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Conventional vs non-conventional sources with schematic

Short answer

Conventional sources (coal, gas, nuclear) are finite, polluting, with high fuel cost, and large centralised plants. Non-conventional sources (solar, wind, micro-hydro) are renewable, low-polluting, often intermitent, and can be small/decentralised. A grid-connected solar PV plant uses a PV array, DC combiner/MPPT, inverter to AC, step-up transformer, and feeds the 11 kV grid.

What are differences between conventional and non-conventional sources of energy? Draw a schematic diagram of one of the power generating stations with non-conventional sources.

Differences

Conventional sources (coal, oil, gas, nuclear, large hydro in many texts) are long-established, mostly finite, and used in large central plants. Non-conventional sources (solar, wind, small/micro hydro, biomass, geothermal, tidal) are newer, mostly renewable and often small and decentralised.

BasisConventionalNon-conventional
NatureMostly exhaustibleRenewable, inexhaustible
PollutionHigh (CO₂, ash, waste)Low or nil
Running costHigh (fuel)Low (free fuel)
OutputSteady, dispatchableOften intermittent
ScaleLarge, centralisedSmall to medium, decentralised
TechnologyMatureDeveloping

Schematic: grid-connected solar PV power plant

  Sunlight
     |
 [PV array] --DC--> [DC combiner/
  (modules)          MPPT charge]
                          |
                     [Inverter DC->AC]
                          |  400 V AC
                   [Step-up Tx 0.4/11 kV]
                          |
                     [CB / meter]
                          |
                     11 kV grid
  (optional: battery bank on DC side)

Working:

  1. PV modules convert sunlight directly into DC electricity (photovoltaic effect).
  2. Strings of modules are combined, and the MPPT controller keeps them at the maximum power point.
  3. The inverter converts DC to grid-synchronised 3-phase AC.
  4. A transformer steps up the voltage and the power is fed into the grid through protection and metering. An off-grid plant uses a battery bank to store energy for the night.

Example: the 25 MW grid-connected solar plant at Devighat, Nuwakot, feeds Nepal's national grid in this way.

✓ Answer checked by Claude Opus 5.5 (high effort)

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