Clean Domestic Fuels Enhancement Act of 1991

Clean Domestic Fuels Enhancement Act of 1991 - Title I: Nonvehicular Oil and Natural Gas Provisions - Directs the Secretary of the Energy to expand research and demonstration programs regarding: (1) certain natural gas recovery and cofiring techniques; and (2) natural gas heating and cooling technologies. Authorizes appropriations for such programs and for Federal fuel cells research and development.

Amends the Renewable Energy and Energy Efficiency Technology Competitiveness Act of 1989 to direct the Secretary to: (1) solicit proposals for, and provide financial assistance to, joint ventures for fuel cell technology demonstration; and (2) conduct a program to promote the early commercial application of fuel cell systems for the production of electricity by demonstrating such systems in Federal buildings. Authorizes appropriations.

Authorizes specified aggregate appropriations for enhanced oil recovery research and development.

Directs the Secretary to implement a research, demonstration and commercialization program for high efficiency heat engines. Authorizes appropriations.

Directs the National Academy of Sciences to study and report to the Congress on factors affecting the domestic natural gas industry and its role in worldwide gas production.

Amends the Internal Revenue Code with respect to domestic oil and natural gas production. Allows independent producers to deduct from alternative minimum taxable income intangible drilling costs in the same amount as allowed in computing ordinary income. Allows the enhanced oil recovery credit to be offset against the minimum tax.

Title II: Alternative Fuels and Fuel Economy - Authorizes appropriations for research and development of natural gas vehicles. Directs the Secretary to implement a research and demonstration program on techniques related to improving natural gas and other alternative-fuel vehicle technology. Authorizes appropriations.

Amends the Internal Revenue Code to provide an investment tax credit for certain property, facilities, and vehicles related to clean-burning fuels.

Amends the Natural Gas Act to declare its provisions inapplicable to the sale or transportation of Vehicular Natural Gas (VNG) by an entity that is: (1) not otherwise a natural gas company; or (2) subject primarily to regulation by a State commission.

Declares that a company shall not be considered a gas utility company under the purview of the Public Utility Holding Company Act of 1935 solely because it owns or operates facilities used for retail distribution of vehicular natural gas.

Authorizes the Secretary to enter into coopertive agreements and joint ventures with governmental or regional transit authorities to demonstrate the feasibility of using alternative-fueled vehicles. Authorizes appropriations.

Sets forth a timetable for the attainment of certain percentages of alternative-fueled vehicles in Federal agency fleets and certain State government fleets.

Requires the Secretary of Labor to implement a technician training and certification program with respect to the installation of equipment which allows either dual-fuel vehicles, or alternative-fueled vehicles. Authorizes appropriations.

Directs the Secretary of Energy to implement a program and provide financial assistance for the development and commercialization of natural gas and other alternative fuels for use in passenger fleets, light-duty trucks, and heavy-duty trucks. Authorizes appropriations.

Directs the Administrator of the Environmental Protection Agency (EPA) to establish: (1) carbon dioxide emission target levels for specified motor vehicle model years; and (2) a fee and rebate program related to carbon dioxide emissions compliance standards.

Directs the Secretary of Energy to: (1) conduct a study to determine whether the use of alternative fuels in nonroad vehicles would contribute substantially to reduced reliance on imported energy sources; (2) institute certain programs to promote VNG; and (3) report to the Congress on selected aspects of Federal, State and local governmental policies concerning alternative-fueled vehicles.

Declares that the Clean Air Act shall not apply to vehicles converted to operate exclusively on alternative fuels until the effective date of certain EPA rules. Prohibits enforcement of any State anti-tampering rule with respect to any vehicle converted to operate exclusively on clean alternative fuels.