window.fbAsyncInit = function() { FB.init({appId: “”, status: true, cookie: true, xfbml: true}); }; (function() { var e = document.createElement(“script”); e.async = true; e.src = document.location.protocol + “//connect.facebook.net/en_US/all.js”; document.getElementById(“fb-root”).appendChild(e); }()); Why can solar energy be not used everywhere? Is it very expensive to tap it?