Originally Posted By: Shannow
How'd I miss this thread ???
Capacity factor is the GWHr produced by a plant over the course of a year (365 days), divided by the number of GWHr available in a year...a regular year is 8760 hours.
This is where the table above reflects the unreality of the green movement.
There's dispatchable capacity, which is the capacity that a system controller can call upon to meet system needs, and a marketter can bid in to sell electricity for a profit.
There harvestable energy, which is the solar wind, tidal energy, that the systems take from the environment, and contribute to the grid, with nobody being able to press a button and ramp it up/down...it's non dispatchable...it's there when it's there, and not there when it's not.
The former can have a capacity factor of 100% (minus breakdown), the latter can have a capacity factor of what's available in the environment (minus breakdown).
Nate1979, that means that nameplate to namplate, you need to install at least 3 times an much wind, on average and in actuality much more than coal, nukes, hydro and gas...
Looking at the above table, the Coal, Nukes, Gas, and to a pretty great extent geothermal have a CF less than (100%-breakdown), simply because they are dispatchable generation, being called upon by, and marketted into a market...they could all be run flat out at 95%CF (100%-breakdown) if need be.
Europe is feeling the sting from wind, as they have been building their farms on 30% CF,and getting mid 20s...people have been talking up the wind, getting funding, and underdelivering....they need to put in 4 times nameplate, and still make an allowance for no wind days.
NATE1979, and you have to allow for non wind days in the system...or start cutting off the customers...or having the old standbys there, available at a few minutes notice to prop up wind, and carry solar through the night.
turtlevette is part right, hydro pumped storage is great.
Need an order of magnitude more solar and wind than the nameplates, generating as and when they can pumping water up hill, to dams that don't exist yet and would never get approvals if they were proposed, and enough hydro to replace the current baseload...and still need some massive machines with huge intertias, governors, and a governing margin running full time to control the frequency of said system.
Thermal isn't going away (it may, and should well be nukes), but it's needed to be there.
And the CF table needs to be read with what the plant can produce 24/7 should it be needed in mind.
My point was that there is nothing new here. I have sat through many technical reviews of PV technology as part of my job. This type of comparison is always taken into account when you review serious cost per watt comparisons (or grid parity).
Cost per watt is cost per watt. If I want so much power within a year I have to build certain size plants to output that much power. Those plants have a CAPEX and OPEX.
So, this type of "comparison" of yearly energy output is a way to negatively put in light those technologies whose output is not consistent.
The error here is people who compare directly nameplate capacity of one plant vs another plant. This is the fault of the ignorant person doing the comparison not the technology because the people who actually do this for a living this is nothing new.