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RENEWABLE ENERGY SOURCES
'Energy from Sunlight'

GENERALLY.

    The Clean, Environmentally Friendly, Renewable Energy Sources (RES) are the Sun / Photovoltaic Systems (PV), the Wind / Wind Energy of Wind Turbines (WTG), Hydroelectric Power Plants (HP), Geothermal sources, Hydrogen Cells (H2) from sunlight, technology under development and the waves / tides of the sea, in certain areas and limited areas.

      The currently used, non-clean forms of energy emit or leave residues, some of which are directly dangerous, such as nuclear radiation and nuclear combustion residues, Carbon Dioxide (CO2) from the combustion of hydrocarbons, which exacerbates the greenhouse effect of the atmosphere on Earth but also locally in polluted closed areas, and other more or less toxic residues.

Scientists are sounding the alarm and their suggestions are many of high cost, which is relatively small compared to the losses/destruction from alternating droughts, flooding of cities and large coastal areas (zero or minimal elevation difference from the sea surface), as a consequence of the expected dramatic climate changes. Such as the El Ninio phenomenon, hurricanes, the melting of glaciers (N. and S. Poles), neutralization of the Gulf Stream of the Atlantic Ocean.

Unfortunately, the major countries (G8), responsible for the largest percentage of atmospheric pollution, despite the agreements (Kyoto, …) and the declarations for saving the environment, do not have the will to realistically face the whole situation. Conditions are becoming increasingly difficult, because the USA and the European countries, one after the other, are sliding into economic recession, so the fight for economic recovery will undoubtedly be at the expense of the environment!

Not that the burden on the environment from industrial pollution is reversible, but the development and exploitation of RES will contribute proportionally to the cleanliness of the environment, a window of optimism has opened. In addition, RES and Alternative forms of energy, in relation to oil, are economically advantageous. The EU finances the corresponding research and promotes with co-financing the programs of renewable, environmentally clean, energy sources, mentioned above.

   The perpetual wheel with spokes powered by the Sun, Wind and Water, is today a reality and can, as a Hybrid System, draw perpetual energy from nature.

2. Impure Alternative Forms of Energy.

    This category includes biofuels, energy from waste recycling and Natural Gas, which release less CO2 when burned, i.e. are relatively clean forms of energy, alternatives to polluting and expensive oil.  

3. Exploitation of energy sources.

      All forms of energy can be used autonomously locally, but for many users distributed over a large area, in addition to the central station or production stations, the corresponding transmission and distribution network is needed.

That is, the exploitation of an energy source depends on many factors, the relevant analysis is the subject of a technical and economic study, this article simply mentions the main ones, namely:

The cost of energy production/extraction, safety of transportation and use (and user devices) and environmental pollution, a very important factor, which if neglected, will cost much more to repair in the future.

4. Greece's plans.

           a. The Greek Ministry of Development (MHD) plans to cover 2010% of the country's total energy needs by 20, with EU funding, from the exploitation of RES(1).

          b. It has been established and highlighted by the Ministry of Energy and Rural Development that there are three main factors that hinder the rapid development of RES. The first is the incomplete connection/transmission network of Electricity from the planned locations of energy production stations. The second is the delay in the formation of the necessary legislative framework and the issuance of PD, in accordance with EU directives, and the third is bureaucracy.

 c. These difficulties were recently expressed by the representatives of large Spanish companies (energy production), who accompanied the Prime Minister of Spain, during his official visit to our country in early July of this year, and stated that there is a fourth unacknowledged "factor..." (2), which prevents companies from making investments in RES of 3.5 billion Euros, while our country is anxiously seeking investments of this type/amount with an inflow of foreign capital.

4. Advantages of RES.

      a. Renewable energy sources each have their advantages and of course some limitations, we will refer to Waterfalls, Wind and especially Solar energy sources.

          1) The ability to extract energy from RES, apart from natural periodicities and fluctuations, is perpetual.

          2) They are inexhaustible and free to use. The sun and wind are available geographically without restrictions.

