Tag: renewable energy

What is renewable energy?

17 December 2020

Sustainable bioenergy

These differ to non-renewable energy sources such as coal, oil and natural gas, of which there is a finite amount available on Earth, meaning if used excessively they could eventually run out.

Renewable resources can provide energy for a variety of applications, including electricity generation, transportation and heating or cooling.

The difference between low-carbon, carbon neutral and renewable energy

Renewables such as wind, solar and hydropower are zero carbon sources of energy because they do not produce any carbon dioxide (CO2) when they generate power. Low-carbon sources might produce someCO2, but much less than fuels like coal.

Bioenergy that uses woody biomass from sustainably managed forests to generate electricity is carbon neutral because forests absorb CO2 from the atmosphere as they grow, meaning the amount of CO2 in the atmosphere remains level. Supply chains that bring bioenergy to power stations commonly use some fossil fuels in manufacturing and transportation. Therefore woody biomass is a low carbon fuel, when its whole lifecycle is considered.

Managing forests in a sustainable way that does not lead to deforestation allows bioenergy to serve as a renewable source of power. Responsible biomass sourcing also helps forests to absorb more carbon while displacing fossil fuel-based energy generation.

Nuclear is an example of a zero carbon source of electricity that is not renewable. It does not produce CO2,but it is dependent on uranium or plutonium, of which there is a finite amount available.

Managing forests in a sustainable way that does not lead to deforestation allows bioenergy to serve as a renewable source of power.

How much renewable energy is used around the world?

Humans have harnessed renewable energy for millions of years in the form of woody biomass to fuel fires, as well as wind to power ships and geothermal hot springs for bathing. Water wheels and windmills are other examples of humans utilising renewable resources, but since the industrial revolution fossil fuels, coal in particular, have been the main source of power.

However, as the effects of air pollution and CO2 produced from burning fossil fuels become increasingly apparent, renewable energy is gradually replacing sources which contribute to climate change.

In the year 2000 renewable energy accounted for 18% of global electricity generation, according to the IEA. By 2019, renewable sources made up 27% of the world’s electrical power.

Why renewable energy is essential to tackling climate change

The single biggest human contribution to climate change is greenhouse gas emissions, such as CO2, into the atmosphere. They create an insulating layer around the planet that causes temperatures on Earth to increase, making it less habitable.

Renewable sources of electricity can help to meet the world’s demand for power without contributing to global warming, unlike carbon-intensive fuels like coal, gas and oil.

Bioenergy can also be used to remove CO2 from the atmosphere while delivering renewable electricity through a process called bioenergy with carbon capture and storage (BECCS).

Forests absorb CO2 from the atmosphere, then when the biomass is used to generate electricity the same CO2 is captured and stored permanently underground – reducing the overall amount of CO2 in the atmosphere.

Humans have used renewable energy for millions for years, from wood for fires to wind powering boats to geothermal hot springs. 

What’s holding renewables back?

The world’s energy systems were built with fossil fuels in mind. This can make converting national grids difficult and installing new renewable energy sources expensive. However, as knowledge grows about how best to manufacture, build and operate renewable systems, the cost of deploying them at scale drops.

There are future changes needed. Renewables such as wind, solar and tidal power are known as intermittent renewables because they can’t generate electricity when there is no sun, wind or the tidal movement. For future energy systems to deliver enough power, large scale energy storage, as well as other flexible, reliable forms of generation will also be needed to meet demand and keep systems stable.

Renewable energy key facts:  

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The 8 biggest things in renewable energy

18 July 2018

Power generation

Powering a whole country is a big task. The equipment that make up power stations and electricity systems are measured in tonnes and miles, and pump gigawatts (GW) of electricity around the country. With the world’s electricity increasingly coming from renewables, this big thinking is key to powering long-term change.

From taller wind turbines to bigger batteries, these are the massive structures breaking energy records.

Germany’s giant wind turbine and the plan to beat it

As wind power becomes ever more prevalent, one of the key questions that needs answering is how to get more out of it. One way is to build taller turbines and longer blades. Putting turbines higher into the air sets them into stronger wind flows, while longer blades increase their generating capacity.

The world’s tallest wind turbines are currently in Gaildorf, Germany and stand at 178 metres with the blades tips reaching 246.5 metres. Built by Max Bögl Wind AG, the onshore turbines house a 3.4 megawatt (MW) generator that can produce around 10.5 gigawatt hours (GWh) per year.

However, turbines continue to grow and GE has announced plans for the Haliade-X turbine, which will ship in 2021. At 259 metres in total the offshore turbine is almost double the height of the London Eye and will spin 106 metre blades, generating 67 GWh per year.

