Renewable energy has grown leaps and bounds over the last decade. Part of the drive has come from Kyoto protocol coming into force. The depleting fossil fuels reserves and the volatility of the market has also forced many countries to look the other way. Factoring into this push for localized energy generation is also the insecurity of supply. China for instance is heavily reliant on coal imports the same way USA is on Oil. However, the two countries have taken a very different approach in securing their future energy needs. USA has strengthened their Naval presence on all trade routes. They have consolidated their military presence around countries that supply oil. On the other hand China has taken entirely different measures. Within a very short span of time, it has reduced it has consumption of coal drastically. As can be seen, China reduced coal import by 30 per cent from the year 2014 to 2015. during the same period China increased it Wind power capacity by 33.5% and Solar power by 73.7%.
At present that China stands as the biggest consumer of electricity (5,463.8 TWh/yr). Being the workshop of the world that saw double digit growth for over a decade, its electricity needs eclipse all other countries. Formulating a prudent energy policy, it is no wonder that some of the biggest renewable energy projects are based in China.
Biggest Hydro Power- Three Gorges Dam-China
The Three Gorges Dam in China is the largest hydro power project in the world with a 22.5 GW capacity. It is not only the biggest hydro power project but the biggest power plant in the world. It spans across the Yangzte River and has a huge spillway capacity 116000 m3/s. It houses 34 Francis type turbines (32 Turbines of 700 MW and 2 Turbines of 50 MW) and annually generates 87 TWh at a capacity factor of 45%. In 2014, the three Gorges Dam set a world record for the highest annual production for 98.8 TWh. To put this figure into perspective, this capacity is more than the annual consumption of 161 countries including Belgium and Malaysia.
It should be noted that the biggest power plants around the world are based on Hydro power. Out of the 10 largest Power plants in the world, 9 are based on hydropower.
Biggest Windfarm- Gansu-China
The largest installations of Wind farms are on-shore. This is because of lower commissioning and maintenance costs. The largest Wind farm is in China with a current capacity of 7965 MW (as of April 2016), which is set to increase to 20,000 MW by 2020. Even with its current capacity it remains second to only the three Gorges dam, narrowly edging the Kashiwazaki-Kariwa Nuclear plant. It is also five times bigger compared to its closest rival of same technology (1500 MW, Muppandal India). Because of the enormity of the project, it is being completed by over 20 developers. Once completed, the Wind farm will have over 13000 turbines and its output would be comparable to the Three Gorges Dam of around 90 TWh. Although the total land area of the windfarm is hundreds of square kilometres, but because wind turbines only take up 1% to the total footprint of the farm, the remaining land can be used for agriculture.
Biggest Biomass –Drax-England
Drax power plant is one of the biggest thermal power plants in the UK with a capacity of 1320 MW. It is basically a coal fired plant but is capable of co-firing a large range of biomass. Drax started in 1974 as purely a coal fired power plant. It remains the biggest emitter of CO2 in the UK. However the plant has made serious efforts since the 2000’s in improving its environmental credentials. After adding the biomass capability, it can burn wood pellets, peanut shell husk, sunflower pellets husk and rape meal. Most of the biomass is sourced from the US.
One of the biggest problems with power plants made in the 70’s in the UK is the lack of an integral system that can capture and utilize the heat generated during the process of electricity generation. Therefore the efficiency of old coal fired plants hardly exceeds 35% . Whereas CHP plants across the English Channel in Netherlands are over 95% efficient. Note that at least one 300 MW unit at Drax runs entirely on Biomass. By 2017, 3 of the six units are planned to run on Biomass alone.
Biggest Solar Farms
There are different kinds of technologies by which solar energy can be harnessed. Most efficient of these is the Stirling –dish systems (Conversion efficiency of 31%), but the technology is not favoured because of its high capital cost. Solar Farms can produce electricity directly through PV or indirectly, through Solar Thermal energy. Within this primary classification, there are further technologies available. For instance Solar Thermal plant can be based on Power Tower, Solar Trough or Solar Stirling Dish System.
Solar PV – Solar Star-USA
Solar Star is 579 MW project in California USA. The plant area is around 13 Square Kilometres. The PV power plant uses one of most efficient panels available (Sunpower) and employs a single axis tracking system. This allows the panels to orient themselves facing east at sunrise to facing west at sunset. Because of efficient panels and tracking system, the Solar star power plant has a much lower foot print compared to other solar PV farms. For example, the Antelope Valley Solar ranch has less than half the capacity of 266 MW, but is spread on an area of 20 sq km, because it uses relatively inefficient thin-film (CdTe) panels. Policies in California (USA) have always been environment friendly and have incentivized large scale renewable projects. Although it has been knocked of the perch by China, but California once boasted the biggest windfarm in the world.
Solar Thermal- Ivanpah-USA
The Ivanpah Solar Thermal power plant has a capacity of 392 MW with an annual generation of around 1.08 TWh. It uses the power tower technology in which a huge array of heliostats concentrate solar power on a small metallic plate at the top of the tower. The heliostats employ a three axis tracking system and are oriented by computer controlled motors and solar feedback. Such power plants only work in arid zones where there is an abundance of direct sunlight. The Ivanpah plant has three units and hence has a total of three power towers.
Biggest Wave Farm – Aguçadoura- Portugal
Not only the Agucadoura wave farm is the world’s biggest, but it was also the world’s first. It has a capacity of 2.25 MW. The Agucadoura farm utilized the first generation of Pelamis Wave Energy Converters. The wave farm has 3 attenuating energy converters each 750 KW in capacity and has had a fair share of teething problems. It was shutdown two months after its inauguration. The developer Pelamis were in the process of launching P2 , second generation energy converter, when they went into administration. Wave power technology compared to Wind and Solar energy is still maturing. There is tremendous potential in wave energy and several engineering organizations have come up with designs that are robust and can sustain a hostile marine environment.
It is interesting to note that renewable energy projects make some of the biggest power plants around the world. Their contribution is vital if we are to move away from the age of carbon.
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