Combining RSS Feeds and Sorting with fetch_feed

This code should work. I commented out one of your feeds. When I uncomment it, it stops sorting things correctly. It seems that there is something wrong with it. It doesn’t get formatted in the browser correctly like the rest either.

<ul>
<?php 
$rsslist = array(
    #'http://www.pewenvironment.org/rss/campaigns-8589935316',
    'http://www.ashrae.org/RssFeeds/ashrae.xml',
    'http://www.districtenergy.org/blog/category/idea-activity/feed/',
    'http://www.districtenergy.org/blog/category/industry-news/feed/',
    'http://www.nrel.gov/news/press/rss/rss.xml'
);

// Fetch all of the feeds into a simplePie mashup
$rss = fetch_feed($rsslist);
// Set the max items to either 10 or all items if there are less than 10
$maxitems = $rss->get_item_quantity(10);

// Get the items (0-10)
$rss_items = $rss->get_items(0, $maxitems); 

// If there are no items, output that
if ($maxitems == 0) {
    echo '<li>No items.</li>';
// Otherwise loop over the items
} else {
    foreach ( $rss_items as $item ) { ?>
        <li>
        <?php echo $item->get_date() . $item->get_permalink(); ?>
        </li>
    <?php 
    }
}
?>
</ul>