Hacker News Reader

Comment by vondur | Hacker News Reader

I know California has reduced the incentives to purchase solar panels. You have to also have a battery backup system which increases the costs considerably. I'm guessing we may have too much solar in the day and not enough storage for the energy created.

View on HN

The battery increases the upfront cost but also increases the roi very much (at least where I am living). You get way less money for feeding energy to the grid than you have to pay for withdrawing energy(as you said some utilities even limit/forbid feeding during peak hours). In my case that means (Austria): Sell 1 kWh - 0,04€ Buy 1 kWh - 0,25€

Don't you have to replace the batteries every few years though? That should be factored in the equation.

You have to replace everything you own on some cadence. Eventually I'll need to replace the battery on my solar system. I'll also need to replace the panels at some point and even the roof the system is installed on.

My solar system uses a Tesla powerwall. I'd expect its real world performance over time to be about the same as what you see in batteries for Tesla vehicles.

most batteries can last 10+ years

Modern lithium batteries can last decades! LFP batteries can take thousands of discharges cycles, and most systems wouldn’t be designed to fully drain the batteries anyways (keeping them at more optimal levels of charge to maintain capacity).

solar systems don’t require that much ongoing maintenance. There just aren’t many consumable components. (And battery recycling is getting better by the year)

Oh yeah, it's just the initial cost goes up and the payoff time becomes longer. And you were one of the people who had installed solar panels, the rewards for it are reduced.

Wrong, payoff time will be shorter. Why: During the next few years energy suppliers will "force" people, who feed energy to the grid into flexible pricing, so the reward for producing will be less and less ( current flexible prices https://markt.apg.at/en/transparency/cross-border-exchange/d... ) and the incentive for having a battery is getting stronger. For my situation that means almost zero energy costs from March to October. Even in December and January it covers 30-50% of the total energy demand (heat pump).

A partly cloudy or partly sunny day produces some insane changes in output without a battery system to smooth them out

There is a limit to the size of the instantaneous increases and decreases in generation that the other generators on the grid can compensate for

Reply on news.ycombinator.com