Notes

Introduction
According to the World Energy Outlook Special Report 2018 in [1], overall 80% of energy demand is provided by conventional energy(oil, fossil fuel, gas etc) in the whole world , which causes major environmental problems, e.g., smog pollution and over 90% of total greenhouse effect.

To evolve the environmental problems, scientists are working for the solution to sustain the earth for the future generation. Perhaps renewable energy sources like Solar energy, Wind energy are being increasingly in demand because they are free natural resources and are continuously restoked. We can use it as much as we can and there is no restrictions or limitations on using them and also they have very less impact on the environment.

Solar energy is the green energy which transform thermal energy into electric energy. it's miles the cleanest and inexperienced power resources that's available within the whole global. wind energy describes the system by means of which wind is used to generate power and it is enough to supply massive amount of electricity and it has lesser effect by way of the conventional strength .

Wind turbine:
Wind turbines convert wind energy to electricity for distribution using DC generator. Wind turbines are generally classified depending on their axis of rotation such as 1) Vertical axis wind turbine (VAWT) 2) Horizontal axis wind turbine (HAWT) . The horizontal axis generally have better performance than vertical axis. The main difference between these two turbines is their operating axis. In HAWT the rotor axis is parallel to the ground and in VAWT it is perpendicular to the ground. Vertical-axis wind turbines come in several varieties, including the eggbeater-style Darrieus model.

Wind power calculation:

Pw=CPAPV3/2
Where, cp= power coefficient of wind turbine
A= area
PW= Wind power
V= speed of air
Р= air density

Solar Panel:
Solar panels produce renewable clean energy while securing low utility rates. Photovoltaic solar panels absorb sunlight as a source of energy to generate electricity. Photovoltaic modules use light energy (photons) from the Sun to generate electricity through the photovoltaic effect. The majority of modules use wafer-based crystalline silicon cells or thin-film cells. Depending on construction, photovoltaic modules can produce electricity from a range of frequencies of light.

The estimation formula to get output electricity generated by photovoltaic system is :

E = A * r * H * PR
E = Energy (kWh)
A = Total solar panel Area (m^2)
r = solar panel yield or efficiency(%)
H = Annual average solar radiation on tilted panels (shadings not included)
PR = Performance ratio, coefficient for losses (range between 0.5 and 0.9, default value = 0.75)



Charge controller:
A charge controller, charge regulator or battery regulator limits the rate at which electric current is added to or drawn from electric batteries. In solar applications, charge controllers may also be called solar regulators. A charge controller with MPPT( maximum power point tracker )capability frees the system designer from closely matching available PV voltage to battery voltage. The main function is to select suitable source either wind or solar to store the charge to avoid the overcharging of battery unit.