ใครว่างๆ ช่วยแปลให้ผมหน่อบครับ

Generating Electricity in the Future

One of the major difficulties in using electricity instead of fossils is that most electricity is produced  using coal and natural gas. In the United States for example . 70 % of all electricity is generated by coal and natural gas-fired power plants of consequently society will not only need to generate greater amounts of electrical power but also produce progressively less of it with fossil fuels. considering the vast amount of energy we consume accomplishing this goal will be difficult. the solution is to make use of existing technology to ramp up electrical production on a massive scale and from as many non-carbon sources as possible. At the same time we should reduce  electrical  consumption through  the expanded  use of solar heating and  geothermal heat.  Equally  important  would be conservation and  increased efficiency measures. Note that clean coal  technology and carbon sequestration  ( Chapter 16 )  many make it feasible to continue generating electricity but it is not yet known whether the new technology  will work on a large scale.
         One  of  the common objections regarding the use of non-carbon and renewable  of generating electricity  is  that higher  costs  will  harm  the economy . From  Table 14.1 one can see  that coal  and natural  gas are generally  the most economical  means of producing  electricity. However if one includes the environmental costs associated with fossil fuels  (e.g. pollution and global warming )  these fuels become economically less attractive  .Proposed taxes  and so-called  cap-and-trade  systems  (Chapter 16 )  are designed  to address the environmental  impacts of fossil fuels and to make alternative sources more  cost  competitive. Also note in Table  14.1  that nuclear power is relatively expensive compared to coal and natural gas. As described earlier the higher cost of nuclear power is one of the primary reasons U.S. utility companies stopped  building new plants after 1990.
         Another key aspect of electrical power is whether a  particular energy source used to generate electricity is  available  continuously or intermittently.  Because  electricity  cannot  be  stored  in large quantities  utility companies  are  forced to  generate  enough electricity to  meet whatever the demand is  twenty-four  hours a day  seven days a week.   As  illustrated in Figure  14.31  electrical demand itself fluctuates  reaching  a peak in the  afternoon and then dropping to a minimum called base lose.  This base load always occurs at night when human activity  is  at its lowest . Power  
FLGURE 14.31 Electrical demand and production fluctuates on a daily cycle  which  is related to human and industrial activity.  Demand goes up during   the day as human activity increases   then  falls to a minimum or  base level at night.  Utility companies must provide a steady amount of power to meet base load requirements  yet maintain enough excess capacity to ensure that peak demand can be throughout the year.
plants therefore must continuously produce enough power to meet base load demand  and yet still have enough additional capacity to meet  peak demand  each and every  day.  Electric utility companies generally prefer  stored forms of energy  particularly   fossil and nuclear power  because they make it adjust production to meet the constantly changing demand.  In contrast  intermittent forms  of energy  such ad solar and wind do not same flexibility in adjusting electrical  production to meet demand.  Tidal power is highly  reliable  but it is not continuous due to the cyclic  nature of tides.  Hydro and geothermal energy are storms of energy that can produce  electricity   continuously   but  suitable   sites  are   geographically  limited  thus are  not   available everywhere.   Finally  there is  ocean  thermal energy    conversion  (OTEC)    which can generate electricity in a continuous manner.  The problem is that  OTEC  is restricted  t o tropical  waters  and  large-scale  commercial production has yet to occur.
         Ultimately  there are two basic issues that need to be resolved for the United States to replace fuels s its primary  of  generating  electricity.  The first  is that  United States must finally  open its disposal  site for high-level radioactive waste from nuclear power plants  ( Chapter 15 ).The waste disposal issue must be addressed before  nuclear   which has a proven  record of  providing  large amounts power  can be expanded significantly. The  other  is that  intermittent  forms  of energy need  to be  integrated into the  electrical grid  ( collection of transmission lines ) in such a way that utility companies still meet daily  peak demand .  One solution would be to feed electrical  power from solar  wind  and tidal sources into  the  intermittently then use the flexibility  of nuclear power plants to ensure that peak demand would always be met.  Another option would be for power companies to product excess electricity at night from wind and tidal  and then use it to product hydrogen. The hydrogen  could later  be  used  in  fuel cells to  generate  electricity  and help meet  peak  demand  or to  fill intermittent gaps in production due to cloudy skies or decreased winds .  The hydrogen could also be sold to filling stations to power care that run on hydrogen fuel cells.
          Some  energy  experts  believe that in  the future  electricity will not be  supplied  solely from  relatively   small  number of large  centralized power  plants as  is the case  today .  As illustrated in Figure 14.32  what is envisioned  instead is a more  decentralized  system in which  electricity  is  produced from numerous sources distributed across the grid . Such a distributed system will  likely include nuclear power plants to ensure that to electrical is  met during  periods when  various  intermittent  sources are not providing power.  Although more complicated   this  system  is  feasible  because  solar  wind  and tidal  resources  are  usually  intermittent  at different   times.  For  example   wind  and  tidal  can  still  be generating  power  at night  at  when  solar is not available  whereas solar can provide energy during   the day to help fill gaps in wind
         FIGURE   14.32   Homes  and  businesses   receive   power  from   an   electric   grid  system  consisting  of interconnected  transmission lines. Most grids today receive power from a few centralized power plants but as electrical l  production  from  alternative  sources  increases  grids will become  more  decentralized. Eventually rooftop photovoltaic panels (photo inset) will allow individual homes to feed excess electricity  back into grid  creating a more  distributed   system  of  power  generation.  Excess  electricity   cold also  be used  to  product hydrogen for hydrogen for filling care that run on hydrogen fuel cells.
                        

ช่วยแปลหน่อยครับ T.T
แสดงความคิดเห็น
โปรดศึกษาและยอมรับนโยบายข้อมูลส่วนบุคคลก่อนเริ่มใช้งาน อ่านเพิ่มเติมได้ที่นี่