Engro 49.5MW Wind Energy Plant at Gharo

This week we went to visit Tenaga Wind Farm in Gharo being commissioned by Engro Pakistan. The project has a total capacity of producing 49.5 MW of electrical energy from 31 turbines rated at 1.6 MW each (one turbine out of the 31 produces 1.5 MW). The total cost of the project is $120 m and it is expected that this investment would be recovered in 5-6 years. The cost of a unit (kwhr) is going to Rs.15 as agreed with the Government of Pakistan.

The total energy produced annually would be 134 GWh which can be used to calculate the average power produced by the 31 wind turbines.

Power = Energy/Time = (134,000,000 kwhr)/(365 x 24 hours) = 15296 kW = 15.3 MW

That is the project would produce on average only 30.9 % (15.3 / 49.5) of its rated capacity. Furthermore the electrical energy needs to be converted to a level suitable to be supplied to the national grid. For this the electrical energy is converted from 690 Volts AC to 33,000 Volts AC. Lastly the project would be monitored and maintained by General Electric (GE) for two years as this is part of the turbine purchase contract. Three such projects are at various stages of installation in Gharo and seven such projects  are being undertaken in Jhimpir which is the preferred wind corridor in Sind due to quality/firmness of the soil there.

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Pakistan Council of Renewable Energy Technologies (PCRET)

Pakistan did realize the potential of Alternate Energies quite early and National Institute of Silicon Technology (NIST) was formed in 1981 to conduct research in the area of Solar Energy. Later on Pakistan Council for Appropriate Technology (PCAT) was formed in 1985. These two organizations were merged together under the umbrella of Pakistan Council of Renewable Energy Technologies (PCRET) in 2001. The government of Pakistan also formed the Alternate Energy Development Board (AEDB) in 2003. Although these organizations have been working in the Alternate Energy sector for more than 30 years but there are not many achievements to be proud of. Some pilot projects have been initiated by PCRET and AEDB in remote parts of the country but there is no holistic approach to overcome the energy crisis besetting the country (one interesting initiative that has been taken by the Government of Pakistan in recent times is the Quaid-e-Azam Solar Park in Bahawalpur).

One interesting initiative undertaken by PCRET is indigenous development of 3rd Generation Solar Cells using Nanotechnology. However,the Solar Cells developed using this technique have very low efficiency (around 1%) as compared to international standards (around 10%). Nonetheless, this is an important step towards indigenous development and it is hoped that the efficiency of these Solar Cells can be improved with time so that they are of some practical use. Some of the products developed by PCRET in the area of Solar Thermal are Solar Desalination Plant, Solar Water Heater, Solar Cooker and Dehydrator.

As per PCRET website the total installed capacities of various Alternate Energy technologies in Pakistan are:

1. Installed 538 Microhydel Power Plants  (5-50 KW capacity) with total capacity of 7.8 MW, 70,000 houses electrified.

2. Installed 155 small wind turbines (0.5 KW to 10 KW) with total capacity of 161 KW in Sindh and Balochistan, electrifying 1560 houses and 9-coast guard check posts.

3. Installed 300 Solar PV systems with total capacity of 100 KW electrifying 500 houses, mosques, schools and street lights.

4. Installed 4000 Biogas Plants (size 3&5M3/day, producing 18000 M3/day).

5. Developed 6-models of efficient smokeless cook stoves for cooking and space heating.

6. 100,000 mud stoves have been built in rural houses; saving 36500 tons of fuel wood per year.

7. Installed 21 solar dryers with total capacity of processing 5230 Kg of fruit per day.

Earthquake Resistant and Energy Efficient Homes - PAKSBAB

After the devastating earthquake of 2005 which destroyed nearly half a million rural homes in Pakistan, there was an urgent need to build earthquake resistant homes. Thus came into being PAKSBAB which is the short form of Pakistan Straw Bale and Appropriate Buildings. So far PAKSBAB, from its limited resources, has build 27 homes in northern parts of Pakistan. These homes have been built using indigenous resources and by training the local people in construction of straw bale houses.

A typical straw bale house has an area of 576 square feet and costs $3000 on average. This  turns out to be $5.2/square feet which is less than half the cost of brick and mortar houses. A typical home comprises of two rooms, a verandah and a kitchen and requires around 1200 hours of labour. So 6 people working for 8 hours daily can construct a straw bale house in 25 days!

