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When wind is added to an existing diesel generation plant, the cost of the turbine and controls is compared to the dollars saved on diesel fuel. In 2004 for villages (under 1,000 people) in Alska, Village Electric Cooperative powered by diesel gensets, the average price was $0.38/kWh, broken down as follows:

2004

2008

Percent

Percent

Fuel

46

77

Operation and maintenance

21

9

Renewal and replacement

19

8

General and administration

14

6

Since then, the cost of diesel has increased significantly and the percent cost of fuel and electricity ($0.55/kWh) has increased accordingly. This is the reason for the renewed interest in wind turbines. For villages in Nunavik, Canada, served by Hydro Quebec, diesel fuel represented 54% of the operation cost and, as above, that percent will increase.

FIGURE 12.3 Hybrid (wind/PV/diesel) renewable village power system for Subashi, Xinjiang Province, China. (Photo by Charlie Dou. With permission.)

At Ascension Island, the simple payback was estimated to be 7 years for the addition of two 900 kW wind turbines in a high-penetration system. This saves an additional 2,400,000 L of diesel per year, and for diesel at $1.50/L that would be $3,600,000/year, and so the simple payback would be around 3 years. Most wind-diesel systems will not be this dramatic. High-penetration systems will also save on diesel maintenance, since the diesel gensets will not operate as many hours.

The three 100 kW wind turbines produce around 675,000 kWh/year as part of a wind-diesel plant at Toksook Bay, Alaska. The wind turbines displace 196,000 L of diesel per year, and if the cost of diesel at bulk price is $1.50/L, or even more, that produces a savings of $300,000 per year. If the installed cost for the wind turbines was around $1,500,000, then the simple payback would be 5 years. In May 2008, bid price for bulk diesel in remote Alaska was as high as $1.90/L.

At St. Paul Island, Alaska, the installed cost was $905,000 ($ 1999) for a wind-diesel system [16] that provided power to an industrial complex (no grid). The high-penetration, no-storage system consisted of one wind turbine, 225 kW, and two 150 kW diesel generators. The cost of energy from the system was $0.15/kWh, compared to diesel grid costs of $0.43/kWh ($ 2004). Since then, two more wind turbines have been added to support economic development and to generate enough power for residential consumption.

Costs for renewable village power systems vary widely, as most systems are components from different suppliers and manufacturers, and of course are located in remote locations. The best example is China's SDDX project (2002-2005), which consisted of 721 PV, wind, and PV/wind renewable village power systems (15,540 kW), 292 small hydro stations (113,765 kW), and 15,458 small single-household units (1,103 kW) with an installed capacity of 130,408 kW (see Table 10.7). The total investment was 4.7 * 109 Yuan (~$570 million), or an average of $4,370/kW [17, chap. 6].

The cost was $178,000 for one village hybrid system (Figure 12.3) in a remote region of China ($ 2003). This included everything from power generation to the mini grid transmission lines. The configuration is two 10 kW wind turbines, 4 kW PV, 30 kVA diesel, 1,000 Ah battery bank, and a 38 kVA DC-AC inverter. At 54 kW the installed cost was $3,300/kW, which is very reasonable for a remote location. The renewable part of the system produces around 150 kWh per day. The unknowns in calculating the cost of energy are percent of the energy supplied by the diesel generator, cost of diesel fuel, levelized replacement costs, and operation and maintenance. A known major cost is that the battery bank will be replaced every 5 to 7 years.

Small hybrid systems are available, which usually can be set up as modular systems.

Company

Size

Wind

PV

Battery

Inverter

Energy

kW

kW

kW

kWh

kW

kWh/year

$

Bergey

10.1

7.5

2.6

84

6

12,000

57,000

Bergey

1.2

1.0

0.18

10.6

1.5

1,200

7,800

Southwest

1.3

0.40

0.88

750

Most manufacturers do not supply prices on their websites. Notice that shipping and installation to remote locations will increase the cost, sometimes to double the cost of the energy components. From the initial cost and energy production the cost of energy can be estimated.

For village power, which source do you choose: wind, photovoltaic, or hybrid wind/PV? For the hybrid system, a life cycle cost analysis would determine the ratio of wind to PV. The advantages of PV are no mechanical moving parts and everything is at ground level. For comparison, suppose the local resources for both wind and solar are good, and a 20 kW system is needed for village power. The capacity factor for wind is 25%, and for solar it is 4 h/day at peak power, 80% sunshine. The estimated yearly production for wind is 43,000 kWh and for PV is 6,000 kWh. Also, installed cost for wind is cheaper than installed cost for PV, so the reasons for choosing wind power are obvious. That is also the reason that hybrid systems have more wind than PV power, five or more times greater.

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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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