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| x                                                 | QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES EXCHANGE ACT OF 1934  |
|---------------------------------------------------|-------------------------------------------------------------------------------------------|
|                                              |                                                                                      |
| For the quarterly period ended September 30, 2010 |
|                                              |
| or                                                |
|                                              |                                                                                      |
| o                                                 | TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES EXCHANGE ACT OF 1934 |

| Delaware                                                      |   | 22-3324608                           |
|---------------------------------------------------------------|--------|--------------------------------------|
| (State or Other Jurisdictionof Incorporation or Organization) |   | (I.R.S. Employer Identification No.) |

| 1314 King Street, Wilmington, DE         |   | 19801      |
|------------------------------------------|--------|------------|
| (Address of Principal Executive Offices) |   | (Zip Code) |

|   | (302) 888-7444                                             |   |
|--------|------------------------------------------------------------|--------|
|   | (Registrant’s Telephone Number, Including Area Code) |   |

| Not Applicable                                                                     |
|------------------------------------------------------------------------------------|
| (Former name, former address and former fiscal year, if changed since last report) |

| Large accelerated filer  o | Accelerated filer  o | Non-accelerated filer  o            | Smaller reporting company  þ |
|---------------------------------|--------------------------------|-----------------------------------------------|---------------------------------------------|
|                            |                           | (Do not check if a smaller reporting company) |

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TABLE OF CONTENTS

|                                                          |                                                                                        |   |
|---------------------------------------------------------------|---------------------------------------------------------------------------------------------|--------|
| PART I.          | FINANCIAL INFORMATION                                                                       | Page   |
|                                                          |                                                                                        |   |
| Item 1.                                                       | Financial Statements                                                                        | 1      |
|                                                          |                                                                                        |   |
| Item 2.                                                       | Management’s Discussion and Analysis of Financial Condition and Results of Operations | 7      |
|                                                          |                                                                                        |   |
| Item 3.                                                       | Quantitative and Qualitative Disclosures About Market Risk                                  | 9      |
|                                                          |                                                                                        |   |
| Item 4.                                                       | Controls and Procedures                                                                     | 9      |
|                                                          |                                                                                        |   |
| PART II.                                                      | OTHER INFORMATION                                                                           |   |
|                                                          |                                                                                        |   |
| Item 1.                                                       | Legal Proceedings                                                                           | 9      |
|                                                          |                                                                                        |   |
| Item 1A.                                                      | Risk Factors                                                                                | 9      |
|                                                          |                                                                                        |   |
| Item 2.                                                       | Unregistered Sales of Equity Securities and Use of Proceeds                                 | 9      |
|                                                          |                                                                                        |   |
| Item 3.                                                       | Defaults Upon Senior Securities                                                             | 9      |
|                                                          |                                                                                        |   |
| Item 4.                                                       | Reserved                                                                                    | 9      |
|                                                          |                                                                                        |   |
| Item 5.                                                       | Other Information                                                                           | 9      |
|                                                          |                                                                                        |   |
| Item 6.                                                       | Exhibits                                                                                    | 10     |
|                                                          |                                                                                        |   |
| SIGNATURE                                                     | 11                                                                                          |

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ITEM 1. FINANCIAL STATEMENTS

