James Goddings 3131147

Case Study of Fawley Power Station
10/2014
Module title: Thermofluids (EEA_5_104_1415)
Module Leader: Dr. Mark Ellis
Course: Mechanical Engineering (BEng) 592
Student Name: James Goddings
Student Number: 3131147
London South Bank University
Department of Mechanical Engineering
Faculty of Engineering, Science and the Built Environment
103 Borough Road, London, SE1 0AA
www.lsbu.ac.uk

Case Study of the efficiency of Fawley Power Station JamesGoddings3131147
2
Contents
Background..................................................................................................................................3
Scope...........................................................................................................................................4
Analysis........................................................................................................................................4
Discussion.................................................................................................................................. 17
Conclusion ................................................................................................................................. 19
Tables........................................................................................................................................ 20
References................................................................................................................................. 22

3
Background
In the early 1970s the population of the U.K. was increasing, household electrical appliances
were becoming more affordable, and industry was becoming more energy intensive. This
resulted in an “annually increasing demand for electricity of 8%, which corresponds fairly
closely to an exponential growth rate with a doubling time of less than 10 years.” (2.)
This required the Central Electricity Generating Board to initiate the construction of the
equivalent of four 2MW power stations annually to meet the current demand and provide
future capacity for increasing demand.
An ambitious scheme of building a series of very high output fossil fuelled power stations,
alongside a continuing development of nuclear power stations was embarked upon. Fawley
is an example of one the fossil fuelled plants that was designed to be one of the largest and
most efficient steamcycle power generation stations in the world.
It was decided that a series of plants with three to four 500MW generation sets would be
commissioned. The location of these plants was decided upon to spread the demand on the
National Grid the proximity of sites to water for cooling and proximity and transport delivery
access of fuel.
“The condenser cooling water requirement for a directly cooled station such as Fawley at
full load is between 4.5 and 6.5 x l09 litres per day, or about five times the dry weather flow
of the Thames at Teddington.” (2.). For this reason the plant was situated at the mouth of
Southampton water, adjacent to the Solent and Fawley Oil Refinery, which was decided
upon as the most suitable fuel source. At the time of conception oil was inexpensive, during
1974 this was to change, however coal would have been unfeasible, ”the ‘normal operation’
of such a station calls for about 20 return journeys per working day of the largest currently
practicable coal trains.” (2.) This claimwill be investigated further in the final section.

4
Scope
The scope of this report is to investigate the efficiency of one of the 500MW generator sets
at Fawley, this will be supported by data and information obtained from a literature review
and a visit to a similar oil fired power plant at Littlebrook, consisting of 3 660MW generator
sets, built in the early 1980s.
Analysis
Figure 1.1 is a schematic for one 500MW generator set at Fawley Power Station which has
been simplified to include a single Open Feedwater Heater and a single Low Pressure
Turbine (LPT), that along with the High Pressure Turbine (HPT) and Intermediate Pressure
Turbine (IPT) drive the Generator via a common shaft. It includes a single Reheat Cycle
between the HPT and IPT excludes waste heat exchangers that preheat the water and oil fed
to the boiler, however later an assumption is made that approximately accounts for this
omission.

5
Boiler
Main Feedwater
Pump
Condensate Extraction Pumps with
De-aerator
Condenser
500MW
Generator
Open
Feedwater
Heater
HPT IPT LPT
Figure 1.1 Schematic of Fawley Power Station Numbering Steam
States at Each Stage

6
Figure 1.2 is a hand drawn scale chart of the steam cycle for the schematic in Figure 1.1
describing the Temperature and Entropy of the water/steam at each stage in the cycle, and
by inclusion of the saturation curve, also describing the state/quality of the water/steam.
This chart has been produced with reference to (1.) and Table 1.1 which has been populated
by reference to (1.) and by the following calculations.
Calculation 1.1 An example of a linear regression calculation, calculating the temperature at
System State ① with data from (1.)
𝑇① = (
( 𝑇𝑦 − 𝑇𝑥)[°𝐶]
( 𝑃𝑦 − 𝑃𝑥)[𝑃𝑎]
∗ (𝑃𝑦 − 𝑃①)[𝑃𝑎]) + 𝑇𝑥
𝑇① = (
(29 − 26.7)[°𝐶]
(0.04 − 0.035)× 105[𝑃𝑎]
∗ (0.037 − 0.035) × 105
[𝑃𝑎]) + 26.7[°C] = 27.6[°C]
Linear regression was used to calculate the Temperature, Pressure, Entropy and Specific
Volume of each System State using data from (1.) where direct values were not present.
Calculation 1.2 Enthalpy calculation for the enthalpy at System State ②c with data from
Table 1.1 and (1.), including calculation of the isentropic work done by the Condensate
Extraction Pump.
ℎ② 𝑐 = ℎ① + 𝑊𝑐𝑒𝑝
𝑊𝐶𝐸𝑃 = 𝓋 𝑓①(𝑃② − 𝑃①)
ℎ② 𝑐 = ℎ① + 𝓋 𝑓①(𝑃② − 𝑃①)
ℎ② 𝑐 = 115.6 [
𝑘𝐽
𝑘𝑔
] + 0.0010037[
𝑚3
𝑘𝑔
] (38− 0.037) × 105
[𝑃𝑎]
ℎ② 𝑐 = 119.4[
𝑘𝐽
𝑘𝑔
]
𝑊𝐶𝐸𝑃 = 3.8[
𝑘𝐽
𝑘𝑔
]

