4 ms·
Extreme efficiencies in STC W per square cm (or meter) are primarily of interest to things where room to mount PV cells is extremely constrained. Such as on sat
by walrus01 4y ago
Extreme efficiencies in STC W per square cm (or meter) are primarily of interest to things where room to mount PV cells is extremely constrained. Such as on satellites. Look at triple junction GaAs based cells used in satellite applications for example.
There are a large number of research-lab-only PV cells made in the last 10-12 years which greatly exceed 23% but are economically unfeasible or impossible to purchase for ordinary use. Some of this tech does trickle down eventually, however.
Of more practical real world interest is $ per STC watt for a panel you can buy in a 20-panel pallet load from an ordinary PV wholesaler. Like a figure of $0.28 USD/W for nominally 380W rated 72-cell monocrystalline Si panels for rooftop or ground mount applications. Meaning that a pallet of 20 panels would be somewhere around $2100 to $2200 USD to purchase plus freight.
In approximately the last 12 years we've seen things go from if you buy a pallet of "cheap" mass market 72-cell panels, you'd get 320W rated per panel (STC rating of about 4.44W per cell), to now being able to buy something that is 380W rated as mentioned above, approximately 5.27W per cell. All under STC measurement conditions which are only a rough approximation of real world sunlight of course. The same panels typically measure 1.99 x 0.99 meters so you can do the math on the improvement in STC W per square meter if mounting space is a limiting factor.
https://footprinthero.com/standard-test-conditions https://footprinthero.com/standard-test-conditions
- einpoklum 4y agoThis is also relevant to large-scale installations. For a single family home, perhaps you don't care if you use 30% of the roof area or 32.5%; but if you're building a solar farm for a whole city, then those extra 2.5% are a good number of Km^2 which you can save; or have as extra safety-margin production capacity.
- skykooler 4y agoIt's also relevant to some edge use cases, such as solar powered aircraft or solar cars, where space for panels is extremely limited.
- sacrosancty 4y ago
- krallja 4y agoThe cost of the panels is already such a small fraction of residential install cost. My panels were definitely under a buck a watt (maybe 15% of the total cost). The installation cost (i.e. paying for a team of a dozen guys to dangle in harnesses on my steep roof for three days) absolutely dominated the invoice (50-60%). The second most expensive was the batteries (about 20%). The remainder went into the hundreds of other parts (inverter, cut-off, conduit, circuit breakers, cables, MPPTs, brackets, safety stickers…) needed for a functioning & legal system. And a couple hundred bucks of fees to the city for permitting and inspection, and a couple hundred bucks for the off-shore engineers to draw the system design docs. I won't make a profit for decades, unless the price of grid power shoots up. It would make more sense in a place with higher power costs. But I can keep the lights on if there's a power outage, without the maintenance costs (and noise) of a hydrocarbon-fueled generator. If you're installing solar for monetary gain, don't put it on your roof, buy/lease cheap land and build a solar farm. My electricity provider even lets you buy in on syndicated solar farm deals, if you don't want to manage the process yourself; you get the generated kWh credited back on your power bill!
- slyall 4y agoThere was a story last week about commercial solar farms having panel flat on the ground and some people posted about putting home solar setups flat (or slightly elevated with a brick and tied down). Saving money with the setup beats getting the last percent out of the install. Although probably only some rural home-owners are going to be able/allowed to just put the panels flat on the ground. https://news.ycombinator.com/item?id=33926683 https://news.ycombinator.com/item?id=33926683
- 0cf8612b2e1e 4y agoFor a residential install (10s of square meters, not thousands). I would still feel more comfortable laying down some concrete first to minimize the chance of spoilage from vegetation. Plus something cheap for elevation from any flooding (bricks, cinder blocks, etc).
- 4y ago
- jacquesm 4y agoKeep an eye on the panel construction though, the gold standard is glass-glass but there are plenty of other materials used for the sandwich (and the sealing!) and not all of them will stand the test of time.
- Chilko 4y agoNot just that, the other trend is that panels used for solar farms have massively increased in size & capacity. The panels we are now buying for our solar farms are 660W, and over 2 meters long. While not as feasible for roof mount (although we're speccing 575W panels for commercial rooftops), these large panels reduce our associated balance of system costs on a $/W basis.
- coryrc 4y ago> you can buy in a 20-panel pallet load from an ordinary PV wholesaler Recommendations for wholesaler or even just examples? (West coast preferred)
- walrus01 4y agoKrannich Solar USA minimum quantity will be one pallet typically