Net metering with solar panels Contd…
Under the new tariff structure, a consumer is required to pay the relevant tariff corresponding to the particular unit range for the entire monthly consumption, rather than calculate it on a slab by slab basis. Under this situation, the net metering system offers an opportunity for both the mid- and high-consuming householders to benefit by getting an appropriate size solar panel installed in his premises enabling him to reduce the number of units billed from a higher slab to a lower slab, while keeping the consumption the same. For example, a householder consuming 300 units a month could bring down his billed consumption to 120 units by installing a 1.5 kW panel generating about 180 units monthly. It will bring down the billing from a slab charged at Rs. 26 a unit to a lower slab charged at Rs. 15 per unit. He can then save Rs. 8,400 a month or Rs. 108,000 annually. The cost of such a system which is about Rs. 700,000 can be recovered in less than 7 years.
In a second case, if a householder currently consuming about 200 units a month could get a smaller panel say a 1 kW installed, it will reduce his consumption by about 110 units a month which will enable him to come to the 61-90 unit slab, charging only Rs. 8.50 a unit. He can then have a saving of Rs. 5,874 a month or about Rs. 70,500 annually. A cost of such a panel is about Rs. 450,000 and this could be recovered within about 6.4 years. In both cases, for the rest of the life time of the panels which is expected to be more than 25 years, the householder will get a bonus every month. When the electricity tariff goes up in the future, which will invariably happen, his bonus will correspondingly get enhanced.
Considering the cost of individual PV panels sold in the market and those of the net-metering inverter systems, there is a wide price difference and the vendors seem to be fleecing the customers. I wonder whether any local R&D institute involved in electronics such as the NERD Centre, Ja-Ela or the ACCMT, Katubedda made any effort to develop locally inverter circuitry necessary for connecting the solar panels to the grid. It would have been then possible to set up an industry here to manufacture inverter systems which could be offered to consumers at a more affordable price. The potential high demand for these systems would justify setting up a local industry even now.
There is a positive role that the policy makers could play to make the net-metering system popular. As done in many other countries, consumers investing on solar panels need to be granted certain concessions such as rebates and tax deductions on the capital, reduced import duty and low-interest loans. Every kilowatt installed will add up to megawatts and could off-set the megawatts required to be installed by the government at enormous costs. Assuming one watt of installed capacity costs US$ 1.5 as in the case of Puttalam coal plant, installing a 1000 W panel will relieve the government from installing a similar capacity thermal plant and thus save US$ 1,500 or about Rs. 180,000. Hence, a consumer investing Rs. 450,000 on a 1 kW solar system deserves a rebate of Rs. 180,000 or 2/5 of the capital. Anyone doubting the benefits of solar systems should do an internet search to see for himself the extent to which these are used in other countries.
Dr Janaka Ratnasiri
“Polipto” and its Fourth Anniversary
Norochcholai coal power plant
(Pic. courtesy ofbarista.media2.org)
The Island editorial of 25.07.2012 says in its last paragraph “Why the Norochcholai power plant described as an ultra modern power generation facility fails so often defies comprehension”. I am afraid Mr. Editor, you are making a mistake here. Who has described this power plant as an “ultra modern power generation facility”? Even in CEB literature, it has not been described that way. According to the plant’s EIA report, it is a conventional plant burning pulverized coal under sub-critical conditions with efficiency of about 35%. On the other hand, the technology adopted in most countries for coal power plants today is supercritical combustion with efficiency more than 40%. In more advanced countries including China, ultra-supercritical technology with efficiency more than 45% is used. Does the Norochcholai plant belong to any of these two categories for it to be described as an ultra modern facility?
The CEB engineers have a different view. According to a news item in the Island of 27.04.2012, CEB Engineers have protested on many occasions claiming that the Chinese contractor was delivering a substandard plant. In another news item appearing inSRILANKABRIEF website dated 30.04.2012, senior CEB engineers, associated with the troubled Norochcholai coal power plant, have complained that even after more than a year of commercial operation the Chinese contractor is yet to provide vital documents such as the Operation and Maintenance manuals and ‘as-built’ drawings of the facility.
It had also been reported in the media that Minister Patali Champaka Ranawaka has appointed a high-powered four member committee last February to probe the recurrent breakdowns of the coal power plant and the report would be expected in two months. Now, two months have long past and the report would have been submitted. For the general public who are now called upon to stay in dark for hours with the power cuts introduced, it would be some consolation if they are told what was wrong with the coal plant.
One important aspect the committee should have looked into was whether the plant is a brand new one or one that has been de-commissioned recently. It is customary for any manufacturer supplying products for overseas markets to have all instruction manuals prepared in English to be given along with the product. Apparently, it has been not so with the plant delivered here, according to CEB engineers. One could only infer from this that the plant is not a new one.
According to China Daily of 02.07.2007, more than 100 such (supercritical and ultra-supercritical) power generation units are now being built by Chinese power generator suppliers and international manufacturers for a new generation of larger power plants to replace in three to five years, the inefficient, small thermal power stations built during the hectic business expansion of the 1980s and ’90s. China is not going to scrap the decommissioned plants. Could the plant sold to Sri Lanka be one of those decommissioned plants?
Dr Janaka Ratnasiri