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An  Introduction  to  the  Electrical  Grid  By  Nicholas  L.  Cain  (nicholas.cain  [at]  cgu)  February,  2013    The  electrical  grid  transports  electricity  from  power  plants  to  customers  via  a  complex  network  of  transmission  lines,  substations  and  distribution  circuits.  With  utilities  required  to  make  use  of  renewable  energy  from  both  remotely  located  and  distributed  power  sources,  grid  operators  face  a  host  of  challenges.      Authorities  in  developing  nations,  such  as  China  and  India,  are  rapidly  building  new  transmission  systems  to  meet  demand.  In  advanced  industrial  nations,  such  as  the  US,  operations  have  never  been  more  complicated  with  requirements  to  balance  intermittent  sources  of  renewable  power  (such  as  wind  turbines)  with  traditional  power  plants,  ensure  distributed  energy  resources  are  safely  used,  and  protect  against  disruptions  caused  by  weather  or  accident.      The  traditional  design  of  the  power  grid  in  most  nations  consists  of  overhead  high  voltage  transmission  lines  (HVTLs)  that  move  alternating  current  (AC)  power  long  distances  on  large  towers  (see  diagram  below).  AC  power  is  constantly  changing  direction  at  a  set  frequency  (in  the  US,  60  cycles/second).  Transmission  lines  are  connected  to  lower  voltage  sub-­‐transmission  and  distribution  circuits  through  substations  where  power  is  switched  and  converted.      

 Source:  U.S.  Department  of  Energy,  "Benefits  of  Using  Mobile  Transformers  and  Mobile  Substations  for  Rapidly  Restoring  Electric  Service:  A  Report  to  the  United  States  Congress  Pursuant  to  Section  1816  of  the  Energy  Policy  Act  of  2005."  2006  

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One  common  misconception  is  that  the  power  grid  is  one  integrated  system.  In  fact,  the  power  transmission  system  in  the  US  is  composed  of  three  regional  power  grids  (Western,  Eastern  and  Texas)  each  of  which  is  a  complicated  network  of  power  lines  and  generation  facilities  administrated  in  large  part  by  independent  system  operators  (ISOs)  or  regional  transmission  organizations  (RTOs)  (see  diagram  below).    

 Source:  FERC,  Accessed  2/21/13:  http://www.ferc.gov/industries/electric/indus-­‐act/rto/elec-­‐ovr-­‐rto-­‐map.pdf    Developments  in  the  electrical  grid  are  driven,  in  part,  by  the  generation  facilities  that  utilities  are  buying  power  from,  by  demand  from  customers  to  make  use  of  distributed  resources  and  by  endogenous  trends  in  transmission  technology.  The  American  Associate  of  Civil  Engineers  called  in  2009  for  an  additional  $29.5  billion  in  yearly  spending  (over  five  years)  to  modernized  the  existing  grid  and  improve  the  nation’s  power  infrastructure  (ASCE,  2009).  To  aid  our  understanding  of  transmission,  let’s  look  briefly  at  these  major  trends.    

Renewable  Energy  and  Renewable  Portfolio  Standards  

The  deployment  of  US  renewable  energy  generation  facilities  has  grown  significantly  in  the  last  decade.  Over  the  first  quarter  of  2011,  American  renewable  energy  production  (11.6%)  was  greater  than  the  production  of  energy  from  nuclear  power  (11.1%)  (Giest,  2011).  The  exploitation  of  these  renewable  resources  is  being  driven  by  various  environmental  quality  laws  and  by  renewable  portfolio  standards  (RPS),  which  require  that  a  certain  amount  of  customer  load  be  served  by  renewable  sources.  RPS  have  also  been  used  in  Europe  and  Asia  at  the  national  level.  To  meet  

REGIONAL TRANSMISSION ORGANIZATIONS

This map was created using Energy Velocity, December 2012

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these  goals,  and  to  comply  with  air  quality  and  water  quality  regulations,  utilities  have  been  buying  and  planning  to  buy  remote  sources  of  renewable  energy  such  as  wind,  solar,  geothermal,  biomass  and  small-­‐scale  hydropower.1    In  the  US,  hydropower  and  biomass  were  the  two  largest  sources  of  renewable  energy  in  recent  years,  however,  wind  power  has  also  grown  into  a  significant  source.  Although  installations  of  solar  and  geothermal  are  growing,  the  overall  amount  of  power  produced  from  these  sources  is  small  (US  EIA,  2013).  However,  this  is  beginning  to  change  with  the  development  of  several  dozen  large-­‐scale  desert  solar  projects  including  14  projects  with  6  GW  of  capacity  to  be  built  on  federal  land  in  the  desert  southwest  (MSNBC,  2012).  To  connect  these  remote  sources  of  power  to  the  grid  is  requiring  RTOs  and  utilities  in  the  US  to  invest  in  high-­‐voltage  transmission  projects.    

