Opting for a solar inverter is a smarter choice

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In India, the summer season and shortage of electricity go hand in hand. But inverters can come to your rescue. Though a variety of electrical  inverters are available in the market, opting for a solar inverter could be a smarter choice. A solar or a PV inverter is just like any electrical inverter, converting direct current (DC) into alternating current (AC). There is nothing unique about a solar inverter except for the fact that it works on green and clean energy. However, with solar inverters, one has to take care of a few things like DC voltage fluctuation, environmental conditions, protection from dust, etc. These inverters are safe and can be kept inside a room, while the PV panel can be located on the rooftop.

By Himanshu Yadav

Saturday, June 19, 2010: The demand for solar inverters is slowly but steadily picking up. This growth is attributed to the growth in the Indian solar PV market, especially in the past three years. Subsidies provided by the government, reduction in PV module prices and awareness about green energy are driving the growth of this market. According to a Frost & Sullivan report, “The Indian solar PV market has grown from a 10 member sector to a well organised market with more than 30 world class PV module and cell suppliers. The aggregate module production capacity rose from less than 60 MW in 2005 to more than 1 GW in 2009, setting India up as a possible major manufacturing hub for the global solar PV market.”

Segments that are driving demand

Solar energy is now being used in almost every segment, whether it is in government enterprises, corporations or households. Amongst all the renewable forms of energy, this form of energy has caught the eye of both public and private sector companies as solar powered devices are easy to design and the source of power is readily available.

Earlier, solar inverters were used for only lighting purposes. But now they are used in almost all sectors like at power stations, banks, etc. The industry feels that the market for solar products like inverters will explode in the coming years. This is due to the fact that increasing demand has resulted in reduction of prices. As R K Bansal, managing director, Uniline Energy Systems, states, “Whenever there is a new product in the market, its initial price is high because of the costs involved in R&D and design. In electronics products, prices depend on the demand and quantity. As the demand rises, prices get reduced. With demand rising, production costs also get reduced.”

N K Verma, chairman, Parker Group of companies, states, “Solar inverter solutions are a matter of opportunity rather than cost viability. There are many areas where grid power is not available at all. For these locations, particularly in tier II and III cities and in rural areas, solar inverters are a boon. Parker Power has launched solar inverter solutions at very competitive prices, catering to all segments of the market. The consumer sector, and particularly the farming sector, appreciates this solution over and above DG sets.”

“Rural and hilly areas, hotels, government sector, NGOs and even households in locations that suffer long power cuts are creating a demand for solar inverters,” shares Yogesh Dua, managing director, upsINVERTER.com.

The range

Most power electronics companies are manufacturing solar inverters. There are three broad categories of solar inverters available in the market.

Grid tie inverters: These inverters are tied to the grid and they take the power when solar power is not sufficient for the connected utilities. They give back the power back to the grid when it is in excess. Special energy meters are required to measure net consumption.

Stand alone inverters: These inverters use direct current, which is stored in several batches of batteries that are charged by arrays of solar panels.

Battery backup inverters: These inverters draw energy from storage devices that are charged through dedicated chargers and they send additional energy to grids. During utility outage, battery backup inverters supply AC current to chosen loads.

Among these three types of inverters, grid inverters use the latest technology available in the Indian market. Normally, solar inverters are available in the range of 300 VA to 300 KVA.

According to Bansal of Uniline, in India only two to three companies provide grid inverters. “With a grid inverter, if you have surplus power, you can feed it to the local electricity line, while if you have deficit power, you can withdraw the power from the normal electricity line, for example, BSES, NDPL, etc. The meters for such inverters work in two directions. For example, if a solar panel system generates power of 100 kVA, but the demand is only 50 kVA, then the extra 50 kVA power goes back to local electricity line, and during night the same draw the power for your use,” explains Bansal. “Grid inverters are costlier than the conventional inverters.”

Besides grid inverters and hybrid inverters, heavy duty inverters are also available in the market. Hybrids are solar inverters with inbuilt charge controller that come with the option of charging the batteries both by solar energy as well as the mains utility, with an automatic changeover from mains to battery and battery to mains, like a regular inverter. It employs an inverter circuitry, a two level battery charging feature from the mains, a solar charge controller and a fast changeover mechanism during power failure and resumption.

Heavy duty inverters are of higher capacity and are useful for enterprises and industries. Says Dua, “Solar inverters are now being manufactured with higher efficiency, in more compact sizes, are light weight, and can be connected in parallel to the grid.”

Buyer’s challenge and buying trends

The major challenge that buyers face is the non-availability of the full range of solar products in the market. Environmental conditions, a heavy investment and the requirement of a larger space for solar products are the other problems they face. Indian customers are quite cost conscious, hence their basic requirement is a product with higher efficiency at a reasonable price.

Shaji S, director, technical, Convergence Power Systems Pvt Ltd, says, “Buyers are looking for reasonably priced products. On account of the high PV module prices, the solar inverter prices are on the higher side. Once the demand increases and the PV module prices come down sharply, solar inverters will become very economical.”

Bansal states, “The cost of one inverter is not very high. It is the complete solution that is expensive. A 1 KV inverter costs Rs 6,000 but 1 KV solution can cost Rs 1 lakh. The panel cost constitutes approximately 90 per cent of the total expenditure. However, the decrease in PV module prices in recent times has benefited customers considerably and the subsidies offered by the government are encouraging. Earlier, it used to be Rs 250 per watt and now it’s Rs 80-100 per watt—this is because the demand has increased. The government is also offering a 50 per cent subsidy on solar projects.”

Buying tips

There are many companies in the solar space that manufacture solar inverters. But buyers must plan their requirements before they make a purchase. Power requirements, how many appliances need to be run on the inverter, backup time and credibility of the company are some factors to be considered.

As Bansal states, “A buyer should check the credibility of the company to be reassured about the service support they can provide. Availability of the product, reliability and after sales support from the nearest location possible are what need to be checked before making a purchase.”

Shaji adds, “A solar inverter needs to be rated correctly and the user must check whether the solar panels provide enough current. An overestimation of ratings will affect the cost significantly.”

Dua says, “It is important to check the efficiency of the inverter because better efficiency will mean a lower cost. Also, users must ensure that the company provides after sales service for the longest possible period.”

Most companies manufacturing solar inverters usually ensure good service support for their customers. A majority offer onsite sales support, which ensures representatives are sent directly to the location to check the product. “Uniline offers onsite warranties and during the warranty period the product is repaired by our engineer, onsite,” says Bansal.

Explains Dua, “All our systems are designed with single card reliability since there are very few connection/connector related problems. If a customer faces any technical fault, this card can be replaced by courier as well.”

Electronics Bazaar, South Asia’s No.1 Electronics B2B magazine

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