Jobs in manufacturing and export dominate the clean-energy sector and offer more opportunities and better pay for low- and middle-skilled workers than the national economy as a whole.

These are just two of many observations, conclusions, and recommendations made in Sizing the Clean Economy: a National and Regional Green Jobs Assessment, a new report from The Brookings Institution.

The report acknowledges difficulties in assessing the "clean economy." Primarily, there are no standard definitions and data to quantify what is occurring. Also, while good state-level information is being developed, "strikingly little" is known about the nature, size, and growth of the clean economy at the critical regional level. Also, there is no comprehensive national database on the spatial geography and subindustries of the clean economy.

To overcome some of these limitations, Brookings researchers worked with Battelle’s Technology Partnership Practice to develop, analyze, and comment on a detailed database of establishment-level employment statistics pertaining to a "sensibly defined" assemblage of clean economy industries in the United States and its metropolitan areas. According to Brookings, the resulting information, which covers the years 2003 to 2010 and every county in the nation, is the "first study of the U.S. clean economy to provide timely information that is both comprehensive enough in its scope and detailed enough in its categorization to inform national, state, and regional leaders on the dynamics of the U.S. low-carbon and environmental goods 'super-sector'."

Among other areas, the report focuses on the size of the clean economy. Researchers estimate that the sector employs 2.7 million workers. While modest, this number exceeds employment in the fossil fuel industry. Most clean economy jobs reside in mature segments such as manufacturing and provision of public services such as wastewater treatment and mass transit. A smaller portion is in newer segments that respond directly to energy-related challenges, such as solar photovoltaic, wind, fuel cell, smart grid, biofuel, and battery industries.

The report notes that in the survey years the clean economy grew at 3.4 percent annually, which lagged behind the national economy, which grew by 4.2 percent per year. "However, this measured growth heavily reflected the fact that many longer-standing companies in the clean economy — especially those involved in housing- and building-related segments — laid off large numbers of workers during the real estate crash of 2007 and 2008, while sectors unrelated to the clean economy (mainly health care) created many more new jobs nationally," the researchers assert.

Acknowledging also that the private sector must play the lead role in advancing the clean economy, the Brookings report places emphasizes the need for strong assistance by all levels of government. The federal government in particular must ensure the existence of well-structured markets, a favorable investment climate, and a rich stock of cutting-edge technology as well as strong regional cast. This would constitute a change in direction for the clean economy, which at present, is "almost certainly" hampered in growth by significant policy problems and uncertainties, the report states.

Among the specific recommendations the report directs at government are:

• Intensified green-procurement by all levels of government
• Placing a price on carbon and passing a national clean energy standard by the U.S. Congress
• Adoption or strengthening of their own clean energy standards and reforming electricity markets by states
• Expediting green building permitting and adopting innovative financing tools by localities