It&rsquo;s a 98-degree August day. Air conditioners along Prospect Avenue near 42nd Street are running at full bore.</p><p>Suddenly the whirring stops, all at once, without anyone touching a thermostat.</p><p>Someone miles away at Kansas City Power & Light decided residents on this block could stand a slightly warmer home for a while to save energy. </p><p>That&rsquo;s the future, and it&rsquo;s called the smart grid. Someday it could be in your own home and in millions more nationwide.</p><p>Kansas City&rsquo;s urban core in the Green Impact Zone will be the testing ground for advances in the smart grid, which is the name for a project to upgrade electrical devices in your home and upgrade power lines in the area. </p><p>&ldquo;The rest of the country is looking to Kansas City to lead on this,&rdquo; said Danny Rotert, spokesman for U.S. Rep. Emanuel Cleaver, a Kansas City Democrat who has been the driving force behind the green zone.</p><p>Boulder, Colo., already has installed an advanced smart grid designed to reduce energy costs and provide the potential for renewable energy.</p><p>Now KCP&L is looking to try the next generation of smart grid in the green zone, the $200 million effort to make 150 blocks in central Kansas City more energy efficient.</p><p>&ldquo;The green zone is really a sandbox to deploy some of these newer technologies,&rdquo; said Chuck Caisley, a KCP&L spokesman.</p><p>To simplify, think of power lines becoming two-way, like the Internet. That lets you see in real time how much energy you&rsquo;re using, and possibly cut back. And it lets utility companies monitor &mdash; and at times control &mdash; how much power you&rsquo;re using.</p><p>Sound scary? It does to some utility watchdogs and others who fear hackers or terrorist attacks. </p><p>But half of KCP&L&rsquo;s grid already allows for a dispatcher to send messages to customers&rsquo; meters and then receive a message with information about how that meter&rsquo;s working. That also allows the utility to see immediately where power outages have occurred. </p><p>KCP&L posts that information on its Web site and is working to upgrade the rest of its grid to allow real-time monitoring. </p><p>The green zone is expected to go much further, experimenting with some new smart-grid ideas:</p><p>&bull;Networks that allow the utility to adjust appliances, such as lowering a water heater&rsquo;s temperature when it&rsquo;s not in use so it cycles fewer times.</p><p>&bull;Thermostats, appliances and meters that the utility can signal to reduce energy use during peak times, such as on hot days. KCP&L already adjusts the thermostats of about 34,000 customers in Missouri and Kansas as part of a voluntary pilot project. </p><p>&bull;Meters that show customers, in real time, how much they are spending on energy. </p><p>&bull;Devices that allow KCP&L to see how much energy is being produced by home solar panels and small wind turbines. KCP&L would then be able to efficiently coordinate the energy being used by appliances in the home.</p><p>The grid also clears the way to distribute unused electricity from home solar panels and plug-in electric cars. There&rsquo;s the potential for a home to become its own energy plant, contributing to the grid and then getting paid for that contribution, Rotert said.</p><p>The smart-grid approach has collected some critics, including those who fear it allows power companies to intrude, like Big Brother, into the lives of their customers.</p><p>Some customers are squeamish about signing up for programs that give control of their appliances to their utilities, said Mindy Spatt, spokeswoman for The Utility Reform Network in San Francisco.