UPSC Prelims 2024 Q27: Science & Technology – Energy & Environment
- (a) Only one
- (b) Only two
- (c) Only three
- (d) All four
Answer: (d) All four
Explanation
Distributed Energy Resources (DER)
A Distributed Energy Resource (DER) is any small-scale energy technology that generates, stores, or manages power close to the point of consumption - as opposed to large centralized power plants.
DER Classification - Each Option:
| Resource | DER? | Why |
|---|---|---|
| 1. Battery storage | YES | Battery Energy Storage Systems (BESS) are classic DERs - store excess electricity (from solar/wind) and release during peak demand. Used in homes, businesses, and grids. |
| 2. Biomass generators | YES | Small-scale biomass generators (using agricultural waste, wood) at community/industrial level qualify as DERs - decentralized generation close to consumption. |
| 3. Fuel cells | YES | Fuel cells (hydrogen fuel cells, natural gas micro-CHP) generate electricity at point of use - highly efficient DERs used in buildings and vehicles. |
| 4. Rooftop solar PV | YES | Rooftop solar photovoltaic systems are the quintessential DER - installed at consumer premises, generate power locally, can export surplus to grid. |
All four qualify as Distributed Energy Resources → Answer: All four
DER vs Centralized Grid:
| Feature | DER | Central Grid |
|---|---|---|
| Scale | Small (kW-MW) | Large (GW) |
| Location | Consumer premises/community | Central plants |
| Grid interaction | Two-way (prosumer) | One-way |
| Resilience | Higher local resilience | Single-point failure risk |
Answer: (d) All four.
Why each option is right or wrong
- (a) Incorrect. '1 and 4 only' would exclude biomass generators and fuel cells — both are recognized DER types. Biomass generators provide distributed generation; fuel cells are used in buildings as micro-CHP systems.
- (b) Incorrect. '1, 2 and 4 only' would exclude fuel cells — fuel cells are a growing DER category, particularly hydrogen fuel cells for buildings, vehicles, and grid edge applications.
- (c) Incorrect. '2, 3 and 4 only' would exclude battery storage — battery storage (BESS) is one of the most rapidly growing DER categories, critical for integrating variable renewables.
- (d) CORRECT. All four — battery storage, biomass generators, fuel cells, and rooftop solar PV — are Distributed Energy Resources, characterized by small scale, proximity to consumption point.
Key point
All four are DERs: Battery storage, Biomass generators, Fuel cells, Rooftop solar PV. DER = small-scale, decentralized, near point of consumption. Opposite of large centralized power plants.
Remember
All four — battery storage, biomass generators, fuel cells, and rooftop solar PV — are Distributed Energy Resources (DERs). DERs are small-scale, decentralized energy technologies located near the point of consumption.
Common mistakes
- Doubting biomass generators as DERs — small-scale biomass generators (farm biogas, community biomass plants) absolutely qualify as distributed energy resources.
- Not knowing fuel cells are DERs — hydrogen and natural gas fuel cells installed at buildings or industrial sites are DERs that generate electricity with high efficiency.
- Thinking DER means only solar — while rooftop solar is the most visible DER, the category includes any small-scale energy resource near the point of use.
Exam tip
DER = Distributed Energy Resource = any small-scale energy at point of use. Examples: Rooftop solar, Battery storage (BESS), Fuel cells, Small wind turbines, Micro-hydro, Biomass generators, Demand response. DERs enable 'prosumer' model (produce + consume).
Sources
- International Energy Agency (IEA) — Distributed Energy Resources
- Ministry of New and Renewable Energy (MNRE) — Distributed Generation Policy