Tag Archives: renewable energy

Solar Tracking Systems

To harness as much solar energy as possible, collection surface must always be perpendicular to the sun’s rays and this can only be achieved if modules are equipped with a solar tracking mechanism.
Using these mechanisms, total energy received in a day can be up to 35% higher compared to that received by a static module.

This difference in performance is reduced in cases of frequent cloudy days and in all those weather conditions in which the relationship between energy received by direct radiation and that received by diffuse radiation tends to decrease. That is why it is only recommended to use it in areas of low cloudiness.

A detailed analysis must be carried out to verify that performance increase achieved more than compensates for energy consumption and the cost and maintenance of monitoring mechanisms.

The two types of movement are:

1. Single axis: only allows rotation around a horizontal, vertical or inclined axis. You can track sun azimuth or height, but not both at the same time.

Ver las imágenes de origen

2. 2-axis: in addition to the east-west rotation movement, a second rotary movement on a horizontal axis is also possible by varying the module angle with respect to the horizontal plane. They can be monopost (a single central support) or carrousel (several supports distributed along a circular surface).

Ver las imágenes de origen

We can find different solar tracking systems. The most common are:

1. Passive tracking systems: These devices do not use electricity or have a motor. There are two North American patents. The first (Robbins Engineering) is based on Freon gas pressure expansion and contraction contained in two cylinders located on each side of the structure. The second (Zomeworks) is a gravity system based on the variation of the weight of a fluid contained in a container that when evaporated passes to another.

2. Tracking by sensors: the sensor is the element that allows the detection and measurement of the lack of direction between the sun vector and the normal to capture surface. The sensor is usually made up of pairs of photosensitive elements mounted on the module and moving in solidarity with it.
The photosensors use direct solar radiation to detect sun position. Tracking impossibility when sun occultations occur and need to spend time recovering address when sun reappears are inherent characteristics of all systems of tracking based on photosensors.
Deviation detected by the photosensors transmits an actuation signal that controls motors operation to achieve module movement. Constant speed motors are often used that operate intermittently so that the addressing error is kept within a tolerance band.
Systems using photosensors are used for small and medium systems.
Between one day’s sunset and the next day’s sunrise, the module must be placed in the sunrise position because once the sun has risen, much time would be lost in the 180º turn necessary to regain direction. For this, a clock is used that generates the appropriate order.

3. Tracking by calculated coordinates: this system follows sun position by calculating its astronomical coordinates and does not require solar rays physical presence. This circumstance renders coordinate systems immune to cloudy days and other circumstances that can produce addressing errors in a photosensor, as happens for example with flashes.
The use of computer controlled systems has the additional advantage that certain changes can be made at software level only.
It can also include additional functions such as bringing the modules to a position of maximum security against inclement weather or the return at night.

Sopelia has developed Solar Layout, the Android App that allows to obtain the inclination, orientation and distance between rows of photovoltaic modules at the installation site.

This content was extracted from the Commercial Technical Manual of Photovoltaic Solar Energy and is part of Sopelia Solar e-learning.

All you need is Sun. All you need is Sopelia.

Solar PV Latin America

Latin America generates about 7% of the world’s electricity and non-traditional sources account only for 6% of the energy mix.

It is expected that by 2050 over 20% of the electricity generated in the region will come from non-hydro renewables.

May the contribution of photovoltaics be significant?

This technology has great potential in the region, but is still marginalized to the background among the countries’ energy choices and many times what is done about it is just to “stand” and very little is accomplished.

Compared to the rest of the world, the rate of solar photovoltaic energy implementation in Latin America is very low.

Annually the installation of about 100 GW of solar photovoltaic energy is expected worldwide and usually only 1% corresponds to this region.

However, the fact of not having been one of the pioneer regions where the development of this technology began will allow learning from other regions or countries mistakes.

We must distinguish between solar industrial development (manufacturing of modules and other components) and solar energy (solar electricity).

Solar industrial development in the region has difficulties with the sharp drop in solar modules’ prices.

In contrast, solar electricity production is favored by the fall in modules prices and makes solar photovoltaic energy more competitive.

The average cost of 1 W of installed solar PV has dramatically dropped in recent years and most projections indicate that this trend will continue. The underlying costs associated with solar photovoltaic energy will also continue to decline.