The main advantages of straw bale houses over brick and mortar houses are highlighted below.

1. Energy efficiency, since straw is a good insulator

2. Non toxic products are used (light straw, clay and wood)

3. Cheap materials are used resulting in a cost that is half that of a regular house

4. Resistant to earthquakes

Energy Efficient House

Tightly packed walls and a gravel weighted foundation creates better weather-proofing

 

Energy Efficient House

Twice as energy efficient as a conventional house, straw bale makes for environmentally friendly earthquake-proof homes

Energy Efficient House

Clay-plaster reinforced, a fabricated straw bale house costs half the expenses of modern building for every square foot

Straw bales required for the construction of these energy efficient and earthquake resilient homes are built using manually operated farm jacks and locally manufactured compression moulds. Furthermore the local industry is being encouraged to supply straw bales and other materials required for these projects. Additional appropriate building methods that PAKSBAB is promoting include passive solar, rainwater catchment, solar lamps, high-efficiency cooking and heating, and the use of natural building materials such as light straw clay, wattle and daub, and cob.

Wind Power - Indigenous Development Opportunities

Pakistan is blessed with solar and wind energy. We have discussed solar in our previous articles, now let us have a look at wind map of Pakistan. It can be seen from the figure below that unlike solar which is available in most parts of the country wind power is available in only limited corridors along the coast and some northern parts of the country. It is well known that a wind speed of at least 12 miles per hour (5.4 meters per second) is required for the wind turbine to work. If we look at the major cities we can say that wind power is available in the cities of Karachi,  Hyderabad, Quetta and Islamabad.

Wind Map of Pakistan

Wind Map of Pakistan

Like solar, wind projects also require a large initial investment. Wind power projects can be divided into two main categories namely on-shore and off-shore. The typical cost for these projects in the developed world, is analyzed by IRENA in a study conducted in 2012. It can be deduced from this study that for on-shore projects the cost is $1.7-$2.45 per Watt. This can be compared to price of solar for Quaid-e-Azam Solar Park Bahawalpur which is around $1.31 per Watt.  Off-shore projects require even higher initial investment, with price per Watt ranging from $3.3 to $5.0.

If we look closely at the costs for an on-shore project we see that 64% of the cost goes into the construction of wind turbines. Within this category the major cost is associated with the rotor blades and tower. These two components of the wind turbine account for more than 30% of the total cost. Other major contributor to the total cost is the foundation which accounts for 16% of the total cost. For off-shore projects the rotor blades and tower contribute about 50% to the total cost.

Wind Power Cost

Wind Power Cost

A description of the main components of the Wind Turbine is given below (reproduced from IRENE document).

Tower: These are most commonly tapered, tubular steel towers. However, concrete towers, concrete bases with steel upper sections and lattice towers are also used. Tower heights tend to be very site-specific and depend on rotor diameter and the wind speed conditions of the site. Ladders, and frequently elevators in today’s larger turbines, inside the towers allow access for service personnel to the nacelle. As tower height increases, diameter at the base also increases.

Blades: Modern turbines typically use three blades, although other configurations are possible. Turbine blades are typically manufactured from fibreglassreinforced polyester or epoxy resin. However, new materials, such as carbon fibre, are being introduced to provide the high strength-to-weight ratio needed for the ever larger wind turbine blades being developed. It is also possible to manufacture the blades from laminated wood, although this will restrict the size.

Generator: The generator is housed in the nacelle and converts the mechanical energy from the rotor to electrical energy. Typically, generators operate at 690 volt (V) and provide three-phase alternating current (AC). Doubly-fed induction generators are standard, although permanent magnet and asynchronous generators are also used for direct-drive designs.

Transformer: The transformer is often housed inside the tower of the turbine. The medium-voltage output from the generator is stepped up by the transformer to between 10 kV to 35 kV; depending on the requirements of the local grid.

Bottomline: For Pakistani companies interested in indigenous development of small wind turbines (0.2kW - 100 kW) a good point to start is to develop rotor blades and towers which contribute to 30% cost of an on-shore wind power project (this increases to 50% for off-shore projects). The material used could be steel or wood which is easily available in the local market. One can also experiment with lighter materials that increase the efficiency of the system. A small wind power project of 3000 Watts can easily support all the appliances of a typical household in Pakistan (except the heavy loads such as air conditioners or large freezers/refrigerators).