Micro-grids and modern technology for decentralised power distribution

Micro-grids with ability to coordinate and control the local demand and the distributed energy resources to maintain the voltage at standard levels, is the alternate solution to the conventional power grid.

With a view to ensure uninterrupted power supply, issues of power cuts, failures, and scheduled load-shedding have been reduced significantly in urban India in the last few years. However, it is not the same story in rural India which continues to be plagued with power supply issues.

Micro-grids aiding against the intermittent energy supply in outback and rural areas
The urban and rural inhabitants are not dissimilar in their aspirations for quality energy supply, better customer services and grievance redressal. However, the majority of the rural inhabitants cannot afford to pay for energy non-uniformly throughout the year. Talking about the essential aspects of grid in possible Professor Dr. Jayashri Ravishankar, Senior Lecturer, UNSW says “Rural household incomes are linked to agricultural productivity, which is seasonal by nature; this means incomes are not steady throughout the year. Therefore, while energy budgets vary within a year, consumers need solutions which can accommodate a variety of budgets without altering the service quality.”

With wind and solar contributing jointly into the microgrid, these energy plants can offer immense potential in ensuring continuous power supply in rural areas. Homes equipped with rooftop solar panels are also accompanied by lithium-ion batteries to serve as storage systems. Just like how fuel cells are used to generate power by means of a chemical reaction, this hybrid model can further be scaled up using a community micro-grid to enable its shared use, instead of having to depend on individual storage options.

Stabilising voltage fluctuation and variability
One of the key advantages of micro-grids is that they can generate varying amounts of energy, corresponding to the power needs and theload. However, the amount of power generated must match the requirement, after taking into consideration transmission losses. Thus, the energy generated can be distributed among all homes connected to the micro-grid, allowing those which do not generate power to utilise the excess energy produced. This model will help both homes businesses connected to the micro-grid, to enjoy an uninterrupted supply of power, and enable the stabilisation of voltage fluctuations.

Micro-grid infrastructure is economical than electric power grids
While conventional electric power grids are massive in size, micro-grids are, evidentially, much smaller in size. However, micro-grids function similar to the conventional electric power grid, with their capacity for power generation varying from as low as 5KW to as much as a few GW, depending on the need and requirement. A micro-grid system consists of a small network of energy users and energy generators, usually a mix of rooftop solar plants and a wind turbine, connected to the central grid. Power moves between multiple nodes in the framework, and is redistributed immediately. Owing to this, the cost of micro-grid infrastructure is considerably lower than conventional electric power grids. It should be noted that microgrid as a concept/technology platform can retrofit into existing grid infrastructure (ideally needing no extra infra investment) and the burden of technical losses on the distribution companies is further reduced by encouraging consumers to invest in solar rooftop systems and battery storage system.

This has been further amplified by the falling prices of solar panels, and as a result, solar power generation, owing to the many initiatives undertaken by the government, and the subsidies and tax breaks offered. While the cost of Lithium-ion batteries, the main storage option for micro-grids, continues to be a significant deterrent, it is expected that upcoming technological advancements, taking cue from leaps made by countries like Australia, will further help make batteries and storage solutions, and in turn, micro-grids, cheaper and more affordable, in the years to come.

Micro-grids as the future of electrified India
The existing grid structure in India, built in stages over decades, is plagued by a number of integration and technical issues, due to which it has been unable to enhance its renewable energy intake potential. Therefore, the utilisation of renewable energy sources, by means of a micro-grid, can serve as a perfect solution to this, in the meantime. Furthermore, when rooftop solar panels are installed to power homes, lithium-ion batteries are utilised to store the excess energy generated. Through a micro-grid, this energy can be instantly redistributed for use by several different industries,with varied applications, instead of requiring expenditure on storage options. However, with storage solutions being intrinsically linked to the renewable energy sector, the excess energy stored in batteries can also be used to charge electric vehicles and several other appliances, to reduce dependence on the grid. This can help ensure that each and part of the country is able to receive a sufficient supply of energy, and pave the path towards a 100 per cent electrified India.

The intermittent nature of renewable energy sources has been a concern to the distribution companies. Even though batteries can accommodate these intermittencies to some extent, their cost is not very encouraging.” This demands granular demand response and local control of the renewable sources. Microgrids supported by modern technology platforms can help move to much more decentralised control.

While advanced energy markets like Australia with much higher penetration levels of renewable energy sources is now looking for flexible pricing options, Australian energy-technology start-up Village Energy in collaboration with Andhra Pradesh Southern Power Distribution Company Limited (APSPDCL) is already running pilot microgrid projects in India which features granular demand response driven by real-time dynamic price engine. These technology platforms also allow active consumer interaction with the grid creating a win-win situation for the distribution company and consumers.

In certain regions in rural India, the outgoing feeder from substation supplies to more than 5 villages. If the substation regulates the feeder voltage to maintain standards, it would mean the village connected to that feeder but far from substation will experience low voltage. If the substation supplies with a higher feeder voltage to maintain standard voltage in the last village on feeder, the consumers in the village closer to substation will experience sustained overvoltage. The conventional thought process offers infrastructure as a solution, i.e., build more substations or replace the aging distribution transformers with the on-load tap-changing transformers which is costly. The alternate cost-effective solution is microgrids with ability to coordinate and control the local demand and the distributed energy resources to maintain the voltage at standard levels. When implemented at scale such microgrids can also provide ancillary services to grid.

In rural India, it is found that the accessibility to financing and lack of education/awareness is a contributing factor to lower individual consumer investment into renewable energy sources. A model that can provide the right education, financial tools, manage incentives and encourage local entrepreneurship may improve solar-rooftop penetration in rural distribution systems.

Curtailing the rural energy demand to incentivise the consumption pattern
Rural distribution grids face a bigger challenge from their consumer base in comparison to urban grids – rural energy consumption is much more homogenous, particularly during peak hours. For example – apart from essential services, commercial or agricultural demand during evening hours is almost very low, this means demand curve is driven by the residential consumption pattern, which is homogenous in most rural areas. Demand response in rural areas is a bigger challenge in comparison to urban areas. In urban areas, utilities incentivise large industrial/commercial customers to curtail demand to accommodate daily peaks. Currently, there are very few solutions which can help curtail rural energy demand, by providing customers incentives to change their consumption patterns. Village Energy is attempting to achieve demand response in rural microgrids, using economic indicators to change consumer behaviour, in India.”

One of the challenges of electricity distribution utilities is the rigid tariff structures. The residential customers are highly subsidised and have no incentive to change their behaviour. Further, the subsidies discourage residential customers from investing in DER sources like solar rooftop. The key lesson from off-grid operators in India is that customers in rural areas are willing to pay a premium for reliable service at times when they need it most. They do this by controlling their monthly energy budgets. Current tariff structures fail to meet both, the customer and utility requirements for rural energy service provision. A dynamic pricing structure is required to encourage customers, utilities and, spur DER investments.