A Goa Empowered by the Sun: Solar Energy for Today and
Iris CF Gomes
Solar power is an efficient way of reducing carbon dioxide emissions and the dependence on electricity. Resources are available in Goa to diminish the reliance on the electricity department and even sell the excess power to the department. Vijaydatta Lotlikar, who has been using solar power for over two decades, spoke at the Friday Balcao with his solar cooker in tow as an exhibit.
Vijaydatta is the well-known ‘Coconut man’ from Parra, Goa, who made a name for himself by producing awe-inspiring artefacts out of coconuts, holds an engineering degree and has, by his own ingenuity, harnessed solar energy to power various appliances in his house. He says some deterrents to obtaining solar energy are the lack of awareness of this type of energy, the appliances that run on this energy and where they are available for purchase.
Beginning with an explanation of how a solar cooker works, Vijaydatta says people are usually put off by the fact that you cannot use the solar cooker during the monsoons unless there is a period of sunshine in between. But the solar cooker can be used at least for 8 months of the year which still makes a huge difference in cutting the cost of cooking gas utilisation. A simple device, the solar cooker looks like a small trunk. They are available with an aluminium as well as a fibre glass body, with the latter making the cooker lighter in weight. You can get solar cookers in other metals too. There is a new model of solar cooker that can be mounted onto a window on the south side of the house to avail of sunlight.
The particular solar cooker that was brought as an exhibit is actually a solar oven. The covering opens to reveal a mirror on the inside of the lid. This is the reflector that reflects sunlight onto a panel with two layers of toughened glass separated by a gap. The panel is placed over the box and perfectly covers it to stop any air from escaping. There is also a catch that can be used to stop the panel from opening up due to heat pressure. Below this glass panel, which can be lifted up, are the circular steel containers painted with matte black boiler paint. The black paint is essential because it is the colour that best absorbs the sun’s rays. The reflector can be adjusted to catch the sun’s rays. However even if it is not optimally adjusted, it still does the job albeit a bit slowly. While foods like meat may require the best angle to capture the sun’s rays, there is no real need to keep changing the position of the solar cooker with the sun’s routine movement.
The food cooked in the solar cooker does not burn and the food cooks far more evenly compared with a stove top. But the food could become dry or overcook if the correct amount of water is not added. This is the part that requires a bit of trial and error before you can determine the correct amount of water and the right amount of cooking time for a dish. Vijaydatta advises that fewer containers in the solar cooking reduces cooking time. You can keep up to three containers if there are foods that can be easily cooked. Other than frying, the solar cooker is good for baking, roasting and steaming.
Once a couple of food dishes are placed in the cooker, it is impossible to remove only one in between as this would cause the heated air to escape. It is best to put together dishes that have approximately the same cooking time. To remove the items from the cooker when they are ready, one has to wear cooking gloves for safety against burning oneself. This solar cooker can be placed anywhere there is direct sun available. When not in use, the cooker should be shut and covered.
One cooker can cook a meal for a family of four without any problem. One cooker is not feasible for festive occasions like parties according to Vijaydatta who has used two cookers for a party of 12-13 people as an experiment. The only maintenance required for this particular solar cooker is the repainting of the black containers (avoid scrubbing the outer part of the container) and replacement of the reflective glass if it is damaged.
The cooker with the aluminium body costs about 3900-4000 rupees. A 50% government subsidy can be availed of to reduce the pricing. They can be obtained from Goa Energy Development Agency (GEDA) but only after placing an order. The government has established Akshay Urja Shops that sell solar energy products in North Goa and South Goa. One can buy solar panels to generate electricity in the house, solar water heaters or solar cookers from these outlets at a reasonable price or purchase them from private shops and agencies and make a request for the government subsidy to be made applicable to these just as it has been in the case of solar water heaters.
Vijaydatta also mentions parabolic solar cookers that cook food within 15 or 20 minutes but says you need to watch the cooker as food may burn. The other drawbacks are that it takes some technical understanding to operate them and they take up more space than the solar oven. There are also solar panel cookers but they are best used one dish at a time and hence are limiting.
Solar water heaters are popular with hotels because of the amount of electrical energy that is saved. These too can be obtained for regular household use with a subsidy. Some of the varieties are the evacuated tube collector solar water heater (Rs 14,000-16,000) and the copper coil solar water heater (18,000 for 100 to 125 LPD, or Litres Per Day). On these one can receive for up to 100 LPD a subsidy of Rs 2000. ‘A solar water heater of 100 LPD is sufficient for a small family of four to five persons,’ says Vijaydatta. An income of up to Rs 8,00,000 allows you to claim the subsidy for the water heaters. Those afraid of monkeys destroying the water heater can protect it with a metal mesh or netting.
‘We can produce our own electricity. We don’t have to depend on the electricity department,’ says Vijaydatta, who produces 300 watts of solar-powered electricity to power the bulbs in his house and aims to power 90-95% of his house with solar generated electricity. One can use a solar charge controller, which regulates voltage and the current, to channel solar energy to inverters. A solar inverter or converter converts the DC energy of the solar panels (photovoltaic cells) into a usable AC output. The solar panels that are either fitted on the roof or any other external structure facing the right direction to harness solar power have a life span of about 25 years. The battery that is charged with the solar energy has a life span of 3-4 years. The price of a 100 watt panel is about Rs 4000 while a battery costs about Rs 800 and the solar converter costs around Rs 500.
4 LED 8-9 watt bulbs can run for at least 6 hours on a fifty watt generating panel provided the battery is a new one. Solar panels of different wattages are available and are decidedly monkey-proof and water resistant. There are monocrystalline and polycrystalline solar panels of which the monocrystalline cells are more effective and would cost about Rs 9000. Now there are silicon photovoltaic cells as well.
‘Generating one’s own electricity and using solar power to cook food and heat water has a sense of achievement and satisfaction that is unparalleled,’ says Vijaydatta as he encourages all to make an investment in solar energy.
*This article is based on a talk and discussion held at the Friday Balcao.