Clean energy is not necessarily clean

Wind turbines or solar collectors do not emit carbon dioxide when turning sunlight and wind into electricity. But the production of these devices consumes a lot of materials and emits a lot of CO2. The exploitation of energy from the sun and wind seems clean at last, so it is not.

After wind turbines are cement factories, steel rolling mills. And after photovoltaic panels are silicon factories. These clusters produce CO ₂ and solid wastes that affect the people's respiratory system, upset the ecological environment of rivers and lakes, and cause other negative impacts on people.

1GW wind power costs 125 tons of steel

The construction of facilities for installation of clean energy extraction equipment is also often complicated in design, large in size and costly in construction materials. For example, to build hydroelectric dams for the production of 1GW of electricity, 1,240 tons of concrete is required. Meanwhile, to get a 1GW nuclear power plant costs only 560 tons of concrete. The production of iron and steel also emits more CO2 than the production of concrete. Yet to get 1GW of electricity requires 125 tons of steel for pinwheel production, or 140 tons of iron and steel to build dams, while to build a 1GW nuclear power plant requires only 60 tons of steel. .

The production of silicon for photovoltaic panels also consumes a lot of energy for the process of melting materials at high temperatures. Therefore, solar power is ultimately evaluated as an indirect source of energy that emits the most carbon dioxide among renewable energy sources. One study has shown that in tropical countries, dams can emit methane equivalent to a thermal power plant.

In renewable energy sources, solar power indirectly releases the most CO2.(Photo: TL)

Every electricity releases CO ₂

CO ₂ emission from clean energy extraction to collect 1kWh of electricity

Solar power: 60g
Wind power: 9 - 25g
Hydro: 8g

Not only does it break the natural landscape, wind turbines make noise when spinning, and frighten birds. The whirring sound is an almost irreparable disadvantage of wind turbines. Therefore, in order to solve this problem, the experts proposed to install wind turbines on floating platforms. Solar panels do not cause noise like wind power, do not emit carbon dioxide directly, but the process of producing these batteries produces many kinds of toxic waste, especially solid waste. With hydroelectricity, the impact on the environment is even greater. Dams submerge areas of biological diversity, blocking the flow of silt, which are detrimental to the downstream. The rise in water temperature will reduce the amount of oxygen affecting fish species and cause many toxic algae to thrive.

While France has 400MW wind power, solar power reaches 26MW, geothermal power is about 550MW, Germany is proud to be exploiting clean energy efficiency with wind power output of 16,000MW, solar power is 800MW, geothermal power is 4,300MW. But in 2004 Germany still emitted 10.46 tons of CO ₂ per capita, while this figure in France was 6.71 tons and the European average was 7.96 tons. The reason is that electricity production in Germany is based on coal, while France relies on nuclear and hydroelectricity. Clean energy extraction does not help reduce emissions efficiency, so Germany recently decided to turn to nuclear power.

Challenges of science and technology

Clearly, in order to develop clean energy effectively, there must be many inventions in the manufacture of energy conversion equipment. A pinwheel 30m diameter produces about 250kW of electricity, while a 80m short circuit will give 2,500kW. Therefore, wind turbines are currently focused on improving the propeller for longer. However, pinwheels of 5MW capacity currently have a height of up to 180m and require very high technical reinforcement. The solution tested by Canadian oil company Talisman Energy is to create a support of steel pipes like a tripod. Alan Mac Askill, director of the project, said: 'This structure allows us to fix a fast column of 5MW off Scotland in deep water with only 1,200 tons of steel, while the old technique needs 1,800 tons. . We hope to benefit 20% of the cost '.

With solar power, the fact that mining stations in Europe never exceed 10% of capacity, so this source of electricity is more expensive than thermal power and nuclear power about five times. But cheaper silicon production is contributing to lowering the cost of solar power. Another improvement is mixing a polymer (ie a plastic) such as PPV into a coal derivative. The problem is that the photovoltaic panels from this mixture have a short lifespan and an operational efficiency is still a problem . controversial!

The main problem of hydropower is reservoir capacity. Dams equipped with a regulating system can bring the water level higher, like a pump station combining two different water levels, which is considered a perfect solution to increase the capacity up to 90 % But the construction of a pump system is very expensive and people have to play risky games with huge blocks of water: to be able to play 10kWh, 43 tons of water must be lifted higher than 100m!

Exploiting clean energy is still a challenge for science and technology.