Photovoltaics: Generating electricity from the sunlight
The sunlight, freely available almost everywhere on the Earth, contains on average about 1 kW of energy per m2. It is the main energy source of our earth, which sustains the climate and ecosystem by maintaining temperature, creating rivers and winds, etc. This free energy can also be converted directly into electricity by means of solar PV panels.
In the case of grid-connected solar homes, power is fed (sold) to the grid when there is a surplus generation, and drawn (purchased) from the grid when the generation is absent or insufficient to meet the demand. Sadly, in Nepal, we don't have any regulation allowing individuals sell power back to the electricity authority in this manner.
PV, an environmentally friendly and renewable energy generation technology, is considered very promising in supplying a significant portion the future electricity demand. In 2007, about 4GW of PV panels were produced worldwide, and the cumulative production was more than 12 GW. By 2010, PV is expected to generate about 35 GW of electricity (source: PV status report 2008, Joint Research Center, European Commission).
There are basically two kinds of PV installations. One is the isolated system, in which the PV generator is not connected to the local or national network, and is the only source of electricity to supply the target load. All PV systems in Nepal fall into this category. In such systems, a storage system, consisting of rechargeable batteries, is needed to provide electricity during non-shiny hours. The storage requirement increases the system cost, as well as makes it difficult to realize large-scale generation. The other is the grid-connected system. Almost all residential as well as large-scale PV systems worldwide, covering about 90% of the total PV generation, fall into this category. Large PV installations feed the generated electricity directly into the local or national supply network. In the case of grid-connected solar homes, power is fed (sold) to the grid when there is a surplus generation, and drawn (purchased) from the grid when the generation is absent or insufficient to meet the demand. Sadly, in Nepal, we don't have any regulation allowing individuals sell power back to the electricity authority in this manner.
Can solar electricity be a solution to Nepal's energy problem?
A basic 120 W solar system in Nepal currently costs about Rs. 125,000 ($1,600). Considering the system life of 25 years, and 5 hours of daily sunny hours, its electricity would cost about Rs. 23 per kWh, which is much higher than what we are currently paying to the NEA.
There is no doubt that PV is an attractive source of electricity for many remote villages in Nepal, and thousands of houses are already enjoying this clean energy. In many cases, electrifying a village by PV is cheaper than extending the grid (by the way, the grid in the current situation is almost useless). But, can it be a long-term solution to our ever-increasing power crisis?
The most serious problem with PV generation is its high cost at present. A basic 120 W solar system in Nepal currently costs about Rs. 125,000 ($1,600). Considering the system life of 25 years, and 5 hours of daily sunny hours (“peak suns”), its electricity would cost about Rs. 23 per kWh, which is much higher than what we are currently paying to the Nepal Electricity Authority (NEA).
The high initial cost of a PV system is set to decrease significantly over the coming years, as a large number of industries as well as governments in many developed countries are actively engaged in R&D to lower the energy cost of PV generation as well as expand its penetration. The Japanese PV roadmap aims to reduce the PV electricity cost to the residential tariff level (23 Yen/kWh) by 2010, industrial tariff level (14 Yen/kWh) by 2020, and a highly competitive level for high scale generation (7 Yen/kWh) by 2030 (source: PV roadmap 2030, New Energy and Industrial Technology Development Organization/NEDO).
In Nepal's current situation of power chaos, can PV be utilized as a solution? Well, different locales have different potential energy sources including PV, and we should compare their economical, technical as well as environmental aspects. Nonetheless, those who can afford PV system, even in urban areas, can enjoy its much more reliable electricity than the current grid supply, and thereby also contribute to improve the reliability of the grid by somewhat relieving its burden.
As for the government and the NEA, they should make suitable rules to allow the grid connection of residential PV systems. It not only eliminates the need for expensive batteries, but also effectively creates a distributed generating system. Along with a subsidy program, a large-scale adoption of PV is possible. As mentioned earlier, this is the most popular PV system in the world. For example, In Japan, out of 1.9 GW of PV installations, 1.6 GW is the grid-connected residential buildings (source: H. Matsukawa, PV Seminar, 2007). There is no reason why we are not yet allowed to use it in Nepal.