Of our picks for stocks that can benefit from the environmental movement, one became a takeover target and most posted impressive returns. By Andrew Tanzer, Senior Associate Editor December 17, 2007 The Kiplinger Green 25 continues to post high-energy results. Our index of 25 green stocks is up 17% from August 20, 2007, when we set the index, through the middle of the day on December 17. Standard & Poor's 500-stock index eked out a 1% gain during the same stretch of time. RELATED LINKS The Kiplinger Green 25 The Kiplinger 25 Best Funds An Under-the-Radar Overseas Fund And now we have the first takeover of an index component. Ingersoll-Rand has announced a $10 billion acquisition of Trane (symbol TT), which until late November was known as American Standard (ASD). Ingersoll will pay Trane shareholders $36.50 a share in cash and 0.23 of each of its shares for each share of Trane. The announcement propelled Trane's stock price up 21.8% on December 17, to close at $45.31. Ingersoll covets Trane's heating, ventilation and air-conditioning business. Trane is particularly strong in energy-efficient systems, which will benefit as high energy prices encourage building owners to replace outdated units. Advertisement Indeed, the push for cheaper, cleaner and renewable sources of energy can be seen in the performance of the Green 25. The three best performers, Suntech Power Holdings (STP), SunPower (SPWR) and MEMC Electronics Materials (WFR), respectively up 124%, 93% and 56%, are all cashing in on strong demand for solar power. The returns of the power-generator builders -- McDermott International (MDR), Shaw Group (SGR) and ABB (ABB) -- have also been electrifying, up 46%, 24% and 22%. Ormat Technologies (ORA), which specializes in running geothermal power plants, has gained 19%, and trash-to-energy Covanta (CVA) is up 24%. The more mainstream utilities of Exelon (EXC) and FPL Group (FPL), both of which rely heavily on nuclear energy, are up 18% and 16%, respectively. The biggest losers so far in the Green 25 are Tenneco (TEN), down 24%, and Trinity Industries (TRN), off 20%. We liked Tenneco for its position in fuel-efficient emissions equipment for diesel engines, but for now the company is weighed down by the auto slump. Trinity makes railcars that are used to haul, among other things, ethanol. Ethanol volumes have zoomed, but it's been tough to make profits in the industry.