Historically, distributed generation meant combustion generators (e.g. diesel gensets). They were affordable, and in some cases reliable, but they were not clean. While many people will tolerate dirty generation thousands of miles away from them, they think twice when it is outside their bedroom window or office door.
Recently, solar has become a popular distributed generation option. Although the output is clean it is also intermittent, making it an incomplete strategy for businesses that need power around the clock, including when the sun is not shining.