At the current pace, the ambitious target of raising the share of renewable sources in the energy mix to 40 percent by 2022 is likely to be achieved before the stipulated deadline, experts said
New Delhi: While noting that at the current pace, the ambitious target of raising the share of renewable sources in the energy mix to 40 percent by 2022 is likely to be achieved before the stipulated deadline, industry experts have placed a caveat: before the country reaches that target, the national power grid will have to be strengthened and prepped up for transmitting the huge amount of renewable energy (RE) generated.
Speaking on the sidelines of Gridtech 2019, NM Sheth, Deputy Engineer (Engineering) with Gujarat Energy Transmission Corporation Ltd (GETCO) said, “As of today, the share of RE is 22 percent. Today, the grid is strong enough. But there is ambitious planning by the government to increase the capacity to 40 percent by 2030. In that case, grid strength will have to be built after analysis. So, a lot of planning, action and involvement is required from various stakeholders.”
Why does the grid need to be RE-ready?
Currently, the power grid is built in a way so that it can carry electricity generated from conventional sources, like coal, which does not fluctuate as much as the power generated from renewable sources. As of now, it does carry power produced from green sources of energy, but the amount of power transmitted is less. If the quantum of power being sent via the national transmission infrastructure is dialled up, as the government plans to do by 2022, there would be problems because the nature of electricity is different.
The challenges of RE integration
“In a grid, there’s a synchronous machine, whether it’s a thermal powerhouse or a nuclear powerhouse or a hydro powerhouse. The machine’s operation is highly stabilised and the size of these plants is quite big, usually around 200 MW or 500 MW or 800 MW. But if you see renewable power plants, they are smaller in size. They would be around 1 MW or 2 MW, both solar and wind. In that sense, their operation becomes highly erratic. The reason behind their indisciplined operation is their extremely weak inertia. In case of a synchronous machine, there’s a rotatory mass and huge inertia. So, huge inertia gives a lot of opportunity to the grid operator to work in a stabilised way. They are able to control the frequency, voltage. But in the case of renewables, it is very difficult to control the voltage,” explained Dr Manohar Singh, Engineering Officer at Central Power Research Institute. Singh has an MTech from IIT Roorkee and a PhD in Power Engineering from IIT Delhi.
“One of the ways to address this is to look at countries that have achieved over 40 percent RE integration. We need to take references from worldwide, wherever countries are generating power from renewable sources”
He added, “The voltage is determined by the synchronous machine. But here, these are smaller units. They will try to fight against each other. So, it becomes very difficult to operate the grid in a voltage-controlled manner. However, these challenges are visible only when penetration goes beyond 30 percent.”
According to Sheth, the problem with renewable energy is that it can pollute the grid if not controlled in a proper way and it also tends to fluctuate a lot and can produce mal-interruptions.
“One of the ways to address this is to look at countries that have achieved over 40 percent RE integration. We need to take references from worldwide, wherever countries are generating power from renewable sources,” said Sheth.