7
Calculation 1.3 Enthalpy calculation for the enthalpy at System State ④ with data from
Table 1.1 and (1.), including calculation of the isentropic work done by the Feedwater Pump.
ℎ④ = ℎ③ + 𝑊𝑐𝑒𝑝
𝑊𝐹𝑊𝑃 = 𝓋 𝑓③(𝑃④ − 𝑃③)
ℎ④ = ℎ③ + 𝓋 𝑓③(𝑃④ − 𝑃③)
ℎ④ = 1087.0[
𝑘𝐽
𝑘𝑔
] + 0.0012510[
𝑚3
𝑘𝑔
] (165− 40) × 105
[𝑃𝑎]
ℎ④ = 1102.7[
𝑘𝐽
𝑘𝑔
]
𝑊𝐹𝑊𝑃 = 15.7 [
𝑘𝐽
𝑘𝑔
]
Calculation 1.4 An example of a linear Specific Volume Calculation, calculating the Specific
Volume at System State ④ with data from Table 1.1/(1.) and Table 1.2
𝑣 [
𝑚3
𝑘𝑔
] =
1
𝜌 [
𝑘𝑔
𝑚3]
𝜌𝑓𝑖𝑛𝑎𝑙 =
𝜌𝑖𝑛𝑖𝑡𝑖𝑎𝑙 {1 −
(𝑃𝑓𝑖𝑛𝑎𝑙 − 𝑃𝑖𝑛𝑖𝑡𝑖𝑎𝑙)
𝐸
}
1 + {𝛽𝑖𝑛𝑖𝑡𝑖𝑎𝑙(𝑇𝑓𝑖𝑛𝑎𝑙 − 𝑇𝑖𝑛𝑖𝑡𝑖𝑎𝑙)}
𝑣 𝑓𝑖𝑛𝑎𝑙 =
𝑣𝑖𝑛𝑖𝑡𝑖𝑎𝑙(1 + {𝛽𝑖𝑛𝑖𝑡𝑖𝑎𝑙(𝑇𝑓𝑖𝑛𝑎𝑙 − 𝑇𝑖𝑛𝑖𝑡𝑖𝑎𝑙)})
{1 −
𝐸
(𝑃𝑓𝑖𝑛𝑎𝑙 − 𝑃𝑖𝑛𝑖𝑡𝑖𝑎𝑙)}
Where 𝛽 = 𝑉𝑜𝑙𝑢𝑚𝑒𝑡𝑟𝑖𝑐 𝑇𝑒𝑚𝑝𝑒𝑟𝑎𝑡𝑢𝑟𝑒 𝐶𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡
𝛽 𝑤𝑎𝑡𝑒𝑟 = 𝑠𝑒𝑒 𝑇𝑎𝑏𝑙𝑒 1.2[
1
𝐾
]
and 𝐸 = 𝐵𝑢𝑙𝑘 𝑀𝑜𝑑𝑢𝑙𝑢𝑠 𝑜𝑓 𝐸𝑙𝑎𝑠𝑡𝑖𝑐𝑖𝑡𝑦
𝐸 𝑤𝑎𝑡𝑒𝑟 = 2.15 × 109
[𝑃𝑎]
𝑣④ =
0.0012511[
𝑚3
𝑘𝑔
](1 + {2.036 × 10−3
[
1
𝐾
](523.45 − 523.45)[𝐾]})
{1 −
2.15 × 109
(165 × 105 − 40 × 105)
}[𝑃𝑎]

