171–180 of 282 posts
To deeply decarbonize you need to meet current demand and also make enough to charge the energy storage systems...on a cloudy string of winter days.
However we will see headlines like this for the next 20 years at least.
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Every time I do the math, any money I would spend on a solar system, would be better invested in an energy utility and just collect the dividend to pay my electric bill. If you want to do solar for the environment, fine - I won't fault you - but if you are doing it to save/make money, there are better places to invest.
That's a super interesting angle I had never considered! Part of my reason for thinking about solar is that if I'm going to spend 10k on a backup generator it might be far smarter to spend that on solar. For me the invest and pay cycle doesn't address the problem I'm solving. But I absolutely learned something today.
Anyway, if you want to use it as a backup, you'll need to oversize the solar so the battery can get you through power outages on cloudy days.
At that point PG&E will pay you 10-20% market rate for the excess energy you produce on most days. It's much better to dump those electrons into an EV battery than into the grid. My commute costs $4/week in electricity I don't send to PG&E, vs 20x that for the gas for the same commute.
(The EV gets 4.5 miles/kWh, and PG&E pays $0.04 / kWh, or $.008/mile. The old car gets 30mpg. At $5/gallon, that's $0.16/mile)
The punchline: Budget money for an EV for each of your household's commutes when you purchase the solar panels. Regardless if whether you buy panels, consider charging at work, assuming your employer subsidizes it and/or has solar panels.
(Also, check the milage on the EV you want. 3-5 mi/kWh is typical, but they can vary from 1 to 7.)
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I’ve been trying to do the math for my own home, are solar panels actually cash flow positive, once you account for efficiency decrease overtime etc.? It always seemed like one barely breaks even in 2 decades
Solar in California is often breakeven after 4 to 7 years. Enphase enables microgrid systems, and the IQ8 can keep your house powered even when the grid is down, and even without batteries –– something never before possible. https://enphase.com/sites/default/files/2021-10/IQ8SP-DS-000... Worth nothing that PG&E is working with CA Democrats to try to kill rooftop solar. They want renewables, but only if distributed us…
The Democrats (and Arnold) pushed back hard against the proposed NEM 3 rates that would have killed rooftop solar.
I have nothing nice to say about PG&E.
Their math seems off. I really don't see how you get to 97% renewable when the state was burning natural gas to generate 2.8 GW of non-renewable power and had about 1.1 GW of nuclear at the time. There might be some funny math here where they assign all of the "dirty" power generated in the state to exports and can claim that that California is running on renewable power. Source: https://www.caiso.com/TodaysOutlook/P…
The energy is pretty perfectly fungible so it makes about as much sense credited to the state as it does to the wider grid. If you just look at CA it generated 97% of its energy needs in state from renewable energy at that time. That it was connected to a larger grid so it was generating excess power dirtily doesn't really change that math.
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In that case the metric of how much power the state requires in the context of renewable energy is useless. Instead state the % of overall energy production in the state being renewable.
Disagree. "97% of some state's energy production was renewable" doesn't tell you much, because they could be a state that hardly burns any fossil fuels. "California managed to produce enough renewable energy to power 97% of the needs of a state the size of California" actually tells you how much renewable energy it generated, and why that's a big deal.
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It may be still better to run nuclear plants then. We'll need data from modern nuclear designs, (especially the small ones) but renewables are not exactly free to run. Storage degrades, solar degrades, lithium needs to be mined, turbines mean lots of mechanical parts, etc. We may learn that running just the renewables common today is even more uneconomic.
The maintenance burden you suggest for wind turbines is exaggerated. Compared to a gas car there are way fewer moving parts in common wind turbines, and some designs with no moving parts are being tested: https://www.windpowerengineering.com/dutch-wind-wheel-genera... Additionally, battery degradation appears to be primarily related to high speed charging. In decade old battery packs that were not charged at extreme…
I can't exaggerate the maintenance burden for the turbines, because I didn't claim what it is, beyond that it exists. We'll have to compare it to new nuclear plants before stating which becomes uneconomical.
Solar degradation is commonly estimated at 20% in 25y, but then we get inverter failures on top of that which account for ~80% of issues in home installations. Batteries are commonly estimated to lose 20% capacity in 10y. All of those stack up too. Again - we'll have to compare the actual numbers which we don't have yet.
Trying to match variable supply to a fixed retail electric rate is certain to cause energy gluts and shortages.
For example, I'd be happy to charge my electric car during price minima, heat the electric water heater to the max when power is cheap, and run the A/C to the cold end of comfort when electrons are plentiful.
If electricity is cheaper to generate when the sun is shining, the retail price of electricity should reflect that. In fact, the retail price should fluctuate minute by minute, so that demand can be shaped to match supply. Trying to match variable supply to a fixed retail electric rate is certain to cause energy gluts and shortages. For example, I'd be happy to charge my electric car during price minima, heat the ele…
If electricity is cheaper to generate when the sun is shining, the retail price of electricity should reflect that. In fact, the retail price should fluctuate minute by minute, so that demand can be shaped to match supply. Trying to match variable supply to a fixed retail electric rate is certain to cause energy gluts and shortages. For example, I'd be happy to charge my electric car during price minima, heat the ele…
We know this because until recently, this ‘ideal situation’ that you propose was available by a company called Griddy, that went balls up when their consumers got absolutely slammed during the Texas snowstorms, and the idea of having the wholesale price if you’re a retail consumer became a very very silly idea
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I’ve been trying to do the math for my own home, are solar panels actually cash flow positive, once you account for efficiency decrease overtime etc.? It always seemed like one barely breaks even in 2 decades
Solar in California is often breakeven after 4 to 7 years. Enphase enables microgrid systems, and the IQ8 can keep your house powered even when the grid is down, and even without batteries –– something never before possible. https://enphase.com/sites/default/files/2021-10/IQ8SP-DS-000... Worth nothing that PG&E is working with CA Democrats to try to kill rooftop solar. They want renewables, but only if distributed us…
Where I live, a different regime is being introduced: - a capacity tariff: a base grid charge, calculated based upon quarterly average peak consumption - a feed-in rate: a wholesale rate compensation for injecting self-produced green electricity into the grid (my current rate: 0.064€/kWh) - a retail rate by one's electricity provider (my current rate: .02869€/kWh) - subsidies for installation of solar (up to 300€/kW peak) and storage (up to 30%)
This at least conceptually incentivises both of solar installation and peak shaving. Solar is less ridiculously profitable for me, but still a no-brainer in terms of profitability.