Expansion and Operation Strategies in a Renewable and Hydro-Based Island Power System

Transcription

1 Expansion and Operation Strategies in a Renewable and Hydro-Based Island Power System 4th IEEE and Cigré International Workshop "Hydro Scheduling in Competitive Markets", Radisson Blu Royal Hotel in Bergen, Norway, Bergen, June 14th - 15th, 2012 Egill Benedikt Hreinsson University of Iceland May 30, 2012 Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable and May Hydro-Based 30, 2012Island1 Power / 22 S

2 Outline 1 Introduction The objectives of the paper Icelandic system overview with generation and resources 2 Generic model formulation 3 Modeling requirements and time frame LTM and STM interaction Zones for different time scales Time scale decomposition STM time scale representation 4 Conclusions Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable and May Hydro-Based 30, 2012Island2 Power / 22 S

3 Introduction The objectives of the paper The objective of the paper Give an overview of generation, load and resources in the small island system of ICELAND. Discuss new markets and export with wind integration. Present a generic hydro based system operations problem. Discuss model objectives and time frame (scale) requirements for this problem Draw some conclusions regarding modeling approaches to meet future requirements Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable and May Hydro-Based 30, 2012Island3 Power / 22 S

4 Introduction Icelandic system overview with generation and resources The Iceland Electrical Power System Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable and May Hydro-Based 30, 2012Island4 Power / 22 S

5 Introduction Icelandic system overview with generation and resources Review of generation Total installed capacity in Iceland about 2.5 GW. Principal plants: Hydro: Geothermal: Kárahnjúkar (690 MW) Hellisheiði (303 MW) Búrfell (270 MW) Nesjavellir (120 MW) Hrauneyjafoss (210 MW) Reykjanes (100 MW) Blanda (150 MW) Svartsengi (75 MW) Sigalda (150 MW Krafla (60 MW) Sultartangi (120 MW) Bjarnarflag (3 MW) Sog (90 MW in 3 plants) Krafla (60 MW) Vatnsfell (65 MW) Straumsvík (35 MW) (Gas Andakíll (8 MW) turbine) Elliðaár (3 MW) Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable and May Hydro-Based 30, 2012Island5 Power / 22 S

6 Introduction Icelandic system overview with generation and resources Location of Hydro and Geothermal Projects Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable and May Hydro-Based 30, 2012Island6Power / 22 S

7 Introduction Icelandic system overview with generation and resources Geothermal stations Reykjanesvirkjun Kröflustöð Svartsengi Nesjavallavirkjun Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable and May Hydro-Based 30, 2012Island7Power / 22 S

8 Introduction Icelandic system overview with generation and resources Hydroelectric stations Vatnsfellsstöð Fljótsdalsstöð Lagarfossstöð Mjólkárvirkjun Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable and May Hydro-Based 30, 2012Island8Power / 22 S

9 Introduction Icelandic system overview with generation and resources Dettifoss Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable and May Hydro-Based 30, 2012Island9Power / 22 S

10 Introduction Icelandic system overview with generation and resources Primary energy use in Iceland from 1940 to 2010 Primary energy utilization (PJ) Fractional breakdown: Coal Oil Peat Geothermal Hydro Coal Oil Geothermal Hydro Figure 2: Primary energy use in Iceland from 1940 to 2010 in PJ (PetaJoule) Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable andmay Hydro-Based 30, 2012 Island 10 Power / 22 S Mór

11 Introduction Icelandic system overview with generation and resources Electrical energy sales of Landsvirkjun Landsvirkjun Electricity sales (TWh/year) 14 Energy Intensive Industry General Demand Landsnet Alusuise (1969) Elkem (1979) Century Aluminium (1998) Alcoa (2007) Figure 3: Electrical energy sales of Landsvirkjun; Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable andmay Hydro-Based 30, 2012 Island 11 Power / 22 S

12 Introduction Icelandic system overview with generation and resources Submarine cable interconnections 1170 km 1250 km k 1900 km LEGEND: 760 km Iceland HVDC link options (Under consideration) North Sea Supergrid (Proposed) Existing Norned, 580 km Figure 4: Iceland HVDC Cable Routes, NORNED and the North Sea Supergrid Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable andmay Hydro-Based 30, 2012 Island 12 Power / 22 S

13 Generic model formulation Model formulation max p,x,v,s f (p) (1) f is the objective function representing benefit, such as income minus cost, and p is a vector of generation and load variables. (1) is subject to the following constraints, where (2) are the water balance equations with hydraulic network topology and deterministic inflow series: g w (v, x, s) = 0 (2) v is a vector of reservoir volumes, x is the release and s is spill in all periods in all reservoirs. The vector of Lagrange multipliers, Λ w, with (2) are water values at each instant in each reservoir or (3), Λ w = [ λ w1, λ w2, ]T (3) Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable andmay Hydro-Based 30, 2012 Island 13 Power / 22 S

