 6,059 Plus: Non-Core Canada project loss (413) - (413) - Adjusted EBITDA 20,824$ 19,191$ 42,185$ 41,824$ Adjusted EBITDA margin 10.2% 10.6% 8.3% 8.8% Non-GAAP net income and EPS: Net income attributable to common shareholders 8,493$ 5,715$ 13,680$ 8,763$ Impact of redeemable non-controlling interests 298 95 (673) (149) Plus: Restructuring and other charges 8 2,630 252 6,059 Plus: Non-Core Canada project loss (413) - (413) - Plus: Income Tax effect of non-GAAP adjustments - (868) (44) (1,430) Non-GAAP net income 8,386$ 7,572$ 12,802$ 13,243$ Diluted net income per common share 0.19$ 0.12$ 0.30$ 0.19$ Effect of adjustments to net income (0.01)$ 0.04$ (0.02)$ 0.09$ Non-GAAP EPS 0.18$ 0.16$ 0.28$ 0.28$ Adjusted cash from operations: Cash flows from operating activities (39,386)$ (7,654)$ (90,756)$ (47,376)$ Plus: proceeds from Federal ESPC projects 48,304 26,316 122,340 65,075 Adjusted cash from operations 8,918$ 18,662$ 31,584$ 17,699$ Three Months Ended September 30, Nine Months Ended September 30,

©2017 Ameresco, Inc. All rights reserved. 12 PERFORMANCE BY SEGMENT Revenues Adjusted EBITDA Revenues Adjusted EBITDA September 30, 2017 U.S. Regions 78,185$ 4,523$ 180,770$ 4,577$ U.S. Federal 63,873 9,673 170,903 25,900 Canada 14,719 1,205 33,211 2,426 Small-Scale Infrastructure 27,295 10,404 64,889 25,192 All Other 20,672 1,507 56,246 3,771 Unallocated corporate activity - (6,488) - (19,681) Total Consolidated 204,744$ 20,824$ 506,019$ 42,185$ September 30, 2016 U.S. Regions 83,652$ 8,046$ 195,856$ 13,156$ U.S. Federal 46,498 6,337 128,266 18,961 Canada 12,018 1,004 40,023 2,164 Small-Scale Infrastructure 21,790 10,730 61,543 25,500 All Other 16,640 444 51,314 1,231 Unallocated corporate activity - (7,370) - (19,188) Total Consolidated 180,598$ 19,191$ 477,002$ 41,824$ Three Months Ended Nine Months Ended Performance by Segment (in thousands):

©2017 Ameresco, Inc. All rights reserved. 13 LINE OF BUSINESS REVENUE – THREE MONTHS U.S. Regions U.S. Federal Canada Small-Scale Infrastructure All Other Total Consolidated 2017 Revenues: Project 72,720$ 53,818$ 11,959$ 9,526$ 2,745$ 150,768$ Energy Assets — 1,152 1,013 16,080 280 18,525 O&M 4,251 8,903 — 1,645 — 14,799 Integrated-PV — — — — 10,686 10,686 Other Services 1,214 — 1,747 44 6,961 9,966 Total Revenues 78,185$ 63,873$ 14,719$ 27,295$ 20,672$ 204,744$ 2016 Revenues: Project 79,271$ 35,329$ 9,531$ 4,434$ 2,824$ 131,389$ Energy Assets — 1,102 924 15,650 304 17,980 O&M 4,306 10,067 134 1,605 — 16,112 Integrated-PV — — — — 7,119 7,119 Other Services 75 — 1,429 101 6,393 7,998 Total Revenues 83,652$ 46,498$ 12,018$ 21,790$ 16,640$ 180,598$ Line of Business Revenues By Segment for the three months ended September 30 (in thousands):

©2017 Ameresco, Inc. All rights reserved. 14 LINE OF BUSINESS REVENUE – NINE MONTHS U.S. Regions U.S. Federal Canada Small-Scale Infrastructure All Other Total Consolidated 2017 Revenues: Project 165,217$ 139,814$ 26,124$ 13,806$ 4,345$ 349,306$ Energy Assets - 2,688 2,316 45,952 845 51,801 O&M 12,762 27,814 - 4,784 - 45,360 Integrated-PV 2,791 - - - 29,187 31,978 Other Services - 587 4,771 347 21,869 27,574 Total Revenues 180,770$ 170,903$ 33,211$ 64,889$ 56,246$ 506,019$ 2016 Revenues: Project 182,435$ 94,596$ 32,913$ 14,542$ 5,590$ 330,076$ Energy Assets - 3,008 2,041 42,586 916 48,551 O&M 12,875 30,662 449 3,661 - 47,647 Integrated-PV - - - - 21,605 21,605 Other Services 546 - 4,620 754 23,203 29,123 Total Revenues 195,856$ 128,266$ 40,023$ 61,543$ 51,314$ 477,002$ Line of Business Revenues By Segment for the nine months ended September 30 (in thousands):

Your Trusted Sustainability Partner ameresco.com