Current scenario and an eye to the future

In 2009, renewable energy supplied an estimated 16% of global final energy consumption – counting traditional biomass, hydropower, wind, solar, geothermal, modern biomass, and biofuels.

The following graph is illustrative:

In 2010 in the EU27, energy from renewable sources was estimated to have contributed 12.4% of gross final energy, compared with 11.7% in 2009 and 10.5% in 2008. It is expected that the EU will reach the target of a 20% share of total energy consumption from renewable sources by 2020.

What prevents us from using more Renewable Energy Sources?

The main reason is that up to recently the production and use of RES was very expensive compared with fossil fuels. Moreover, RES are not a guaranteed energy source; take for instance a sudden drop of wind speed or a cloudy day. In addition, in order to better exploit some RES, installations have to be built in remote areas, thus making the job of connecting them to the main grid both expensive and difficult.

However, things are changing rapidly. Policies came into place that helped the increase of demand for RES worldwide, which in turn resulted in a rapid decrease in their production costs. Considering the increase in oil and gas prices in the last years and the incentives provided by governments you can easily realize why the growth of RES is here to stay.

  An Eye to the Future

Wouldn’t it be fascinating to produce all our energy needs by renewable energy sources? One thing is sure, the technology already exists and we have the motives to do so. In fact we may not be so far away from achieving that! The EU 2050 energy roadmap

3 states that "The share of RES rises substantially in all scenarios, achieving at least 55% in gross final energy consumption in 2050. The share of RES in electricity consumption reaches 64% in a High Energy Efficiency scenario and 97% in a High Renewables Scenario that includes significant electricity storage to accommodate varying RES supply even at times of low demand".

Several other associations and governments claim that the goal of energy produced 100% by renewables is feasible in the next decades. Here however, the key issue is electricity storage, a task not so easy. Since the energy from renewables is not continuous or controllable we have to store the electric energy which is produced in periods of availability of RES to be used when there is a shortage of it. This can be done using advanced technologies like superconductor energy storage systems, supercapacitors, hydrogen storage, compressed energy storage, hybrid power plants consisting of renewables and hydro pump storage, to name just a few. Could it be the answer in the quest for a 100% RES share? This remains to be seen.

Why do we need Renewable Energy Sources?

There are plenty of reasons. First of all, if we don’t expand their use, existing reserves of fossil fuels will run out, since they cannot be renewed! Also, non-renewable energy sources are responsible for the greenhouse effect, causing global warming, which endangers our planet and future generations. Don’t forget that oil and gas are mostly imported goods in the European Union. This means that by increasing the percentage of RES in our energy mix, the security of energy supply in EU increases as well! Last but not least, hundreds of thousands of new jobs are foreseen to open in the RES industry in the following years, contributing to fighting unemployment especially for young people.

What are Renewable Energy Sources?

As the term implieas, they are sources that can be renewed and never run out! Non-renewable sources include fossil fuels, e.g. oil, coal, gas, and their deposits are limited and can be exhausted. Renewable energy sources include solar, wind, biomass, hydro, geothermal and ocean power.

Solar Energy

With this term we refer to the energy provided by the sun through radiation. The sun is the most powerful source of energy and this energy is free, as long as we exploit it! Technologies are categorized as either active or passive. Active technologies convert solar energy into a form we can use directly either electrical or thermal. Such are photovoltaic cells that convert sunlight directly into electrical energy, like the picture over right, the solar collectors for domestic hot water heating or even solar space heating and cooling, the solar concentrators that use mirrors to focus solar irradiation and generate intense heat, turning water to steam and generating electricity using certain machines and even solar ovens. Passive technologies seek to place buildings in a favorable orientation towards the sun or use special materials and architectural designs to exploit solar energy.

 

Wind Energy

The energy of wind has been known and exploited for millenniums, either in windmills or in sailing. Nowadays, we can exploit wind energy using special blades to capture wind and machines to transform it to electrical energy. Wind turbines are installed both onshore and offshore in places where wind speed is generally high and constant.

Biomass

Biomass has been used since man invented fire and used to burn wood to heat or cook! It refers to the energy embodied in plants and organic material. Plant biomass comes from the sun through the photosynthesis process, when they capture solar energy and on the other hand animals eat plants! Biomass includes a wide variety of materials including wood, energy crops (grown specifically for energy applications), agricultural and forest residues, food waste and organic components from municipal and industrial waste. A variety of conversion technologies exist to convert biomass energy into other usable form. Such technologies either converts the energy in forms that can be used directly (heat or electricity), or may convert it to another form, such as liquid biofuel or combustible biogas.

Hydropower

Water also, is a renewable energy source since it is recharged through the cycle of evaporation and precipitation. Its power was known since ancient years and was exploited through dams, water mills and irrigation systems. The energy of the falling or moving water can be harnessed by various technologies. Water wheels can transform it directly into mechanical energy (i.e. water mills), turbines and electrical generators can transform it into electricity.

Geothermal Energy

Geothermal energy refers to the energy stored and created inside the earth in the form of thermal energy. At times this energy is released to the surface through volcanoes and geysers, or is available constantly e.g. through hot springs. Geothermal energy can be harnessed to produce electricity or for heating and cooling purposes. It can be acquired from deep underground reservoirs through drilling, or from other geothermal reservoirs closer to the surface. Geothermal energy can be used in residential applications also, e.g. small geothermal heat pumps.

Ocean or Marine Energy

This is a renewable energy that is underexploited so far. It refers to the mechanical energy carried by ocean waves and tides or to the thermal energy of the ocean coming from the sun. Covering almost 70% of earth surface, oceans may prove to be the renewable energy of the future, however harnessing ocean energy to produce electricity is not cost-effective currently.