7 ms·

> Tilting/tracking systems are a nightmare that is horribly expensive to maintain long term. It makes no sense to consider them at grid scale. Single axis tilt

> Tilting/tracking systems are a nightmare that is horribly expensive to maintain long term. It makes no sense to consider them at grid scale. Single axis tilting bifacial is overwhelmingly the cheapest, lowest maintenance cost per energy, lowest LCOE energy in any location with good solar resource. https://list.solar/news/single-axis-bifacial/ https://list.solar/news/single-axis-bifacial/ https://emp.lbl.gov/utility-scale-solar/ https://emp.lbl.gov/utility-scale-solar/ It makes no sense to build out $30/MWh 35% CF wind resource which you will curtail 30% of or $60/MWh offshore wind when there is $20/MWh 30% CF solar available that produces during the lulls (thus decreasing your storage and curtailment needs).

robomartin 4y ago
Again. No. The National Renewable Energy Laboratory has already shown this is a bad idea. The summary reads (emphasis mine): "Annual energy simulations were updated to evaluate the kWh/m2 boost achieved in single-axis tracking systems using bifacial modules. Measured bifacial energy gains of 7%-9% and rear irradiance gains of 11% were recorded, agreeing with modeled expectation within 1%-2% absolute, and matching global average expectation. Additional system energy gains of 0.5%-1.5% are predicted to be achieved by optimizing tracker behavior, adapting to cloudy conditions." - single-axis tracking - bifacial modules - gains of 7%-9% Figure 10a shows a best-case maximum annual energy production gain of 1% to 1.3% (aproximately). Why? Because, among other things, if you tilt panels you can't pack them in so tightly. That's basic geometry. In fact, if you do the math, it is better to reduce the geographically-dictated optimal tilt angle and fix it at a lower angle in favor of tighter packing. Put simply, rows of panels will cast a shadow on the panels behind the row. Also, ground-bounce inside the array is seriously curtailed by shading. Bifacial is interesting for some types of installations, not necessarily for grid-scale, where they gains could be in the order of 1% or less. Wait! How did we go from 9% gains to 1% annual energy gains? What? Because SOLAR PANELS DO NOT PRODUCE ANY ENERGY FOR 50% OF THE DAY. And, SOLAR PANELS ARE DEEPLY AFFECTED BY CLOUDS, WEATHER AND DIRT. Which means that a 9% power generation gain measured while operating ends-up translating into 1% or less in energy collection gains in a year. Don't agree? Well, go argue with the National Renewable Energy Laboratory then. You must know more than they do. Here: https://www.nrel.gov/docs/fy19osti/72039.pdf https://www.nrel.gov/docs/fy19osti/72039.pdf You are still missing the most important point: The advantages for wind are very large and across a range of parameters. You are talking about 1% gains by adding complex and costly-to-maintain tracking systems. I am talking about achieving 95% reliability with 1/4 the storage requirements, with 1/12 the land, 33% lower maintenance cost, etc. Not even close.
- Schroedingersat 4y ago
  Please learn to read, or at least learn some basic arithmetic to check if your misinterpretation is even logically coherent. This is a rather extreme example of condescending from a position of ignorance. Made even worse by literally having the correct answer in front of you. Being so confidently wrong all the time must be incredibly exhausting. The 1% is the additional gain for smart tracking algorithms (such as going to 0 degree tilt during diffuse light) on top of the bifacial gain of 5-15% which is on top of the tilting gain of 15-25%. This is stated clearly in the paper. Take this EIA report as an example (california utility installations have a high share of single axis): https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_6_07_b https://www.eia.gov/electricity/monthly/epm_table_grapher.ph... The amount of overprovision needed to provide a consistent monthly output is lower with wind and solar than with either alone. Wind outperforms solar watt for watt significantly in winter. Solar outperforms wind marginally in summer, but at $0.7-1.1/W for a 2022 tilting system vs $1.10-1.30/W for wind. This trend is echoed on a day to day and hour to hour basis as well. Repeating unsubstantiated statistics based on comparing an all wind system to an all solar system also doesn't add anything to the discussion. You are correct in that bifacial tilting systems don't magically increase GHI, but they do provably gather the valuable off-noon energy much more cost effectively (whilst leaving 30-40% of the noon energy on the table). More importantly they gather a much larger proportion of diffuse light, so the minima aren't as low during cloudy weather.
  - robomartin 4y ago
    Hopeless. The energy produced by 100 acres of wind requires 1200 acres of solar...and you are going on and on about a purported 5%, 10%, 25% gain. Who gives a fuck? Any accountant would take a 100 acre solution over a 1200 acre nightmare. You seem to be exquisitely capable of attempting to derail conversations with irrelevant noise. Energy production per installed GW: Wind: 3.07 TWh/GW Solar: 1.33 TWh/GW (solar is reliably off half the time) Land use per GW: Wind: 750 acres/GW Solar: 3,900 acres/GW Land use to provide all Tesla Master Plan solar + wind: Wind: 1 Hawaii (area of all islands) Solar: 12 Hawaii's or, Wind: 2.5% of California Solar: 30% of California Annual Operations and Maintenance costs : Wind: 1.00 Solar: 1.33 times wind O&M Initial investment in factories: Wind: $212 billion Solar: $ 11 billion Storage required for 95% reliability: Wind: 3 hours Solar: >12 hours Wind requires 4x less batteries, with all the cost, recycling and ecological advantages this delivers. Build supply chain origin: Wind: Diverse Solar: Heavy reliance on China Long term supply chain (maintenance, parts, etc.) origin: Wind: Diverse Solar: Heavy reliance on China (forever) These are facts from Tesla's Master Plan Part 3 and the sources they list. And you are arguing over an imaginary 25% gain? Even if you are right, the comparison isn't even close. If you want to invalidate my ideas about wind, attack the list I just reprinted above --which means, attack the data and sources provided by Tesla. BTW, operation and maintenance costs on a fixed solar system --per MPP3-- is already 33% greater than solar. Tracking solar is even more expensive. I don't have a clue how much. I'll guess 50% (and I'll be I am right). You are missing the forest for the trees. Have a good life.

