Net Metering - Net Purchase and Sale

Net purchase and sale is a different method of providing power to the electricity grid that does not offer the price symmetry of net metering, making this system a lot less profitable for home users of small renewable electricity systems.

Under this arrangement, two uni-directional meters are installed—one records electricity drawn from the grid, and the other records excess electricity generated and fed back into the grid. The user pays retail rate for the electricity they use, and the power provider purchases their excess generation at its avoided cost (wholesale rate). There may be a significant difference between the retail rate the user pays and the power provider's avoided cost.

Germany, Spain, Ontario (Canada), some states in the USA, and other countries, on the other hand, have adopted a price schedule, or feed-in tariff (FIT), whereby customers get paid for any electricity they generate from renewable energy on their premises. The actual electricity being generated is counted on a separate meter, not just the surplus they feed back to the grid. In Germany, for the solar power generated, a feed-in tariff is being paid in order to boost solar power (figure from 2009). Germany once paid several times the retail rate for solar but has successfully reduced the rates drastically while actual installation of solar has grown exponentially at the same time due to installed cost reductions. Wind energy, in contrast, only receives around a half of the domestic retail rate, because the German system pays what each source costs (including a reasonable profit margin).