This week at TreeHugger: Is there any technology more overdue than solar-powered air-conditioning? The internal combustion engine will someday be replaced by electric motors, but in the meantime, here are 5 technologies that are making it better. Day4 Energy announced a breakthrough with a solar panel that is 25% cheaper. And finally, there are an estimated 705 million CRT televisions in the USA, each of which contains toxic lead. We've been writing for many years about how solar-powered air conditioning is a big "duh!", and should be used more widely. After all, it's when you have lots of sun that you need A/C the most, and anything that helps smooth out peak demand on the electrical grid can help delay the construction of new polluting power plants. In the long run, the internal combustion engine (ICE) is on the way out and electric motors are on the way in, but ICEs have been around for so loooong that we should be careful about announcing their demise. They're going to stick around a while longer, and so it's very important to make them as efficient and clean as possible. Here are 5 fuel-saving technologies. Day4 Energy, a startup from Burnaby, British Columbia, Canada, has announced that it has created a process to cut costs for multicrystalline silicon solar panels by about 25%, from about $4 per watt to $3 per watt. The good news is that unlike other exotic solar technologies, these panels should be on the market soon. 23.9 million — That's the number of CRT televisions that will be thrown out in 2008, adding up to an estimated 711,029 tons of televisions. "Numbers for end-of-life TVs have been over 20 million per year since 2005, and are expected to go up to almost 25 million by 2010. Compare this to 10 years ago, when the numbers were closer to 12 million sets disposed of per year. " TreeHugger's EcoModo column appears every Tuesday on Gizmodo.