Variability and intermittency in generation

Assembled from 15 blocks · 3 evidence · 10 related

1. Story
2. The property that distinguishes wind and solar from every generator that burns something: their output is set by the weather rather than by an operator. It is worth separating three distinct problems that the single word "intermittency" conflates. The first is *variability* — output changes continuously, predictably in the case of the solar day, less predictably in the case of wind — and is handled by forecasting, reserve and flexible plant. The second is *diurnal mismatch*: solar produces at midday and demand peaks in the evening, a gap of hours that storage genuinely solves. The third is *sustained low output*: multi-day, region-wide conditions in which neither wind nor solar produces much, which is a problem of energy rather than power and which four-hour batteries do not address at any price. Capacity factors frame the scale of the task — solar photovoltaics typically deliver something like ten to twenty-five per cent of nameplate over a year depending on latitude and climate, onshore wind roughly twenty-five to forty-five per cent, offshore wind higher again. The cost of variability is therefore not a single number but a function of penetration: negligible at low shares, rising as the cheap flexibility is used up, and dominated at high shares by the rarest and least tractable events rather than by the average day.
3. Knowledge
4. Variability and intermittency in generation
5. Connections
6. Lithium-ion battery storage
7. Nuclear fission power
8. The duck curve
9. Dunkelflaute (dark doldrums)
10. Transmission and grid interconnection
11. German power prices spike during a December Dunkelflaute
12. Evidence
13. The reference source for world energy balances, final energy consumption by carrier, generation mix, technology cost trends and scenario pathways used throughout this pack. V55 verification basis: no edition was retrieved in this session — iea.org was refused by the network egress proxy — so every figure attributed to this series is stated as a magnitude with the specific gap named on the citing record, and no current-year quantity should be presented to a reader without confirmation against a named edition.
14. Supports the sectoral emission structure used throughout this pack, the treatment of industry process emissions as distinct from energy emissions, the assessment of technology cost declines in solar, wind and storage, and the identification of aviation, shipping and heavy industry as hard-to-abate. V55 verification basis: not retrieved in this session; no chapter, table or page number is cited because none could be confirmed, and every sectoral share attributed here is given as a range rather than a figure.
15. Supports the description of the net-load shape, the deepening midday belly and steepening evening ramp, and the growth of solar and wind curtailment in California. V55 verification basis: not retrieved in this session; the original duck chart publication year is given as approximate, and no ramp magnitude or curtailment volume is quoted as a figure.