Sustainable power some facts some confusion Sudipta De

Sustainable power– some facts some confusion Sudipta De Professor Department of Mechanical Engineering Jadavpur University Kolkata E-mail: de_sudipta@rediffmail. com, sde@mech. jdvu. ac. in

“Teaching is transfer of ignorance from one to many”

“Seminar is transfer of confusion from one to many”

Some confusion ……. Is conventional coal based power sustainable? No !!!! Is coal based power from IGCC with 100 % CO 2 capture sustainable? Yes !!! May be !! Is solar power sustainable? Absolutely yes !!!! No !!!!

Prof. De…. . I need some more clarifications to answer these questions…. . • Are you asking whether in past, now, later (next year or after a long time) ? (i. e. , time frame!!!) • Are you asking whether locally or globally ? (i. e. , population size!!!) • Are you asking for Kolkata, Washington or Lima…. ? (i. e. , site dependence!!!) • Are you asking whether theoretically or practically? (i. e. , social, political feasibility !!!)

Then, how do we define sustainable power ? ? ……. . no formal definition ? Concept of sustainability (and not sustainable power) is formally defined……. The report “Our Common Future” by the United Nations’ Brundtland Commission in 1987: The Commission defined ‘Sustainability’, more particularly, ‘Sustainable Development’ as, ‘Development that meets the needs of the present without compromising the ability of future generations to meet their own needs’

Extrapolation for sustainable power …. … • That are not depleted (at least substantial) by continued use. • The use of which causes no environmental degradation (at least not substantial) • The use of which has no health hazard or social injustice (at least substantial) But still……… --- Politically feasible? --- Any other future vulnerability ? --- May be some more issues…….

Some facts (and confusion……) Fact 1: “ 19 th and 20 th centuries saw a massive ‘development’ through industrial revolution. Main source of energy in this period was fossil fuels. ” Confusion: 1. Was fossil fuel based power sustainable during that period? 2. Does it still continue to be the same if used with proper technology (principally, environmentfriendly)? Though not sustainable for longer time frame as it will be exhausted. But supply logistics, matured technology, ……. are most standard for it.

Fact 2: “Nuclear power is virtually inexhaustible” Confusion: 1. Is it sustainable? At least for a much longer time frame, …CO 2 -free, . . ……. 2. Only challenge is the safety issue…. . Should we not address this as a technological challenge and harness this power as a sustainable option? 3. But still it is only ~13% of world electricity. Is it principally due to social and political inhibitions?

Fact 3: “Renewable power initiative is substantial. But still it is only ? ? % of world electricity” Confusion: 1. Is this the only visible option? 2. Renewable includes different options… Should we always speak about different renewable options separately and never renewable power as a whole. 3. More effort should be for renewable or CO 2 -free fossil power? 4. What about bio-fuel vs food security ?

Fact 4: “Saving of one unit of power is always better than generating one unit, whatever efficient the system may be. ” Confusion: 1. Is the best sustainable power is not at all any power ? 2. Is power saving, either by efficiency increase or by demand side management the most favorable option equivalent to ‘sustainable power’ ? 3. Should there be more investment in research and development on demand side management and energy efficiency ?

Summing up……. . • To improve technologies for harnessing the fossil and nuclear power. These should be used with much lower environmental and social impacts. --- compulsion during transition to full renewable power. • To develop and deploy renewable power on a much wider scale. --- obvious option for indefinite time frame. • To make major improvements in the efficiency of energy conversion, distribution and use. --- best, so do it as much as possible. • However, these recommendations may change in future. --- no final recommendation is possible for sustainable power.

A few case studies……. . Some of our work on sustainable power (or rather on sustainable development? )

Development of an artificial neural network model for the steam process of a coal biomass cofired Combined Heat and Power (CHP) plant in Sweden (Energy- The Int. J. , 2007) 1999 1982 1999 Reblading 126 MW 186 MW 16

Artificial neural network (ANN) modeling

Table: Accuracy of ANN-modeling for the sub-module 2 Number of hidden neuron 17 Mean Error (%) Max Error (%) Min Error (%) 0. 250 1. 931 0. 000 18

A novel IGCC plant with membrane O 2 separation and carbon capture by carbonation-calcinations loop (Int. J. of Greenhouse Gas Control (Elsevier), 2011) CO 2 depleted flue gas CO 2 for storage Steam Carbon ation Calcination Ca. O Air Steam Ca. CO 3 Syngas G C Flue gas SRU Air Recirculated CO 2 for calcinations Gasifier Steam Syngas coal ITM GC Syngas Estimation through simulation: • Increase of CO 2 capture by 75% • Efficiency (LHV) by 3. 8%

An EU initiative for future generation IGCC power plant using hydrogenrich syngas: simulation results for the baseline configuration (Applied Energy (Elsevier), 2012) Penalty is 21. 6% loss in efficiency for CO 2 capture in proposed IGCC plant

Biomass integrated gasification combined cogeneration with or without CO 2 capture – a comparative thermodynamic study (Renewable Energy, 2014)

50 45 40 35 30 25 20 15 10 5 0 ARTIFICIAL THERMAL EFFICIENCY Net reboiler heat duty (MW) 1, 4 1, 2 1 0, 8 0, 6 Post-combustion carbon capture 0, 4 Pre-combustion carbon capture 0, 2 0 • • 0 0, 1 0, 2 0, 3 0, 4 Carbon capture efficiency 0, 5 0, 6 250 Economic loss for CO 2 capture ($/tonne) Capture performance (CP) WITHOUT CAPTURE POST-COMBUSTION PRE-COMBUSTION CARBON CAPTURE 5 4, 5 Post 4 combustion 3, 5 carbon capture 3 2, 5 Pre 2 combustion 1, 5 carbon capture 1 0, 5 0 0 0, 2 0, 4 0, 6 Carbon capture efficiency 200 POSTCOMBUSTION CARBON CAPTURE 150 PRECOMBUSTION CARBON CAPTURE 100 50 0 0 0, 2 0, 4 Carbon capture efficiency 0, 6 Thermodynamic modeling in Aspen Plus® for conceptualized cogeneration plants with carbon capture using amine solution is developed. Results show that reboiler heat duty increases sharply beyond 50% of CO 2 capture. For plants with CO 2 capture, utility heat is utilized for CO 2 capture process Operational condition may be decided within this range of carbon capture efficiency (0 -0. 5) depending on specified requirement of CO 2 capture.

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