Innovation In the Power Industry 2022

INTRODUCTION:

Electricity, a versatile form of energy determines the economic progress of any country. If one digs into the historical background of power generation, one would witness the steady growth both conceptually and even technologically.  Englishman Stephen Gray is credited with the demonstration of electric conduction which led to invention of glass friction generators in Germany in 1740.  This triggered invention of battery in 1800 followed by Humphry Davy’s first effective ‘arc lamp’ (1808) and Hans Christian Oersted’s relationship between electricity and magnetism (1830) which marked the most pivotal contribution to modern power systems.  Michael Faraday and Joseph Henry invented the primitive electric motor (1831) documenting that an electric current through a wire moving near a magnet – establishing the principle of the generator.  One had to wait until 1870 to witness a dynamo that produced a steady direct current by a Belgian inventor – Zenobe Gramme. These opened up flood gates on electricity’s potential to light and power the world.

Thomas Edison (1882) is credited for a full-scale central power station to distribute electricity to end-users in the high profile business district of New York City.

RENEWABLES AND NONRENEWABLES:

The first coal fired steam generators provided slightly superheated steam for steam engines driving direct current dynamos.  The first steam turbine generator of just 1.6% was built by Sir Charles Parsons in 1884 and an improved efficiency after two years later. The power units of 1 to 10 MW started in the early 1900s.  The pulverized coal steam generator with improved coal combustion was demonstrated at Oneida Street Station, Wisconsin in 1919.  This set the face for betterment of power stations with the first once through steam generator with supercritical main steam pressure in the 1950s. 

Apart from Coal, more efficient Natural Gas power plants creating less pollution than coal based, became more popular.  Coal and gas power generation is classified under non-renewable sources.  This was followed by Nuclear Power Plants which contribute to 11% of electricity in the world.  Though nuclear power plants produce very little emissions, accidents like Chernobyl disaster and Fukushima disaster have forced certain reservations.

Nonrenewable sources being limited, they need to be used carefully or move into an alternate source like the renewables which include solar, wind, water, tidal and biomass.

However, mounting environmental concerns led to Clean Air Act in the 1970s by Nixon administration which was followed by development of emission control technologies as well. 

POWER GENERATION BY 2050:

Conventional sources like coal (Nonrenewable) are increasingly being replaced after peaking at more than Ten Thousand Terawatt hours in 2018.  It is estimated that this would oscillate between seven to eight thousand terawatt hours per year and account for less than 20% of the global power generation by 2050.  Electricity generation from renewables however, is expected to grow more than triple between 2020 and 2050.  The past decade saw a boom surpassing 2.8 terawatts.  In fact, Asia witnessed largest renewable production at 2.45 thousand terawatt hours.

In view of the above, the electricity generation is estimated to increase by nearly 70% in the coming three decades to reach 42 thousand terawatt hours by 2050.  It is believed that renewables at that year is likely to be the largest source of global electricity with 56% of electric power in the world.

Karnataka, one of the top 3 Indian states has a cumulative installed RE capacity of ~15.9 GW, as of March 2022.  Further, it is among the very few states in India who have consistently met their Renewable Purchase Obligation (RPO) targets.  The enhanced focus on solar facilitated “Karnataka Solar Policy 2014-2021” in May 2014 and is being replaced with new RE Policy for 2022-2027.

With the kind of emphasis on renewables in the decade 2020-2030 in view of the ‘Carbon Neutral’ achievement, it is imperative that the world could witness competitive technological improvements.  In fact, the reason why every country is eyeing on renewable is basically because of its economics now and the technological advancements over the period.  Both solar and wind have progressed excellently and may outsmart fossil fuels especially coal.  The following table provides advantages and disadvantages of solar/wind and Hydro for a comparative assessment later, in this article:

RENEWABLES – TECHNOLOGICAL ADVANCES

Despite the enthusiasm for renewables, it seems to have taken a battering in recent years for two reasons – government subsidies cut back and investor sentiment being lukewarm. It is also reported that solar farms to onshore and offshore wind have scaled back many ambitious renewable projects in favor of more trustworthy – fossil fuels.

This opens up a debate again whether it is worth banking on renewables or there is a need to opt for sustainable sources of energy at least in the developing parts of the world that lack natural resources found elsewhere.  It is in this regard that the promotion of technological advances by Iberdrola in Kenya is worth noticing.  The company with an installed capacity of 14,250 MW has a pioneering commitment to the renewable energy development.  It is building 61 MW Kinangrop Wind Farm in Kenya, one of the largest wind power with electricity generation to power 1,50,000 homes in the country. In addition, it is venturing into marine technology devices that are capable of harnessing waves and tides from oceans for electricity generation and transportation.

