Basics of energy modelling III: Time representation and considerations CLEWS Summer School, ICTP (Trieste), Italy, 13 June, 2017

Time representation Long-term energy system models: Span a large time horizon (e.g. 2015 – 2050) Consider a large set of technologies Span a large geographical region (e.g. USA, Africa, Europe, China) Need to capture temporal variations: Variability of supply (e.g. wind, solar, hydro) Variability of demand (e.g. seasonal, monthly, weekly, daily) Peak load requirements Trade-off between level of detail and computational cost

What are Time Slices? Each year divided into representative time periods known as Time Slices: (Summer-Winter-Intermediate) x (Day- Night) = 6 Time Slices (Jan-Feb-Mar-…-Dec) x (Weekday- Weekend) x (Day-Night) = 48 Time Slices (365 days) x (24 hours) = 8760 Time Slices Number of Time Slices in OSeMOSYS is practically unlimited Time Slice definition is consistently applied for the entire model 8760 Electricity demand Water resources

Example of Time Slice definition 2017 2050 Model horizon Annual Seasonal Weekly Daily Source: R. Loulou, U. Remne, A. Kanudia, A. Lehtila, and G. Goldstein. Documentation for the TIMES model: Part I. ETSAP, April 2005

Time Slice-related parameters Year Split: Duration of each Time Slice as a fraction of a year Capacity Factor: Fraction of a technology’s capacity that can be utilized in each Time Slice Specified Annual Demand*: Fraction of annual demand for a commodity in a each Time Slice *Accumulated Annual Demand: Total annual demand for a commodity. Can be balanced in any Time Slice. Supply and demand for commodities is balanced for each Time Slice

Time Slice Definition (Example of Bolivia) Yearly load curve and hydro production for Bolivia in 2012. Based on the hydro power production and the months with high electricity demand, the year was split into the following sections

Time Slice Definition (Example cont.) Year divided in four Seasons Season 1: 1st January to 30th April Season 2: 1st May to 31st August Season 3: 1st September to 30th November Season 4: 1st December to 31st December

Time Slice Definition (Example cont.) Season 1 Season 2

Time Slice Definition (Example cont.) Season 3 Season 4

Time Slice Definition: Exercise 1 01:00-07:00 07:00-18:00 18:00-22:00 22:00-01:00 Seasons 6 hours 11 hours 4 hours 3 hours Season 1 (Jan-Apr) ? Season 2 (May-Aug) Season 3 (Sep-Nov) Season 4 (Dec)

Time Slice Definition: Exercise 1 Time (duration) 01:00-07:00 07:00-18:00 18:00-22:00 22:00-01:00 6 hours 11 hours 4 hours 3 hours Total = 24 hours Season 1 (Jan-Apr) 120 days 0.08219 0.15068 0.05479 0.04110 Season 2 (May-Aug) 123 days 0.08425 0.15445 0.05616 0.04212 Season 3 (Sep-Nov) 91 days 0.06233 0.11427 0.04155 0.03116 Season 4 (Dec) 31 days 0.02123 0.03893 0.01416 0.01062 Total = 365 days Total = 8760 hours

Exercise 2: Earlier example, with TimeSlices NOTE: ‘SpecifiedAnnualDemand’ instead of ‘AccumulatedAnnualDemand’ YearSplit Day Night 6:00-18:00 18:00-6:00 12 hours Summer 4 months 0.1667 Winter Intermediate SpecifiedDemandProfile Day Night 7:00-19:00 19:00-7:00 12 hours Summer 4 months 0.15 0.05 Winter 0.5 0.1 Intermediate

Exercise 2: Earlier example, with TimeSlices

Exercise 2: YearSplit

Exercise 2: SpecifiedAnnualDemand

Exercise 2: SpecifiedDemandProfile

Exercise 2: Demand

Exercise 2: Results

Exercise 2: Results