Hotter summers, longer outages: Can solar panels be the answer?

The sultry June and July weather would have forced you to keep the AC on for hours almost every day. This has pushed up not just the electricity bill, but the carbon footprints too. Amid concerns over the environment and outages due to inadequate coal stocks at thermal power plants, there have been questions on whether solar panels can be a suitable alternative for generating electricity.
“Solar panels, or photovoltaics (PV), capture the sun’s energy using photovoltaic cells and convert it into electricity. Fortunately, for those of us living in Delhi-NCR, the cells do not require direct sunlight all the time. It can still work on a cloudy morning, although less electricity will be generated in that case,” says Aviruch Bhatia, an expert on energy efficiency and renewables at TERI. Solar PV cells are nestled between layers of semi-conducting material, usually silicon. When light shines on them, electrons collide, and this creates a flow of electricity. “The panels should be exposed to as much light as possible. You should also ensure there is no shade from buildings or trees,” he says.
“The solar PV produces DC power, which can be converted into AC through an inverter. We can also store power using batteries.” The electricity that we usually get is 60% coal and fossil fuel and 40% renewable energy. One unit of electricity – one kilowatt hour -- from the grid can emit 800 grams of CO2 into the atmosphere. “For instance, if we use an AC of 1,500 watts for 10 hours. 15,000 KWH of electricity (multiplied by 10) will be consumed in a day. It will also emit 120kg of CO2 in the air. Here, if we talk about solar PV, it is a no carbon emission mode. It’s clean energy. But some emission will be there while extracting silicon and processing the material. This is 25gm per 1 KWH. This is 30 times less electricity than we normally consume,” he adds.
But how much space is required to set up a solar system? “We have a solar constant, which is 1,360 watt/square metre. This is the energy from the sun that will fall on 1sqm of area in the atmosphere. But on earth, we have different altitudes and surfaces, which affects radiation. Then, we cannot generate everything into electricity. In DelhiNCR, about 500 Watt/sqm fall daily on a roof on an average. So, six hours of sunlight can generate about 3KWH/sqm of solar energy on the surface. Moreover, the solar PV panels can convert around 15% of the solar energy,” explains Bhatia. The biggest benefit of solar panels is lower electricity costs, though installation costs are still on the higher side.
People storing electricity in batteries can, however, sell the power to the discom. “It’s important to ensure the solar panel’s size is big enough to cover the house’s energy needs. You may also install a solar battery or an energy storage system that will store the electricity the panels generate. This will allow you to store electricity generated during the day for use at night.
People can become more self-sufficient and reduce the amount of electricity,” says Koshy Cherail, programme director (renewable energy) at the Centre for Science and Environment. To save on electricity, people should run washing machines and dishwashers during the day, when the panels are most effective. The panels should also be cleaned regularly. “Its maintenance is easy compared to other renewable energy modes,” says Cherail.