China’s ‘Great Wall of Solar’

China has pumped substantial investment into solar power, including the world’s biggest solar plant in electricity generation and sheer size. Dubbed the ‘Great Wall of Solar’, the Tengger Desert Solar Park has a capacity of more than 1.5 GW and covers 43 km2 of desert.

The next largest, by comparison, is India’s Kurnool Ultra Mega Solar Park, which covers just 24 km2 and generates 1 GW. However, rampant investment by the country means there are several projects in the pipeline that will break the 2 GW mark and will set new records for solar power plants.

Morocco takes solar to new heights

Concentrated solar power (CSP) takes the technology skywards by using thousands of mirrors, known as heliostats, and focusing the sun’s rays towards a central tower. This heats up molten salt within the tower, which is then combined with water to create steam and power a turbine – like in a thermal power plant.

Morocco’s Noor Ouarzazate facility (pictured in the main photo of this article) is home to the world’s tallest CSP towers. At 250 metres tall, 7,400 heliostats beam the sunlight at each tower, which have a capacity of 150 MW and can store molten salt for 7.5 hours. Its record will soon be matched by Israel’s 121 MW Ashalim Solar Thermal Power Station when it begins operating this year.

However, never one to be outdone when it comes to tall structures, Dubai plans to build a 260 metre CSP tower in 2020 as part of the Mohammed bin Rashid Al Maktoum Solar Park, which at 700 MW will be the world’s largest single-site CSP facility.

Three Gorges Dam

China’s monster mountain dam

The Three Gorges Dam on China’s Yangtza river might be the world’s most powerful hydropower dam with its massive 22.5 GW capacity, but a different Chinese dam holds the title of the world’s tallest.

Jinping-I Hydropower Station is a 305-metre-tall arch dam on the Yalong River. It sits on the Jinping Bend where the river wraps around the entire Jinping mountain range. The project began in 2005 and was completed with the commissioning of a sixth and final generator in 2014, which brought its total capacity to 3.6 GW.

Itaipu Dam and hydropower station

Brazil and Paraguay’s river arrangement

While it may be tall, at 568 metres-long, Jinping-I is far from the longest. That mantle belongs to the 7,919 metre-long Itaipu Dam and hydropower station that straddles Brazil and Paraguay and has an installed capacity of 14 GW.

The power station is home to 20, 700 MW generators, however, as Brazil’s electricity system runs at 60Hz and Paraguay’s at 50Hz, 10 of the generators run at each frequency.

Biomass domes that could hide the Albert Hall

Using a relatively new material, such as compressed wood pellets as a renewable alternative to coal in large thermal power stations creates new challenges. Biomass ‘ecostore’ domes help tackle storage problems by keeping the materials dry and maintaining the right temperatures and conditions.

Unlike cylindrical, concrete silos, domes also offer greater resistance to hurricanes and extreme weather. This is important in areas such as Louisiana where this low carbon fuel  is stored at the Drax Biomass port facility in 35.7 metre high, 61.6 metre diameter domes before it is shipped to Drax Power Station.

The power station itself is home to four of the world’s largest biomass domes. Each is 50.3 metres high and 63 metres in diameter – enough to hold the Albert Hall, or in Drax’s case 71,000 tonnes of biomass.

South Korean coastline takes the most from the tides

Beginning operation 1966, the Rance Tidal Power Station, in France was the first and largest facility of its kind for 45 years. The power station made use of the 750 metre-long Rance Barrage on France’s northern coast with a 330-metre-long section of it generating electricity through 24, 10 MW turbines.

It was overtaken, however, in 2011 with the opening of the Sihwa Lake Tidal Power Station in South Korea. The facility generates power along a 400-metre section of the 12.7 km Sihwa Lake tidal barrage and generates a maximum of 254 MW through ten 25.4 MW submerged turbines.

The battle to beat Tesla’s giant battery

South Australia has become a battlefield in the race to build the world’s biggest grid scale storage solution. Tesla constructed a 10,000 m2, football pitch-sized 100 MW lithium-ion battery outside of Adelaide at the end of 2017 which is connected to a wind power plant and can independently supply electricity to 30,000 homes for an hour.

However, rival billionaire to Tesla’s Elon Musk, Sanjeev Gupta plans to take on the storage facility with a 140 MW battery to support a new solar-powered steelworks, also in South Australia.

The excitement around battery technology’s potential means the title of world’s biggest will likely swap hands plenty more times over the next decade. This contest won’t just be confined to batteries. As countries increasingly move away from fossil fuels, bigger, wider and taller renewable structures will be needed to power the world. These are the world’s largest renewable structures today, but they probably won’t stay in those positions for long.