| RIDGEWOOD ELECTRIC POWER TRUST IV                                                            |   |
|----------------------------------------------------------------------------------------------|--------|
| CONDENSED CONSOLIDATED BALANCE SHEETS                                                        |   |
| (in thousands, except share data)                                                            |   |
|                                                                                         |   |   |   |   |   |   |
|                                                                                         |   | September 30, |   |   | December 31, |   |
|                                                                                         |   | 2010 |   |   | 2009 |   |
|                                                                                         |   | (unaudited) |   |   |   |   |
| ASSETS                                                                                       |   |   |   |   |   |   |
| Current assets:                                                                              |   |   |   |   |   |   |
| Cash and cash equivalents                                                                    |   | $ | 7,146 |   |   | $ | 7,804 |   |
| Due from affiliates                                                                          |   |   | 684 |   |   |   | 606 |   |
| Prepaid expenses and other current assets                                                    |   |   | 26 |   |   |   | 24 |   |
|             Total current assets |   |   | 7,856 |   |   |   | 8,434 |   |
| Investment                                                                                   |   |   | 549 |   |   |   | 2,001 |   |
|                                                                                         |   |   |   |   |   |   |   |   |
| Total assets                                                                                 |   | $ | 8,405 |   |   | $ | 10,435 |   |
|                                                                                         |   |   |   |   |   |   |   |   |
| LIABILITIES AND SHAREHOLDERS’ EQUITY (DEFICIT)                                         |   |   |   |   |   |   |   |   |
| Current liabilities:                                                                         |   |   |   |   |   |   |   |   |
| Accounts payable and accrued expenses                                                        |   | $ | 2 |   |   | $ | 98 |   |
| Due to affiliates                                                                            |   |   | 69 |   |   |   | - |   |
|            Total liabilities          |   |   | 71 |   |   |   | 98 |   |
|                                                                                         |   |   |   |   |   |   |   |   |
| Commitments and contingencies                                                                |   |   |   |   |   |   |   |   |
|                                                                                         |   |   |   |   |   |   |   |   |
| Shareholders’ equity (deficit):                                                        |   |   |   |   |   |   |   |   |
| Shareholders’ equity (476.8 Investor Shares                                            |   |   |   |   |   |   |   |   |
|     issued and outstanding)                                              |   |   | 8,519 |   |   |   | 10,502 |   |
| Managing Shareholder’s accumulated deficit                                             |   |   |   |   |   |   |   |   |
|    (1 management share issued and outstanding)                                |   |   | (185 | ) |   |   | (165 | ) |
| Total shareholders’ equity                                                             |   |   | 8,334 |   |   |   | 10,337 |   |
|                                                                                         |   |   |   |   |   |   |   |   |
| Total liabilities and shareholders’ equity                                             |   | $ | 8,405 |   |   | $ | 10,435 |   |

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| RIDGEWOOD ELECTRIC POWER TRUST IV                |   |
|--------------------------------------------------|--------|
| CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS  |   |
| (unaudited, in thousands, except per share data) |   |
|                                             |   |   |   |   |   |   |   |   |   |   |   |   |
|                                             |   | Nine Months Ended September 30, |   |   | Three Months Ended September 30, |   |
|                                             |   | 2010 |   |   | 2009 |   |   | 2010 |   |   | 2009 |   |
|                                             |   |   |   |   |   |   |   |   |   |   |   |   |
| Operating expenses:                              |   |   |   |   |   |   |   |   |   |   |   |   |
| General and administrative expenses              |   | $ | 329 |   |   | $ | 526 |   |   | $ | 118 |   |   | $ | 83 |   |
| Management fee to Managing Shareholder           |   |   | 233 |   |   |   | 491 |   |   |   | 78 |   |   |   | 163 |   |
| Total operating expenses                         |   |   | 562 |   |   |   | 1,017 |   |   |   | 196 |   |   |   | 246 |   |
|                                             |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Loss from operations                             |   |   | (562 | ) |   |   | (1,017 | ) |   |   | (196 | ) |   |   | (246 | ) |
|                                             |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Other (expense) income:                          |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Equity in loss of RILG                           |   |   | (1,451 | ) |   |   | (2,137 | ) |   |   | (371 | ) |   |   | (1,033 | ) |
| Equity in loss of Maine Hydro                    |   |   | - |   |   |   | (231 | ) |   |   | - |   |   |   | (139 | ) |
| Other income (expense), net                      |   |   | 10 |   |   |   | 367 |   |   |   | 4 |   |   |   | (8 | ) |
| Total other expense, net                         |   |   | (1,441 | ) |   |   | (2,001 | ) |   |   | (367 | ) |   |   | (1,180 | ) |
|                                             |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Net loss                                         |   | $ | (2,003 | ) |   | $ | (3,018 | ) |   | $ | (563 | ) |   | $ | (1,426 | ) |
|                                             |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                                             |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Managing Shareholder – Net loss            |   | $ | (20 | ) |   | $ | (30 | ) |   | $ | (6 | ) |   | $ | (14 | ) |
| Shareholders – Net loss                    |   |   | (1,983 | ) |   |   | (2,988 | ) |   |   | (557 | ) |   |   | (1,412 | ) |
| Net loss per Investor Share                      |   |   | (4,159 | ) |   |   | (6,267 | ) |   |   | (1,169 | ) |   |   | (2,962 | ) |
| Distributions per Investor Share                 |   |   | - |   |   |   | 15,000 |   |   |   | - |   |   |   | - |   |