Micro-­‐Grids  and  Distributed  Energy  Resources  

Along  with  this  demand  to  integrate  remote  sources  of  renewable  power,  grid  operators  are  also  being  asked  to  fundamentally  reconfigure  the  distribution  network  to  allow  the  use  of  distributed  energy  resources  (DER).  In  addition,  damage  cause  by  recent  high-­‐profile  storms,  such  as  hurricane  Sandy,  is  stimulating  renewed  interest  in  micro-­‐grids,  which  allow  small  areas  to  isolate  themselves  from  the  larger  grid  in  an  emergency  and  make  use  of  DER  (Berst,  2013).  Although  distributed  energy  resources  can  reduce  the  need  for  new  transmission,  integrating  large  amounts  of  DER  is  requiring  major  investments  in  grid  control  and  monitoring.    

Electricity  Demand,  Demand  Management  and  Energy  Efficiency  

Since  the  grid  connects  producers  with  consumers,  how  much  energy  that  consumers  are  expected  to  require  is  an  important  area  of  research.  Although  residents  of  the  US  have  more  electronics  than  ever  before,  equipment  is  growing  more  efficient.  Improving  efficiency,  combined  with  the  sharp  economic  downturn  of  2009,  has  resulted  in  a  reduction  in  demand  for  power  (Smith,  2013).      Energy  efficiency  has  been  driven  by  everything  from  building  codes  to  appliance  standards.  Energy  efficiency  (EE)  programs  and  regulations  are  being  put  into  effect  by  every  level  of  government  and  by  a  wide  range  of  stakeholders  across  every  economic  sector  (Doris,  Cochran  and  Vorum,  2009).  EE  programs  include  rebates  for  energy  efficient  equipment  and  incentives  for  efficient  practices  and  purchases.    

                                                                                                               1  Large-­‐scale  hydropower  is  clean  in  that  it  produces  no  air  pollution,  however  the  environmental  and  social  impacts  of  large  dams  are  so  intense  that  it  is  usually  not  considered  a  renewable  source  of  power  by  most  state  RPSs.  These  impacts  can  include  the  emissions  of  GHGs,  along  with  destruction  of  habitat  and  disruption  of  ecosystems.  Worldwatch  Blog  outlines  the  issues  (Accessed  2/22/13):  http://blogs.worldwatch.org/revolt/revisiting-­‐the-­‐issue-­‐of-­‐emissions-­‐from-­‐hydropower/    

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Another  way  to  reduce  demand,  and  especially  peak  demand,  is  via  “demand  management”  techniques.  Some  utilities,  such  as  Southern  California  Edison  (SCE)  have  already  implemented  limited  automated  demand-­‐response  programs  that  allow  the  utility  to  modulate,  for  example  a  customer’s  air  conditioner  during  peak  hours  of  electrical  demand.  SCE  also  offers  a  range  of  special  rates  and  incentives  to  “peak  shave”  and  reduce  demand  during  times  of  highest  load.2  Demand  management  techniques  can  also  reduce  the  need  for  new  transmission  infrastructure.    

Smart  Grid  Technologies  

The  smart  grid  is  usually  understood  to  be  a  power  grid  that  features  integrated  computer-­‐based  systems  that  allow  two-­‐way  communication  with  customer  meters,  generation  supplies  and  other  grid  infrastructure  (see  diagram  below).    

   The  development  of  the  smart-­‐grid,  industry  experts  claim,  will  enable  real-­‐time  demand  management,  allow  utilities  to  balance  DERs  and  remote  renewables,  and  monitor  and  control  the  grid  to  ensure  reliability  in  the  face  of  equipment  failures  or  natural  disasters.                                                                                                                      2  SCE  lists  13  separate  programs  and  incentives  under  “demand  response.”  These  range  from  discounts  for  customers  who  reduce  remand  on  peak  to  direct  control  of  equipment.  See  full  list  online  at  (Accessed  2/20/13):  http://www.sce.com/b-­‐rs/demand-­‐response-­‐programs/demand-­‐response-­‐programs.htm#Automated_Demand_Response    

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One  well-­‐known  component  of  the  smart  grid  is  the  household  smart  meter,  which  is  remotely  readable  via  wireless  technology.  However,  smart  grid  technologists  would  highlight  that  smart  meters  are  just  one  possible  piece.  An  even  more  crucial  area  of  innovation  is  in  the  digital  control  of  grid  infrastructure  such  as  generation  facilities,  HVTLs,  substations  and  line  equipment.      Computer-­‐based  visualization,  control  and  management  technology  for  large-­‐scale  infrastructure  has  already  become  standard  in  the  US  for  major  grid  operators,  such  as  the  California  Independent  System  Operator  (CAISO)  (pictured  below).    

