On Monday, Cassandra Vinograd at the WSJ’s Energy Roundup told us about Merrill Lynch’s new Energy Efficiency Index. You can read more about the index here. As our regular readers know, we are big believers in energy efficiency as an investment thesis, and think significant opportunities will materialize in this space in the coming years. On Tuesday, Todd Woody at Business 2.0 wondered whether a small Norwegian company was about to reverse 100 years of automotive history. Could we be looking at the next wonder-boy of the clean automotive movement? On Wednesday, Dan Lewis at AEI shared a few post-mortem thoughts on Biofuels Corp with us. As the cleantech industry matures and a group of winners emerges from the pack, expect to see the body count go up. On Thursday, Biopact told us about an interesting jatropha biodiesel deal in Mozambique. Jatropha is currently generating a lot of buzz as a potential source of feedstock for large-scale biodiesel production. Many emerging markets, for their part, are looking hard at biofuels as a potentially-lucrative trade to get involved in. Time to start paying attention to jatropha players in the South? On Thursday, Environmental Finance reported on E. ON’s (NYSE:EON) latest alternative energy move. Besides the fact that $4.1 billion over 2.5 years is a significant amount of money, the interesting thing here is that this project is one of the first major off-shore wind farms in the world. Off-shore wind offers many promises, and is an area worth keeping an eye on. On Saturday, Sebastian Blanco at AutoBlog Green told us about Paris Hilton’s latest attempt at appearing environmentally-conscious. This admittedly doesn’t have much to do with cleantech investing, but I got a good laugh out of it. The Week in Cleantech is a weekly roundup of our favorite cleantech and alt energy blog posts and stories from across the web. If you know of a good piece that you think should be included here, don’t hesitate to let us know!