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| RIDGEWOOD ELECTRIC POWER TRUST IV                   |   |
|-----------------------------------------------------|--------|
| CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS     |   |
| (unaudited, in thousands)                           |   |
|                                                |   |   |   |   |   |   |
|                                                |   | Nine Months Ended September 30, |   |
|                                                |   | 2010 |   |   | 2009 |   |
| Cash flows from operating activities:               |   |   |   |   |   |   |
| Net cash (used in) provided by operating activities |   | $ | (658 | ) |   | $ | 3,207 |   |
|                                                |   |   |   |   |   |   |   |   |
| Cash flows from financing activities:               |   |   |   |   |   |   |   |   |
| Cash distributions to shareholders                  |   |   | - |   |   |   | (7,224 | ) |
|                                                |   |   |   |   |   |   |   |   |
| Net decrease in cash and cash equivalents           |   |   | (658 | ) |   |   | (4,017 | ) |
| Cash and cash equivalents, beginning of year        |   |   | 7,804 |   |   |   | 11,683 |   |
|                                                |   |   |   |   |   |   |   |   |
| Cash and cash equivalents, end of period            |   | $ | 7,146 |   |   | $ | 7,666 |   |

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|                        |   | Nine Months Ended September 30, |   |   | Three Months Ended September 30, |   |
|-----------------------------|--------|---------------------------------|--------|--------|----------------------------------|--------|
|                        |   | 2010                            |   |   | 2009                             |   |   | 2010 |   |   | 2009 |   |
|                        |   |                            |   |   |                             |   |   |   |   |   |   |   |
| Revenues                    |   | $                               | 8,229  |   |                             | $      | 10,401 |   |   | $ | 3,070 |   |   | $ | 3,429 |   |
|                        |   |                            |   |   |                             |   |   |   |   |   |   |   |   |   |   |   |
| Gross (loss ) profit        |   |                            | (722   | )      |                             |   | (2,112 | ) |   |   | 743 |   |   |   | (756 | ) |
|                        |   |                            |   |   |                             |   |   |   |   |   |   |   |   |   |   |   |
| Loss from operations        |   |                            | (4,119 | )      |                             |   | (6,059 | ) |   |   | (1,053 | ) |   |   | (2,930 | ) |
|                        |   |                            |   |   |                             |   |   |   |   |   |   |   |   |   |   |   |
| Net loss                    |   |                            | (4,119 | )      |                             |   | (6,063 | ) |   |   | (1,054 | ) |   |   | (2,931 | ) |
|                        |   |                            |   |   |                             |   |   |   |   |   |   |   |   |   |   |   |
| Trust share of loss in RILG |   |                            | (1,451 | )      |                             |   | (2,137 | ) |   |   | (371 | ) |   |   | (1,033 | ) |

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|                               |   | Nine Months Ended  |   |   | Three Months Ended |   |
|------------------------------------|--------|--------------------|--------|--------|--------------------|--------|
|                               |   | September 30, 2009 |   |   | September 30, 2009 |   |
|                               |   |               |   |   |               |   |
| Revenues                           |   | $                  | 2,045  |   |               | $      | 470 |   |
|                               |   |               |   |   |               |   |   |   |
| Gross profit (loss)                |   |               | 336    |   |               |   | (166 | ) |
|                               |   |               |   |   |               |   |   |   |
| Loss from operations               |   |               | (462   | )      |               |   | (278 | ) |
|                               |   |               |   |   |               |   |   |   |
| Net loss                           |   |               | (462   | )      |               |   | (278 | ) |
|                               |   |               |   |   |               |   |   |   |
| Trust share of loss in Maine Hydro |   |               | (231   | )      |               |   | (139 | ) |

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ITEM 2.  MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

|   | · | the timing and terms of any sale of the Trust’s assets, |
|--------|--------|---------------------------------------------------------------|

|   | · | the outcome of the matters described in Part I, Item 1, Note 7. “Commitments and Contingencies” of this report, |
|--------|--------|-----------------------------------------------------------------------------------------------------------------------------|

|   | · | whether the landfill gas-fired electric generating project will be able to obtain financing required to expand and make planned changes to its operations, |
|--------|--------|------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | · | changes in political and economic conditions, or federal or state regulatory structures, |
|--------|--------|------------------------------------------------------------------------------------------|

|   | · | government mandates, including those associated with climate change, |
|--------|--------|----------------------------------------------------------------------|

|   | · | the ability of customers to pay for energy received, |
|--------|--------|------------------------------------------------------|

|   | · | supplies and prices of fuels, |
|--------|--------|-------------------------------|

|   | · | operational status of generating plants, including mechanical breakdowns, and |
|--------|--------|-------------------------------------------------------------------------------|

|   | · | volatility in the price for electric energy, natural gas or renewable energy. |
|--------|--------|-------------------------------------------------------------------------------|