 Folsom  control  center  of  California  Independent  System  Operator.  Accessed  2/22/13:  http://www.caiso.com/about/ISO%20Photo%20Library/ControlCenterFolsom1_resized.jpg      In  pilot  programs  being  funded  by  the  federal  government,  operators  are  attempting  to  create  sophisticated,  integrated,  two-­‐way  systems  that  fuse  real-­‐time  grid  control  with  control  of  distributed  energy  resources  and  customer  equipment.  This  area  of  smart  grid  development  allows  utilities  to  match  demand  for  power  with  a  diverse  array  of  generation,  transmission  and  demand  management  assets  (U.S.  Department  of  Energy,  no  date).      Although  billions  are  being  invested  and  many  projects  are  being  put  into  place,  the  smart  grid  is  still  in  its  early  stages.  The  U.S.  Department  of  Energy  has  also  created  a  Smart  Grid  Investment  Grant  project  that  has  dispersed  $3.4  billion  in  funding  to  various  projects.  Despite  this  investment,  according  to  some  utility  managers,  “we  still  have  a  long  way  to  go”  in  constructing  a  US  smart  grid  (Edmonds,  2013).    

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Environmental,  Social  and  Political  Issues  The  grid  has  impacts,  both  environmental  and  social.  Power  infrastructure  is  a  classic  locally  unwanted  land-­‐use  (LULU)  and  the  perceived  negative  externalities  of  generation  facilities,  power  lines,  and  substations  can  generate  substantial  and  sustained  individual  opposition  (Cain  and  Nelson,  2013).    Regulatory  issues  are  challenging  for  power  lines  because  they  are  usually  large-­‐scale,  running  hundreds  of  miles  and  crossing  many  federal,  state  and  local  boundaries—  thus  requiring  oversight  from  many  levels  of  government  and  the  participation  of  many  stakeholders.    The  regulatory  environment  is  complicated.  CAISO,  for  instance,  is  regulated  by  the  Federal  Energy  Regulatory  Commission,  complies  with  technical  standards  administered  by  the  North  American  Electric  Reliability  Corporation,  and  is  part  of  the  Western  Electricity  Coordinating  Council  (WECC).  Generation  facilities  are  licensed  by  states,  but  require  local  land  use  permits.  Transmission  facilities  are  often  multi-­‐state  and  thus  require  regional  coordination  or  interstate  planning  as  well  as  relevant  involvement  of  municipalities  and  stakeholders  along  the  way.  

Conclusion  The  US  doubtlessly  needs  significant  investment  in  the  systems  that  compose  our  grid—to  modernize  existing  equipment,  add  smart  grid  systems,  and  improve  the  high-­‐voltage  backbone  to  move  renewable  power  to  cities.      At  the  regional  level,  improvements  to  the  US  grid  could  also  allow  the  balancing  of  large  amounts  of  renewable  energy  with  gas-­‐fired  and  other  sources  of  baseload  generation.  A  new  paper  by  Budischak,  et  al  (2013)  outlines  how  the  PJM  grid  region  could  transition  to  an  almost  totally  clean  grid.  In  the  diagram  below,  the  authors  show,  using  four  years  of  real  weather  data,  that  100  GW  of  wind,  combined  with  sufficient  energy  storage,  and  gas-­‐fired  back  up,  can  generate  90%  to  99%  of  needed  power.    

   Some  industry  experts  and  researchers  believe  that  improving  the  connections  between  the  three  major  interconnects  could  improve  our  use  of  efficient  resources—and  the  Tres  Amigas  super-­‐conducting  interconnection  project  has  been  proposed  to  do  just  that  (Blair,  2012).  

