Every morning at the ShrinkNano Headquarters, we see the same large white building across the way. As the warm Southern California sun tracks its daily route, illuminating the buildings various sides, we can’t help but wonder how much energy is being wasted. A back of the envelope calculation suggests quite a bit.
The building is L-shaped, with the L being 65 meter by 65 meters, 25 meters thick and 11 meters high. These are really rough distance estimates, derived from a combination of Google Maps, ratio-proportion measurements with a pencil and counting paces. The roof, which is illuminated throughout the day, has a surface area of around 2625 square meters. Depending on the angle and time of day, the illuminated area on the side of the building is between 715 square meters and 1430 square meters.
According to NREL, our location in Southern California has on average 5-9 kWh/m^2/day of solar energy. The roof likely receives somewhere between 13125 kWh and 23625 kWh and the sides somewhere between 3575 kWh and 12870 kWh per day.
Silicon solar panels cost ~150$ per square meter and are about 23% efficient. They cannot be placed in windows and do not absorb off-angle lighting well, so we apply a 60% reduction to the energy received. We’d estimate 1535 kWh – 3360 kWh is generated over 3565 m^2 of panels which cost $534,750.
OptiSol costs ~10$ per square meter and is about 12% efficient, currently (we anticipate that 20% is readily achievable and have observed 17% in prototypes). OptiSol can be placed in windows and can absorb off-angle lighting, so we apply a 40% reduction. We’d estimate 1200 kWh – 2625 kWh is generated over 4055 m^2 of panels which cost $40,550.
An average home uses about 1500 – 3000 kWh per month. The building across the way probably wastes enough solar power in one day to power an entire home for a month. Cladding the building in standard silicon solar cells would probably cost upwards of $500,000. You’d trade wasted power for wasted money. Our initial research projections suggest that a comparable amount of energy could be produced by OptiSol… for around $50,000.
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