ENERGY | Therevolution

Geothermal Power

Bio-Energy

Sourcing 100% of our energy from renewable sources is possible.

According to WWF's Climate Vision for 2050, if the right technologies are put in place, low-impact renewable energy sources could provide 70% of energy supplied globally.

Biomass can be used to supply heat, generate power and fuel transportation.

As a fuel, it may include wood, wood waste, straw, manure, sugar cane, palm oil, soy and many other by-products from a variety of agricultural processes.

It can be used directly, such as wood burning for heating and cooking.

Or indirectly, by converting it into a liquid or gaseous fuel – ethanol from sugar cane, biodiesel from palm oil, or biogas from animal waste.

Unlike oil, coal and gas, bioenergy is a renewable energy made out of biological material that can be harvested again and again.

Traditional biomass includes fuel wood and charcoal for domestic use, rice husks, other plant residues and animal dung. These resources are mostly used on a small-scale, particularly in developing countries.

Modern biomass usually involves large-scale uses and is a substitute for conventional fossil fuels. This includes forest wood and agricultural residues, urban waste, and biogas and biofuels from energy crops, such as plant oils and plants containing starch and sugar.

Geothermal power comes from the heat of the Earth. Tapping into this energy source – which doesn't require the burning of fossil fuels – is a clean, renewable way to produce electricity.

The use of geothermal energy is clean and renewable, and requires no burning of fossil fuels. Geothermal power plants emit only excess steam and very few trace gases – 1,000-2,000 times less CO2 than fossil fuel power plants. They also take up very little land compared to traditional fossil fuel plants, and advanced drilling techniques minimize the impact of drilling wells.

The electricity produced is also more available, as fossil-fuelled power plants produce electricity 65-75% of the time compared to 90% from geothermal power plants.

While geothermal resources are not spread uniformly, geothermal heat pumps can be used almost anywhere. When a heat pump is used to provide domestic heating, the savings on electricity alone can outweigh the cost of installing and running the system. Where geothermal energy is used in agriculture, such as to heat greenhouses, heating costs can be cut by up to 80%.

A tremendous amount of energy can be tapped from our oceans. Wave and tidal power are increasingly joining the mix of promising offshore renewable energy resources.

Waves are driven primarily by the winds. Capturing this energy is not easy but technology is becoming more readily available.

Wave energy can be converted through: channel systems that funnel the waves into reservoirs float systems that drive hydraulic pumps oscillating water column systems that use waves to compress air within a container. The mechanical power created from these systems either directly activates a generator or transfers to a working fluid, water or air, which then drives a turbine or generator.

Tides are driven primarily by the gravitational pull of the moon. Tidal power works by harnessing ocean tides, especially in narrow river mouths or sea straits, to produce energy. Tidal streams are converted into electricity by forcing the water through turbines, which activate a generator.

Options include dams, tidal lagoons and tidal stream systems.

Tidal power generators can be expensive to set up. However, they have the potential to deliver cheaper electricity in the long term.

Hydroelectric power is one of the most widely used and cheapest ways to generate electricity today. Although there are a number of environmental issues associated with this form of renewable energy, there are ways to reduce the impacts. Hydroelectric power plants generate about 16% of the world's electricity.

Hydroelectric power for the most part is pollution-free, but there are environmental and social impacts involved. The operation of hydropower stations, which includes the construction of dams, can represent a significant disturbance to the natural environment and local communities. In developing countries, local populations tend to benefit less from hydropower as the generated electricity is often exported to urban regions or outside the country.

One low-impact option is to improve existing hydropower stations and make them more efficient. The process of retrofitting old stations with modern equipment helps ageing dams produce more electricity. Typical investments include:

replacing turbines and generators adding machines to facilitate periods of high demand increasing storage capacity by raising the height of the dam

Such modifications can be done relatively quickly, and provide an opportunity to reverse existing environmental damage, such as providing fish passage facilities.

Ocean Energy

Hydroelectric

Energy

Solar Energy

Wind Power

Solar power is one of the cleanest forms of energy. It emits zero greenhouse gases or other pollutants, uses no water and produces no waste. In the face of the daunting challenge of climate change, solar power will become an important part of our energy future. In theory, the entire present energy consumption of the world could be met by an area smaller than 1% of the world’s deserts if they were covered with solar thermal electric plants.

Passive solar – using sunlight for energy without the use of active mechanical systems – ensures that buildings make the most use of the sun to regulate light and temperature.
Solar thermal collectors use the solar radiation falling on them to heat tap water. They can also serve for space heating.
Different types of photovoltaic modules convert solar radiation directly into electricity. Such modules are increasingly integrated in buildings, and can, for example, be used as roof tiles.
Different types of solar thermal power plants use solar heat by concentrating solar radiation – such as through mirrors focused on a solar power tower or by means of parabolic troughs – to heat up water and conveying the steam to a turbine.
Simple mirror-based systems can help in saving gas, kerosene or wood through solar cooking.

Global wind energy potential is huge. It can be harvested nearly everywhere – in valleys, on mountains, at sea.

In 2008, more wind power capacity was installed in the EU and the US than any other electricity-generated technology. In China, total capacity doubled for the 4th year in a row. By 2010, China plans to install some 18 GW of additional wind capacity – about the equivalent of erecting 1 wind turbine per hour with a capacity of 1 MW from now till then. Over 80 countries around the world now have commercial wind power installations, including Mongolia and Pakistan. More projects are under development in Ethiopia, Kenya and Tanzania.

The size of commercial wind turbines can vary between 250 kw and 6 MW.

A 5 MW turbine can produce more than 15 million kWh in a year. This is enough to power 1,500 to 15,000 households, depending on their average electricity consumption. Offshore wind turbines can produce more electricity due to better wind conditions.

Wind energy has become very efficient and, in many cases, onshore wind is competitive with or even cheaper than nuclear or fossil fuels. Offshore wind is still relatively expensive and needs support to grow and achieve economies of scale. A single 1.5 MW wind turbine over its lifetime can save about 80,000 tonnes of brown coal. The future of wind energy lies in large-scale, onshore and offshore wind parks that connect to regional super grids to provide clean and efficient electricity.

"Even though fossil fuels have benefitted hugely from government support throughout the last century, some renewable energy sources such as hydro, onshore wind and geothermal energy are very close to, and often even cheaper, than fossil or nuclear fuels. To realize this huge potential, we need to further develop new technologies and ambitious support schemes." WWF