BIOMASS SUPPORTED SOLAR THERMAL HYBRID

POWER PLANT

INDEXIntroduction

Working principle of STPP

Proposed biomass supported STPP

Advantages

Conclusion

INTRODUCTIONUse of non-renewable energy cause

environmental pollution and also they gets depleted

Pollution free, freely available renewable sources are best alternative

Solar power plants are widely used but its main problem is variability

Biomass plants are also used but its fuel availability in large amount is difficult

INTRODUCTION contd..

To overcome the disadvantages of both power plants they are combined

By shared use of some of the equipments effective cost is less than simple addition

Effective operating hours and therefore overall energy generation is higher

Hence this can be considered as technology for future

WORKING PRINCIPLE OF SOLAR THERMAL POWER PLANT

Need of solar thermal power plant is increasing due to increased fuel cost and environmental pollution

Working similar to conventional thermal power plant

Steam is generated through solar thermal energy instead of fossil fuel

METHODOLOGIES USED

Parabolic Trough Collector System

Parabolic Dish Focus System

Central Receiver System

Diagram of parabolic trough

WORKING . .Most cost effective and reliable among the

three

 It is constructed as a long parabolic trough-shaped mirror, generally made of polished metal 

Heat transfer fluid (usually oil) runs through the tube to absorb the concentrated sunlight.

Heat from this HTF is used to produce super heated high pressure steam 

Diagram of parabolic dish STPP

Tracks the sun by rotating about two axes and rays are brought to a point focus

Receiver is placed at the focus

Working fluid in the receiver gets heated

Using this heat steam is produced

Steam drives a prime mover to generate electricity

Central Receiver System

WORKING . .

Solar radiation reflected from arrays of large mirrors which are called heliostats is concentrated on a receiver situated at the top of a supporting tower

A molten salt is used as working fluid and medium of thermal storage

Characteristics of STPP

Collects thermal energy from sunrise

When obtained energy is insufficient stored energy is used

Hence constant electrical output is obtained

Stored energy will be depleted sooner and thereafter no energy production

PROPOSED BIOMASS SUPPORTED STPP FOR STABLE AND CONTINUOUS OPERATIONLarge amount of budget will be required for

building of large storage system

Biomass supported plant can contribute to generate electrical energy continuously

An auxiliary boiler is used to heat water whose fuel is provided from the biomass plant

It maintain rated parameters of STHPP

Hence generate electrical energy stably and continuously

Solar thermal power plant with an auxiliary boiler

In addition an auxiliary boiler is placed

Fuel to boiler is provided from the biomass plant

Steam from the boiler is given to the turbine in case of insufficient solar radiation

Characteristics of STHPP with auxiliary boiler

Storage energy of STHPP remain almost constant throughout the day

So the electrical energy produced is stable and continuous

Thermal energy is relatively easier and less costly to store compared to electrical energy

Sensible heat storage is most commonly used heat storage

Thermal storage system of STHPP consists of two distinct tanks

CONTRIBUTION OF THERMAL ENERGY STORAGE SYSTEM

CONTD . .One contains working fluid leaving the solar

reflector and other contains cooled working fluids leaving the steam generator

Tanks must be of same size, in case of unavoidable disturbances entire contents should be stored in one tank

Thermal energy is passed to storage if the temperature of heat source is higher than heat loads and vice versa

BIOMASS FOR STPPObtained from biological materials such as

plants, trees, waste, sewage gas etc

The effectiveness of power generation requires availability of biological materials and their transportation

Combustion gases from the auxiliary boiler are conveyed to flue gas cleaning system and cleaned gases are released to atmosphere

We must integrate the correct sources of energy for optimal power supply to a region

It depend on geographical characters of region, transportation, transmission and distribution lines

ADVANTAGE OF BIOMASS SUPPORTED STHPPRedundant energy is stored during sunny days

When the parameters of steam cannot reach rated value during insufficient solar radiation, then biomass plant starts to operate

Thus mixed steam reaches to rated value at exit of receiver

Ensures 100% use of renewable sources to generate electricity

Reduce pollution and increase the efficiency of STHPP

FURTHER RESEARCH FOR STHPP SYSTEMTo minimize the cost of large solar thermal

energy storage system

The operation of auxiliary boiler fed from biomass fuel should be more optimized and automatic for stable and reliable operation

CONCLUSIONEnsure to use 100% renewable sources

Stable and continuous mode of operation

The storage system of STHPP contributes to save biomass fuel that will increase the overall efficiency of the plant

This plant can be considered as most important modes to use solar thermal and biomass power in future

The world’s first plant combining biomass and solar thermal energy in

Catalonia

It can generate 25 MW of power enough to supply 75000 houses

It consist of almost 2,688 solar panels

Using this renewable energy plant will prevent 24,500 tones of CO2 from being released into the atmosphere.

REFERENCED. Mills, "Advances in solar thermal

electricity technology”

Z. Y. Ming and W. Jun, "Trough system and tower system”

G. Celli, et al., "Optimal location of biogas and biomass

generation plants"

WORKING . .

Used to drive Stirling engine to generate electricity

A Stirling engine is a heat engine operating by cyclic compression and expansion of the working fluid, at different temperature levels such that there is net conversion of heat energy to mechanical work( Stirling engine)

Alpha type Stirling engine. There are two cylinders. The expansion cylinder (red) is maintained at a high temperature while the compression cylinder (blue) is cooled. The passage between the two cylinders contains the regenerator

Alpha type Stirling engine

ABSTRACT

Non-renewable resources are in a edge of depletion

Energy efficient renewable sources are needed for our future

Biomass supported STHPP is a solution

Energy generation totally from renewable sources

Sources

Estimated cost/KW (in USD) Estimated combined

cost/KW (in USD )

Solar thermal plant 3,149

5,018

Biomass plant 1,869

ESTIMATED COST OF PROPOSED BIOMASS SUPPORTED SOLAR THERMAL HYBRID POWER

PLANT