Renewable Energy

12 August 2009
by Ina Dimireva -- last modified 02 February 2012

Renewable sources of energy – wind power, solar power (thermal, photovoltaic and concentrated), hydro-electric power, tidal power, geothermal energy and biomass – are essential alternatives to fossil fuels. Their use reduces our greenhouse gas emissions, diversifies our energy supply and reduces our dependence on unreliable and volatile fossil fuel markets (in particular oil and gas).

Renewable Energy Road Map

The Renewable Energy Road Map (RERM) was put forth in January 2007 by the European Commission to propose “a long-term vision for renewable energy sources in the EU.” Renewables are “indigenous,” not reliant on uncertain fuel availability, and their “decentralised” nature makes them less vulnerable to localized failures and targeted attacks and thus more secure.

In their March 2007 summit, European leaders signed up to a binding EU-wide goal of getting 20 percent of energy needs from renewables, such as biomass, hydro, wind and solar power, by 2020. A commitment to achieving a 10 percent share of biofuels in transport by 2020 was also agreed.

The Road Map envisions renewables as the “stepping stone” to increased security of supply and reduced GHG emissions. In September 2007, the European Parliament voted to set binding sectoral targets for renewables, and the Commission was to include provisions for such in its proposed renewables legislation, due early 2008. Such binding targets are opposed by some member states, who desire more “flexibility” in carrying out the 20/20/20/10 goals.

All member states have adopted national targets for a percentage of electricity from renewables (not including nuclear) by 2010, according to a 2001 EC Directive, although the EU was predicted to fall about 2 percent short of the Directive's overall EU target of 12 percent. The RERM said it's possible that "electricity production from renewables could increase... to approximately 34% of overall electricity consumption in 2020," far beyond the current goal of 20%. (pg. 11)

The following technologies play a role in Europe’s renewable energy policies:

Wind

The Road Map predicts that wind energy could compose 12 percent of EU electricity by 2020, a third of which could come from offshore installations. The wind energy sector has grown by almost 30 percent a year, especially in Denmark, Germany and Spain. The UK is also expanding its wind capability. The London Array will be the world’s largest offshore wind farm, to be built over 20 kilometres from Kent. It will have over 300 turbines and, when completed, is expected to provide 1 gigawatt of electricity.

In the future, projects similar to the giant, deep-water turbines of the Beatrice oilfield in the North Sea may add to the wind-energy mix. Erected in 45 meters of water, plans are in the works to construct 200 similar turbines in the Beatrice field, each with 200 foot blades capable standing up to North Sea winds.

In the future, laddermills may be an important source of energy. Composed of a series of “kiteplanes” strung on a very long cable, they can harness wind energy at a height of 30,000 feet, where wind speed can be up to twenty times faster than at sea level. A loop of kiteplanes is estimated to be able to produce up to 100 Megawatts of electricity. A team of academics at Delft University are working on a “demonstrator” for 2008.

Solar

Compared to other renewables, photovoltaic (or PV) energy, which transforms sunlight directly into electricity, is expensive. The energy used in production and implementation of PV can take over a year to recover. PV does not work at night and productivity is decreased on cloudy days and during the shorter winter months. According to the RERM, however, the cost of traditional photovoltaic energy is expected to drop 50 percent by 2020, as technology improves and mass-production becomes cheaper.

In the future, the implementation of heliostats, or directed mirrors, may rejuvenate interest in solar energy technology. A heliostat follows the path of the sun, maximizing its angle in relation to the direction of sunlight. This focused sunlight can be directed at a PV cell, increasing light intensity and thus electricity generation, as with a project by Solar Systems in Victoria, Australia. Heliostats have also been used in conjunction with Solar-thermal power plants like the PS-10, which is currently operating outside Seville, Spain. The PS-10, a project of Solucar energy, uses heliostats to focus light onto a point in a central tower, creating intense heat that transforms water in the tower into vapour, which circulates, turning steam turbine generators to create electricity. The project cost 1.5 billion Euros, and was subsidized by the Spanish government and the European Union. At its completion in 2013 it will provide 300 megawatts of power, enough for an estimated 180,000 homes.

Hydropower

Although most hydroelectric dam sites are already developed, there are other types of less invasive, eco-friendly hydropower. Small hydroelectric projects run in natural water flows and even simple waterwheels offer potential for environmentally friendly, non-invasive power generation. But hydropower also refers to ocean wave and tidal energy. The largest wave farm in the world is planned off the coast of St. Ives in Cornwall. Called Wave Hub, it will be a “hub” attached to the ocean floor, into which are connected a variety of wave energy generation devices. It is hoped that the hub project will eventually generate 20MW of electricity.

In the future, projects like the Pelamis wave machine may fulfill greater energy needs. A square kilometer of snake-like, hinged Pelamis generators, roughly the size of a passenger train, can generate about 30 Megawatts of electricity. The Enersis project, several kilometers from Aguçadoura, Portugal, is estimated to produce 500 Megawatts of electricity when it is completed. Enersis, a Portuguese renewables company, is developing a wave project with the support of Ocean Power Delivery Ltd. of Edinburgh.

Biomass

At present, the EU generates about 4 percent of its total energy with biomass, or 2/3 of all renewable energy, much of which as a by-product of forestry. Biomass can include biofuels and is also a method of generating energy and even for creating fossil fuel products like plastics. Biomass is integral to such applications as “cogeneration,” which is essential to the EU’s heating and cooling initiatives.

Nuclear

Conventional nuclear energy may or may not be an official “renewable” power source, though it is not included in the RERM as such. Although it became unpopular during the Cold War, nuclear currently supplies one-third of the EU’s electricity. EU Energy Commissioner Andris Piebalgs said in an EP press release, “It will be difficult to achieve our climate change goals without the use of nuclear energy,” and the Commission has taken an “agnostic” stance to conventional nuclear development in the member states.

In the future, one of the primary concerns about nuclear power, disposing of nuclear waste, might be addressed by projects like the experimental [MYRRHA] (http://www.sckcen.be/myrrha/home.php) reactor, located at Mol in Belgium. Among other applications, the MYRRHA is used to research transmutation, the process of transforming one radioactive isotope, like plutonium, into another by bombarding it with neutrons, reducing the half-life of nuclear waste to only a few decades.

In the future, nuclear might also include the theoretically safer and potentially limitless power of fusion reactions. The ITER is an experimental tokomak (a type of fusion reactor) for which the EU, via Euratom, will provide half the 10 billion euro expenditure. Based in Cadarache, France, the International Thermonuclear Experimental Reactor will conduct experiments with plasma energy and nuclear fusion over the next thirty years.

Future Coal and Carbon Capture

With global energy prices rising, and world reserves enough for decades of production, coal has made a comeback. But even with coal-fired power becoming progressively “cleaner,” coal today is still the dirtiest fossil fuel and is not expected to be zero-CO2 for decades. The eventual goal of zero-CO2 coal is intimately related to carbon capture and storage, a process of collecting the carbon from burning and storing it deep underground, for example in depleted oil fields.

Current advanced coal technologies include Integrated Gasification and Combined Cycle (IGCC). The process gasifies or liquefies coal for more efficient burning (50 percent) or use in a modified engine. There are also super-critical boilers systems that can be fitted on existing coal power stations, and initiatives to remove the pollutants from pulverized coal before it is burned, though research has been slow to develop.