ENABLING HIGH PENETRATION OF WIND ENERGY IN THE PACIFIC NORTHWEST - PowerPoint PPT Presentation

ENABLING HIGH PENETRATION OF WIND ENERGY IN THE PACIFIC NORTHWEST OPERATING ENVIRONMENT Cesar Silva Monroy – Graduate Student Prof. Richard D. Christie University of Washington Energy Seminar – Sept. 25, 2008

OVERVIEW 1. Introduction 2. Wind Integration Issues 3. High Penetration Examples 4. Measures of the Problem 5. Strategies for Integration 6. Conclusions Slide 2

1. INTRODUCTION • Wind power is growing rapidly in the U.S. and worldwide because: – Increased concern on climate change and as part of efforts to reduce greenhouse gases – Government policies such as production tax credit (PTC) to promote the use of renewable energy technologies – Public initiatives, also known as renewable portfolio standards (RPS), such as the Washington Energy Independence Act (I-937) – Wind power technology advances such as higher wind capacity factors and lower O&M costs Source: 20% Wind Energy by 2030, DOE Source: Annual Report on U.S. Wind Power Installation, Cost, and Performance Trends: 2006, DOE Slide 3

2. WIND INTEGRATION ISSUES • Wind’s variability and uncertainty makes wind power different from other conventional power plants – Feb 24, 2008: Approximately 1.1 GW of industrial and commercial loads served by ERCOT (Texas) were shed as emergency response to drop in West Texas wind energy production from 1700 MW to 300 MW in about 2½ hours – June 1, 2006: Portugal suffered a 700 MW wind energy decrease, corresponding to 60% of capacity in 8 hours – Jan. 8, 2005: There was a decline of 2000 MW, 83% of total capacity, in a period of 6 hours in Denmark – Dec. 24, 2004: More than 4000 MW of wind energy decrease within 10 hours which corresponds to 58% of capacity in North Germany Slide 4

2. WIND INTEGRATION ISSUES • When compared to conventional generation, wind’s stochastic nature results in: – Lower controllability – Higher variability – Lower predictability 45 40 Wind speed (mph) 35 30 25 20 15 10 5 0 3/12 3/19 3/26 4/2 4/9 Time Data source: Idaho National Lab Slide 5

2. WIND INTEGRATION ISSUES • Power system operation before wind power: Generation = Load – Generation is controllable and schedulable – The load follows a pattern highly predictable – Power system paradigm: Generation changes to match the load variations Slide 6

2. WIND INTEGRATION ISSUES • Power system operation with wind power: – Wind generation is not controllable and difficult to schedule – Wind is a paradigm shift for the power system: Controllable generation changes to match the load minus the stochastic generation variations Controllable Generation = Load - Stochastic Generation • Today, power systems use their imbalance capability employing controllable generation to cope with wind power variations Slide 7 Source: 20% Wind Energy by 2030, DOE

2. WIND INTEGRATION ISSUES • What happens when the controllable generation cannot follow these variations? • There will be incidents such as violations to control performance standards or system instability • How can these incidents be avoided? • Identifying wind penetration limits – Economic limit : cost-effectiveness of new wind power plants is driven down by the high costs of interconnecting new wind projects, making them economically not viable – Control limit : the power system does not have sufficient resources to meet ACE criteria such as CPS1 and CPS2 – Physical limit : wind power variations could result in power system collapse $/MWh Integration cost Wind (%) l E l C l P penetration Slide 8

2. WIND INTEGRATION ISSUES • The relationship between cost and wind penetration levels is particular to each system • We want to allow for wind integration at lowest possible cost • How to increase controllable resources at lowest possible cost, shifting the wind integration cost curve and limits? $/MWh Integration cost Wind (%) l E l E l C l P penetration • New paradigm: Controllable resources must match the variations from non- controllable resources • Increasing controllable resources will allow higher penetration levels Slide 9

2. WIND INTEGRATION ISSUES • As wind penetration increases, the way traditional generators operate will change MW – Base load units P pk – Marginal units – Peaking units Load 0 8760 Hours • How does this change in operation practices affect current controllable generation? • How does it affect other infrastructure in the power system? Slide 10

