Solar Rooftop Panels in Apartments – Installation Cost and Benefits

Neighborhoods of Tomorrow 2018 by ADDA which was conducted on 8th of September 2018 addressed several trending topics for gated communities and Energy Efficiency / Solar Rooftop for Gated Communities was one of them.

Sumedha Malaviya on Solar Rooftop in Apartments

Our first expert speaker of the day was Sumedha Malaviya, Senior Project Associate in the energy program at World Resources Institute India. WRI is a research organization that works on issues at the nexus of environment and development and has offices in Bangalore, Mumbai, and Delhi. Sumedha leads and supports WRI’s initiatives on energy efficient buildings, demand-side management and sustainable cities in India and globally.

Energy Consumption Issues in Gated Communities

TIDE and WRI partnered for a study on energy consumption in common areas of apartment communities. The programme, named Vidyut Rakshaka, is been running in Bangalore for past 2.5 years. As the pattern of development of gated communities is at an increasing pace, a major challenge other than the energy consumption in individual households would be that of common area amenities like swimming pool, gym etc. The first step of the study was to look at the energy consumption pattern in apartment communities and then come up with ideas to reduce this energy demand through energy efficiency and renewable energy intervention. Also, connect the residents with the right solar vendors and service providers for implementation.

They started the study with 10 apartment communities ranging from 90 to 1500 units. They went for field visits and noticed several issues like leakages in water pumps ignored, very low awareness about the transformers and more. Most of the communities do not have a standard procedure to monitor the energy consumption and electricity bill of the common area comprises of 15-20% of the annual maintenance charges, which is an alarming amount. Even the amount communities are paying for electricity from DGs were fairly high. The good things they found are that rainwater harvesting and STPs are working well in most of the communities.

They also concluded that water pumping is the major consumer of energy – mainly due to the usage of old pumps and the wrong sizes of the pumps, which decreases the efficiency of pumps.

Many communities have changed all the lightings to LED and still, complain that their bill remains the same. It is because the percentage of energy consumption by lights is very low comparatively.

The condition of usage of DGs in apartments is really bad with no one has any idea of how much diesel is being consumed as the DG logs are not maintained properly. No automatic controllers in Lift lights is another element that has a major impact on energy consumption.

The Challenge

The RWAs consider energy efficiency topic as too technical and do not take up any initiatives as such but as Ms. Sumedha mentioned that awareness should start from residents. In order to simplify the whole process, they are coming up with toolkits or guidelines for the residents. One important part is to conduct a technical audit to get a quotation for the right pumps, DGs and right lightings for the apartment complex. Also, AMC for pumps is ignored by most of the communities which are actually very important.  

Their study concluded that with minor changes in these types of types of equipment, the electricity bill can be reduced to even 8%. Once the energy efficiency is taken care of, then communities should think about implementing a Rooftop Solar system.

Kazi Zaman, a volunteer at the Bangalore Apartments’ Federation, has been tracking the renewables industry for many years now and has served on the Board of Directors of a leading Indian wind turbine manufacturer. He gave a detailed session on Roof Top Solar system and its economic and environmental impacts.

Kazi Zaman on Solar Rooftop costs and installation in Apartments

He mentioned that since there are empty roof spaces anyway, why not use it for something beneficial to us as well as the environment. The solar panels are semiconductors, which generates Direct current when sun rays fall on it and are converted to Alternate Current using inverters. The excess electricity generated is pumped back to the grid.

Advantages of Solar Rooftop Panels at Apartments

A few obvious advantages of solar rooftop systems are Zero fuel cost, no air or noise pollution and more. Unlike a few years back, now the solar system can be integrated with the existing electrical system and because there are no moving parts like that of a windmill in a solar panel, the maintenance cost is also very low in this case. Another major benefit of a solar panel system is that, as the load and point of generation is very close to each other, the Transmission and Distribution losses are extremely low.

The installed capacity of solar has increased from 2.6GW to 23GW in last four years.

Cost and Benefits of Solar Panels in Housing Societies

Why is installing solar has suddenly compelling?

Firstly, the cost of the Solar panel from 1976 to today has decreased to 99% and another reason is the introduction of the net metering system.

Due to the infirm nature of power by solar, the surplus was stored in Lead batteries which were expensive and even the maintenance charges of these batteries were really high. Now, through the Net metering system, the surplus is exported to the grid and the consumer has to pay only the net amount. Building the right sized Solar panel system is very important to maximize the benefit.

Mr. Kazi also spoke about different economic models of Rooftop Solar system – The Capex and Opex model.

The Capex model is basically where the consumer purchases, owns and is responsible for the panels. So the risk factor is on the individual. Whereas the Opex model is similar to renting out the roof and the consumer pays for the electricity. It makes more sense as the price is still cheaper than the BESCOM rates and the risk factor is not there for the individual. But, when the economic benefit is considered, in the Opex model, the service provider shares a major part of the benefit.

He concluded the session sharing that BAF is carrying out a study to come up with hybrid solutions which address the weakness of both models. One is a Capex model with Robust generation guarantee from the service providers which reduces the risk. Second is a buyback option for Opex model where the consumer can rent it out for a while and later the Solar Panels can be bought by the individual to get the maximum economic benefit out of it.

Ashok, Senior Project Associate for Renewable Energy at WRI India was the final expert speaker on the topic Rooftop Solar system. He provides research and analysis, communications and outreach support to the Green Power Market Development Group in India.

Ashok on Solar Rooftop costs and installation in Apartments

We would think that the maximum energy consumption would be in the commercial sector. But it’s surprising that according to the BESCOM data, the bulk growth in energy demand is happening with the domestic consumers. Mr. Ashok also explained about different policies by Karnataka government regarding the Roof Top solar system. The first one was the Karnataka Solar policy 2011-2016 which aimed at generating 6000 MW from solar by 2021. There was no mention of Rooftop Solar in the policy. Then, a midway course correction was introduced – Karnataka Solar Policy 2014-2021 which aimed at 3% of total energy consumption from solar and also promote Rooftop solar generation and technologies with both net and gross metering systems.

What’s the difference between net and gross metering system?

In the case of a net metering system, both energy import and export are recorded in the net meter. The difference between export and import readings is the actual energy consumed/delivered.

In a gross metering system, all the electricity generated by the Solar Rooftop System is exported to the grid and all the electricity required for consumption by the consumer is imported from the grid. The electricity bill is paid separately according to the consumption and the consumers are paid a tariff for the electricity exported to the grid.

When the final result is considered, it’s almost the same for both systems. The consumers can choose according to their convenience.

Karnataka, being a forward-thinking state when it comes to Solar, has an online application system, where you can select a system installer from the approved list and get started.

So, when you come to implementation, the cost of a Rooftop solar is INR 40,000/kW ( for 1-10kW) and for residential purposes, you are allowed to install a system with a capacity 100% of the sanctioned load. So the cost makes sense!

So as far as all the discussions we have seen at the Neighborhoods of Tomorrow, what we primarily noticed that the problem isn’t with the awareness as well. The real barrier is the lack of motivation. Everyone is worried about the payback period, which is 5-7 years. But a Rooftop solar can provide power for next 25 years at least, along with a major impact on the environment as well!

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