Power Purchase Agreements
The output of utility-scale solar power stations is almost always fed into the grid for sale into the bulk electricity market, though a few (often roof-top) plants supply a local electricity user.
Bulk power is sold under a PPA or power purchase agreement with an electricity utility. We refer to this buyer as the 'power off-taker'.
In open markets the plant owner, who is selling the power, may have a choice of off-taker. In regulated markets there may be only one electricity utility operating in the relevant area.
Utility-owned solar power plant
Some utilities own the power stations, rather than buying the power from an indepent power producer.
A map of utility-owned plants is available here.
Basis of the data used
The data used for the analysis and the table on the left is derived from operating projects of 4MWAC+ on the Wiki-Solar Database, according to these criteria.
Power off-takers are identified against 19% of the operating capacity on the Wiki-Solar Database (of which these top 30 account for 18%). The total capacity for power off-takers listed may therefore be on average up to 5 times that identified here.
Some off-takers in this list also fulfil other roles in utility-scale projects, and some utilities also own and operate their own plant for example. The figures quoted here apply only to their power purchase activities. Where companies have maps, however, these will show all their projects.