8
𝑣④ =
0.0012511[
𝑚3
𝑘𝑔
]
{1 −
(165 × 105 − 40 × 105)
2.15 × 109 }[𝑃𝑎]
𝑣④ = 0.0012438[
𝑚3
𝑘𝑔
]
An Open Regenerative Feedwater Heater has been included in this analysis; this combines
steam bled from the HPT exhaust with water pumped from the condenser. Due to the lack
of information available for the amount of steam typically bled from a plant in service, (upon
enquiring, an engineer at Littlebrook Power Station offered that this quantity varies
constantly), a calculation follows for the mass fraction of steam required per kg of water to
heat the saturated mixture to the temperature that the Feedwater is fed to the boiler at
Littlebrook Table 1.3.
Calculation 1.5 Mass fraction calculation for the fraction of steam required from HPT
exhaust.
𝑄 = 𝑚𝑐 𝑝(𝑇𝑓𝑖𝑛𝑎𝑙 − 𝑇𝑖𝑛𝑖𝑡𝑖𝑎𝑙)
𝑄 𝑤 = 𝑐𝑓𝑝(𝑇𝑓𝑤 − 𝑇𝑖𝑤)
𝑄𝑠 = 𝑚 𝑠 𝑐𝑔𝑝 (𝑇𝑖𝑠 − 𝑇𝑓𝑠) + ℎ 𝑓𝑔
𝑚 𝑠𝑏 =
𝑐𝑓𝑝(𝑇𝑓𝑤 − 𝑇𝑖𝑤)
𝑐𝑔𝑝 (𝑇𝑖𝑠 − 𝑇𝑓𝑠) + ℎ 𝑓𝑔
𝑚 𝑠𝑏 =
4.27 [
𝑘𝐽
𝑘𝑔𝐾
] (250.3 − 130.0)[°𝐶]
7.10 [
𝑘𝐽
𝑘𝑔𝐾
] (312.8 − 250.3)[°𝐶]+ 1714.8[
𝑘𝐽
𝑘𝑔
]
𝑚 𝑠𝑏 = 0.238
∴ 𝑚 𝑠𝑐 = 1 − 0.238 = 0.762

9
With the mass fraction data it is possible to calculate the Thermal Efficiency of the steam
cycle of the generator set.
Calculation 1.6 Calculation of the Work Output of the High Pressure Turbine.
𝑊𝐻𝑃𝑇 = ℎ⑤ − ℎ⑥
𝑊𝐻𝑃𝑇 = 3403.0[
𝑘𝐽
𝑘𝑔
] − 2996.5 [
𝑘𝐽
𝑘𝑔
]
𝑊𝐻𝑃𝑇 = 406.5[
𝑘𝐽
𝑘𝑔
]
Calculation 1.7 Calculation of the Work Output of the Intermediate Pressure Turbine.
𝑊𝐼𝑃𝑇 = 𝑚 𝑠𝑐(ℎ⑦ − ℎ⑧)
𝑊𝐼𝑃𝑇 = 0.762 (3503.6[
𝑘𝐽
𝑘𝑔
] − 2911.0[
𝑘𝐽
𝑘𝑔
])
𝑊𝐼𝑃𝑇 = 451.6 [
𝑘𝐽
𝑘𝑔
]
Calculation 1.8 Calculation of the Work Output of the Low Pressure Turbine.
𝑊𝐿𝑃𝑇 = 𝑚 𝑠𝑐(ℎ⑧ − ℎ⑨ 𝑠)
𝑊𝐿𝑃𝑇 = 0.762 (2911.0[
𝑘𝐽
𝑘𝑔
] − 2551.6[
𝑘𝐽
𝑘𝑔
])
𝑊𝐿𝑃𝑇 = 273.9 [
𝑘𝐽
𝑘𝑔
]
It is notable that an assumption has been made that the LPT produces work for the entirety
of the expansion from State ⑧ to ⑨. During the expansion from State ⑧ to ⑨ the
saturation line is crossed (see Figure 1.2) indicating that liquid water would condense during
the expansion, however in turbines of this type liquid water must be excluded or the turbine
would be severely damaged due to the speeds and forces involved. Thus the steam must
exit the turbine exhaust before this point, carrying the remaining heat energy with it. In the
simplification made in Figure 1.1 the waste steam heat exchangers that preheat water
pumped to the feedwater heater, and oil fed to the boiler have been excluded. These
processes would make use of this heat energy overlooked in this assumption, therefore it is

