Zero Marginal Energy Cost

This is the cost of electricity derived from photovoltaics. No storage.

Question: Derive the cost per kilowatt hour for PV panels that cost $200 per kilowatt - is that the current bulk cost? Assume the standard lifetime, and inverters that cost $100 per kilowatt - is that the correct cost? Assume no storage, and mounting cost of $10/kw because it is building-integrated.

Chat says: https://chatgpt.com/share/6978447d-0958-8010-a31f-e4e788cab0bf

Wiring is DC bus at 500V carrying 200A or 100kW, linear array say of 200 feet long, 10 panels deep, each panel connecting with a long ga 14 wire back to 300A bus (30 wires *50'=1500 feet of 14 ga XHHW-2 at 28 cents per foot (https://www.wireandcableyourway.com/xhhw?srsltid=AfmBOooslPMla7YGEH_a-hYczUjDOT7sFuHo1TGrGclpjhzmGPIkSgPW)) and 4/0 cable at $2.5/foot makes for $500+$500. So I pay $1000 in wire for 100kw or $10/kW in wire, so wiring cost is negligible. Combiner is $55/6kW, or about $10/kw. Engineering is open source reference design. Conduit - is $340/100kW or $3/kw. So total not including labor is $333/kW for hardware. Labor is about 20 minutes per panel (4 mount points through panel, 4 screws to mounts, marking 20 long lines , and 3D printed mounts) for about 100 hours - or $2500 - for 100 kW - or $25/kw - making total with labor come out to under $400/kW.

Design rationale: use fat pipe of 4/0 aluminum for a DC bus carrying 150A (15 strings of 10A) on 2 sides, each side of long building. This way, no MC4 extenders are required. This eliminates the XHHW-2 above but adds a second 4/0 wire, at same cost. This is actually more robust than going to 350kcmil wire at higher cost.

This makes cost of electricity 0.8 cents/kWhr. https://chatgpt.com/share/6978447d-0958-8010-a31f-e4e788cab0bf

But PV lasts more than 25 years. Under the assumption of lifetime design inverters - the cost drops to 1/2 of this - down to 0.4-0.5 cents per kWhr.

This shows less than 1/2 the utility-scale cost structure, but executed on the microscale.

Verify

• Joshua sez - If assume ~1200kWh/kW/year, you have $400/kW, Lasts 20 years= 24,000 kWhs puts it at less than 2 cents/kWh (1.7 c/kwhr)

• 1367 kwhr/kw installed per year in missouri - [1]
• 1.7 cents / 30*20 (30 instead of 20 years), then divided by 1367*1200 for actual Missouri - gets us to 1 cent.