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   Smart-­‐grid  based  approaches,  such  as  those  being  pioneered  by  Southern  California  Edison  in  Irvine  and  Consolidated  Edison  in  New  York,  are  another  possible  future.  In  this  vision  grid-­‐scale  renewables  and  fossil  fuel  generation  sources  work  in  tandem  with  dispatchable  distributed  energy  resources,  electric  vehicles,  and  real-­‐time  demand  management  to  maximize  efficiency  and  reduce  emissions  (U.S.  Department  of  Energy,  2010).

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References  American  Society  of  Civil  Engineers  (ASCE)  (2009).  2009  Report  Card  for  American’s  Infrastructure.  

Accessed  2/21/13:  http://www.infrastructurereportcard.org/fact-­‐sheet/energy  

Bahrman,  M.  (2013).  HVDC  (high  voltage,  direct  current)  and  Grid  Modernization.  Altenergyman.com.  Accessed  2/21/13:  http://www.altenergymag.com/emagazine/2013/02/hvdc-­‐high-­‐voltage-­‐direct-­‐current-­‐and-­‐grid-­‐modernization/2039  

Blair,  S.  (2012).  Tres  Amigas  to  Link  Grids.  ENR:  Engineering  News-­‐Record,  269(12),  8-­‐9.  

Berst,  J.  (2013).  NJ  utility  proposes  $3.9  billion  to  protect  grid  from  future  megastorms.  Accessed  2/21/13:  

http://www.smartgridnews.com/artman/publish/Business_Strategy/NJ-­‐utility-­‐proposes-­‐3-­‐9-­‐billion-­‐to-­‐protect-­‐grid-­‐from-­‐future-­‐megastorms-­‐5533.html  

Budischak,  C.,  Sewell,  D.,  Thomson,  H.,  Mach,  L.,  Veron,  D.  E.,  &  Kempton,  W.  (2012).  Cost-­‐minimized  combinations  of  wind  power,  solar  power  and  electrochemical  storage,  powering  the  grid  up  to  99.9%  of  the  time.  Journal  of  Power  Sources.  

Cain,  N.  L.,  &  Nelson,  H.  T.  (2013).  What  drives  opposition  to  high-­‐voltage  transmission  lines?.  Land  Use  Policy,  33,  204-­‐213.  

Doris,  E.,  Cochran,  J.,  and  Martin  Vorum.  (2009).  Energy  Efficiency  Policy  in  the  United  States:  Overview  of  Trends  at  Different  Levels  of  Government.  NREL/TP-­‐6A2-­‐46532.  Accessed  2/21/13:  http://www.nrel.gov/docs/fy10osti/46532.pdf  

Edmonds,  M.  (2013).  Managing  the  Smart  Grid.  GridTalk:  S&C  Electric  Company’s  Corporate  Blog.  Accessed  2/21/13:  http://www.sandc.com/blogs/index.php/2013/01/managing-­‐the-­‐smart-­‐grid/  

Giest,  E.  (2011)  Renewable  Energy  Production  Surpasses  Nuclear  in  U.S.  Forbes.  7/7.  Accessed  2/21/13:  http://www.forbes.com/sites/ericagies/2011/07/07/renewable-­‐energy-­‐production-­‐surpasses-­‐nuclear-­‐in-­‐u-­‐s-­‐2/  

Kiger,  P.  (2012)  High-­‐Voltage  DC  Breakthrough  Could  Boost  Renewable  Energy.  Accessed  2/21/13:  http://news.nationalgeographic.com/news/energy/2012/12/121206-­‐high-­‐voltage-­‐dc-­‐breakthrough/  

O’Grady,  E.  (2012)  Sluggish  electric  demand  plagues  U.S.  utilities.  Reuters.  May  11.  Accessed  2/21/13:  http://www.reuters.com/article/2012/05/11/utilities-­‐us-­‐demand-­‐idUSL1E8SB40C20120511  

Smith,  R.  (2013)  U.S.  Electricity  Use  on  Wane.  The  Wall  Street  Journal,  January  2.  

U.S.  Department  of  Energy,  Smart  Grid:  An  Introduction.  U.S.  Department  of  Energy.  Accessed  2/21/13:  http://www.smartgrid.gov/the_smart_grid  

U.S.  Department  of  Energy  (2010).  Southern  California  Edison  Company:  Irvine  Smart  Grid  Demonstration  Project.  Accessed  2/22/13:  http://www.smartgrid.gov/sites/default/files/socal-­‐edison-­‐oe0000199-­‐final.pdf  

Appendices  Data  Sources  of  Note:  This  Energy  site  has  a  useful  tool  to  compare  the  capacity  factor  and  LCOE  for  various  kinds  of  generation:  http://en.openei.org/apps/TCDB/