Some facts about Solar Energy

Solar Energy is:

• Scalable
• Cheap and Predictable
• Low Capacity factor= 10-20% only
• Lifetime is quite good- 20-30 years.
• Carbon footprint is more than Wind energy- 48 gCo2/kWh
• Global installed capacity is 227 GW
• Global Energy Production is 235 TWh, i.e 0.08 kWh/Person/day
• Solar energy serves about 1.2% of the global energy demand
• Solar energy accounts for 4% of the renewable energy produced throughout the world.

Something to know about Wind Energy

Only 59.3% of the energy of the wind can be converted into mechanical energy. The Commercially available wind turbine has about 40-50% of the wind energy into mechanical energy. Average Co2 footprint for Wind energy is 11 gCO2/kWh for onshore farm and 12 gCo2/kWh for the offshore farm.

Today the wind energy share 2.3% of the global energy demand and this is about 10% of the all renewable energy produced in this world. This data is tantamount to 0.19 kWh/person/day= 0.07 Human unit/person/day

Denmark has developed good amount of wind energy. The wind installed capacity in denmark is about 5 GW and the annual energy production is 14.13 TWh.  Looking at the kWh/W, its only 2.8 kWh/W. The capacity factor comes out to (2.8/(365*24/1000) 0.32 only. In comparison with the capacity factor of hydro electricity 0.7, it can be concluded that the wind energy produces less electricity per installed capacity than hydro electricity. The amount of energy produced from wind turbine depends on the wind speed. The wind speed is dependent on daily and seasonal wind profile, terrain, and the height at which we extract energy from wind.

Power from wind turbine
E= 1/2 mv^2
m=density* volume

=ρ*A*v*t

E/t= 1/2*ρ*A*v*v^2

P=(1/2) ρ*A*v^3

The power produced from wind turbine is proportionla to cube of wind velocity. 

A turbine with rated power 1.5 MW is the power that can be produced by wind turbine at rated speed. The efficiency of turbine drastically reduces at low speed as well as high speed apart from the rated speed.

Key Points to be remembered about Hydro Electricity

Typically, the carbon footprint of hydroelectricity is only 24 gCo2/KWh whereas the carbon footprint of Coal fired power plant is much larger, 820 gCO2/KWh.

In 2015, hydroelectricity was only 16.6 % of the global energy demands. for 7.4 billion people living in this world, this energy is equivalent to 1.47 KWh/person/day which is tantamount to 0.5 human unit only. The share of hydroelectricity is considered to rise up to 25% of the global energy share.

Energy density calculation in hydropower design
Suppose, in a suitable land for hydropower development has the rain gauge reading of 500 mm/ year.
Rain= 500 mm/year
Rain= 0.5m^3/m^2/ year= 0.5*1000*10
= 500 kg/m^2/year

Potential energy of water Epot= mgh
=500*9.8*100 (h=100)
=490n Kj
Epot= 490*9.8*100
=0.14 KWh/m^2

Including losses, evaporation, and leakage, only 20% energy from hydropower dam is used for voting.

Use of Energy by sector

Transportation= 25% of the global energy use.

Residence and Buildings= 20% of global energy use

Industrial Sector= 54% of the total energy used.

Rest of the sector share only 1% energy.

Transportation= fuel or battery or direct supply for Car, Bus, Train, aeroplane sector
Residential= Heating, Cooling, Refrigeration, Air conditioning, Cooking, lighting etc.
Industrial= Iron and steel industry, Aluminium industry, wood industry, food industry, chemical industry, irrigation projects, drinking water projects, fine products etc.

Working mechanism of Bi-metallic strip in miniature circuit breaker.

Working mechanism of Bi-metallic strip in Miniature circuit breaker

How the vacuum circuit breaker operates?

There are two different springs are employed for opening and closing purpose. View it from the following link.
closing and opening of vacuum circuit breaker

Measurement of Energy

16 watt Lamp if used for 24 hours continuously consumes only 0.13 Human Unit of energy where as the energy produced by 500 MW coal fired power plant is equivalent to energy required for being live for 4.1 million people.