Comment by jillesvangurp

HVDC cables are kind of an often overlooked solution to net zero. Moving power over long distances, across timezones is kind of a super power. The main obstacle to scaling this from a few GW to tens/hundreds of GW is cost. Just by laying more cables can you increase capacity between regions and their ability to share excess power to each other. But each cable is a multi billion dollar project. Which means that there is only a little bit of capacity to move power around but not a lot. For example Europe can import a few GW of African solar in the middle of the winter. But it could probably need hundreds when it is dark and not windy there.

Likewise cross Atlantic cables have been talked about but so far don't exist. Same with getting power from the East coast US to the West coast and vice versa. The east coast goes dark while the west coast is still producing lots of solar. And in the morning on the west coast, it's afternoon on the east coast. There is a bit of import/export between California (solar) and Canada (wind / hydro). But it could be much more.

Cables have another important function: they can be used to charge batteries. Batteries allow you to timeshift demand: e.g. charge when the sun is out, discharge when people get home in the evening. And off peak, the cables aren't at full capacity anyway meaning that any excess power can easily be moved around to charge batteries locally or remotely. Renewables, cables and batteries largely remove the need for things like nuclear plants.

Yes it gets dark and cloudy sometimes but those are local effects and they are somewhat predictable. And if the wind is not blowing that just means it is blowing elsewhere. Wind flows from high pressure to low pressure areas. Globally, there always are high and low pressure areas. If anything, global warming is causing there to be more wind, not less. So, global wind energy production will always maintain a high average even if it drops to next to nothing locally. Likewise, global solar production moves around with the sun rise and sun set and seasons but never drops to zero everywhere. If it's night where you are, it isn't on the other side of the planet. If it's winter where you are, it isn't at -1 * your latitude.

If long distance cables get cheap and plentiful, that's a really big deal because this allows for moving around hundreds of gwh of power. HVDC allows doing that over thousands of kilometers across oceans, timezones, and continents. Cheaper HVDC lowers the cost of that power.