Alternativni izvori energije
Renewable energy sources are lower costing energy sources and there are several types. There is biomass energy, solar energy, wind energy, geothermal energy, wave energy, and hydroelectric energy. All of these sources are renewable or are available in amounts that cannot be depleted significantly or easily. Each type of energy source has advantages and disadvantages, but fossil fuel energy is responsible for global warming and smog buildup in certain areas that are highly populated so they should be replaced with more earth-friendly, renewable energy sources.
The direct conversion of sunlight into electricity is a very elegant process to generate environmentally friendly, renewable energy. This branch of science is known as “photovoltaic” or “PV”. PV technology is modular, operates silently and is therefore suited to a broad range of applications and can contribute substantially to our future energy needs.
There are four basic components: the Solar Panels, a Charge Controller, a Power Inverter, and the Storage Batteries, required producing electricity from the sun.
The area required for mounting a PV array depends on the output power desired and the type of module used. An area of around 8 m2 will be required to mount an array with a rated power output of 1kW, if monocrystalline modules are used (the most efficient modules type). If multicrystalline modules are used an area of around 10 m2 will be required for a 1kWp system.
Cost estimation for a case study in Dubrovnik:
At today’s price, for 1Kw PV system (grid connection) costs about 4000 Euros including solar panels, inverter, wiring and installation. According to the solar radiation in Dubrovnic which is 4,9 kWh/m2/day , the production of electricity by PV system would be 1380 kWh/year.
Based on the new legislation about using renewable energy sources in Croatia, electricity produced by PV system can be sold to the national grid with 3,40 Kn/kWh for installed power less than 10 kW.with considering of electricity price, total cost for electricity production will be 4692 Kn/year, and the pay back time is 6,4 years. The good news is that today's solar panels have a life expectancy of 25 to 30 years or more.
Solar hot water system:
Solar hot water is water heated by the use of solar energy. Solar heating systems are generally composed of solar thermal collectors, a fluid system to move the heat from the collector to its point of usage. The system may use electricity for pumping the fluid, and have a reservoir or tank for heat storage and subsequent use. The systems may be used to heat water for a wide variety of uses, including home, business and industrial uses. Heating swimming pools, under floor heating or energy input for space heating or cooling are more specific examples.
In many climates, a solar heating system can provide up to 85% of domestic hot water energy.
Hot water demand:
If the yearly energy consumption for the hot water production is known one can recalculate the yearly amount of hot water by the following procedure:
QHW = Efos x f x ηsys
VHW = QHW / (Cw x dT)
QHW = Measured heat requirement (kWh/a)
Efos = Amount of fuel consumption per year in m³ Gas or Litres Oil
f = exchange factor converting m³ gas or litres oil to kWh
ηsys = efficiency of the heating system (-)
VHW = hot water quantity (l/a or kg/a)
Cw = specific heat capacity of water (= 1.16 Wh/kg°C)
dT = temperature difference between hot and cold water (°C)
The energy consumption of Gas for producing hot water is 7.500 m³ per year. The hot water
temperature (required storage temperature) is 55°C, the mean cold water temperature is
15°C. The heating system consists of a heater with a system efficiency of 80%.
QHW = 7.500 m³/a x 10 kWh/m³ x 0,8 = 60.000 kWh/a
VHW = 60.000 kWh/a / (1.16 Wh/kgK x 40 °C) = 1.293.000 kg/a
= 1.293 m³/a
= 3.542 litres/d (55 °C)
Consumption of water during a day is rather difficult to estimate accurately. Consumption can be assumed to be continuous during the day. In general it can be taken that every person uses (40÷60) Lit/day of hot water. For hotels and auto camps consumption can be as high as (80÷120) Lit/person.day.
Croatia government passed a new rule in the parliament about power generation from renewable energy. New tariff system is determined for electricity generation from renewable energy sources. This tariff system is based on the reasonable costs of operations, construction, replacement, reconstruction and maintenance of facilities that use renewable energy and cogeneration facilities, and a reasonable refund of the investment.
the price to encourage the production of electricity from plants using renewable energy source is significantly high(3,4kn/kWh) to pay back all cost and investment during the acceptable period. Depends on the market price for PV panels the pay back time would be even less.
|Type of plant||Price (kn/kWh)|
|a. solar power plant|
|a.1. solar power plant installed capacity up to and including 10 kW||3,40|
|a.2.solar power plant installed capacity greater than 10 kW up to and including 30 kW||3,00|
|a.3. solar power plant installed capacity greater than 30 kW||2,10|
|c. Wind turbine||0,64|
|d. power plants based on biomass|
|d.1. solid biomass from forestry and agriculture (residue, straw, seed ...)||1,20|
|d.2. solid biomass from wood-processing industry (bark, sawdust, chaff ...)||0,95|
|e. geothermal power plants||1,26|
|f. power plants Biogas from agricultural plantations (corn silage, ...) and the organic residues and waste from agriculture and food-processing industry (corn silage, manure, slaughter waste, waste from the production of biofuels ...)||1,20|
|g. power plants running on biofuels||0,36|
|h. Landfill gas power plant and gas from the plant for waste water||0,36|
|i. power plant from other renewable energy sources (sea waves, tides ...)||0,60|
Our company is offering the consultancy services for all steps from bank loan and fund procedure to implementation of PV system on the field. For more detail information please contact us here.