The new turbines are more efficient and powerful and use wind optimally with high yields with better capacity factors.  There has been a lot of consolidation especially among original equipment manufacturers (OEMs) – merger of Siemens and Gamesa into a single company. Higher wind turbine towers and longer blades for capacity increase and electricity generation thus reaching cost reduction are being promoted. Drones and HD cameras (turbine inspection) and thermal cameras (internal abnormalities) which provide high definition images and video footage are solving a number of issues.  In addition, predictive maintenance reduces the need for a technical crew to visit frequently.  Even offshore wind is in a phase of transformative improvement. Installing much larger turbines farther into the sea (deeper waters) that can handle faster winds is another option that may make wind option attractive.

Solar has similar technological advancements – Passive Emitter Rear Contact (PERC) of the 1980s gained greater popularity as mainstream solar modules.  They are indeed an upgrade from regular mono-crystalline modules in efficiency.  The roof top solar to make individual units and extended to community living independent is mandated through appropriate regulations.  Floating solar (25% more costly than ground) gained importance and about 2 GW has been installed by now.  Solar roadways (one can walk and drive), space-based solar power (satellites in Earth’s orbit capture radiation from the sun to convert into electricity) and hybrid power (combined with other technologies) plants are a few more novelty in the solar sector.

Both wind and solar would depend greatly on storage options – Battery Energy Storage System (BESS) for smooth output and reduce ramp rates for medium and large power plants.

Digital technology has been playing its role in the power sector too – Artificial Intelligence (AI), Machine Learning (ML) and block chain have a role in demand predictions, generation predictions from wind and solar and wholesale price predictions. Block chain is used to create and maintain peer-to-peer electricity trading platforms.

WAY FORWARD

Electricity generation has indeed travelled quite a bit from 1800 till date to witness the developments in the power sector – fossil fuels to renewables.  It is also clear on the advantages and disadvantages of various fuel sources in electricity generation which is so very vital for an economic prosperity.  However, ignorance of many hidden ill effects of the renewables combined with the digital technology seems to have become contagious in the world, today.

There is also a belief that solar and wind either individually or combined may not replace fossil fuels as one has been hoping for.  What therefore, is the way forward to meet the growing demand of electricity in the current scenario?  In order to understand this, let us visit the options starting with fossil fuels.

Fossil fuels especially, coal and gas has been the mainstay until recently considering the strong voices to combat climate change.  It is not right to believe that the choice of fuel sources were any different from the beginning.  It is just that sources (coal and gas) were opted as they were plenty.  Indiscriminate usage of coal compared to gas seems to have landed us into the greatest challenge of the century – climate change.  Temperature across many parts of the world is shooting up year after year and the consequences of this are reflected not only in temperatures but even on the vital resources like, water as well.  Many other hidden consequences are still not clear to humans as Nature is pretty complicated to comprehend.

There are still a few options for a concerted effort on balanced usage of the fuel sources in order to maintain a certain balance in our effort to combat climate change.  It is not possible to discard a particular source which has served us for such a long time without proper assessment and appropriate strategy.

FOSSIL FUEL AND RENEWABLE COMBINATION

Coal and Solar:

The basic principle of coal power is rotating the turbine through steam generation.  Coal fired boilers operate either at subcritical or supercritical conditions.  Two phase mixture of water and steam are replaced by supercritical fluid at boiler pressure above 22.12 MPs and corresponding temperature of 3740C.  The operating efficiency of subcritical is about 37% compared to 40% of supercritical.  Ultra supercritical however, reaches an efficiency of 45 to 48% or even higher in a few cases with steam pressure of more than 27 MPa and steam temperature of 5800C.  Coal consumption accordingly would be higher for ultra-supercritical.

Considering the large areas of coal fired power plants, imagine if the water could be heated to an extent with solar before feeding it to the boiler for steam generation.  This would reduce the coal consumption considerably (minimizing the land requirement for ash disposal) and consequently, emissions also get reduced.  This is one of the options under ‘Hybrid Generation’.

Pulverised coal and Biofuel

The calorific value of Indian coal is 3750 KCAL/KG.  After beneficiation one could achieve 4150 and the imported coal clocks 5400.  Bio-fuel records a calorific value of 36100 (Pongamia), 42,673 (Jatropha) and there are other non-edible oils at least in India, as well.  Lab experiment revealed that a spray of biofuel to pulverized coal shoots up calorific value considerably and consequently, reduction in coal consumption and lower gaseous emissions.

The above examples demonstrate that one could play with combination of fuel sources in order to achieve not only better efficiency but, even better emissions.

CONCLUSION:

Solar energy cannot alone replace fossil fuels though has the advantage of achieving significant energy savings – clean energy devoid of toxic waste and no greenhouse gases.  Similarly, biomass emits little greenhouse gas but, has a limited supply as intensive use would cause negative impacts – deforestation, soil erosion, soil and water pollution. Hydropower can be stored in reservoirs and has a great potential as only 20% of sites are exploited in the world.  Similarly, wind energy cannot alone substitute fossil fuels. The limitations that both solar and wind have as explained above are not the solutions for power generation.

A K Shyam, 373, Canarabank Layout, I Main, 1st Cross, Vidyaranyapura Post, BENGALURU-560 097,  Karnataka, India.  E-mail: [email protected]