          3) The cost of pumping energy, apart from the cost of the initial installation, is almost zero and the 'subsequent maintenance' is minimal.

          3) They keep the environment clean against the burning of coal (coal, peat), petroleum products and natural gas, which pollute the atmosphere with Carbon Dioxide (CO2). The total electricity generated by PPC in Greece (excluding waterfalls) is around ten (10) Gw or 10.000 Mw, the burning of peat releases 2.800.000 tons of CO2 annually. (Note 3)

5. Waterfalls.

          a. Very clean source, although for very large units, over 20 Mw, it is necessary to study and take seriously the environmental impacts, for the protection of the immediate area of ​​the project and the neighboring ecosystems.

         b. Energy production facilities are costly, as is the electricity transmission network.

  c. The availability of waterfalls is relatively limited and decreasing in Greece, due to the reduction of water reserves annually, due to the corresponding reduction in rainfall. However, there is scope for the development of water reservoirs, electricity production at a local level, while using the water for irrigation of crops, which today mostly end up unexploited in the sea.

6. Wind Energy (Wind Turbines)

        a. A very important source of energy for Greece. Wind farms are already being developed in many areas and especially on the islands where the PPC Electricity transmission networks are very expensive and because it is vital to use electricity locally - autonomously and additionally for the desalination of seawater on the arid islands of the Aegean.

       b. Technology today has succeeded in enabling a wind turbine to produce 2-3 MW. The size and aesthetics of wind turbines are a limitation and therefore the selection of the appropriate installation site for wind farms is necessary.

      c. The cost/power ratio of wind turbines is low and profitable as an investment.   

7. ' Energy from Sunlight'

a. The energy of the Sun is a blessing, it activates the entire food chain with the photosynthesis of chlorophyll, the change of seasons for the life of flora and fauna. Important for the climate of Greece, Solar Energy can be extracted, with the technology of Photovoltaic cells and devices, easily and beyond the initial cost, without operating costs and minimal maintenance for the long life of the PV devices.

  b. has all the advantages of RES, mentioned above, with the only limitation being at night and during periods of lack of sunshine, due to cloudiness, for these reasons the systems are hybrid, i.e. they are combined, at least, with parallel accumulators.

  b.. PV technology is of three types:

     1) Thin Film Silicon with an efficiency of 7-10%

     2) Multi-type silicon with an efficiency of 12-14%, these are known as flat cells (panels)

     3) Simple silicon type with an efficiency of 14-17%, they are also flat cells (panels)

4) Silicon and other impurities, Triple Junction technology. Arrays of reflectors with collectors for converting solar radiation into electrical energy 25% & thermal energy 26%, total (51%).

         a) The very small Triple Junction elements are placed at the focus of the parabolic mirror / reflector and in this way collect the sun's radiation, they are safe from falling fragments, or hail in similar cases.   

         b) These PVs are also called Concentrated (CPV), due to their construction with concave mirrors and PV elements at the focus of the mirror and incident solar radiation is multiplied 1250 times, ensuring high efficiency. In terms of solar energy exploitation rates, it yields 25% electrical & 25% thermal energy (hot water), a total of 50% energy.

         c) An additional, but very important advantage is that, for a given electrical power, 1/3 of the space required is required compared to that required by classic panels (flat panels). Convenient installation of high-power PV (CPV) on building roofs, etc.

   d. Figure (3) depicts the triple energy production mechanism, which is easy and low-cost to upgrade for the technology in question, because the small silicon 'Triple junction' element will be replaced.

 d. Diagram (4) shows the efficiency increase curve of all PV types. Today, the efficiency of Triple Junction is twice as high as that of other types.

e. Large PV Triple Junction PV System & reflectors

This system, on the roof of the 22-acre building, produces 1.5 MW and also provides hot water of equivalent energy. In contrast, classic panels require three times the area for the same electrical power, without providing hot water.

f. Hybrid PV systems in conjunction with other RES.