10
a fair approximation to make that this heat energy is utilised in the cycle as efficiently as if it
continued to be expanded through the LPT.
Calculation 1.9 Calculation of the Heat Input from the Boiler to the steam to increase the
temperature from State ④ to State ⑤.
𝑄④−⑤ = ℎ⑤ − ℎ④
𝑄④−⑤ = 3403.0[
𝑘𝐽
𝑘𝑔
] − 1087.0[
𝑘𝐽
𝑘𝑔
]
𝑄④−⑤ = 2316[
𝑘𝐽
𝑘𝑔
]
Calculation 1.10 Calculation of the Heat Input from the Boiler to the steam during Reheat to
increase the temperature from State ⑥ to State ⑦.
𝑄⑥−⑦ = 𝑚 𝑠𝑐(ℎ⑦ − ℎ⑥)
𝑄⑥−⑦ = 0.762(3503.6 − 2996.5)[
𝑘𝐽
𝑘𝑔
]
𝑄⑥−⑦ = 386.4[
𝑘𝐽
𝑘𝑔
]
Calculation 1.11 Calculation of the Thermal Efficiency of the “Ideal” Isentropic Steam Cycle
of one generator set, including calculation of the Net Isentropic Work from the cycle.
𝜉𝑖𝑑𝑒𝑎𝑙 𝑐𝑦𝑐𝑙𝑒 =
𝑊𝐻𝑃𝑇 + 𝑊𝐼𝑃𝑇 + 𝑊𝐿𝑃𝑇 − 𝑊𝐶𝐸𝑃 − 𝑊𝐹𝑊𝑃
𝑄④−⑤ + 𝑄⑥−⑦
𝜉𝑖𝑑𝑒𝑎𝑙 𝑐𝑦𝑐𝑙𝑒 =
(406.5 + 451.6 + 273.9 − 15.7 − 3.8) [
𝑘𝐽
𝑘𝑔
]
(2316.0 + 386.4)[
𝑘𝐽
𝑘𝑔
]
𝜉𝑖𝑑𝑒𝑎𝑙 𝑐𝑦𝑐𝑙𝑒 = 0.412 = 41.2% 𝑇ℎ𝑒𝑟𝑚𝑎𝑙 𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦
𝑊𝑁𝑒𝑡 = 𝑊𝐻𝑃𝑇 + 𝑊𝐼𝑃𝑇 + 𝑊𝐿𝑃𝑇 − 𝑊𝐶𝐸𝑃 − 𝑊𝐹𝑊𝑃
𝑊𝑁𝑒𝑡 = 1112.5 [
𝑘𝐽
𝑘𝑔
]

11
Calculation 1.12 Calculation of the Efficiency of the “Closed” Actual Steam Cycle of one
generator set, only taking into account the efficiency of the Turbines from Table 1.4.
𝜉 𝑎𝑐𝑡𝑢𝑎𝑙 𝑐𝑙𝑜𝑠𝑒𝑑 𝑐𝑦𝑐𝑙𝑒 =
{ 𝜂 𝑇𝑢𝑟𝑏𝑖𝑛𝑒( 𝑊𝐻𝑃𝑇 + 𝑊𝐼𝑃𝑇 + 𝑊𝐿𝑃𝑇 )}−(𝑊𝐶𝐸𝑃 + 𝑊𝐹 𝑊𝑃 )
(𝑄④−⑤ + 𝑄⑥−⑦)
𝜉 𝑎𝑐𝑡𝑢𝑎𝑙 𝑐𝑙𝑜𝑠𝑒𝑑 𝑐𝑦𝑐𝑙𝑒 =
({0.85(406.5 + 451.6 + 273.9)} − (15.7 + 3.8)) [
𝑘𝐽
𝑘𝑔
]
(2316.0+ 386.4)[
𝑘𝐽
𝑘𝑔
]
𝜉 𝑎𝑐𝑡𝑢𝑎𝑙 𝑐𝑙𝑜𝑠𝑒𝑑 𝑐𝑦𝑐𝑙𝑒 = 0.349 = 34.9% 𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦
Calculation 1.13 Calculation of the Efficiency of the “Open” Actual Steam Cycle of one
generator set, taking into account the efficiency of the Turbines, Generator, Pumps and
Boiler from Table 1.4.
𝜉 𝑎. 𝑜𝑝𝑒𝑛 𝑐𝑦𝑐𝑙𝑒 =
{ 𝜂 𝑇𝑢𝑟𝑏𝑖𝑛𝑒 × 𝜂 𝐺𝑒𝑛𝑒𝑟𝑎𝑡𝑜𝑟 ( 𝑊𝐻𝑃𝑇 + 𝑊𝐼𝑃𝑇 + 𝑊𝐿𝑃𝑇 )} − {
1
𝜂 𝑃𝑢𝑚𝑝
(𝑊𝐶𝐸𝑃 + 𝑊𝐹𝑊𝑃 )}
1
𝜂 𝐵𝑜𝑖𝑙𝑒𝑟
(𝑄④−⑤ + 𝑄⑥−⑦)
𝜉 𝑎. 𝑜𝑝𝑒𝑛 𝑐𝑦𝑐𝑙𝑒 =
({(0.85 × 0.98)(406.5 + 451.6 + 273.9)} − {
1
0.82
(15.7 + 3.8)})[
𝑘𝐽
𝑘𝑔
]
1
0.89
(2316.0 + 386.4) [
𝑘𝐽
𝑘𝑔
]
𝜉 𝑎𝑐𝑡𝑢𝑎𝑙 𝑜𝑝𝑒𝑛 𝑐𝑦𝑐𝑙𝑒 = 0.303 = 30.3% 𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦
Finally the Mass Flow Rate of steam through the cycle can be determined, then the heat
input rate to that steam calculated, and an analysis of the mass flow rate of various fuels to
evaluate their practicalities as a fuel source for a plant of this size.