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|   | - | an increase in legal fees and development expenses for planned plant expansion and |
|--------|---|------------------------------------------------------------------------------------|

|   | - | a decrease in power generation revenue in the 2010 period as a result of the termination of a long-term power contract in January 2010 and electric generation being sold at a lower aggregate price in the open market until September 2010. |
|--------|---|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

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ITEM 3.              QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

ITEM 4.              CONTROLS AND PROCEDURES

ITEM 1.              LEGAL PROCEEDINGS

ITEM 1A.           RISK FACTORS

ITEM 2.              UNREGISTERED SALES OF EQUITY SECURITIES AND USE OF PROCEEDS

ITEM 3.              DEFAULTS UPON SENIOR SECURITIES

ITEM 4.              RESERVED

ITEM 5.              OTHER INFORMATION

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ITEM 6.              EXHIBITS

| Exhibit No. |   | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|-------------|--------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|        |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| 2.1         |   | Interest Purchase Agreement dated as of July 26, 2010 by and among Ridgewood Electric Power Trust I, Ridgewood Olinda LLC, Ridgewood Electric Power Trust III, Ridgewood Electric Power Trust IV, Ridgewood Power B Fund/Providence Expansion, Ridgewood Renewable Power LLC, solely in its capacity as Sellers’ Representative, Brea Parent 2007, LLC, Rhode Island LFG Genco, LLC, Ridgewood Renewable Power LLC, Ridgewood Power Management LLC and MIP II BioPower LLC (incorporated by reference to Exhibit 2.1 to the Current Report on Form 8-K filed by the Registrant with the SEC on July 29, 2010). |
|        |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| 10.1        | *      | First Amendment to the Amended and Restated Site Lease and Landfill Gas Delivery Agreement dated as of July 20, 2009, by and among Rhode Island Resource Recovery Corporation, Ridgewood Gas Services LLC and Rhode Island LFG Genco, LLC (incorporated by reference to Exhibit 10.1 to the Quarterly Report on Form 10-Q filed by Ridgewood Electric Power Trust III with the SEC on November 15, 2010).                                                                                                                                                                                                                 |
|        |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| 10.2        | *      | Second Amendment to the Amended and Restated Site Lease and Landfill Gas Delivery Agreement dated as of August 13, 2010, by and among Rhode Island Resource Recovery Corporation, Ridgewood Gas Services LLC and Rhode Island LFG Genco, LLC (incorporated by reference to Exhibit 10.2 to the Quarterly Report on Form 10-Q filed by Ridgewood Electric Power Trust III with the SEC on November 15, 2010).                                                                                                                                                                                                              |
|        |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| 31.1        | *      | Certification of Randall D. Holmes, Chief Executive Officer of the Registrant, pursuant to Securities Exchange Act Rule 13a-14(a).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|        |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| 31.2        | *      | Certification of Jeffrey H. Strasberg, Chief Financial Officer of the Registrant, pursuant to Securities Exchange Act Rule 13a-14(a).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|        |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| 32          | *      | Certifications pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of The Sarbanes-Oxley Act of 2002, signed by Randall D. Holmes, Chief Executive Officer of the Registrant, and Jeffrey H. Strasberg, Chief Financial Officer of the Registrant.                                                                                                                                                                                                                                                                                                                                                     |

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SIGNATURES

|                    | RIDGEWOOD ELECTRIC POWER TRUST IV |
|-------------------------|-----------------------------------|
|                    |                              |   |
|                    |                              |   |
| Date: November 15, 2010 | By:                               | /s/  Randall D. Holmes |
|                    |                              | Randall D. Holmes |
|                    |                              | President and Chief Executive Officer |
|                    |                              | (Principal Executive Officer) |
|                    |                              |   |
|                    |                              |   |
|                    |                              |   |
| Date: November 15, 2010 | By:                               | /s/  Jeffrey H. Strasberg |
|                    |                              | Jeffrey H. Strasberg |
|                    |                              | Executive Vice President and Chief Financial Officer |
|                    |                              | (Principal Financial and Accounting Officer) |

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