3. HIGH PENETRATION EXAMPLES a. Denmark b. Ireland c. Spain d. Western U.S. Slide 11

3. HIGH PENETRATION EXAMPLES • The Western U.S. is a leader in the U.S. in terms of total wind installed capacity (California: 2,439 MW, Washington: 1,163 MW and Oregon: 882 MW) • An addition of new wind projects is expected in order to meet new demand for renewable energy as required by RPS in WA, OR and CA • Increase wind installed capacity across the Western interconnected system • How does this situation compare to other examples of high wind penetration? • Europe presents many scenarios with different characteristics Slide 12 Source: Annual Report on U.S. Wind Power Installation, Cost, and Performance Trends: 2006, DOE

3a. DENMARK • Wind energy was supplying over 20% of the energy demand in Denmark by the end of 2006 • Denmark is interconnected to the Nordic countries, Germany and France • Nordic countries have a lot of hydro-generation (Norway: 99%, Sweden: 50%, Finland: 17%) • The mix generation resource in France is dominated by nuclear energy (78.3% of total electric power generation) • Germany also has wind generation spread along the country, with a higher concentration in the Northeast region (5.7% wind penetration) • Denmark can export wind energy when the wind blows, and import it when it does not • The regional wind penetration level is high, but the system penetration level is low • Wind is geographically spread over the country Slide 13

3b. IRELAND • Wind supplies nearly more than 7% of Ireland’s energy demand according to data from 2007 • Small electric system with low level of interconnection to other systems • The primary fuels used to generate electricity are natural gas, coal and peat • Renewable energy will continue to grow thanks to energy policies with targets such as: – Supply of 15% and 33%of total electricity consumption using renewable sources by 2010 and 2020 respectively – 500 MW installed tidal energy by 2020 • The Irish government has also set targets for increasing the interconnection capacity of the island Slide 14

3c. Spain • Wind power plants reached 16% of the total intalled capacity in Spain and supplied 10% of the electric energy in 2007 • Spain’s electric grid is managed by a single entity or system operator (Red Electrica de España) • Installed capacity (86 GW) is far greater than the peak demand (45GW) • Wind is geographically diverse • Generation mix is composed of mainly combined cycle units (24%), hydro (19%), nuclear (9%) and coal (13%) REE presentation – Wind forecasting workshop, Portland, OR 2008 Slide 15

3d. WESTERN U.S. • Most of wind power generation is concentrated in areas like western Washington and Oregon • Load centers are generally located far from the wind generation areas • Wind power seems to be located in the wrong side of the transmission bottlenecks • The generation mix is dominated by hydro-generation in the Pacific Northwest • California presents a different generation mix, with natural gas being the primary fuel • All of these conditions make the Western interconnection system a very particular case for wind integration Slide 16

4. MEASURES OF THE PROBLEM a. Control Performance Standards (CPS1 and CPS2) b. Loss of Load Probability (LOLP) and Expected Unserved Energy (EUE) c. Reserves Slide 17

4a. CONTROL PERFORMANCE STANDARDS • Control Performance Standards (CPS) 1 and 2 were developed under the old power system paradigm • Intended to identify areas with poor control performance • The Area Control Error (ACE) is used as the basis of analysis • Statistical analysis that deals with the body of the error probability distribution, and not with the tail • Are these standards too strict in an environment with high stochastic penetration? Should they be relaxed? Slide 18

4b. LOSS OF LOAD PROBABILITY AND EXPECTED UNSERVED ENERGY • LOLP is a measure for comparing service reliability and is “the fraction of time during which loss of load may be expected to occur during any future period” • EUE is defined as “expected amount of energy not supplied by the generating system during the period of observation, due to capacity deficiency” • These indicators are based on probability analysis • Some important questions are: – Are they adequate for stochastic resources? – Do they need to be redefined in the presence of new controllable resources such as demand response and wind curtailments? Slide 19

4c. RESERVES • Current methods for reserve estimation are operating fine for present levels of wind integration • As wind penetration level increases it is necessary to capture the need for increasing reserves • Are current methods adequate for this task? • A too low value of reserves results in excessive interruptions • A reserve value too high results in excessive costs • Do current reserve definitions capture all the controllable aspects of the power system? Slide 20