PV installed capacity of Latin American countries has always been oriented to isolated applications to meet the needs of rural populations without access to electricity network.

Only after 2014 solar photovoltaic projects began to attract capital.

Latin America has 51 solar photovoltaic plants in operation and 625 MW of installed PV in 2014, compared to 133 MW in 2013. They have announced 23 GW projects, 5,2 GW in contracts, 1,1 GW under construction and 722 MW in operation.

From GTM Research consultancy recent studies show that the installed capacity in MW has increased 370% in 2014 and is expected to rise 237% in 2015.

This figure could be revised downwards following the price collapse that has rocked the oil industry and the commodity sector in recent months.

Today, in Latin American countries with good levels of radiation and without large subsidies in the energy market, the model of solar PV is self-sustaining.

In some cities in Mexico, Brazil, Chile and Peru, the solar PV cost is situated very close to grid parity.

Countries like Costa Rica, Guatemala, Mexico, Panama, Dominican Republic and Uruguay already have national laws and regulations in place for connecting photovoltaic generators under the net metering system.

The most suitable places to locate large plants are the deserts near the Pacific coast and northeastern Brazil.

Over the next 20 years it is expected that the investment in solar photovoltaic energy per year will reach about U$S 100.000 million worldwide.

A forecasted development of 3,5 GW is estimated in Latin America by 2016.

Could this be possible?

To know it, we are going to do a country-by-country analysis because there are very different realities.

Solar Energy in Latin America

Before evaluating the solar potential of the region, we will expose some macro variables.

Latin America includes Argentina, Bolivia, Brazil, Chile, Colombia, Costa Rica, Cuba, Ecuador, El Salvador, Guatemala, Haiti, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Dominican Republic, Uruguay and Venezuela.

It has 22.222.000 km2 (approximately 13.5% of the planet’s land surface) and more than 600 million inhabitants.

The region has a remarkable political and economic diversity and is unstable because of the continued monetary policy focus shift.

Currently, in Latin America 3 types of economic systems are recognized.

The capitalists, with open economies that rely on the free market and free trade agreements. Some of these countries are Peru, Chile, Mexico, Colombia, Panama and Costa Rica.

Countries that, even though argue having an open structure to the world, are clearly protectionists, with a social market or mixed economy. Some of these countries are Argentina, Uruguay, Brazil, Ecuador, Bolivia and Paraguay.

Finally there are a few countries that maintain closed economies with little regard for free market and with a clear tendency to Marxist models. This is the case of Cuba, Venezuela and Nicaragua.

The largest economies by GDP are Brazil, Mexico, Argentina, Colombia and Venezuela.

The most developed in terms of GDP per capita are Chile, Argentina and Uruguay’s economies.

Let us analyze the solar resource available in the region.

Solar energy is evenly distributed, since much of the region lies within the so called ‘Sun Belt’ region presenting the highest solar radiation; with the exception of specific sites, it is a predictable and reliable resource.

What is the main advantage of solar energy over other renewable energies?

Solar energy has a higher degree of integration into the urban environment.

Roof facilities take advantage of idle surfaces to generate clean energy. The country that manages to focus its efforts on such facilities’ development will have the key to its own, and its inhabitants’, energy sovereignty.

Another important factor is that solar installations can be performed by local workers, reducing dependency on technology developers and equipment suppliers (mostly manufactured outside the region). This eliminates the link between the equipment’s sale, installation, commissioning, operation and maintenance; unlike it happens with other renewables.

With some of the best solar resources in the world, Latin America has great opportunities.

Some reasons to be optimistic:

1. Good levels of solar radiation in the region

2. Sustained downward trend in solar systems components’ prices

3. Technology with high potential for generating local employment

4. Increasing public environmental awareness

5. Convenience for many countries to reduce dependence on oil and its derivatives

6. Political will is evidenced by governments of some countries in the region

And some outstanding issues:

1- Investment in modern interconnected transmission networks infrastructure and bidirectional measurement equipment

2- A larger financial market to support solar technology long-term development with loans

3- Legal uncertainty and economic instability in some countries of the region

In upcoming deliveries we will analyze the thermal and photovoltaic solar energy domestic applications’ situation in the region.