Re:Giant batteries and cheap solar power are shoving fossil ...
by aoeusnth1 on Saturday July 13, 2019 @02:20AM
(#20426774)
Wow, what was your price per W? At ~$2.5/W before tax breaks, and a 5% yearly discounting rate, I calculated my TCO was about $0.08/KWh after tax breaks using a spreadsheet to calculate the net present value of the future electricity.
Usually the salesmen will quote you a cost per KWh based on the total energy generated over 25 years divided by the cost of the system. This is usually very far off (in their favor) for two reasons:
- Time discounting: at a generous 5%/year, discounting makes electricity in 20 years only worth 37.6% as much as electricity now.
- Risk: presumably, future increases in panel efficiency and manufacturing techniques will make electricity even cheaper than it is now. By signing a contract or buying a system, you're buying future electricity flows without knowing how much they'll be worth yet.
Usually the salesmen will quote you a cost per KWh based on the total energy generated over 25 years divided by the cost of the system. This is usually very far off (in their favor) for two reasons:
- Time discounting: at a generous 5%/year, discounting makes electricity in 20 years only worth 37.6% as much as electricity now.
- Risk: presumably, future increases in panel efficiency and manufacturing techniques will make electricity even cheaper than it is now. By signing a contract or buying a system, you're buying future electricity flows without knowing how much they'll be worth yet.