Why can't we harness solar energy?

Question

Why can't we use it in a way that would make our air-conditioners run, and our cars run... why Solar Power not currently being implemented more?

Answer 1

A couple reasons.

First is cost, solar cells are not inexpensive to manufacture and are not particularly efficient (around 15% for current PV cells). PV cell output is DC (direct current), so needs an inverter to change it to AC (alternating current) for use in a home, with losses of 20% or so in the conversion.

Second, while PV cells create no pollution once they are constructed, there is CO2 produced, lots of electricity consumed and a substantial amount of toxic/hazardous chemicals used to manufacture them. Some estimates are that it can take over 50% of a PV cells lifespan to reach the 'breakeven' point where it has offset the energy/CO2 used to create it.

Third, a solar cell can only produce electricity while the sun is shining on it. In most areas PV cells have a capacity factor (the amount of time any type of generation actually produces it's rated output) of 15-20%. The rest of the time you need storage (batteries use toxic/hazardous chemicals as well). Backup with conventional generation means you now have redundant systems which both need to be paid for.

Answer 2

1

Answer 3

Solar power is being used at least for now on a small scale. The problem is that the conversion methods are not very efficient and the sun does not always shine.

Many bus stops are lit at night by solar energy it captures during the day. But the technology has far to go.

Answer 4

Who says we can't?

Solar energy, in one form or another, is already widely used around the world to generate electricity and other energy needs. The question should ask, "Why can't we make more use of solar energy?"

In addition to photovoltaic cells which convert radiation from the sun directly into electricity, solar energy provides wind and drives the water cycle. In North America, we use running water at the Grand Coulee Dam, Mica Dam, Hoover Dam, and countless others to generate many megawatts of clean electricity. The water that runs through the turbines at those dams ended up here because of solar energy. Also wind is formed by differences in air pressure, which is a result of solar energy, and wind energy contributes substantially to energy requirements in countries like Denmark and the Netherlands.

Many people use free solar energy to heat their hot water (both domestic and in swimming pools) and dry their clothes.

You could even argue that coal and oil are the result of solar energy, but rather indirectly.

The problems with harnessing solar energy directly to generate electricity, as indicated by other answers, are many:

- the sun doesn't shine at night
- the sun doesn't shine if its cloudy
- solar energy is not efficient in the winter or in northern (or extreme southern) latitudes
- solar energy is not efficient early in the morning and late in the evening, when the sun is low in the sky and not perpendicular to the collectors.
- demand for energy is commonly not in phase with sun's energy output (ie, we have demand for high energy in the evenings for lights and in the winter for heat, when the sun is not capable of producing any usable energy)
- on a per watt basis, solar is very expensive (around 20c compared to coal at 2c and nuclear at 1.7c per kwh with investment-friendly amortizations) so the economic incentives just aren't there yet
- photovoltaic cells produce DC and that can not be distributed without a substantial loss

The average home consumes about 1,000 watts of electricity, and it would take a solar panel of about 50 x 50 meters (160 x 160 feet) to provide that much energy 24 hours per day, and even then it couldn't handle peak loads such as an electric stove for example. On top of all that, storage of electricity is expensive and very inefficient.

While solar energy does have a place in the blend of our energy requirements, it will never form sufficient power for a base load.

Answer 5

We can!
That's what solar panels do.
The reason it's not done more is really just because of a few simple issues. The main one is cost: there are still enough fossil fuels for it to make more financial sense for people to just stick to what they know. Sadly this is extremely damaging, but the truth is that people would much rather spend all that money on a new car, holiday, home extension, etc.

Answer 6

There are many ways to harness solar Energy. Many system are already in Use.

Answer 7

Solar voltaic panels are still expensive.

It would take decades to recoup initial capital outlay. Therefore, industry isn't interested. However, with some research (which is underway) the cost of efficient panels will go down and we will see more widespread use.

Answer 8

I hope that smart e berry is right. Wouldn't it have been great is Bush spent 400 billion on solar panels and only 200 billion on the war, instead of 600 billion on a war that has gotten us NOTHING but DEATH.

Answer 9

We do hsrness solr energy, but the equipment can be very expensive. The answer always depends on economics.. Is the cost exceeeded by the benefits?

Answer 10

we can it is just not efficient enough and it is stll very expensive, u ca install it for ur houde but it is expensive