12
Calculation 1.14 Calculation of the Mass Flow Rate of Steam within the Cycle.
𝑚̇ =
𝑃
𝑊𝑁𝑒𝑡
𝑚̇ =
500000[
𝑘𝐽
𝑠
]
1112.5[
𝑘𝐽
𝑘𝑔
]
𝑚̇ =
500000[
𝑘𝐽
𝑠
]
1112.5[
𝑘𝐽
𝑘𝑔
]
𝑚̇ = 449.4[
𝑘𝑔
𝑠
]
Calculation 1.15 Calculation of the Rate at which Heat is required to be added to the steam
in the cycle as it passes through the Boiler for the ”Ideal” Isentropic Steam Cycle in
Calculation 1.11.
𝑄̇ 𝑖𝑛 𝑖𝑑𝑒𝑎𝑙 = 𝑚̇ (𝑄④−⑤ + 𝑄⑥−⑦ )
𝑄̇ 𝑖𝑛 𝑖𝑑𝑒𝑎𝑙 = 449.4[
𝑘𝑔
𝑠
](2316.0 + 386.4)[
𝑘𝐽
𝑘𝑔
]
𝑄̇ 𝑖𝑛 𝑖𝑑𝑒𝑎𝑙 = 1214459[
𝑘𝐽
𝑠
] = 12.1 [
𝑀𝐽
𝑠
]
Calculation 1.16 Calculation of the Rate at which Heat is required to be added to the steam
in the cycle as it passes through the Boiler for the ”Open” Actual Steam Cycle in Calculation
1.13.
𝑄̇ 𝑖𝑛 𝑎𝑐𝑡𝑢𝑎𝑙 =
𝜉𝑖𝑑𝑒𝑎𝑙 𝑐𝑦𝑐𝑙𝑒
𝜉 𝑎𝑐𝑡𝑢𝑎𝑙 𝑜𝑝𝑒𝑛 𝑐𝑦𝑐𝑙𝑒
× 𝑄𝑖𝑛 𝑖𝑑𝑒𝑎𝑙
𝑄̇ 𝑖𝑛 𝑎𝑐𝑡𝑢𝑎𝑙 = 1651344 [
𝑘𝐽
𝑠
] = 16.5[
𝑀𝐽
𝑠
]

13
Calculation 1.17 Calculation of the Mass Flow Rate and Volumetric Flow Rate of Oil required
to supply the Heating Rate calculated in Calculation 1.16.
𝑚̇ 𝑜𝑖𝑙 =
𝑄̇ 𝑖𝑛 𝑎𝑐𝑡𝑢𝑎𝑙
𝑁𝑒𝑡 𝐶𝑎𝑙𝑜𝑟𝑖𝑓𝑖𝑐 𝑉𝑎𝑙𝑢𝑒 𝑜𝑖𝑙
𝑚̇ 𝑜𝑖𝑙 =
1651344[
𝑘𝐽
𝑠
]
40700[
𝑘𝐽
𝑘𝑔
]
𝑚̇ 𝑜𝑖𝑙 = 40.5 [
𝑘𝑔
𝑠
] = 3499.2 [
𝑡𝑜𝑛𝑛𝑒𝑠
24ℎ𝑟𝑠
]
𝑉̇ 𝑜𝑖𝑙 =
40.5 [
𝑘𝑔
𝑠
]
850 [
𝑘𝑔
𝑚3]
= 0.048[
𝑚3
𝑠
] = 4117 [
𝑚3
24ℎ𝑟𝑠
]
Calculation 1.18 Calculation of the Mass Flow Rate and Volumetric Flow Rate of Coal
required to supply the Heating Rate calculated in Calculation 1.16.
𝑚̇ 𝑐𝑜𝑎𝑙 =
𝑁𝐶𝑉𝑐𝑜𝑎𝑙
𝑚̇ 𝑐𝑜𝑎𝑙 =
1651344[
𝑘𝐽
𝑠 ]
24000[
𝑘𝐽
𝑘𝑔
]
𝑚̇ 𝑐𝑜𝑎𝑙 = 68.8[
𝑘𝑔
𝑠
] = 5944.9 [
24ℎ𝑟𝑠
]
𝑉̇ 𝑐𝑜𝑎𝑙 =
68.8 [
𝑘𝑔
𝑠 ]
850 [
𝑘𝑔
𝑚3]
= 0.081[
𝑚3
𝑠
] = 6993.3 [
𝑚3
24ℎ𝑟𝑠
]
Calculation 1.19 Calculation of the Mass Flow Rate and Volumetric Flow Rate of Biomass
Wood Pellets required to supply the Heating Rate calculated in Calculation 1.16.
𝑚̇ 𝑤𝑜𝑜𝑑 𝑝𝑒𝑙𝑙𝑒𝑡𝑠 =
𝑁𝐶𝑉 𝑤𝑜𝑜𝑑 𝑝𝑒𝑙𝑙𝑒𝑡𝑠

