Economics

Table 9.6 shows the total annual cost of the system and the average unit price of electricity. Both of these will vary from year to year because of weather-induced changes in demand and in supply, particularly in trade and optional generation. The annual cost of the renewables does not change significantly

Note: Key on page 174. Source: EST

Figure 9.6 Generator capacities

Note: Key on page 174. Source: EST

Figure 9.6 Generator capacities

Table 9.5 Annual energy: Technical

summary

TWh

Demand

282.2

Transmission losses

16.9

Supply requirement

299.1

Supply

Renewable

292.2

98%

Spilled

-10.0

-3%

CHP-bio

19.2

6%

Optional

5.2

2%

Storage

2.2

1%

Country supply

308.8

103%

Country surplus

9.7

Trade

-8.8

Country supply

300.0

Notes: 'Renewable' refers to electricity-only renewable systems. 'CHP-bio' refers to biomass-fuelled CHR 'Spilled' is the electricity spilled because it is generated by renewables but cannot be absorbed by demand, storage or export. Source: EST

except for expenditure on maintenance that is related to energy output for that year. Negative energy costs arise because of export. On average, the trade balance for the optimized system is near to zero.

Table 9.6 Annual costs: Economic summary

Annual cost

£UK

Capital

16.7

Energy

-0.7

Store

0.3

Total

16.2

Average 5.4 UK pence/kWh

Average 5.4 UK pence/kWh

Source: EST

The pie chart in Figure 9.7 shows the distribution of annualized expenditure summarized in Table 9.6.

Optional Hydro 1

Wind 2

Note: Key on page 174. Source: EST

Figure 9.7 Breakdown of annualized component costs

Table 9.7 Optimized system details

Demands

Supply

Storage

Renewable®

Electricity

Ileal

tn

>%

P

22

Optional

□J

s a

X

tr.

to

55

C/i

33

Capacity

GW

GW

GW

GW

GW

GW

GW

GW

GW

GW

GW

GW

GW

GW

GW

GW

GWh

GW

GW

GWh

GW

Current

2.5

8.0

4.0

0.5

4.0

13.0

1.1)

32.0

35.0

35.(1

11.7

8.8

5.0

6.0

12.0

J.6

10.0

6.3

24.9

30(1.0

0.0

Maximum

1.0

55

35

35

12

10

5

6

50

100

400

100

100

999

Minimum

0.6

0

0

0

0

0

2

2

0

2

10

2

0

to

Efficiency

86%

25%

25%

25%

60%

60%

92%

88%

77%

88%

99%

97%

98%

Energy

TWh

22

69

35

5

37

114

7.5

41

93

84

35

32

19

■9

5

Capacity factor

86%

14%

30%

27%

34%

42%

44%

5%

-5%

3%

-6%

Unit capital cost

£/kw

2500

2000

1000

1000

2500

3000

1000

1500

200

100

400

100

10

50

5

Operating life

Yis

100

30

20

20

20

25

25

50

35

20

20

20

30

30

30

Discu untcd life

19.8

15.4

12.5

12.5

12.5

14.1

14.1

18.3

16.4

12.5

12.5

12.5

15.4

15.4

15.4

Capital total

a

2.5

65.8

35.0

35.0

29.2

26.5

5.0

9.0

2.9

0.5

4.0

0.6

0.2

15.0

0.0

Capital annuitized

0.1

4,3

2,8

2.8

2.3

1.9

0.4

0.5

0.2

0.0

0.3

0.!

