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Gas imports or solar panels? (media.piefed.zip)
submitted 8 months ago by to c/climate@slrpnk.net
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Gas imports or solar panels?
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[–] 1 point 8 months ago (4 children)

You don't need 1twh of batteries to support 1gw of solar you need 2-4gwh depending on wanting 2 or 4 hours of overnight storage. Prices are dropping so fast, or so low now, that 6 hours is an easy option to choose. But for winter, see my other post on H2, or just don't nuke your legacy power from orbit, and keep them as backup/battery equivalent.

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  • [–] 3 points 8 months ago (3 children)

    You don’t need 1twh of batteries to support 1gw of solar you need 2-4gwh depending on wanting 2 or 4 hours of overnight storage

    At the present state of things, you're definitely right.

    I'm talking about winter, where you can count on solar panels producing... nearly nothing.

    This is a company here in Estonia sharing customers' monthly production numbers. This is a company trying to sell you solar installations, so they have no reason to show any numbers as lower than reality. I clicked through several customer experience pages, and most have ~30x less energy generated in December vs May.

    The Nebraska comparison in your other reply to me doesn't work out because Nebraska is way further south. In December, the sun doesn't "rise" here as much as it "drags its' rotting carcass across the horizon". Okay, we're not as far north as something like Svalbard, but the angle of the sun during solar noon on December 21 (shortest day of the year in the northern hemisphere) is around 7 degrees. In Nebraska it stays around 25 degrees. While we technically get up to 6 hours of daytime even in December, it's usually overcast so average sunshine per day is about 30 minutes over the winter. And if it's not overcast, you can expect it to get cold fast, driving up usage.

    So to go full solar (which I'm discussing as a thought experiment, I don't actually know anyone who wants to go FULL solar), essentially all the energy needs to be generated in about 7-8 months each year, because once the days start getting shorter, they go short REALLY fast. That's going to be a lot of H2 to store.

    or just don’t nuke your legacy power from orbit, and keep them as backup/battery equivalent.

    That's a reasonable suggestion, it's just that we're not burning anything clean like coal here, we're burning shale. It's comparable to lignite (if not worse) in CO2, but way more ash. Yes, shale the actual rock, not shale gas.

    It's super frustrating.

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  • [–] 1 point 8 months ago

    most have ~30x less energy generated in December vs May.

    Believable for shallow roof angles. Steep angles make a large difference, but it's still definitely a challenge for winter peak demand, and huge summer surpluses.

    In Estonia vs Nebraska, 1000 wh/watt/year vs 1800 is a signficant disadvantage, and as you say, December averages 15 minutes/day of solar energy.

    I did pick Nebraska for relatively north and sunny location, with ethanol substitute land use. It has 9-10x Estonia's winter production, and so Estonia definitely seems like a shithole solar location.

    The H2 system still works for Estonia. I made this for you:

    This report outlines the technical and financial feasibility of a self-sustaining

    125 kW Solar / 90 kW Electrolysis microgrid in Estonia. Optimized for the high-latitude constraints of the Baltics, this system leverages a summer hydrogen surplus to subsidize a 24/7/365 1 kW baseload datacenter requirement. 

    1. Core System Configuration 

    • Solar Array: 125 kW DC (Sized to achieve the "Zero-Cost" revenue break-even).
    • Electrolyzer: 90 kW (Sized to swallow 72% of peak solar yield, minimizing battery-to-hydrogen conversion losses).
    • LFP Battery: 185 kWh (Optimized for a 7.7-day "dark-start" winter survival buffer).
    • Baseload Load: 1 kW constant (8,760 kWh/year). 

    2. Financial & Cost Assumptions 

    • Financing: 5% annual interest over a 25-year term ($88.58/year per $1,000 CapEx).
    • Western Premium: 35% markup on base Chinese hardware for logistics, EU import duties, and local Estonian labor/permitting.
    • Hardware Pricing (Installed):
      • Solar: $0.47/Watt ($59,062 total)
      • Electrolyzer + BoS: $675/kW ($60,750 total)
      • LFP Batteries: $108/kWh ($19,980 total)
    • Annual O&M: 1% of total CapEx ($1,397/year). 

    3. Annual Capital & Operating Expense 

    | Expense Category | Amount (USD) | |

    |

    | | Total System CapEx | $139,792 | | Annual Debt Service (5%) | $12,383 | | Annual O&M (1%) | $1,397 | | Total Annual Cost (A) | $13,780 |

    4. Energy Production & Hydrogen Revenue 

    Estonia receives ~950 Peak Sun Hours (PSH) annually. The 125 kW array generates ~118,750 kWh/year. After accounting for the 1 kW baseload (8,760 kWh), the remaining ~110,000 kWh is directed to the 90 kW electrolyzer. 

    • Annual Hydrogen Production: ~6,890 kg H₂ (assuming 16 kWh/kg system efficiency).
    • Hydrogen Revenue (@ $2/kg): $13,780 (B)
    • Net Cost of Baseload (A - B): $0.00 / year
    • Effective Electricity Rate: $0.00 / kWh 

    5. Winter Reliability Analysis (The "Dark-Month" Stress Test) 

    Unlike the Nebraska model, the Estonia configuration faces extreme seasonal variance. 

    • Average December Yield: ~30–35 kWh/day (Enough to cover the 24 kWh/day baseload).

    • Worst-Case "Deep Cloud" Day: ~6–8 kWh/day (

      0.05

      --

      0.07

      PSH

      ).

    • The Survival Buffer:

      • With a 185 kWh battery, the system provides 185 hours (7.7 days) of 100% autonomy for the 1 kW load with zero solar input.
      • If the array yields even 7.5 minutes of "sun hours" (as discussed), the daily deficit drops, extending the buffer to ~12 days.

    • Operational Status: The 90 kW electrolyzer will be completely offline from late October to early March, as all available photons are prioritized for battery health and the 1 kW load. 

    6. Conclusion: The "Latitude Tax" Equilibrium 

    This system represents the Saturation Point for Estonia at $2/kg Hydrogen. 

    • The Win: You have successfully engineered a system where the 1 kW datacenter load is powered for free, as H₂ revenue exactly offsets the $13,780 annual debt and maintenance.
    • The Limit: Adding more solar/electrolysis at this latitude would result in a net loss, as the incremental debt ($42.50/kW) exceeds the incremental revenue ($34.40/kW).
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