14
𝑚̇ 𝑤𝑜𝑜𝑑 𝑝𝑒𝑙𝑙𝑒𝑡𝑠 =
1651344[
𝑘𝐽
𝑠
]
15300[
𝑘𝐽
𝑘𝑔
]
𝑚̇ 𝑤𝑜𝑜𝑑 𝑝𝑒𝑙𝑙𝑒𝑡𝑠 = 107.9[
𝑘𝑔
𝑠
] = 9325.2 [
24ℎ𝑟𝑠
]
𝑉̇ 𝑤𝑜𝑜𝑑 𝑝𝑒𝑙𝑙𝑒𝑡𝑠 =
107.9[
𝑘𝑔
𝑠
]
650 [
𝑘𝑔
𝑚3 ]
= 0.166 [
𝑚3
𝑠
] = 14342.4[
𝑚3
24ℎ𝑟𝑠
]
𝑇𝑦𝑝𝑖𝑐𝑎𝑙 𝑂𝑙𝑦𝑚𝑝𝑖𝑐 𝑆𝑤𝑖𝑚𝑚𝑖𝑛𝑔 𝑃𝑜𝑜𝑙 ( 𝑎𝑣𝑒𝑟𝑎𝑔𝑒 𝑑𝑒𝑝𝑡ℎ 2[ 𝑚]) = 2500 [ 𝑚3]
12[ 𝑚] 𝐹𝑟𝑒𝑖𝑔ℎ𝑡 𝑅𝑎𝑖𝑙𝑐𝑎𝑟 = 5800 [ 𝑓𝑡3] = 100 [ 𝑚3] (3.)
(Figures for Net Calorific Values are sourced from DUKES Calorific Values, available at
https://www.gov.uk/government/statistics/dukes-calorific-values)
Figure 1.3 is a plot of the initial boiler heating, reheat and turbine expansion stages of the
“Ideal” Isentropic Steam Cycle described in the schematic in Figure 1.1 and Calculation 1.11.
Points have also been plotted for the “Closed” Actual Cycle described in Calculation 1.12
taking into account the inefficiencies of expansion through the turbine stages. Calculations
1.20-24 are calculations required for these points.
Calculation 1.20 Calculation of the dryness fraction of the steamat System State ⑨.
𝑠 𝑥 = 𝑠𝑓 + 𝑥(𝑠𝑔 − 𝑠𝑓)
𝑥⑨ 𝑚 =
𝑠⑨ − 𝑠𝑓⑨
(𝑠𝑔⑨ − 𝑠𝑓⑨ )
𝑥⑨ 𝑚 =
(7.1604 − 0.4034)[
𝑘𝐽
𝑘𝑔𝐾
]
(8.5018 − 0.4034)[
𝑘𝐽
𝑘𝑔𝐾]
𝑥⑨ 𝑚 = 0.834 𝑆𝑡𝑒𝑎𝑚 𝐹𝑟𝑎𝑐𝑡𝑖𝑜𝑛

15
Calculation 1.21 Calculation of the enthalpy of the mixture at System State ⑨.
ℎ 𝑥 = ℎ 𝑓 + 𝑥(ℎ 𝑔 − ℎ 𝑓)
ℎ⑨ 𝑚 = ℎ 𝑓⑨ 𝑚
+ 0.834(ℎ 𝑔⑨ 𝑚
− ℎ 𝑓⑨ 𝑚
)
ℎ⑨ 𝑚 = 115.6[
𝑘𝐽
𝑘𝑔
] + 0.834(2551.6 − 115.6)[
𝑘𝐽
𝑘𝑔
]
ℎ⑨ 𝑚 = 2147.2[
𝑘𝐽
𝑘𝑔
]
Calculation 1.21 Calculation of the enthalpy of the steam at System State ⑥ taking into
account the efficiency of the HPT.
ℎ⑥ = ℎ⑤ − {𝜂 𝑇𝑢𝑟𝑏𝑖𝑛𝑒 (ℎ⑤ − ℎ⑥)}
ℎ⑥ = 3403.0[
𝑘𝐽
𝑘𝑔
] − {0.85(3403 − 2996.5)} [
𝑘𝐽
𝑘𝑔
]
ℎ⑥ = 3057.5[
𝑘𝐽
𝑘𝑔
]
Similar calculations were made for each turbine stage and the points plotted by regressing
them along the constant pressure line for that State.

