system
Given the following post, respond as if you're commenting on Reddit:
human
Would it be possible one day to reach 100% renewable energy?

Would we be able to power our entire infrastructure with renewable sources such as solar and wind power, and perhaps also water if we could make it so it wouldn't damage the ecosystem? If so, what do we need that we don't have?
gpt
Reliable, large scale electrical storage. The main problem with renewable energy resources is that, unlike traditional fossil fuels, we can't control them to match energy demand. At the current time, expected power surges to the grid can be controlled through increasing our levels of electricity production. With renewables, we would need large scale energy storage to take up that role in a 100% renewable electricity world. At the current time, we don't have anything suitable for this role, and until we do we'd need something controllable (whether it be fossil fuels or biomass) to stand in for it.

Further to this, Denmark is currently on the road to having a high level of dependence on renewables for its electricity. However to get round the problem, they have agreements and grid connections with both Germany and Sweden to export power to them in times of high renewable electricity production and import from them in times of low production. Obviously this tactic works in the current climate, but still shows they are dependent on traditional methods of electricity generation in times of low renewable resources.