ESTIMATION PRODUCTION OF ELECTRICITY FROM SOLAR POWER PLANTS

Estimation of electricity production is key information for the decision to build a solar power plant. This post explains how to quickly estimate the production of electricity from a solar power plant depending on its location.

1  The importance of using renewable sources

More intensive changes in the energy sector, encouraged by the adoption of certain laws, directives, strategies and guidelines, are already noticeable in developed countries, where the pursuit of a sustainable system is carried out by intensive use of renewable resources and improving energy efficiency.

In most developing countries, which are mainly characterized by conventional energy systems, most often based on the exploitation of fossil fuels, changes in the energy sector are significantly less intense. However, a significant number of them have already undertaken the implementation of part of the obligations, and thus the realization of very ambitious goals in this area. Therefore, the electricity sector of developing countries will not remain outside the influence of the mentioned transformation processes.

EU countries have set ambitious targets to reduce CO2 emissions in the atmosphere up to 20%, and at the same time increasing the share of renewable energy from 8.50 to 20% in the total energy consumption for the EU until 2020.

2.   Solar energy  (A new dimension for solar energy- click here)

The sun is an inexhaustible source of energy. Solar energy from the sun is emitted on Earth by heat and light radiation. Solar radiation can be used for electricity production in photovoltaic plant.

The adopted legislation and careful planning of solar power plants are a good basis for investment . The contribution it makes and the development of this branch of activity, which improves technology, and thus consequently increases the utilization of solar power, reduce equipment costs and costs related to construction and maintenance. Regulations alone are not the only basis for investment. You need quality equipment selection, precise planning and analysis of cash flows.

Solar technology uses solar energy to generate electricity, which can be submitted in a network or used directly at the production site. The fastest growing segment of the solar systems are grid connected systems, because of its flexibility, high the degree of availability of electric power network and generally lower construction costs.

The amount of electricity generated in solar power plant depends on many factors: location, orientation and tilt of the panel, the ambient temperature and shading on. Properly sized system takes into account all of these factors.

 

3.     Estimation production of electricity  from solar power plants

For the calculation of electricity production of solar systems need data on the intensity of solar radiation.

FIGURE 1: Diagram of solar radiation during the year

 (A new dimension for solar energy- click here)

Latitude and longitude are specified the location of the building on which the photovoltaic system. In particular latitude is an important variable in the solar calculations. Also, a very important variable when calculating the solar irradiation surface is the slope and orientation of solar panels.

 

There are several programs that can simulate the operation of a solar system, such as PV f-Chart, DASTPVPS, Greenius, Homer, PVCAD, PV Design Pro, PVS, PV Sol, PVSYST, Solda and many others. Most of these programs can be compared with each other because they are based on the same input parameters. In simulations are subject to change input parameters and so explore and evaluate different configurations of photovoltaic systems with regard to the long term the resulting electricity.

 

Photovoltaic Geographical Information System (PVGIS) provides a list of solar energy resources and the assessment of production of electricity from photovoltaic systems based on the geographical map of Europe, Africa and Southeast Asia. He is part of the "SOLAREC" (Solar Electricity Action) actions contributing to the implementation of renewable energy in the European Union as a sustainable and long-term sources of energy [8]. Across Europe there are hundreds of meteorological measuring stations where directly or indirectly measures the solar radiation. The types of data stored in PVGIS database for the European subcontinent contains three groups of layers 1 km x 1 km resolution:

 

1.    Geographic data: digital elevation models, administrative boundaries, cities

 

2.    Spatially continuous climate data:

-  Daily exposure of horizontal surfaces

-  The ratio of diffuse and global irradiation

-  The optimum angle of inclination of the PV panels to maximize energy efficiency

 

3.    Regional averages for the built area:

-  Annual amount of radiation (horizontal, vertical and inclined optimally area)

-  Annual amount provided for the production of electricity (horizontal, vertical and inclined surfaces optimal)

-   The optimum angle of inclination of the PV panels for maximum energy yield throughout the year

 

4.  Example of estimation prouction of electricity from micro solar power plant in PVGIS

The following were used as starting data:

-          Excerpt-sketch from the cadastre

-          Existing project documentation of the object in question

-          JRC EUROPEAN COMMISSION software package (PVGIS, available for public use)

The orientation of the roofs is oriented in the southeast-northwest axis, with a slope of about 100, so PV panels will need to be placed on a substructure mounted parallel to the roof slope that dictates an angle of 10o, facing southeast.

Geographical data of the object in question are:

-          Geographic latitude……………. 44⁰ 9 ', 57 "

-          Longitude …………… 17⁰ 58 '0 "

-          Altitude ............... ... 327m

The results of satellite image measurements were taken from 18 reference stations in Europe, where the standard deviation of the error in annual insolation was found to be less than 5%.

The intrusion of photo energy will be further reduced due to the surrounding hills and mountains in the months when the sun is "low", but will not affect the results to a greater extent because then the energy from the sun is low.

PVGIS solar power estimates :

Place: 44 ° 9 '57 "north, 17 ° 58' 0" east, altitude: 327 m 

Solar radiation uses databases: PVGIS-classic 

Nominal power of PV system: 23 kWp (polycrystalline) 

Estimated temperature losses: 8.9% (using local temperature) 

Estimated loss due to effects reflection angles: 3.2% 

Other losses (cables, inverters, etc.): 14.0% 

Combined PV system losses: 24.2%

 

	Fixed system: inclination 10o
	Orientation -45O
month	Ed	Em	Hd	Hm
Jan	24.80	770	1.35	41.9
Feb	38.20	1070	2.06	57.7
Mar	64.30	1990	3.54	110
Apr	78.90	2370	4.48	134
May	88.40	2740	5.14	159
Jun	101.00	3020	5.94	178
Jul	106.00	3280	6.28	195
Aug	95.00	2950	5.64	175
Sep	68.30	2050	3.93	118
Oct	49.00	1520	2.77	85.7
Nov	27.80	834	1.55	46.5
Dec	18.60	576	1.03	31.9
		23200		1330

 

Ed: Average daily electricity production from a given system (kWh)

Em: Average monthly production of electricity from a certain system (kWh)

HD: Average daily sum of global radiation per square meter (kWh / m2)

Hm: Average monthly sum of global radiation per square meter (kWh / m2)

 

FIGURE 2: Diagram of changes in electricity production during the year