   1) Hybrid PV systems coupled with accumulators, hydroelectric stations or wind turbines or even electric generators, if necessary, are the most economical solution for areas where we have alternations and fluctuations in the flow of wind, water and of course, when conversely there is no sunshine for the energy output of the PV. In case of autonomous operation, the PV are combined with a large capacity accumulator (battery) arrangement.

 2). Hybrid PV & Geothermal System.

      It is of particular interest, because in our country there are many regions

with geothermal potential. The technology is available, all that is needed is

is the interest of local authorities.

In figure 3, it is shown: 1. Power –Spar layout 2. Electricity, 3. Heat & Steam 4. Lighting A.Spar-Net controller B. Short-term storage tanks C. Geothermal heat pumps D. Long-term storage E. Cooling unit F. Solar lighting components

3) PV installation diagram on the roof of a building for heating and air conditioning.

7. PV Station Development Program, of the Ministry of Energy and Water Resources (RAE. note 4)

    a. The program and time scale for licensing PV stations, as a percentage of the target set, are, by the end of the years: 2007 up to 50%, 2008 70%, 2009 90% and 2010, completion of the target

    b. The gradual installation aims at a gentle and tolerable increase in the Special RES Fee, the Allocation of 500 MWp and the handling of the current situation of applications for PV.

   c. Arithmetic PV on non-Interconnected Islands

       The installation of 700 MW of PV plants is planned, which means: Investments of €4 billion, required subsidies of at least €1,5 billion, electricity production of around 900 GWh per year, i.e. approximately 1,5% of current consumption. The value of the energy produced for 20 years, around €8 billion based on current selling prices (average price €450 / MWh) and in fixed terms.

   d. Reflections and conclusions (Note 4)

         1) The development of PV in Greece is not a matter of a few years but we are at the beginning of a long journey 2) Maturity is required in the recognition and realistic assessment of prospects and returns

        2) The Program was prepared based on current conditions with the prospect of being revised to adapt to developments.

        3) The expected reduction in the cost of PV installation, the increase in their efficiency levels, the increases in the prices of conventional fuels and pollutants and the creation of environmental awareness among consumers for further support for RES, make the prospects for further increase in targets, after assessing these factors, auspicious.  

        4) The possibility of participation of small consumers is ensured. The guaranteed capacity of at least 70 MW in the Territory is equivalent to a program of 15.000 photovoltaic roofs, estimating an average capacity of 4-5 kW per consumer.

        5) The funds are enormous to develop an internal industry/craft and services in the study, construction, design and installation, their financing, etc. with direct benefit to the national economy.

EPILOGUE.

Today we live in an era of overconsumption, precision, environmental pollution from various fumes and carbon dioxide, i.e. degradation of our lives. However, RES technologies are available that can make the dream of ecological housing a reality. Urban planners, engineers in France suggest, not only to get free clean energy from the sun but also to ask it to take on the work of the "gardener" in our home, it is the only one who knows the art of photosynthesis, why do we hesitate?

England is setting an example, recently its government announced that it will co-finance the installation of PV systems in 50.000 homes in order to cover 200 Mw of energy needs, which are currently covered by oil-burning plants. The environment and the poor will benefit.

What is happening in Greece ? The people are being pressured by the accuracy, the high bills of DEKO and PPC, we believe that they deserve more light. Will we let the bureaucracy shade the sun ? We expect the competent steps to be taken faster, we are optimistic and we are waiting at the end of the road!

NOTES

(1) The Hellenic Energy Regulatory Authority (RAE) is responsible for energy policy and production licenses in our country, as well as for the coordination and promotion of energy relations in the EU and the wider region. Its website is very informative.

 (2) In the daily Greek press, which covered the events, the "unconfessed" factor in the article has a name....

 (3) Power units 1 Μw = 1.000 Kw. and one (1) Kwh of energy = 1 Kw of power x 1 Hour. During the production of one (1) Kwh, from the combustion of oil, 0,28 Kg. CO2 is released annually.

(4 ) Data from work by N.G. Boulakis, Dr. Electrical Engineer, RAE Specialist Scientist, internet.