Germany and China are finding out the hard way that switching to renewables isn’t as simple as building more wind turbines and solar panels.

The Guardian reports that leaked plans from the German federal network agency, which manages the country’s power grid, describe how it is planning to cut back its ambitions for wind power in the north of the country because the grid can’t handle it. Wind turbines have been going up rapidly in the north, with the intention of supplying energy to engineering hubs in the south. But recently the government has had to pay wind power providers to reduce their generation because its energy grid is at full capacity. The leaked papers suggest that Germany will halve its wind turbine expansion plans as a result.

A similar story is playing out in China. According to a BBC report, the country has built so many coal-fired power plants, which are slow to turn on and off, that it has to turn its wind turbines off for as much as 15 percent of the time because its grid can’t always handle both being online concurrently. It’s not the first time that China’s renewables eyes have proven bigger than its grid belly, either: it’s been adding solar power installations so fast that it can’t make use of as much as 50 percent of the energy being generated in some provinces.

This is a problem that’s likely to rear its head again and again. India and Australia are both under increasing pressure to build out their grid infrastructure to support renewables. The most impressive example of wind power adoption in the U.S. has played out in, of all places, Texas. It’s only been made possible by a gigantic transmission system that was built to take electricity from the desolate northwest portion of the state to the big cities in the southeast. But it cost $7 billion—a price that could be prohibitive in other regions.

In this, there is a lesson. Swift adoption of renewables is laudable—but only if it’s done in such a way that the resulting energy can be used.

(Read more: BBC, The Guardian, “China’s Solar Binge Is Turning Into a Hangover,” “The One and Only Texas Wind Boom,” “Renewables Are Booming—but Buyer Beware”)