The European Union (EU) has already tuned its energy policy into achieving maximum carbon dioxide (CO2) emissions reduction from power generation plants. In this context, it has already set out a strategic objective of achieving at least a 20% reduction of greenhouse gases by 2020 compared to 1990 levels. This strategic objective represents the core of the new European energy policy. Recognizing the positive effects of renewable energy sources (RES) technologies towards achieving this goal, the EU has taken a range of specific actions in the direction of enhancing the integration of RES in the existing European power generation system as a major step towards the reduction of global warming and climate change phenomena. Specifically, an action plan in the form of an EU Directive (2009/28/EC) on the promotion of the use of energy from renewable sources has been introduced by the EU whereby a target of renewable energy share of 20% out of the gross final energy consumption of the EU has been set to be reached by the year 2020. The RES Directive sets out specific national targets to be achieved by each individual Member State, regarding the share of RES generated in each Member State by the year 2020. For Cyprus, the national target states that the share of energy produced from RES must be at least 13% out of the gross national final consumption of energy in 2020.
In light of the above, the Cyprus Government has launched a number of financial measures in the form of governmental grants and/or subsidies. These financial measures are realized as RES Grant Schemes prepared by the Ministry of Energy, Commerce, Industry and Tourism which aims to provide, among others, support and incentives for the promotion of RES-E utilization in Cyprus. The main types of RES technologies which are promoted under these measures for integration in the Cyprus power system are the following:
- Solar energy
- Wind energy
Solar energy is the energy force that sustains life on earth for all plants, animals and people. The earth receives this energy from the sun in the form of electromagnetic waves, which the sun continually emits into space. The earth may be seen as a huge solar energy collector receiving large quantities of this energy which takes various forms, such as direct sunlight, heated air masses causing wind, and evaporation of the oceans resulting as rain which can form rivers. This solar potential can be trapped directly as solar energy (concentrated solar power and/or photovoltaics) and indirectly as wind, biomass and hydroelectric energy.
The solar energy industry is divided into mainly two markets, the photovoltaic (PV) market and the concentrated solar power (CSP) market. The CSP technology uses the heat radiated from the sun, for purposes such as heating water or power generation. On the other hand, PV solar cells use the properties of semiconducting materials to convert sunlight energy to electricity. The PV industry is far larger than the CSP market.
Winds are caused by the rotation of the earth and heating of the atmosphere by the sun. Due to the heating of the air at equatorial regions, the air becomes lighter and starts to rise, and at the poles the cold air starts sinking. The power in the wind is proportional to the cube of the wind speed. It is, therefore, essential to have detailed knowledge of the wind and its characteristics if the performance of wind turbines is to be estimated accurately.
Wind energy converts the power available in moving air into electricity. Wind turbines turn in by the moving air and drive an electric generator. The generator then supplies the electric current. Wind energy is renewable and environmentally benign. Wind-driven electric generators could be utilized as an independent power source and for purposes of augmenting the electricity supply from grids. Wind energy potential increases very rapidly with increasing wind speed. The annual wind speed at a location is useful as an initial indicator of the value of the wind resource.
Large, modern wind turbines operate together in wind farms to produce electricity. Small turbines are used by homeowners and farmers to help meet localized energy needs. Wind turbines capture energy by using propeller-like blades that are mounted on a rotor. These blades are placed on top of high towers, in order to take advantage of the stronger winds at 30 meters or more above the ground. The wind causes the propellers to turn, which then turn the attached shaft to generate electricity. Wind can be used as a stand-alone source of energy or in conjunction with other renewable energy systems.
There are many onshore wind farms around the world. Offshore wind farms in coastal waters are being developed because winds are often stronger blowing across the sea. It is important to mention that more than 83% of the world-wide wind capacity is installed in only five countries: Germany, USA, Denmark, India and Spain. Hence, most of the wind energy knowledge is based in these countries. The use of wind energy technology, however, is fast spreading to other areas in the world.
The wind energy advantages can be summarized as:
- No fuel is used,
- No wastes or greenhouse gases are produced,
- The land beneath can usually still be used for farming,
- Can supply energy to remote areas and
- Maintenance requirements are minimal.
The wind energy disadvantages can be summarized as:
- The wind is not always predictable (e.g., some days have no wind),
- Some people feel that covering the landscape with these towers is unsightly,
- Can kill birds since migrating flocks tend to like strong winds,
- Can be noisy since wind generators have a reputation for making a constant, low, “swooshing” noise day and night and
- Suitable areas for wind farms are often near the coast, where land is expensive.
Biomass covers a wide range of products, by-products and waste streams from forestry and agriculture (including animal husbandry) as well as municipal and industrial waste streams. Biomass thus includes trees, arable crops, algae and other plants, agricultural and forest residues, effluents, sewage sludge, manures, industrial by-products and the organic fraction of municipal solid waste.
There are three ways to use biomass:
It can be burned to produce heat and electricity; changed to gas-like fuels, such as methane, hydrogen, and carbon monoxide; or changed to a liquid fuel. Liquid fuels, also called bio-fuels, include mainly two forms of alcohol: ethanol and methanol. The two most common biofuels are ethanol and biodiesel. The most commonly used biofuel is ethanol, which is produced from sugarcane, corn, and other grains. A blend of gasoline and ethanol is already used in cities with high air pollution. However, ethanol made from biomass is currently more expensive than gasoline on a gallon-for-gallon basis. Ethanol is mostly used as a fuel additive or oxygenate to enhance the octane and to cut down a vehicle’s carbon monoxide and other smog-causing emissions. So, it is very important for scientists to find less expensive ways to produce ethanol from other biomass crops.
Biodiesel can be used as a diesel additive to reduce vehicle emissions or in its pure form to fuel a vehicle. Concerns about the depletion of diesel fuel reserves and the pollution caused by continuously increasing energy demands make biodiesel an attractive alternative motor fuel for compression ignition engines. Heat is used to convert biomass into a fuel oil, which is then burned like petroleum to generate electricity. Biomass can also be burned directly to produce steam for electricity production or manufacturing processes. In industrialized countries, the main biomass processes utilized in the future are expected to be the direct combustion of residues and wastes for electricity generation. The future of biomass electricity generation lies in biomass integrated gasification/gas turbine technology, which offers high-energy conversion efficiencies. The electricity is produced by the direct combustion of biomass; advanced gasification and pyrolysis technologies are almost ready for commercial-scale use. Biomass power plants use technology that is very similar to that used in coal-fired power plants.
The biomass advantages can be summarized as:
- Waste materials are used,
- The fuel, in some cases, tends to be cheap and
- Less demand on the Earth’s resources.
The biomass disadvantages can be summarized as:
- Collecting the waste in sufficient quantities can be difficult,
- Fuel is burned, so greenhouse gases are emitted and
- Some waste materials are not available all year round.