Commercialization of Alternative Energy Sources and Energy Conservation Technology Act of 1991

Commercialization of Alternative Energy Sources and Energy Conservation Technology Act of 1991 - Authorizes appropriations for FY 1991 through 2000 to implement certain provisions of the Electric and Hybrid Vehicle Research, Development, and Demonstration Act of 1976.

Amends the Internal Revenue Code (IRC) to extend from 1995 to the year 2000 the period of reduced tax rates on certain fuels containing alcohol.

Authorizes appropriations for FY 1991 through 2000 to implement: (1) certain provisions of the Biomass Energy and Alcohol Fuels Act of 1980; and (2) a loan guarantee program for the design and construction of coal liquefaction and oil shale facilities. Directs the Secretary of Energy to establish such a program.

Amends the IRC to provide a 20 percent energy investment credit for cogeneration equipment.

Amends the Energy Policy and Conservation Act to authorize appropriations for FY 1991 through 1993 for: (1) the State Plan program; (2) the energy conservation program for schools and hospitals; and (3) the weatherization assistance program.

Amends the National Energy Extension Service Act to authorize appropriations for FY 1991 through 1993.

Amends the Solar Energy and Energy Conservation Bank Act to repeal the termination of the Solar Energy and Energy Conservation Bank. Directs the Secretary of Housing and Urban Development to reestablish such Bank. Authorizes appropriations for the Bank's operation.

Amends the Harmonized Tariff Schedule of the United States to direct the Secretary of Energy (the Secretary) to monitor certain petroleum product imports and increase the duties on such imports according to prescribed guidelines.