14 Generic model formulation Load, network and market constraints Equation (4) are the load, network and market constraints: (See (8) below) g L (p) = 0 (4) Similarly, the vector of Lagrange multipliers, Λ L, associated with (4) are the shadow power prices at each instant at each node, or (5), Λ L = [ λ L1, λ L2, ]T (5) Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable andmay Hydro-Based 30, 2012 Island 14 Power / 22 S

15 Generic model formulation Technical generation constraints The technical generation constraints are in (6), representing, for instance, the nonlinearities and head dependence in hydro stations: g t (p, x, v) = 0 (6) Finally upper and lower bounds on all the variables are defined by (7): p min p p max v min v v max x min x x max s 0 (7) Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable andmay Hydro-Based 30, 2012 Island 15 Power / 22 S

16 Generic model formulation Subvector for generation/power flow This above definition can be represented by sub-vectors: p = p g p s p m (8) For all periods: p g is vector of generated power in hydro and thermal, (Wind is assumed a deterministic input) p s is a vector of the power flow in the electrical network, for instance using a DC/linear load flow representation (No voltage or phase angle). p m, is a vector of sold energy for instance on the spot market. Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable andmay Hydro-Based 30, 2012 Island 16 Power / 22 S

17 Modeling requirements and time frame LTM and STM interaction Long and short term models Long term model LTM u S u L Short term model STM Figure 5: LTM with time step of a week and a horizon of years. STM with a time step of 30 minutes and a horzon of weeks. Interacting variables (vectors) are u L and u S Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable andmay Hydro-Based 30, 2012 Island 17 Power / 22 S

18 Modeling requirements and time frame Zones for different time scales A generic power system v t,3 Zone 1 x t,3 p g,t,3 Hydro (2) v t,2 Other (5) p g,t,5 Hydro (3) x t,2 p g,t,2 v t,1 p g,t,1 x t,1 Hydro (1) LEGEND: Electrical transmission line Electrical substation/bus Water flow Electrical load/customers/market Time series inflow Electrical generator Zone 2 with both STM and LTM given the presence of short term phenomena Reservoir with inflow Zone 1 where short term phenomena such as daily reservoir fluctuations may be negligible. Therefore LTM may suffice "loads" Wind (4) Electricity spot market or specific contracts/customers Zone 2 Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable andmay Hydro-Based 30, 2012 Island 18 Power / 22 S

19 Modeling requirements and time frame Time scale decomposition Time decomposition into LTM, MTM and STM Load/demand Sep Nov Jan Mar May Jul Sep Nov Jan Mar LTM 1st operational year st operational month STM 24 hours/1 day Figure 6: Time decomposition into LTM, MTM and STM. A level below with very short variations (minutes) could be valuable for wind energy analysis { Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable andmay Hydro-Based 30, 2012 Island 19 Power / 22 S

20 Modeling requirements and time frame STM time scale representation STM interaction and representation 1 C1 - Continuous Load duration curve (LDC) by sorting 8760 hours/year into an LDC, as 1 year s distribution of load. Chronology is thereby removed, and is therefore not well suited to hydro systems with time interdependence. 2 L1 - Stepwise Long Term Load. Derive 12, 26 or 52 load values for a time step in LTM of a week, up to a month. 3 LC2 An LDC added in the week to account for variations within the week. 4 LS1. A complete chronology maintained in all periods of both the LTM (weeks) and STM (hours). 5 LSC. Here we assume the merging of LC2 and LS1: (a) flat load, (b) LDC with wind deducted and (c) total chronology Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable andmay Hydro-Based 30, 2012 Island 20 Power / 22 S

21 Conclusions Conclusions and Discussion Wind resources and spot markets seem likely to pose new interesting challenges to traditional hydro based system modeling and operations. LTM time scales have been used with good results for a hydro system without the wind resource. With the integration of wind and spot markets STM seems an important addition to interact with the new resources/markets and the LTM. The many possible ways of decomposing the time scale and interacting with data between the LTM and STM will affect the accuracy and computational efficiency and should be evaluated carefully with other modeling aspects and methodology. To address transmission constraints and losses in waterways, an STM seems an important aspect of the LTM modeling framework. Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable andmay Hydro-Based 30, 2012 Island 21 Power / 22 S

22 Conclusions Thank you Egill Benedikt Hreinsson University of Iceland Expansion () and Operation Strategies in a Renewable andmay Hydro-Based 30, 2012 Island 22 Power / 22 S