RIO DE JANEIRO -- Secretary of State Hillary Rodham Clinton swooped into Brazil this morning to announce upward of $2 billion in funding for clean energy projects in Africa as well as an agreement between three U.S. agencies to spur private investment in the continent.

Clinton said the State Department, the Overseas Private Investment Corp. (OPIC) and the U.S. Trade and Development Agency would seek to seed the money in clean energy projects as a way to lure private investment in equally big numbers to a continent where only one in four households has electricity.

In a brisk, 10-minute address, Clinton said the funding mechanism would operate much as OPIC does in Asia, using loan guarantees, risk insurance and other financial tools to attract more private-sector dollars.

"Too many people in too many places cannot get access to electricity" in Africa, she said.

The idea is to get clean energy projects past the initial planning phase and expensive environmental impact statements as a way to provide security to private-sector investors who have long been unwilling to plant their money in Africa.

"Why does this gap exist?" Clinton asked, in reference to much of the continent lacking reliable power. "It is because investors in this space often see obstacles and risk that stop them investing in clean energy in Africa. Too few projects even make it past the initial planning phase."

The $2 billion would apparently come from funds that have already been appropriated for foreign development assistance, in addition to $20 million that would catalyze grant financing for project developers. A State Department release on the initiative said the $20 million would require congressional approval.

The announcement comes on the heels of a sweeping new U.S-Africa strategy the Obama administration unveiled last week, aiming to boost trade, security and diplomacy across the continent. Still, some fear the money will be used to spur not only clean energy but also massive hydropower projects or biofuels that could mean deforestation to clear fields for crops.

Others have questioned whether OPIC -- which is focused on investment and job creation overseas -- is the right agency to pursue low-carbon technologies. Clinton and Todd Stern, the U.S. special envoy on climate change, answered both issues during their address today.

Clinton did refer to vast sources of "hydropower in the heart of the continent" during her remarks, as well as "vast geothermal in the East" and "bright sunlight everywhere." Stern, for his part, defended OPIC as the right agency to coordinate the funds because it has a track record of attracting investment.

"OPIC is not a talk shop," Stern said. "It is an action shop."

Clinton added that Bank of America has pledged $50 billion in clean energy investments over the next decade and urged other businesses to follow suit.

"Over the next 20 years, electric power infrastructure will be a $10 trillion industry," she said. "Let's make it clean."

Earlier this month, the OPIC board approved $175 million in financing for two renewable energy funds. One, TPG Alternative & Renewable Technologies Partners, will invest in companies matching the best renewable technologies from the United States and Europe to markets in Latin America and Southeast Asia. The board also approved $50 million for an Africa Growth Fund to invest in environment-related energy infrastructure across sub-Saharan Africa.