17
Discussion
It is immediately evident from Calculation 1.17 -1.19 that choosing oil to fire Fawley power
station was sensible from a transport and storage point of view, and the claim made in the
Background section is feasible based on 20 trains of 168m supplying the four generator sets
with coal, were they operating around the clock see Calculation 2.1.
Calculation 2.1 Calculation of the length of each train assuming 20 trains were required to
supply Fawley with coal were it coal fired.
6993.3[
𝑚3
24ℎ𝑟𝑠
] 𝐶𝑜𝑎𝑙 × 12[ 𝑚] 𝑅𝑎𝑖𝑙 𝐶𝑎𝑟 𝐿𝑒𝑛𝑔𝑡ℎ × 4 [ 𝐺𝑒𝑛𝑒𝑟𝑎𝑡𝑜𝑟 𝑆𝑒𝑡𝑠]
100 [ 𝑚3] 𝑅𝑎𝑖𝑙 𝐶𝑎𝑟 𝑉𝑜𝑙𝑢𝑚𝑒 × 20 [ 𝑇𝑟𝑎𝑖𝑛𝑠 𝑝𝑒𝑟 𝐷𝑎𝑦]
= 168[ 𝑚]
168m is not especially long for a train on U.K. where the maximum length is 600m (on
certain lines) (3.), therefore using a conservative figure of 250m it would be closer to 13
trains per day. By comparison it would require 28 trains per day of wood pellets, or 6
Olympic Swimming Pools of storage capacity per day.
Presently Fawley is in a process of decommission due; to it coming to the end of its life
cycle, the high price of oil, and emissions regulations making the plant obsolete.
An option could be to convert the station to burn wood pellets; a “Carbon Neutral
Renewable Resource”, however the extra energy required to transport them to the power
station and the provision of covered storage to keep the pellets dry make them an
impractical alternative for a power station of this size. Conversions have been implemented
at similar power stations to Fawley where the stations are run in a diminished capacity to
meet peak power demands on the National Grid.
With improvements in smaller turbine and boiler efficiencies it is now feasible to make
smaller biomass power stations of around 100-300MW with 50-150MW generator sets that
exceed the efficiency of older large output fossil fuel fired power stations. These plants form
part of the U.K.s energy strategy going forward, supporting other renewable sources and
nuclear powered power stations.
The current push to develop renewables in the U.K. has resulted in plans to develop wind
farms across the country. To compare the required area to power output, take the proposed

18
London Array Wind Farm, which at the moment is under construction. The London Array
covers 100km2 and is rated at 660MW maximum output (4.), however wind farms in the
U.K. (mainly land based) average approximately 25% of their maximum output annually (5.),
therefore an area of 1200km2, (see Calculation 2.2) an area the size of Greater London,
would need to be covered in wind turbines to generate the equivalent output of a high
output fossil fuelled power station like Fawley running at full output around the clock.
Taking into account the fact that Fawley was designed to operate on 2 generator sets at
1000MW continuously and only on 4 generator sets at 2000MW at peak demand periods,
and the fact that projected Offshore Wind Farm targets are closer to 30% maximum output
annually this figure should be adjusted to 500km2 (see Calculation 2.3).
Figure 1.4 Image showing the size and position of the London Array Wind Farm and area
increases required to equate the output of Fawley from Calculations 2.2.
Courtesy of Google Maps©
Calculation 2.2 Calculation of the increased size the London Array would need to be to
generate the equivalent output of Fawley at full capacity and with the adjustments
discussed.
2000[ 𝑀𝑊]
0.25(660[ 𝑀𝑊])
× 100[ 𝑘𝑚2] = 1212[ 𝑘𝑚2]
1000[ 𝑀𝑊]
0.3(660[ 𝑀𝑊])
× 100[ 𝑘𝑚2] = 505[ 𝑘𝑚2]
Completed
100km2 London
Array

19
Conclusion
The simplification of the schematic of the power plant early on in this study and the
inclusion of an open feedwater heater created difficulties in the analysis of the efficiency at
Fawley, however the figures obtained are realistic and representative of this type of plant.
At the time it was built Fawley power station was the pinnacle of the technology and
remains comparable in efficiency to modern power stations, however due to emissions
regulations it is now outdated and obsolete. Only the most efficient fossil fuelled power
stations meet the new regulations, those with efficiencies below 40% are too polluting.
Upon analysis it becomes evident that the reliance on energy dense fossil fuels for power
generation is hard to break without vast areas to devote to renewables. Reducing demand
for electricity by increasing the efficiency of industry, appliances and lighting coupled with
new and innovative forms of power generation will be needed in the future to meet the
reductions in emissions targeted by authorities for the future whilst providing the electricity
people and businesses require.

20
Tables
Table 1.1 Steam properties at the System States described by Figure 1.1
System
State Phase Temperature Pressure Enthalpy Entropy
Specific
Volume
(o
C) (bar) (kJ/kg) (kJ/kgK) (m3/kg)
① Water 27.6 0.037 115.6 0.3688 0.0010037
②c Water 27.6 40 119.4 0.3688 0.0010019
②h Water 130.0 40 546.0 1.6340 0.0010675
③ Water 250.3 40 1087.0 2.7970 0.0012510
④ Water 250.3 165 1102.7 2.7970 0.0012438
⑤ Steam 541.0 165 3403.0 6.4201 0.02019
⑥ Steam 312.8 40 2996.5 6.4201 0.06075
⑦ Steam 541.0 40 3503.6 7.1604 0.08957
⑧ Steam 250.0 4.5 2911.0 7.1604 0.53490
⑨m Mixture 27.6 0.037 2147.2 7.1604 31.36524
⑨s Steam 27.6 0.037 2551.6 8.5018 37.60800
Table 1.2 Thermal Expansion Coefficient of Liquid Water with Temperature.
Temperature Expansion coefficient
(o
C) 10-3
(1/K)
0.01 -0.07
5 0.16
10 0.088
15 0.151
20 0.207
25 0.257
30 0.303
35 0.345
40 0.385
45 0.42
50 0.457
55 0.486
60 0.523
65 0.544
70 0.585
75 0.596
80 0.643
85 0.644
90 0.665
95 0.687
100 0.752
120 0.86
140 0.975
160 1.098
180 1.233
200 1.392

