Google said on Tuesday that it was pulling the plug on seven projects, including Renewable Energy Cheaper than Coal as well as a Wikipedia-like online encyclopedia service known as Knol.
The plans, which Google announced on its corporate blog, represent the third so-called ``spring cleaning'' announcement that Google has made since Google co-founder Page took the reins in April.
The changes come as Google is facing stiff competition in mobile computing and social networking from Apple Inc and Facebook, and as some investors have groused about rising spending at the world's No.1 Internet search company.
``To recap, we're in the process of shutting down a number of products which haven't had the impact we'd hoped for, integrating others as features into our broader product efforts, and ending several which have shown us a different path forward,'' wrote Google Senior Vice President of Operations Urs Holzle in the blog post.
Google said that it believed other institutions were better positioned to take its renewable energy efforts ``to the next level.''
Google began making investments and doing research into technology to drive down the price of renewable energy in 2007, with a particular focus on solar power technology.
In 2009, the company's so-called Green Energy Czar, Bill Weihl, told Reuters that he expected to demonstrate within a few years working technology that could produce renewable energy at a cheaper price than coal.
``It is even odds, more or less,'' Weihl said at the time. ``In three years, we could have multiple megawatts of plants out there.''
A Google spokesman said that Weihl had left Google earlier this month.
Google noted in its blog post that it would continue efforts to generate ``cleaner, more efficient energy,'' including procuring renewable energy for its data centers.
Among the other projects included in Tuesday's ``spring cleaning'' were Google Knol, Google Search Timeline, Google Gear, Google Friend Connect, Google Bookmarks Lists and Google Wave, an ill-fated social networking and communication service that Google had previously said it would cease developing.
Google said that in December its email and calendar applications will no longer work with Gears technology, which allows Google's software to work when not connected to the Internet. Google said it is working to create offline capabilities into HTML5 technology instead.
Google Friend Connect, which allows website publishers to add social features to their sites, will be retired in March for all non-Blogger websites, Google said. It suggested that websites use its Google+ social network instead.
Earlier this year, Google said it would ``wind down'' Google Labs, a website that offered public access to experimental Google products, as well as terminating products that let consumers monitor their home energy consumption and keep track of their personal health records.
Shares of Google, which finished Tuesday's regular trading session down 94 cents, were up 86 cents at $580.86 in after hours trading.