"This site is EPA’s premier site for accessing EPA publications, with more than 7,000 in stock and 35,000 digital titles, free of charge! EPA’s print publications are available through the National Service Center for Environmental Publications (NSCEP), and EPA’s digital publications are stored in the National Environmental Publications Internet Site (NEPIS) database! You can search and retrieve, download, print and/or order only EPA publications from this site. "
Some of these reports will be also listed in various government databases, like NTIS, NTRL, MarciveWeb DOCS, and also in WorldCat and Google. (NTIS does not provide links or access to the full text.)
"The DOE Green Energy portal is part of the DOE Open Government Plan, which furthers the Administration’s Open Government Initiative. DOE Green Energy contains both current and historical research, including bibliographic citations, technical reports and patent information on different types of renewable energy resources and energy conservation. Subject areas include but are not limited to solar, wind, bioenergy, hydroelectric, geothermal, tidal and wave power, and energy storage."
Besides NTIS, available via Engineering Village/Elsevier, Princeton University now has access to: NTRL (National Technical Reports Library)National Technical Information Service. Over 500,000 documents are available in full-text from departments such as Department of Energy, NASA, and the Environmental Protection Agency.
NTRS differs from NTIS in that it covers more years, mainly from 1960, but as far back as 1800. The database is updated daily and there is full text for about 25% of the reports.
Source: P.U.’s Engineering Library and Database Management Group