As in the rest of the world, India’s main power grid is based on alternating current (AC). This AC current is supplied to consumers at different voltages depending on their demand and type of loads. This saves in transmission losses but the infrastructure for voltage step-up and step-down comes at a cost and so grid power has not been able to reach distant villages and hamlets. The growth in solar power technology and decrease in cost of solar power systems has come up as a solution for this problem. Recent years, has seen growth of Direct Current (DC) Solar microgrids in India, particularly in villages. This article, examines the potential of Solar microgrids in context of India.
What are Direct Current (DC) Solar Microgrids ?
DC Solar microgrids are power grids transferring & running on direct current (DC) in limited geography, whose power generation is by an array of solar panel connected in series to generate power at 230 V DC. This power can be transmitted over distance of 1-2km similar to 230V, AC distribution line using a 2 core cable and supporting poles.
The DC microgrid system centralized solar generation and decentralized storage is the simplest, reliable, cost effective, scalable and highly efficient solution to provide access to electricity to people living without access to electricity.
During the daytime, solar power generation takes place at one centralized location. This power is transmitted to houses, connected to the distribution line through junction boxes mounted on poles. The micro grid charge controller installed in each house steps down 230V-DC to 48V/14V/12V-DC which is used to charge the storage battery and power the energy efficient DC loads in house. During night the controller supply power to the DC loads from stored energy in the battery.
The micro grid charge controller has an integrated prepaid meter that monitors the energy consumption of respective house. This controller installed in each house draws power from the grid to charge the battery and power the DC loads.
History of Microgrids in India:
Microgrid in India was pioneered in 1990s by West Bengal Renewable Energy Development Agency (WBREDA) when it installed a 25KWp solar PV system in Sundarban delta region. Subsequently Chhattisgarh Renewable Energy Development Agency (CREDA) initiated a solar plant in Bilaspur district. By the time of 2001 census, there were an estimated 25,000 remote villages which were considered too remote and warranted off-grid electrification.
Subsequently, several microgrid installation has taken place under the umbrella of Government of India initiatives such as the Remote Village Electrification Programme (RVEP), the Village Energy Security Programme (VESP) and Decentralized Distributed Generation (DDG) scheme across various states like Bihar, Sikkim, Chhattisgarh, Madhya Pradesh, Uttar Pradesh, Odisha, Uttarakhand, Karnataka and West Bengal.
Benefits of Solar Microgrids:
Bridging the electricity gap
It estimated that some 77 million households, about 360 million people, lack access to grid electricity across India. Another 20 million households, 95 million people, are considered under-served, receiving less than 4 hours of grid power per day (Ref). A government Web portal that tracks rural electrification efforts shows that in only four of the country’s 29 states do all of the households have access to electricity.Solar microgrids offer an opportunity to bridge this electricity gap. Examples:
- In Karnataka, the SELCO Foundation has deployed solar-storage remote microgrids to provide energy access in Baikampady Mangalore, Neelakantarayanagaddi Village, Mendare Village, and Kalkeri Sangeet Vidyalaya. Each of these are DC microgrids.
- The Indian Coast Guard operates a microgrid in Andaman Island. Dodgy power reliability was not acceptable for the Chief Ministers Official Residence in Bihar India, which has a 125 kW solar microgrid.
- In the village of Dharnai, Greenpeace has gone beyond activism to solar micro-grid deployment. The village located in northeastern Bihar, became the first to rely on renewable energy resources to meet 100% of its energy needs with the installation of a solar micro-grid in July 2014,
Independence & Reliability
Decentralised Renewable Energy System (DRES) or distributed micro-grids can be designed to meet the specific power needs of different populations on a variety of different scales, and therefore, are an inclusive solution that can meet the needs of diverse economic segments. Microgrids increase reliability through local power generation and storage and provides critical facilities to operate independent of the larger grid when necessary and thus eliminate blackouts.
Microgrids help in job creation, particularly at local level, as well as creating new business opportunities. More investment can be brought into the community and development of microgrids also stimulates innovation through research into more effective renewable energy technologies.
Counter climate change
Solar Microgrids use renewable energy generation technologies, as well as energy storage, energy efficiency and smart grid technology, this in turn helps community to cut its carbon emissions and therefore help to counter climate change.
Challenges to Solar Microgrids
Despite such advantages for communities and being a technically promising investment, microgrids in India have not been scaling up. This is mainly due to existing financial and operational challenges in developing a functional commercial model. An ideal model would be one that generates sufficient revenue from end users to cover upfront capital expenditures and also ongoing maintenance costs while delivering a financial return. Hitherto, ideal implementable microgrid models have not come up due to a lack of cost-effective long-term management, maintenance and revenue collection systems that can ensure financial and operational sustainability.
Take-up is not the only challenge. Creating a micro-grid requires building a micro distribution network with wires and metres. Large-scale utilities are plagued by theft and a lax payment mechanism and these problems transfer to solar micro-grid providers. To reduce theft, the workarounds that businesses adopt are often incredibly inefficient.