Difference between revisions of "Space Based Solar Power"
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The below spreadsheet assumes $1,600,000 per MW as the initial cost and 10% per year of the cost for maintenance. Power satellites run supplying base load, here I assumed ~91% of the time, it may be higher. | The below spreadsheet assumes $1,600,000 per MW as the initial cost and 10% per year of the cost for maintenance. Power satellites run supplying base load, here I assumed ~91% of the time, it may be higher. | ||
| − | The discount rate is 6.8%, same as the government uses for other sources. | + | The discount rate used is 6.8%, same as the government uses for other sources. The accounting period is 20 years and no salvage value is assumed. |
https://docs.google.com/spreadsheets/d/1wDvn369EudkYGsPK3jNt4FmBFpNFtt0ZwDZl_lt_SNM/edit#gid=1481425448 | https://docs.google.com/spreadsheets/d/1wDvn369EudkYGsPK3jNt4FmBFpNFtt0ZwDZl_lt_SNM/edit#gid=1481425448 | ||
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The ratio between the $1600/kW cost and the cost that comes out of the formula (~2 cents per kWh) is close enough to 80,000 to one. Electric power cost is proportional to the cost of a power satellite (or any power source that has no fuel cost) in this ratio for this discount rate and years of service. | The ratio between the $1600/kW cost and the cost that comes out of the formula (~2 cents per kWh) is close enough to 80,000 to one. Electric power cost is proportional to the cost of a power satellite (or any power source that has no fuel cost) in this ratio for this discount rate and years of service. | ||
| − | The UK government has determined that 3.5% discount is proper for projects of this kind. Using 3.5%, the electric cost comes out at just over 1.5 cents per kWh and ~100,000 to one. It's a live spreadsheet, try your own numbers. | + | The UK government has determined that 3.5% discount is proper for projects of this kind. Using 3.5%, the electric cost comes out at just over 1.5 cents per kWh and ~100,000 to one. Extending the accounting period to 30 years at 3.5% brings the cost of power down to 1.24 cents per kWh and a cost of power to cost of investment ratio to ~130,000 to one. It's a live spreadsheet, try your own numbers. A ratio of 80,000 to one is conservative. |
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| + | == Mass of power satellites == | ||
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| + | The original studies done in the late 1970s came up with a mass of ~10 kg/kW. More recent realistic studies have averaged around 7 kg/kW. A few studies have proposed designs under one tenth of a kg/kW. Very light designs require a lot of station keeping against light pressure where designs in excess of 5 kg/kW can average the light pressure over a year. Because a substantial fraction of the construction cost is for transport to GEO, the mass of a power satellite is an important number as is the lift cost to GEO. This analysis will use 7 kg/kW. The number can be adjusted in the spread sheets. | ||
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[[Category:Earth Orbit]] | [[Category:Earth Orbit]] | ||
Revision as of 21:33, 27 October 2014
The Wikipedia's take on the topic is here https://en.wikipedia.org/wiki/Space-based_solar_power
Economics of Solar Power Satellites
In the absence of other forces such as legal requirements, power satellites compete in the energy market.
That means close attention to cost.
Levelized cost of power
The formula for the levelized cost of electricity is here; https://en.wikipedia.org/wiki/Cost_of_electricity_by_source
The below spreadsheet assumes $1,600,000 per MW as the initial cost and 10% per year of the cost for maintenance. Power satellites run supplying base load, here I assumed ~91% of the time, it may be higher.
The discount rate used is 6.8%, same as the government uses for other sources. The accounting period is 20 years and no salvage value is assumed.
The ratio between the $1600/kW cost and the cost that comes out of the formula (~2 cents per kWh) is close enough to 80,000 to one. Electric power cost is proportional to the cost of a power satellite (or any power source that has no fuel cost) in this ratio for this discount rate and years of service.
The UK government has determined that 3.5% discount is proper for projects of this kind. Using 3.5%, the electric cost comes out at just over 1.5 cents per kWh and ~100,000 to one. Extending the accounting period to 30 years at 3.5% brings the cost of power down to 1.24 cents per kWh and a cost of power to cost of investment ratio to ~130,000 to one. It's a live spreadsheet, try your own numbers. A ratio of 80,000 to one is conservative.
Mass of power satellites
The original studies done in the late 1970s came up with a mass of ~10 kg/kW. More recent realistic studies have averaged around 7 kg/kW. A few studies have proposed designs under one tenth of a kg/kW. Very light designs require a lot of station keeping against light pressure where designs in excess of 5 kg/kW can average the light pressure over a year. Because a substantial fraction of the construction cost is for transport to GEO, the mass of a power satellite is an important number as is the lift cost to GEO. This analysis will use 7 kg/kW. The number can be adjusted in the spread sheets.
