according to a 2012 report by pike research, vpp capacity would, from 2011 to 2017, increase by 65%, from 55.6 gigawatts (gw) to 91.7 gw worldwide, generating from $5.3 billion to $6.5 billion in worldwide revenue in 2017. in a more aggressive forecast scenario, the clean-tech market intelligence firm forecasts that global vpp revenues could reach as high as $12.7 billion during the same period.