Solar Energy for Homes

The sun produces 15 000 more energy (for our earth) than the whole energy consumption in the world!

The sun will no doubt in the future be the greatest energy provider as the technology advances. The development is very fast in the renewable energy field in total.

We have experienced rising oil and gas prices and that has of course had a strong impact on our life.

It is also a well-known fact that the oil resources will be used up rather soon. There are different opinions of how long it will last but we might be talking about thirty years.

The world is very dependent on oil, especially diesel, since our whole distribution system builds upon diesel to a very large extent. The ships run on oil and the lorries bringing the merchandise to the shops run on diesel.

There is a lot you can do to lower your costs and also help cut down your carbon footprint or the amount of carbon dioxide – this is one of the main factors in the global warming.

It is very important to consider how you use energy overall. Dr Hermann Scheer, who works with these issues for the German government, has a very good example in his book “The Solar Economy”.

Consider the doorbell, which seems innocent enough. It consumes between 9 – 20 kWh per year while it sits there and is almost never used – perhaps once a day. It is not much for a individual househould but if you consider the 37 millions households in Germany using one, then you arrive at a shocking number.

It corresponds to the use of electricity in a city with 100 000 people – for a whole year!

The electricity for this doorbell could easily be provided by a solar cell of the size of a matchbox and it would cost very little.

On the other hand – what is wrong with a manual doorbell which had before?

By transferring to solar and renewable energy you will increase your interdependency of the national grid. It will give you a predictable cost structure which will not fluctuate with other trends.

It is also a very reliable technology and will hardly fail unless the circumstances are really severe.

It will certainly also increase the value of your house should you ever want to sell it.

Solar and renewable energy is a field which is evolving rapidly and will continue to evolve. When you implement it yourself in your home you will become an expert on how to do it. You could then, if you wish, build a substantial new business around it and arrange courses where you show people on how to do it, how to apply for governmental fonds etc.

Solar heaters and solar panels

Solar heaters are designed to heat water while solar panels are for producing electricity.

In both cases it the light which does the work, either hot water or electricity. It does not matter if it is cold or warm outside as long as there is light. In fact, solar panels are more effective in a cold climate.

Solar heaters

Solar heaters will very fast have a positive effect on your bills, especially if you are living in a place which requires you to heat your house in the cold period of the year.

A solar heater can easily be integrated into your current water based heating system.

A solar heater is a very simple construction as such and if you like to build things you can easily build them for a very low cost.

Almost anything can be turned into a solar heater. You basically need a black container with one water pipe coming in and another one going out.

There a two types of solar heaters: flat one and one with tubes.

The flat solar heaters are good if you live in a sunny area with many hours of sunshine per day with sun right above you. The farther north (or south) you go these will become less efficient.

In solar heater consisting of pipes the rays of the rising or sinking sun will hit the surface for a much longer time.

Professionally made solar heaters last longer and are more efficient than self made ones and they last very long and require in principle no maintenance. The only problem you might encounter will depend on the quality of the water. The more calcium and minerals in contains, the more the system will become clogged eventually. - There are ways around this by reconditioning the water which we will discuss in a later chapter.

According to a study in Denmark, 21 % of the electricity use in a normal household is for washing, dish washing and drying.

A washing machine or a dish washer uses electricity to heat the water much more than for the “washing work”. Thus it makes sense to used hot water from the solar heater instead and save a lot of money here.

Solar panels

There are many misconceptions around solar panels. It is often said that they are expensive and ineffective.

One must ask then in comparison to what?

The efficiency of the original steam engine was around 10 %. This means that of the energy used, 90 % was wasted – in the form of heat.

A gasoline engines has an efficiency of 25 %, a diesel engine of 40 %, while a big electrical engine has an efficiency degree of 92 %.

One can then wonder why our cars use the combustion machine which has such low efficiency when the electrical would be so much the better? In the beginnings of the car there were in fact more electrical cars than combustion cars. What happened? - If you want to know more about this, then get the film “Who killed the electrical car?” and you will have some answers.

You yourself, as a bio-electrical human being, has an efficiency of 25 %, turning food into mechanical energy which means moving around in different ways – sitting still or sleeping for that matter. You are still breathing and your heart is pumping. - The average consumption is around 100 W by the way.

Think about that for a while! So what is the complaint about, really?

A typical solar panel has an efficiency of 15 %. There are already experimental solar panels with an efficiency of 30 % but they are not yet commercially available.

It should be carefully considered though that solar panels often come with a 20 year guarantee and usually last longer than that.

Very few things last that long. Your TV and your computer will not last that long and it is good if they come 1 (Guarantee in Germany: 2 years) year of guarantee.

Not even your bed will last that long

So even if the payback period is e g 5 years then you have 15 – 20 years when you have to pay absolutely nothing and depending on the size of your system you can even make money by selling the surplus electricity to the grid.

Dr. Hermann Scheer calculates that if 10 – 15 % of the surfaces of existing buildings had solar panels it would be enough to supply electricity enough.

The prices will come down and the efficiency will increase but even with the existing solar panels it is well worth starting now.

Tightly coupled to solar panels are batteries. You will have to store the electricity somehow because there will be days without sunshine and there certainly is no sun in the evening or during the night when you want to study or surf the Internet.

There are many different types of battery and it is quite a large subject. The batteries for this purpose must be of a certain type called deep-cycle batteries. They are different from typical starter (car) batteries in that they can be discharged a lot without being damaged and short-lived.

We will return to these questions later.

Conclusion

There is a lot you can do to reduce your costs for energy. In fact, there are already technology available to make you totally independent and probably a supplier of energy to the grid as well.

Certainly it involves changes in your lifestyle. It is necessary to stop using the stand-by functions in your computers, TVs and other appliances unless they are powered by the sun.

In fact, many times the stand-by function uses more electricity per year that the actual use of the equipment itself.

It would for instance have a very profound impact if most people would start using low energy or LED lamps.

We will return to these questions in later chapters.