Cheaper options for solar power

RAPID development in solar energy technologies has made it an alternative to fossil-fuel power generation in many countries.
But Pakistan does not have to depend on borrowed ideas for generating bulk solar power at a high cost, when other economical options are available.
In a bid to overcome electricity loadshedding, the Punjab government has moved to tap possible energy resources for power generation on fast-track basis. An agreement was signed by it in July last year with a German firm to establish a 50-mw solar energy unit at Jalalpur Pirwala, Multan, apparently without conducting any project feasibility study. The first-ever solar farm costing $150 million, was to be installed within six months. But there is no physical progress achieved as yet.
Likewise, the government of Sindh has allowed an independent power producer (IPP) to construct a 50-mw solar power generation unit at Dhabeji and allotted 150-acres land to the investor at a nominal cost. The project, for which an agreement was signed by the sponsor with the same foreign company during the same period at a total cost of $125 million, was scheduled to generate power commercially by December 2011. So far, no construction activity has been undertaken at the site.
Both the projects are based on solar photovoltaic (PV) system and are proposed to be connected to the national grid. Seemingly, the projects are non-starters for a number of reasons. First, solar thermal electricity is the most expensive among other renewable energy resources.
In case of hydropower, and even wind energy, availability, reliability and affordability of power is comparatively much higher, since solar units usually attain the rated output only for about two hours a day around noon.
Also, capital cost is higher. Cost per mw for these solar projects works out to be $3 million, whereas hydropower costs $1.5 million and coal-fired $1 millon per mw, according to international markets.
Second, solar technology selected is not appropriate for on-grid application as its adoptability to the existing grid remains problematic, and in some cases, disruptive to the grid.
The power generation occurs only when sunlight is strong, weather not cloudy and supply to grid fluctuates broadly resulting in irregular, intermittent feed.
Third, the plant module, technology selected and foreign partner are apparently not suitable. The German company specialises in commercial and residential PV systems, having individual installations of maximum one megawatt only, and not having a utility-scale system.
There are no references for large-scale utility projects either in Germany or in export market. It has recently completed a 463-kW commercial project in the UK (equivalent to meet energy requirements of 125 homes on yearly basis).
Primarily, there are two solar systems for generation of electricity using solar energy – directly, using PV system, which is the most common, and indirectly, utilising concentrated solar power (CSP) system. By the end of year 2010, global installed capacity of solar PV power was about 40,000 mw. Germany alone ranked as the world leader in the field has installations of 17,370-mw cumulative capacity.
Normally, the maximum size of a solar electric system is of 20-mw capacity. The Sarnia Solar Project in Ontario, Canada has just become the largest PV solar power plant in the world with the recent quadrupling of its size from 20-mw to 80-mw capacity. The CSP technology is employed for large-scale power generation and has the ability to store energy as sunlight generating strong heat that, in turn, is used for power steam turbine.
The CSP technology, commercially developed in the late 1980s, is now proven and has an installed capacity of over 1,000 mw world over. There are four types of CSP plants: (i) parabolic trough, (ii) compact linear Fresnel reflectors, (iii) dish Stirling (parabolic) and (iv) solar power tower. International Energy Agency (IEA) forecasts that technology could be developed as a source of bulk power in peak and intermediate loads by 2020 and further, in base load, by 2030. Thus, within two decades the CSP technology might be able to compete with coal-fired power generation.
Currently, Mojave Desert of California has the world’s largest power plant, of 354-mw capacity, based on the CSP technology.
Now, Abu Dhabi plans to develop a 100-mw solar power plant adopting the CSP technology. Construction of the plant, which would cost $600 million, is scheduled next month.
Pakistan has abundant solar resources, while almost half of its population is devoid of electricity connectivity. There are about 40,000 villages with more than three million households that are without access to electricity and will remain so for long if allowed to depend on grid connection. Nevertheless, low-technology solar option offers long-term solution for electrification in these far-flung areas.
Based on PV, stand-alone solar systems are being used economically as a source of electric power for remote areas not connected with the grid. By the year 2010, a total of about 650 kW of PV have been installed for village electrification in Sindh and Balochistan. In addition, another 4,500 houses in Dalbandin (Balochistan) have recently been energised with solar power.
Moreover, stand-alone solar systems in the range of 600 watts to 5 kW have been installed in Sindh under the prime minister’s initiative.
Various NGOs have also electrified 485 houses in the FATA, about 2,000 houses in the AJK, and 12 solar panel systems of combined capacity of 3,600 watts in ten villages of Ziarat district (Balochistan). Other applications of solar energy in these areas are solar space heating, water heating, lighting, cooking, process heating, water pumping and telecommunication, etc.
The trend is being followed in urban areas. Besides street lights, a number of public and commercial buildings, including mosques, hospitals and parks, have been illuminated through solar energy. List covers the Quaid-e-Azam’s mausoleum and two systems of 180-kW each on grid solar system in Islamabad.
A number of solar thermal appliances such as solar cookers, solar water heaters and solar lights have been introduced in the country. Punjab also plans installation of tube-wells to be operated with solar energy at a cost of Rs1.36 billion.
Large-scale solar thermal power generation cannot play, and should not be allowed to play, a significant role in meeting power demands mainly for the reason that immense potential exists for hydropower and coal resources, which are abundant and cheap, and comparatively have many advantages for development under local conditions. This potential is required to be harnessed optimally and speedily. Simultaneously, solar PV system also needs to be developed further.