by Ian Bradford
Some of the problems with wind energy are also the problems with solar energy. There are two types of solar energy farms. The first type has a large number of mirrors, (probably parabolic), which follow the sun as it moves during the day. These focus on large tanks filled with water which heat to about 540 deg C. The steam produced is used to drive turbines. The second type, much more in use now, consists of a series of panels each containing a number of voltaic cells. These convert solar radiation directly into electricity.
The world’s largest solar farm is in the Mojave desert in California. It covers 3500 acres (about 1700 Ha). It cost $2.2 billion US to build and each mirror has an area of approximately 8 sq. m. In total there are 170,000 mirrors.
Mirrors and solar panels
So what are the problems with solar farms? With all these mirrors focussing sunlight on a tank of water there will be a zone of air which is extremely hot. Any bird flying in this zone is immediately fried. This accounts for a significant number of bird deaths. Birds do crash into photovoltaic cell panels also possibly thinking that they form a lake.
Because mirrors and panels take up so much land, a number have been built in desert regions. This is hugely expensive and roads have to be formed and power lines erected back to civilisation.
At night time there is no power and for both, very limited electricity produced on dull days.
Disposing of solar panels
Over the past few years there has been growing concern over what happens to solar panels at the end of their life. By 2050, the US will have 10 million tonnes of photovoltaic waste and China 20 million tonnes. There are few incentives to recycle solar panels as the cost of recovering the materials outweighs the cost of extracting what can be recycled.
It is estimated there is 50,000 kg of Cadmium in 1.8 million solar panels. Leaching from broken panels damaged during natural events such as hail storms, tornadoes, hurricanes, earthquakes and so on, but also at decommissioning, is a real concern. In 2015 a tornado broke 200,000 solar panels in Southern California. Hurricane Haria hit Puerto Rico and the nation’s second largest solar farm lost a majority of it panels.
Most solar panels end up in landfills so carcinogenic cadmium and lead can be washed out of the fragments of solar modules over a period of several months. The projection is that worldwide there will be 78 million tonnes of solar waste by 2050. Unfortunately, the glass in solar panels cannot be recycled as they contains impurities including plastics, lead, cadmium and antimony.
Although much is said that solar energy is completely safe for the environment, the truth is that each solar panel is made of harmful chemical materials in a process that generates many toxic by-products such as hexafluoride, sulphur, and silicon tetrachloride. These products are not only dangerous for the environment, but also for humans, and domestic and wild animals.
Some people can react very badly to home installed solar panels. Solar energy systems can be dangerous to health due to the electromagnetic fields emitted. Just one of the scores of health impacts can be increased cancer risk. An inverter is used to change direct current, DC, to alternating current, AC, and the inverter can be a source of “dirty” electricity. Even low level exposure of electromagnetic fields can be dangerous.
Issues with nuclear power
Many overseas countries use nuclear power. It is reliable and clean energy in itself. Nuclear power stations do not give off any pollution. However, it is what left over after that is the problem. What is left over is radioactive waste which has to be stored. At present the energy generated in nuclear power stations is from a fission reaction. In a fission reaction an atom is split into two different atoms. Usually, either Uranium or Plutonium is used in a nuclear reactor in power stations as they are easy to initiate and control.
In an uncontrolled fission reaction we have an atomic bomb. In a controlled fission reaction we have a nuclear power station.
The other type of nuclear reaction is fusion. Here two atoms are made to combine into one atom. So, two hydrogen atoms are forced together to form one atom of helium. Enormous temperatures and pressures are required. When we have an uncontrolled fusion reaction we have the hydrogen bomb — much more devastating than the atomic bomb. Here is the problem. So far we have not been able to produce a controlled fusion reaction.
This, if achieved, will be the answer to our power needs. Why? Because the main by-product is Helium, an inert non-toxic gas. There is no long term radioactive waste to store.
There’s another bonus too. A controlled fusion reaction would produce four times the energy of a fission reaction. However, the problem is in the temperature and pressure needed to force two atoms together because of their repulsive forces. You cannot just do it in an ordinary container. Magnetic fields as a containment ‘vessel” and lately, lasers, have been tried to achieve controlled fusion, but so far without success. It will be achieved eventually and then we will have the answer to our energy needs.