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).

Quaid-e-Azam Solar Park - ROI

The government of Pakistan has recently launched the Quaid-e-Azam Solar Park in the Cholistan desert near Bahawalpur. The project aims to produce 100 MW of electrical energy by end of 2014 and 1000 MW by end of 2016. This is a small step in the right direction. Countries like India, China and Germany are much ahead in the game with installed solar projects of 2600 MW, 20000 MW and 36000 MW respectively. Let us take a closer look at the price that we will have to pay for the energy produced.

The cost of the 100 MW project is around $131 million, that is the price per Watt is $1.31. That seems to be quite good, lets look closely. We know that 400,000 panels are to be installed in the first phase to produce 100 MW of electrical energy. This means that each Solar Panel would produce 250 W and the cost of each panel would be $327.5 or Rs.32750.

Assuming that there is peak solar energy available for six hours daily, each solar panel would produce 1.5 kWhr of energy each day or 547.5 kWhr of energy per year. This amounts to 13687.5 kWhr of energy over a 25 year period (assuming that the performance of the Solar Panels does not degrade over the 25 year period). Now assuming that each unit of energy (kWhr) is sold at Rs.15 the total energy produced by the Solar Panel over its life period amounts to Rs.205312.5 i.e the revenue earned from selling electricity is 6.27 times the investment (205312.5/32750=6.27).

Solar Park Bahawalpur

Solar Park Bahawalpur

In other words the investment is recovered in 4 years and you have free electricity for the remaining 21 years. Please note that the above calculations do not include the operational costs, if any. Also, the above analysis assumes that the performance of the Solar Panels does not degrade over its life time.

Final Comment: The location of the proposed project does not seem to be optimum as Bahawalpur is receiving 2000 kWhr per squared meter per year as opposed to vast expanses of Balochistan that receive 2200 kWhr per squared meter per year.

Solar Resource Map of Pakistan

The map below shows the solar energy falling on a horizontal surface of area 1 m2 during one year. It can be seen that areas of Balochistan and Southern Sindh are most gifted while Peshawar, Lahore and Islamabad also have quite favorable conditions. Lets assume that we are installing a Solar System in Karachi where the annual irradiation is around 2000 kWhr/m2. This means that there is an average daily irradiation of around 5.5 kWhr/m2. This means that a Solar Panel of area 1 m2 would receive 5.5 kWhr per day or 1 kW for 5.5 hours daily. If the above Solar Panel has an efficiency of 20% we can produce 200 Watts of electrical energy from it for 5.5 hours each day.

Solar Resource Map of Pakistan

Solar Resource Map of Pakistan

Note:
1. The above map is for energy collected by a horizontal surface. A suitably tilted surface or a tracking one can obtain significantly more energy.

2. The received energy not only depends upon the relative position of the Sun and Earth but also on the atmospheric conditions such as cloud cover during different seasons.

Solar Payback Time in Pakistan

It is quite well known fact that installing a solar system at your home requires a large initial investment. But it is also known that solar panels have a typical life period of 25 years. Other equipment used in a solar system such as batteries, charge controllers and inverters have a shorter life span and may need to be replaced every 2-4 years. In this article we try to calculate the payback time of a simple solar system that uses all its energy in real time converting DC voltage produced by the solar panel to AC voltage through an inverter.

Let us assume that our load requirement is 500 W and we have 5 solar panels of 100 W each. We next assume that we have an inverter also rated at 500 W. Let us further assume that the solar panels receives peak sunshine for 6 hours daily (this is called Peak Sun Hours and is quite complicated to explain in this brief article). Therefore the total energy produced during a 24 hour period is

500 W x 6 hr = 3000 Whr = 3 kWhr

In one month the solar panel would produce

3 kWhr x 30 = 90 kWhr or 90 units of energy

Now assuming that a unit of energy is sold to you at Rs. 15 (including all the taxes and surcharges) the total savings per month are

90 units x Rs. 15/unit = Rs. 1350

Now let us look at the investment we made in the solar system. Solar panels are widely available in the local market for Rs.100/watt. This results in Rs. 50,000 investment in solar panels. An additional Rs. 10,000 are spent in the inverter. So the total cost of the solar system is Rs. 60,000.

So the payback time of this solar system is

60,000 / 1350 = 45 months or 3.75 years

This is highly encouraging because all your investment is recovered in less than 4 years and you have 21 years of free energy from your solar system.

Solar Payback Time in Pakistan is about 4 Years

Solar Payback Time in Pakistan is about 4 Years

Note:

1. The above analysis is also valid for grid tied systems where the energy is sold to the grid during the off peak hours (day time) and  bought from the grid during peak hours (evening, night time).

2. A real system would also need some batteries to provide backup when there is a power shut down and solar energy is also not available.

3. Although solar system is expected to have 25 years of life, it will not operate at 100% throughout this life period e.g. it might be operating at only 80% after 20 years.