21
220 1.597
240 1.862
250 2.036
260 2.21
http://www.engineeringtoolbox.com/water-thermal-properties-d_162.html
Table 1.3 Design Data of Littlebrook 660MW Boiler (accessed on visit to Littlebrook 16/10/14)
Pressure atfinal superheateroutlet 165.5[bar]
Temperature atfinal superheateroutlet 541[°C]
Boilersteamflow 423[kg/s]
Pressure atfinal reheateroutlet 38[bar]
Pressure atprimaryreheaterinlet 41[bar]
Temperature atfinal reheateroutlet 541[°C]
Temperature atprimaryreheaterinlet 341[°C]
Pressure ateconomiserinlet 184.17[bar]
Temperature ateconomiserinlet 251[°C]
Boilercirculatingpumphead 36.89[m]
Boilerefficiency 88.8[%]
LowerCalorificValue of Fuel 42600[kJ/kg]
Fuel consumption 39.3[kg/s]
Airflowrequiredforcombustion 560[kg/s]
Mass of waterinboilertubes 278[tonnes]
Mass of waterineconomiser 46[tonnes]
Mass of waterinsuperheater 144[tonnes]
Mass of waterinreheater 130[tonnes]
Table 1.3 Steam Cycle Component Efficiency Table
Component Efficiency (Reference)
Boiler 0.89 (Table1.3) and (11.)
Condensate Extraction
and
Boiler Feedwater Pumps
0.82 (6.) and (7.)
Turbines 0.85 (8.)
Generator 0.98 (12.)

22
References
(1.) Rogers,G.F.C. And Mayhew,Y.R.,(2013) Thermodynamicand TransportPropertiesof Fluids,
5th
Edition. Blackwell Publishing
(2.) DOI: 10.1243/PIME_CONF_1965_180_370_02
Proceedingsof theInstitution of MechanicalEngineers,1965 180:60
H. H. Gott and D. R. Berridge
Paper6: Designing a LargePowerStation at Fawley
(3.) http://southstaffsrail.webs.com/railfreightusage.htm - accessed 22/10/2014
(4.) http://www.londonarray.com- accessed 22/10/2014
(5.) StuartYoung Consulting,Analysisof UKWind PowerGeneration November2008 to
December 2010, (03/2011), Issue2, availableat
http://www.jmt.org/assets/report_analysis%20uk%20wind_syoung.pdf
(6.) DOI: 10.1243/PIME_CONF_1969_184_429_02
Proceedingsof theInstitution of MechanicalEngineers,1969 184: 108
P. S.Neporozhniiand A.K.Kirsh
Paper11: Feed PumpsforModern SteamBoiler Applications,Design,Development,and
Operation
(7.) DOI: 10.1243/PIME_PROC_1961_175_045_02
Proceedingsof theInstitution of MechanicalEngineers1961 175: 641
Hydraulic Plantand Machinery Group and H. H. Anderson
Design of Modern Boiler Feed Pumps
(8.) DOI: 10.1243/PIME_PROC_1963_177_022_02
SteamPlantGroup and F.Dollin
SomeDesign ProblemsArising in the Developmentof Very LargeHigh-Speed Turbines
(9.) DOI: 10.1243/PIME_PROC_1945_153_028_02
R. S. Silver
A ThermodynamicTheory of Circulation in Water-TubeBoilers
(10.) 1. R.C. Spencer,K.C.Cotton,and C.N.Cannon,“A Method forPredicting the
Performanceof SteamTurbineGenerators - 16,500 kW and Larger,”ASME,Winter Annual
Meeting,NewYork, Revised July 1974 version.

23
(11.) Technical SupportDocumentfortheFinal Clean Air InterstateRule
Cogeneration UnitEfficiency Calculations
EPA DocketNumber:OAR-2003-0053 March 2005
U.S.EnvironmentalProtection Agency Officeof Airand Radiation
(12.) FujiThermal PowerPlantReview 3 Vol.51, 2005, Fuji Electric Corp.
(13.) DUKES Calorific Values, available at https://www.gov.uk/government/statistics/dukes-
calorific-values)

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