this is tim maya, you against the c o o. off one of germany's for grid operators in germany, more than 40 percent of the tricity comes from renewable sources. it's opposed to reach 80 percent by 2030. so what challenges does a high shelves wind and sold off for a walk? well, for one they make you depend on the weather to exactly what we can expect to the next stage. we unfortunately gotten a lot better at this, but even the best tool cause come change to whether the german was doing because it's loud. so doc doldrums describes times when there is little some and little wins and read off. all right, has nightmare germany produces most of its wind energy and the north, most of its solar energy in the south is currently in no way. it's getting large amounts of wind energy down south where there's a lot of demand from industry, old much solar energy up north for that matter. it's a similar story in the us. most wind energy is generated in the middle of the country, but more than 2 thirds of the population lives here within 100 m