Our Eco House blog

Basically there are two kinds of solar panels. Solar collectors which heat the water and then there are photovoltaic solar panels which converts solar radiation directly to electricity. Both systems use completely different technology and they are related only because they’re using sun as a source of energy.

In the following days and weeks, many of us will take out the Christmas lights from the last year and you might notice that the bulbs are broken and there are no spare bulbs to replace with. So, you decide to buy new ones. But before you do that, let’s spend a little time on thinking.

There are several options you have.

Option 1 - buying new lights with standard bulbs

• Pros - cheaper to buy, warm light
• Cons - high energy consumption (your electricity bill will be higher, more CO2, SO2, NOx, etc. emissions), risk of fire if near the fabric, you probably end up buying new lights next year because they brake more often (more rubbish in landfills)

Option 2 - buying LED lights

• Pros - they consume only 10% of electricity and live 10 times longer compared to standard lights, no risk of fire if near fabrics or burns if accidentally touched
• Cons - more expensive to buy (but they save on electricity), colder light

Option 3 - not buying new lights at all

• You’ll save on the electricity bill and you’ll cause no damage to the environment, but we would not recommend this option especially if you have kids

As you can see there is no option with no cons, but some have more cons than others

PS: We’ve chosen an option 2 because we want light, no heat (95% of energy in standard bulb is emitted as heat) and we don’t want to buy new lights every second year.

Many people are afraid that wind turbines kill a huge number of birds. Opponents of wind power often use this argument to stop development of wind farms but is it really the true?

It is estimated that each year in the USA

• 57 million birds die in collisions with vehicles
• 1.25 million in collisions with tall structures (towers, stacks, buildings)
• more than 97.5 million in collisions with plate glass
• 4 million to 10 million night-migrating songbirds in collisions with telecommunications towers
• household cats in the U.S. are estimated to kill 100 million birds each year

In comparison each wind turbine kills 0 - 2 birds per year at worst.

Global Wind Energy Council (GWEC) figures show that total installed wind energy capacity in 2006 was 74,223 MW

Let’s say that every wind turbine has a capacity of 100kW (usually they have more - even over 1500kW), it gives us around 742,230 wind turbines worldwide.

Let’s count with the worst scenario - 2 killed birds per turbine per year

Wind turbines kill 1,484,460 birds worldwide annually

Let’s have a look at the list above again and bear in mind that those numbers are only from the USA.

Source:
AWEA, 2002
Renewable energy, Godfrey Boyle, 2004
Wikipedia

Alright, you’d like to buy a photovoltaic panel or even several of them to reduce your electricity bill and to lower pressure on the environment but where to start?

First, you should decide how powerful panel you need. Let’s say that you need to power 100W appliance. If you buy a 100W panel will it really deliver 100W? Actually, it’s a bit more complicated. Solar radiation varies from place to place, fluctuate under different weather conditions, etc.

It was necessary to create a standard how to label photovoltaic panels and it was agreed that their output will be measured under these conditions:

• power density (amount of solar radiation) of 1000W per square meter
• temperature of the module or the cell is 25 °C

How can you find out how much solar radiation your area receive? There are maps which will show the average annual solar radiation. Below is a map of Europe.

From the map you can easily find out the 100W panel will produce around 200W in the South of Spain but only around 60W in the Iceland if the panel is facing South and is under the right angle.

Also check how efficient the solar panels are because some panels are more efficient than others. They could vary from around 10% to 20% so you would need twice as big surface of 10%-efficient panels than you would need with 20%-efficient panels. It means that the cheaper 10%-efficient panels could cost more in comparison with delivered power.

Many people still use standard incandescent light bulbs. A product which was introduced 120 years ago, converts only 5% of energy to light and lasts only 1000 hours.

Tip: Change all your light bulbs to energy saving ones.

No matter if you use CFLs or try LEDs, both will consume much less energy than incandescent light bulbs. Also note that incandescent light bulbs will be probably banned soon (at least in EU and Australia).

We also don’t want to hear excuses that you cannot afford buy them because they are expensive. Detailed calculation on our eco forum tells completely something different, just have a look.

Some might complain that CFLs contain mercury which is also harmful to the environment, that is true and you’ll need to recycle old CFLs properly. But mercury emitted from power plants during generating electricity to feed your incandescent light bulbs could be even higher as you can see from the diagram below.

There are various shapes of CFL light bulbs including candle light shapes so nobody can complain that there isn’t their type available. Also various light colours can be purchased. So just choose which colour you like the most.