0.0

! .0

0.0

O&M cost

i/kW/a

25.0

20.0

20.0

20.0

50.0

30.0

20.0

30.0

4.0

2.0

8.0

2.0

0.1

0.5

0.0

0,7

0.7

0.7

0.6

0.3

0.1

0.2

0.0

0,0

0.1

0.0

0.0

0.2

0.0

Energy cost (O&M, fuel)

p/kWh

0.1

0.1

0.1

0.1

0.1

0.1

1.0

10.4

6.9

Energy cost

0.0

0,0

0,1

0.1

0.0

0.0

0.2

-0.9

0.4

0,0

0,0

0.0

0.0

0.0

0.0

To til cost

0.2

5.0

3.6

3.6

3.0

2.2

0.6

-0.2

0.6

0.0

0.4

0.1

0.0

1.1

0.0

Unit cost

p/kWh

2.1

12.1

3,9

4.3

8.4

6.8

3.3

-2.1

11.2

0,0

0.0

0.0

0.0

0,0

0.0

Note: G£ = Ebillion UK; p/kWh = UK pence per kWh. Source: EST

Note: G£ = Ebillion UK; p/kWh = UK pence per kWh. Source: EST

Optimized system: Demand and technology details

Table 9.7 shows further details of the optimized system. Shaded cells contain assumptions; those with bold type are the values changed by the optimizer. The rows labelled minimum and maximum show the allowed range of values, and the row labelled current is the optimized value between those limits. Of note are the energy generated, the capacity factors, and the unit cost of electricity generation shown in the last row. The negative numbers for trade arise because, for this particular year, electricity is exported.

Key to Figures 9.6-9.12 and Table 9.7

Demand

Light

Lighting

Heat

Water and other heating

Space heat

Space heating

Air con

Air conditioning

EV charge

Electric vehicle charging

Ele spec

Electricity specific

Supply

Hydro 1

Hydro 1 generation

Solar 1

Solar PV 1 generation

Wind 1

Wind 1 generation

Wind_2

Wind 2 generation

Wave 1

Wave 1 generation

Tide_1

Tidal 1 generation

CHP-bio

Biomass CHP

Summary

Trade

Trade with France

Optional

Fossil generation

Sup_Req

Required supply

Sup_Var

Variable generation

Sup_Tot

Total generation

Tr_Loss

Transmission loss

Storage

StEl_In

Electricity storage input power

StEl_Sto

Electricity storage capacity

StEl_Out

Electricity storage output power

StHe_In

Heat storage input power

StHe Sto

Heat storage capacity

StHe_Out

Electricity storage output power

Optimized system: Hourly performance

This sub-section illustrates how the optimized system performs hourly for indi-

vidual sample days, and throughout the year. Figure 9.8 shows a winter's day in which the variable supply of electricity from renewables and CHP is greater than demand during the day. Surplus variable generation is exported and placed into energy stores.

vidual sample days, and throughout the year. Figure 9.8 shows a winter's day in which the variable supply of electricity from renewables and CHP is greater than demand during the day. Surplus variable generation is exported and placed into energy stores.

Demands and supply

Demands and supply

onraStHejn r-'-Tl StEJJn

^■TrLoss CZZDUglit

Space heat onraStHejn r-'-Tl StEJJn

^■TrLoss CZZDUglit

Space heat i EV charge lEle spec ■SupVai

Supplies and demand

Supplies and demand

12 hours

Note: Key on p 174. Source: EST

Optional StEl_Out : Trad ein

GSSaStHeJDut mmsohtj

EZZ3 Wind_2 Œ33Wind_l >g=i HydroJ

Figure 9.8 Sample winter's day: Variable supply excess

Figure 9.9 shows a winter's day when demand is greater than variable supply during the day. The deficit is met with import, energy from stores and optional generation.

Demands and supply

Demands and supply

Note: Key on p 174. Source: EST

Figure 9.9 Sample winter's day: Variable supply deficit

Note: Key on p 174. Source: EST

Figure 9.9 Sample winter's day: Variable supply deficit

Source: EST

Figure 9.10 Annual sample: Demands

Source: EST

Figure 9.11 Annual sample: Generation

Source: EST

Figure 9.12 Annual sample: Storage

Figures 9.10, 9.11 and 9.12 show the electricity system performance for four sample months (January, April, July and October), each with five sample days. Figure 9.10 shows how the assumed demands vary due to socio-economic activity and weather patterns.

Figure 9.11 shows the generation from renewables, CHP and optional sources: trade imports are shown as positive, exports as negative.

Figure 9.12 depicts the energy stored (thick lines) and inputs and outputs from the stores.

Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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