robomartin 4y ago

Again. No. The National Renewable Energy Laboratory has already shown this is a bad idea. The summary reads (emphasis mine): "Annual energy simulations were updated to evaluate the kWh/m2 boost achieved in single-axis tracking systems using bifacial modules. Measured bifacial energy gains of 7%-9% and rear irradiance gains of 11% were recorded, agreeing with modeled expectation within 1%-2% absolute, and matching global average expectation. Additional system energy gains of 0.5%-1.5% are predicted to be achieved by optimizing tracker behavior, adapting to cloudy conditions." - single-axis tracking - bifacial modules - gains of 7%-9% Figure 10a shows a best-case maximum annual energy production gain of 1% to 1.3% (aproximately). Why? Because, among other things, if you tilt panels you can't pack them in so tightly. That's basic geometry. In fact, if you do the math, it is better to reduce the geographically-dictated optimal tilt angle and fix it at a lower angle in favor of tighter packing. Put simply, rows of panels will cast a shadow on the panels behind the row. Also, ground-bounce inside the array is seriously curtailed by shading. Bifacial is interesting for some types of installations, not necessarily for grid-scale, where they gains could be in the order of 1% or less. Wait! How did we go from 9% gains to 1% annual energy gains? What? Because SOLAR PANELS DO NOT PRODUCE ANY ENERGY FOR 50% OF THE DAY. And, SOLAR PANELS ARE DEEPLY AFFECTED BY CLOUDS, WEATHER AND DIRT. Which means that a 9% power generation gain measured while operating ends-up translating into 1% or less in energy collection gains in a year. Don't agree? Well, go argue with the National Renewable Energy Laboratory then. You must know more than they do. Here: https://www.nrel.gov/docs/fy19osti/72039.pdf https://www.nrel.gov/docs/fy19osti/72039.pdf You are still missing the most important point: The advantages for wind are very large and across a range of parameters. You are talking about 1% gains by adding complex and costly-to-maintain tracking systems. I am talking about achieving 95% reliability with 1/4 the storage requirements, with 1/12 the land, 33% lower maintenance cost, etc. Not even close.

Schroedingersat 4y ago
Please learn to read, or at least learn some basic arithmetic to check if your misinterpretation is even logically coherent. This is a rather extreme example of condescending from a position of ignorance. Made even worse by literally having the correct answer in front of you. Being so confidently wrong all the time must be incredibly exhausting. The 1% is the additional gain for smart tracking algorithms (such as going to 0 degree tilt during diffuse light) on top of the bifacial gain of 5-15% which is on top of the tilting gain of 15-25%. This is stated clearly in the paper. Take this EIA report as an example (california utility installations have a high share of single axis): https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_6_07_b https://www.eia.gov/electricity/monthly/epm_table_grapher.ph... The amount of overprovision needed to provide a consistent monthly output is lower with wind and solar than with either alone. Wind outperforms solar watt for watt significantly in winter. Solar outperforms wind marginally in summer, but at $0.7-1.1/W for a 2022 tilting system vs $1.10-1.30/W for wind. This trend is echoed on a day to day and hour to hour basis as well. Repeating unsubstantiated statistics based on comparing an all wind system to an all solar system also doesn't add anything to the discussion. You are correct in that bifacial tilting systems don't magically increase GHI, but they do provably gather the valuable off-noon energy much more cost effectively (whilst leaving 30-40% of the noon energy on the table). More importantly they gather a much larger proportion of diffuse light, so the minima aren't as low during cloudy weather.
- robomartin 4y ago
  Hopeless. The energy produced by 100 acres of wind requires 1200 acres of solar...and you are going on and on about a purported 5%, 10%, 25% gain. Who gives a fuck? Any accountant would take a 100 acre solution over a 1200 acre nightmare. You seem to be exquisitely capable of attempting to derail conversations with irrelevant noise. Energy production per installed GW: Wind: 3.07 TWh/GW Solar: 1.33 TWh/GW (solar is reliably off half the time) Land use per GW: Wind: 750 acres/GW Solar: 3,900 acres/GW Land use to provide all Tesla Master Plan solar + wind: Wind: 1 Hawaii (area of all islands) Solar: 12 Hawaii's or, Wind: 2.5% of California Solar: 30% of California Annual Operations and Maintenance costs : Wind: 1.00 Solar: 1.33 times wind O&M Initial investment in factories: Wind: $212 billion Solar: $ 11 billion Storage required for 95% reliability: Wind: 3 hours Solar: >12 hours Wind requires 4x less batteries, with all the cost, recycling and ecological advantages this delivers. Build supply chain origin: Wind: Diverse Solar: Heavy reliance on China Long term supply chain (maintenance, parts, etc.) origin: Wind: Diverse Solar: Heavy reliance on China (forever) These are facts from Tesla's Master Plan Part 3 and the sources they list. And you are arguing over an imaginary 25% gain? Even if you are right, the comparison isn't even close. If you want to invalidate my ideas about wind, attack the list I just reprinted above --which means, attack the data and sources provided by Tesla. BTW, operation and maintenance costs on a fixed solar system --per MPP3-- is already 33% greater than solar. Tracking solar is even more expensive. I don't have a clue how much. I'll guess 50% (and I'll be I am right). You are missing the forest for the trees. Have a good life.