India has set itself an ambitious target of reaching 175 GW of renewable energy capacity by 2022, of which 160 GW is from solar and wind power. This translates to 30% of India’s total installed capacity. The challenge around grid parity for renewable sources is fast receding. Solar power is already below grid parity.
Rapid fall in renewable tariffs will support a faster ramp-up and help meet the clean energy targets as promised in the Paris Climate Agreement.
Can anything hold back this positive march towards a greener tomorrow? Yes, the likely challenge will emanate from the ability to manage the stability of the grid, given the intermittent nature of renewable power sources. For instance, solar power generation peaks during the day, but is not available for supporting the peak demand, which is usually from 7-11 pm.
Even a 20 GW of installed capacity of solar will start creating significant fluctuations for demand from other sources of power. Increasing solar to over 100 GW as planned will skew this even more.
Increasing dependence on renewable power will necessitate larger quantum of flexible back-up sources. Coal power plants do not offer the flexibility of turning off and on when needed without consequences of equipment degradation, lower efficiency and higher cost of generation. A potential way to solve this problem is by using batteries as a back-up option when generation from solar or wind falls.
Take the case of South Australia, where over 50% of the energy supply is now from renewable sources.
However, heavy reliance on wind and solar energy destabilised the power grid and the state was plagued with power outages and grid collapses. To address this, Tesla is installing a 100 MW lithium ion battery to serve as emergency backup. However, adding a storage system to spread the supply duration can add significant cost to the network.
The priority dispatch of renewables is also causing havoc with the traditional generators. In Europe (especially Germany, where renewables constitute 47% of installed capacity), thermal plants are having to back-off their generation. Unfortunately for Germany, coal plants form the base load of power generation and can’t be switched off easily.
This has led to negative power tariffs in some parts of the day as coal power plants choose to keep running rather than take the option of a costly shut down and restart. Conventional power generators in Germany have seen their market valuation drop by as much as 75% in the last three years.
India will also start facing similar issues. With increase in renewable capacity, if we allow for replication of the situation as in Germany, it could adversely affect our thermal coal based industry while also eventually restricting the penetration of renewable power.
To find a solution, India needs to think out-of-the-box and integrate technology trends along with the concept of shared economy. India should leverage the ongoing trend towards electric vehicles (EVs) in the auto industry and the sharing economy concept for sharing the battery capacity.
The Indian government has ambitious plans to sell only EVs by 2030. Even if a fraction of this plays out, it would still put a lot of EVs on India’s roads. Cars are parked for over 90% of the time, potentially allowing the batteries in these cars to feed power into the grid (V2G) when not being used.
A typical EV (Tesla Model 3) has a battery of 75kWh capacity. Assuming capacity utilisation of 20% for solar PV plants, ~65 cars could provide stability to 1 MW of installed solar capacity.
These batteries should ideally get charged when renewable power is available, discharge power into the grid during the peak load times when solar is no longer available, and charge again in the night (between 11pm to 6 am) when the demand is very low.
This will even out the demand curve to an extent and could also support base load generation of thermal plants during the night.
In addition to the lower cost of running an EV, car owners can benefit in two additional ways — They should get paid a charge for providing battery storage facilities and they should get an arbitrage between buying power at cheap rates when it is abundantly available and selling it at higher rates when the demand is high.
While not all EVs can play this stabilising role, those which can, will benefit significantly in terms of additional revenue streams.
There are technical challenges that need to be overcome for this to happen. The batteries in EVs are designed for lower charge cycles compared to those used for storage. Using an EV battery to feed power into the grid will lead to additional wear and tear and degradation of the battery.
On the brighter side, research is underway in multiple countries to improve battery technology and make V2G viable. While the grid stability challenge will be faced by most countries, India with is tropical location, has one of the highest potential for harnessing the solar energy.
In addition, India has large external dependence for its energy needs. Hence, the need to push the combination of solar energy and electric vehicles is far more critical for India, as compared to other nations.
To achieve this in India, the government needs to create supportive policy framework and compatible grid infrastructure. Some key things to be ensured:
Battery Technology: Encourage development of appropriate technology with good V2G characteristics
EVs: Encourage development of V2G cars with 2 way grid interaction
Charging Infrastructure: Deploy charging infrastructure with reverse feed-in ability
Power Distribution: Move to time of the day metering to encourage EVs to charge during high solar generation period and reverse feed energy into the grid during peak demand periods.
This integration between renewable power generation and EV as battery storage will mutually support the growth of renewable power industry as well as the off-take of EVs in India. It can lead to a virtuous circle which can help India advance towards a greener future while also restricting the dependence on imported energy.