Mission Green Delhi

Banking on rooftop solar and WtE to meet its renewable energy targets

The National Capital Territory (NCT) of Delhi recorded an energy demand of 31,825 million units in 2017-18, the eleventh highest in the country, despite its small size. The power supply situation in the UT is adequate at present with 0.4 per cent peak power deficit reported in 2017-18. However, with the increase in Delhi’s population, standard of living and temperatures during the summer months, its power demand has also been increasing at an exceptional rate year on year. As per government statistics, the peak power demand in Delhi reached as high as 6,000 MW on a particularly hot day in May 2018, an 8 per cent increase from the previous year. To meet the growing power demand, a proportionate increase in the city’s power generation capacity is needed.

Delhi has an installed power capacity of 7,884.84 MW, of which roughly 88 per cent is thermal power both coal and gas based, 9 per cent is hydro while only 1.75 per cent is renewable power. However, given the increasing pollution levels, toxic air quality throughout the year and rising concerns over public health, further thermal capacity additions will be hazardous for the NCT. Therefore, the Delhi government is looking to increase the share of renewables in the UT’s total installed capacity.

Preference for rooftop solar

Delhi is highly favourable for solar power generation  as the city receives high solar irradiation with 250-300 days of clear sun in a year. The city’s total solar potential is as high as 2 GW.

Solar is also logical for Delhi since there is a huge difference between the peak demand in summers and winters. This peak demand curve incidentally matches the energy generation curve of solar power plants, making solar a preferred choice for energy generation in the NCT of Delhi. To this end, the UT government released the Delhi Solar Power Policy, 2016, effective from 2016 to 2020, which is applicable to solar installations with capacities of 1 kW or more. The policy focuses on promoting investments under multiple financial models such as capex and RESCO (renewable energy service company) models. The policy includes generation targets, regulations, mandates and incentives. It applies to all electricity consumers and entities that develop and operate power projects in Delhi.

Given that 1 MW of solar requires 4-5 acres of land, ground-mounted solar is not a feasible option for Delhi, due to land constraints. Hence, rooftop solar is being heavily promoted to harness the region’s huge solar potential. Further, it has a large built-up area, which can be used for the installation of rooftop solar systems, and this area is increasing every year with rapid construction taking place all over the city to accommodate the growing population.

Rooftop solar plan

Under the budget for 2018-19, the Government of Delhi has proposed a number of initiatives to increase the share of renewable energy and decrease the dependence on fossil fuels. It has committed to procure at least 1,000 MW of power from wind and solar energy sources. The NCT has 69.57 MW of installed solar capacity and 52 MW of installed waste-to-energy (WtE) capacity as of July 2018 while about 70 MW of solar capacity is in the pipeline. Delhi has a solar potential of 2 GW, which can be utilised for meeting its future power demand.

To increase the solar uptake in Delhi, the government is planning to introduce a group net metering policy targeted at state-run schools, markets and other government buildings. Apart from this, an agriculture-cum-solar farm scheme is planned to be launched this year to incentivise the installation of solar panels on raised structures without affecting farming activities. A Building Energy Efficiency Program is also planned to be implemented for the audit of power consumption in government offices and buildings, starting with those under the power department. The Energy Conservation Building Code will be enforced soon for all new commercial buildings with a connected load of 100 kW or a plot area of 500 square metres.

For consumers in residential complexes, schools, hospitals, and municipal buildings, a solar rooftop demand aggregation programme is planned to be implemented in the RESCO mode. It will benefit consumers with an expected aggregated demand of 40 MW. The government believes that the RESCO model will make it easier for the residential segment to adopt rooftop solar, as it will minimise the upfront capital expenditure for homeowners.

High potential in the WtE segment

Delhi generates 10,050 tonnes of waste per day. Of this, 50 per cent or 4,900 tonnes waste is treated every day in three WtE plants. While the plant at Ghazipur has a capacity to process 1,200 metric tonnes of garbage per day to produce 12 MW of electricity, the Okhla plant turns 1,500 metric tonnes of waste daily into 9 MW of electricity. The plant at Narela Bawana has a capacity to process 2,000 metric tonnes of waste to generate 20 MW of electricity.

The North Delhi Municipal Corporation is soon likely to start the construction of the city’s fourth WtE plant in Bhalswa. The civic agency has awarded the contract to the Essel Group, which will set up the plant on 12 acres of land, next to the Bhalswa landfill. While the construction is underway, the company awaits clearances from the concerned authorities, including the Delhi Pollution Control Committee, by end-2018. The deadline for commissioning the plant is August 2020, but the company will start collecting garbage for generating electricity from the next year onwards.

Future outlook

Delhi can become a leading solar rooftop power generator in India provided this solar energy is managed and distributed well. There are certain challenges that need to be addressed to make this a reality. First, rooftop rights need to be clearly demarcated since Delhi is an overpopulated city with the majority of the population living in buildings with shared rooftops. Although discoms in Delhi are taking proactive measures to promote renewable energy uptake and improve power supply in the region, the  policy implementation is lagging. A proper forecasting and scheduling mechanism is needed to address the demand and supply mismatch. Going forward, there is an urgent need to address these regulatory gaps in order to achieve the city’s renewable targets and leverage its rooftop solar potential.

On the other hand, challenges facing the WtE segment are completely different from those in the solar segment, both in nature and scale. These pertain to lack of proper collection, segregation, treatment and power generation practices. The biggest challenge is effective waste management, which includes segregation of waste at source followed by recycling and resource recovery. Segregation will also help ensure that the waste sent to incinerators has the required calorific value. In Delhi, however, the calorific value of waste is much lower than the international standard or even Solid Waste Management Rules.

As per a study conducted by the Shriram Institute for Industrial Research, Delhi, in May 2017, biodegradable waste in Delhi constituted 55-60 per cent of the total waste. The calorific value of mixed waste was 1,274-1,324 kCal per kg, lower than the value set by the SWM Rules at 1,500 kCal per kg. In fact, according to GIZ’s Waste to Energy Guidelines, 2017, a calorific value of 1,600 kCal per kg is required to run WtE plants without the use of any auxiliary fuel. This is one of the many issues faced in the WtE segment. Overall, the segment is lagging on both technology adoption and policy implementation fronts, and thus has a long way to go.

By Khushboo Goyal


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