Time to focus on power storage rather than only its generation
Energy storage should be part of India’s policy plans for electricity now that renewable sources are gaining in significance
As India powers its post-pandemic recovery, energy occupies a central place. And within the broad contours of energy, electricity is a major issue.
Until recently, India’s policy planning with respect to electricity has been concerned primarily with generation. With transmission a relative laggard and state-owned distribution companies (discoms) in a financial mess, policy has focused on a meaningful contribution from renewable sources, particularly solar. India reached its initial goal of 20 gigawatts (GW) of solar power generation four years ahead of schedule. Subsequently, the government dramatically revised its target upward to achieve 175 GW of renewable sourced power by 2022, of which 100 GW is to come from solar, 60 GW from wind, 10 GW from bio-power and 5 GW from small hydropower. Even as we are behind on our wind power goals, sooner or later, we should be able to deliver on the solar plan.
With such a large generation capacity from renewables coming on-stream in the near future, the emphasis of India’s electricity sector needs to shift downstream. This success paradox is a result of the peculiarity of renewable source power, which can only be generated at specific times during the diurnal cycle (solar and tidal) or during specific seasons (wind). India’s installed capacity now exceeds 375 GW, of which about 137 GW (36%) is from renewable sources including hydropower. India’s capacity has quadrupled in the last 20 years. In contrast, transmission lines have only doubled during that period and per capita consumption has plateaued at a low 1,200 kilowatt hour (kWh) per capita over the last few years.
India needs to add energy storage to its lexicon of policy planning tools for electricity. Without storage, the mismatch between the timing of renewable power generation and actual power consumption (both from the grid and off grid) becomes a major opportunity loss. One might even go as far to say that a blind addition of renewable power should not come before some serious progress has been made on storage. The basic idea in storage is a simple concept in physics. Convert the energy into a different (storable) form and reconvert it when it needs to be used. Conceptually, electricity can be converted to heat, light, chemical, gravitational, or kinetic forms of energy. Technology solutions to the storage problem can be old and new. Among the old solutions are the following: 1) Use renewable energy to compress air and store the compressed air in large natural caverns; 2) Build large scale battery parks to store electricity until it can be time-transferred to the grid; 3) Store energy in a giant flywheel; and 4) Use a two-stage pumped hydro-power system. As of now, the compressed air and battery park solutions are cost- prohibitive for large-scale storage of electricity. Battery design should be robust, allowing for a different holding period for energy (than, say, for a car or mobile phone) and a very different discharge cycle. Japan, China and the US are experimenting with newer battery technologies like vanadium flow, in addition to the well-known lithium-ion variety. Pumped hydro-electric energy storage systems (PHESs) have been in use around the world for the last three decades and are making a comeback, particularly in China.
According to the Central Electricity Authority, India has the potential of nearly 100 GW of PHES capacity, of which only a small part is currently operational. PHESs have a longer service life than most carbon-based plants and could well be an important element of the solution as India presses on with its renewables strategy. A PHES requires a two-stage reservoir, with one altitudinally higher than the first, so that water can pumped upward. As the water is pumped and stored, energy conversion takes place. Reciprocally, when the water is let down the chute, as is typical with hydro-electric power, this energy is reconverted to electricity through a turbine. Among others, India has operational PHES facilities in Purulia in West Bengal, Kadamparai in Tamil Nadu, and Srisailam in Andhra Pradesh. So far, the environmental impact of these facilities has largely been evaluated in a classical sense without taking into account the decarbonization that would result through energy storage.
To take advantage of significant accomplishments in power generation, India’s evolving policy should incentivize investment in storage and transmission and focus also on mitigation of transmission and distribution losses. In addition to an emphasis on PHES for storage, research and development in new battery technologies and pilot projects using other technologies should be undertaken. On the distribution side, the big issues are administrative and financial. Discom balance sheets are broken and a cohesive plan to fix them is required. Yet another plan of ₹3 trillion was announced in the recent budget. Similarly, tariff structures will need to be revised and modernized at both the central and state levels, particularly through state electricity commissions, many of which have become either dormant or spineless. Seductive as it is to talk about more and more generation, the rhetoric will need to shift towards getting power to the consumer on a reliable and consistent basis by turning the focus downstream. That is the best way to stay current.
P.S: “Electricity is just organized lightning,” said George Carlin, an American comedian.
Source : livemint
