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by limaoscarjuliet 423 days ago
In my experience, no matter how many panels you install, Solar can cover power consumption 30-40% of its max capacity. Winter, night, bad weather will eat the rest. To go beyond the 30-40% you will need energy store or alternative sources.

This is still great but not a 100% solution.

2 comments

At scale things look very different. A great deal of nighttime energy use occurs because electricity prices are cheaper at night. Panels to the east of you get sunlight earlier in the day and panels to the west of you get it later in the day. Tracking panels get sunlight across a larger fraction of the day.

Output from panels on a single home are highly correlated seeing large drop offs from an individual cloud, where solar farms across a wide geographic area experience different weather systems. It wouldn’t be cost effective but with absolutely zero storage the US could get 70+% of its electricity from solar. Add wind and hydro to the mix and you can get quite far without grid storage, but adding options lowers costs so there’s an optimal amount of grid storage for any given energy mix.

> A great deal of nighttime energy use occurs because electricity prices are cheaper at night.

Utility companies gave away streetlights, security lights, etc., because they would raise the electricity usage generated at times of lower demand. This minimized the need to spin up and spin down generating plants and let them make money on what would have been otherwise wasted power.

Nighttime lighting doesn't consume all of the excess power generated at night. Utilities have cleverly shifted power consumption loads to later times through TOD pricing for residential and industrial customers.

It's no secret that I'm a big advocate for turning down lights at night. Increasing dependency on solar and batteries would make running electricity-intensive processes and industries cheaper during the daytime and reduce the need for baseload power at night.

> Panels to the east of you get sunlight earlier in the day and panels to the west of you get it later in the day.

I sometimes think about a sci-fi world in which there is a globally interconnected power grid, so solar panels in daylight India can provide power to Spain. And then when the sun shines in Spain, it can generate solar power for California

This model prioritizes generation [0] over storage, by dramatic reliance on transmission systems. That's not inherently a stupid thing to do, but given the reality of global and even national politics, most places are prioritizing storage [1] over generation and limiting transmission goals to national needs.

[0] because India would need to generate not just it's daytime requirements, but also Spain's overnight requirements, and so forth.

[1] because each nation/grid system would need to store significant excess generation to make it through the night/storm systems etc.

Most people who care about independence should be concerned with having a system that can run in island mode but at least 90% of systems installed today are grid tied and cannot function as an island
I care about indepedence, but I also care about scale.

It makes absolutely zero sense for me, a homeowner in New Mexico, to have my own storage facilities capable of getting me through a winter heating season (using air-source heat pumps). It makes much more sense for the storage to be centralized, scaled and managed, while my own PV array contributes to it during the summer time.