Energy transition sans environmental havoc

The ongoing, frenetic renewable energy drive includes a hunt for pumped storage sites inside forests and on top of fragile mountains

https://economictimes.indiatimes.com/opinion/et-commentary/how-to-ensure-indias-green-power-revolution-doesnt-also-wreak-ecological-damage/articleshow/108983088.cms

As India races to achieve the target of drawing half its energy from sources other than fossil fuels by 2030, this very green energy drive also threatens to harm its fragile environment, as power producers scramble to create pumped storage hydro-electric projects. This calls for urgent policy intervention. The ideal solution is to separate renewable energy production from storage, and charge some hydel specialists with the task of building adequate pumped storage capacity in environmentally benign ways across locations, facilitating transmission of green power across the country for such storage and draw-down.

Adani Green Energy Ltd is building the world’s largest renewable energy project in Khavda, Gujarat, putting in place 30,000 MW of wind and solar power generation capacity. The project’s scale is such that it warrants backward integration. This is in addition to the Adanis’ existing wind and solar capacity of 10 GW. Other Adani companies are building photovoltaic panels and wind turbines, and also smelting copper on a large scale, to provide the high-quality electric connectivity such a project calls for.

Other companies are ramping up solar, wind, hybrid wind and solar projects across the country as well, as policy promotes India’s energy transition.

Renewable energy’s major drawback is its intermittency. The sun does not shine at night and does not shine bright enough in mornings, evenings and on cloudy days. The wind does not blow at the same speed all the time. So renewable energy produces a lot of power in relatively short periods and has periods of low to nil power production. The solution, evidently, is to store the power when it is being produced, and then draw down the stored power when power generation dips.

The long-term solution would be green hydrogen. Use the power that is generated by the sun/wind and use it to split water into hydrogen and oxygen. The hydrogen produced in this fashion is labelled green, distinct from the grey hydrogen produced by reforming natural gas with steam. Carbon dioxide is produced in this process, both when water is heated to produce the steam and when the oxygen in water combines with the carbon in methane to release hydrogen. When the CO2 so released is captured and stored, this grey hydrogen is labelled blue hydrogen.

Hydrogen has the property of combustion, as the occupants of the Hydrogen-buoyed airship Hindenburg found out the hard way. This property makes hydrogen a fuel in its own right. It can be burned to produce heat, the heat, in turn used to produce steam, and the steam, to turn a turbine to produce power, much like natural gas, but without any carbon emissions. Hydrogen can be transported with relative ease, converted into ammonia or directly. Hydrogen can even fuel internal combustion engines, apart from combining with oxygen in an electrolyte inside a so-called fuel cell, to produce electricity that can drive an electric car without storage batteries.

Green hydrogen is right now expensive. While both Ambani and Adani in India have publicly committed themselves to investment to bring down the cost of green hydrogen to less than a fifth of its current cost, that remains a solution of the future.

Storing the large quantities of power produced by Gigawatt scale renewable energy in batteries will create deforestation and other ecological disasters across the world, as mining escalates to extract the minerals required to make the batteries. That is not a viable solution.

In the short run, pumped storage is the tried and tested solution. Use the electricity from renewable sourced that cannot be utilized at the time of generation to pump water to an elevated storage, run the water down a steep incline to drive the blades of a turbine and generate power. In large hydroelectric projects, the water is accumulated by building a dam across a river and submerging an expanse of land. In a run-of-the-river project, such submergence of land is redundant, and the water drops along a steep mountainside, to develop the force to turn the turbine.

Instead of burdening India’s green entrepreneurs with the task of locating and building pumped storage sites, obtain environmental clearance and build them individually, it would be ideal for one or more specialized agencies to take on the job of buying the surplus power from grids into which renewable power is fed when it is generated and using the power for which there is no immediate offtake to pump water to an elevation in multiple sites that are environmentally benign and cost-effective.

NHPC in the public sector and the Jaypee group in the private sector are experienced hydropower companies. They could act as aggregators of surplus power and create distributed pumped storage sites. Instead of turning to fragile mountains inside virgin forests, as hydel developers are wont to, they could explore new sites.

Why can’t every highrise building also house pumped storage capacity? Instead of hunting for new locations on unexplored hills and mountains, why not run pipelines on the sides of mountains on whose slopes motorable roads already snake their way up and down?

This would call for inter-state transmission or swapping of power, transforming the voltage at several stages, and require centralized coordination. That adds to cost. But this is vital, if India’s green power revolution is not also to wreak environmental havoc, and incur the cost of inexpert, non-specialised storage.