The use of solar energy is growing and developing at an amazingly fast rate – so much so it will soon be one of the world’s top industries. Due to this rapid expansion in solar energy options now available on the market, plus an equally rapid fall in component prices, it is crucial that you do your research and understand all the potential pitfalls before making any financial commitment to proceed.
Research which type of solar energy system best suites your scenario. Factors such as whether you live in a town or country location, are you in a conservation area, orientation/angle and available area of your site, what are your energy requirements, preference to generate electricity or hot water or both, mains grid connect or stand alone power options, possible constraints with installing all of the equipment on your site.
Installation costs. What can you afford, will you be able to do any of the work yourself, are there any government or council grants available, would this money be more effectively spent improving home insulation, calculate your potential energy cost savings.
Finally, there are many different types of ‘green’ energy sources available on the market today – wind energy, bio-energy, water energy, geothermal energy and gas energy. Make comparisons with your ‘best choice solar option’ and see how the pros and cons from each stack up.
Let’s look at some basic figures about the power resource from direct sunshine. On a cloudless midday it could equate to 1000W/m². This needs to be corrected according to the angle of tilt between the surface and the sun. A major correction being the latitude on earth from the equator. So, for example, in London at 51 degrees north would be about a 60% reduction to being on the equator. It would be further reduced by the season of the year and further still for cloud cover. On average the sun shines about 34% of daylight hours in London. The combined effect of these three factors is that the average raw power of sunshine per square metre of south facing roof in London is roughly 110W/m².
Now let’s look at some rough estimates of the potential power we could harness from the sun. The two most common domestic solar power options are ‘Solar Thermal’ (making hot water) and ‘Solar Photovoltaic’ (making electricity).
Solar Thermal utilizes the simplest technology by heating water directly. Let’s say we have 10m² of south facing solar thermal panels and these are 50% efficient in converting the sun’s 110W/m² into hot water.
50% x 10 m² x 110W/m² which would deliver 13kWh per day
Solar Photovoltaic (PV) panels convert sunlight into electricity. Typical solar panels have an efficiency of about 10%, the more expensive ones could be higher than 20% efficient. An average south facing 20% efficient photovoltaic panel in England would be
20% x 10m² x 110W/m² = 22W/m² which would deliver 5KWh per day
Installing photovoltaic panels is about four times more expensive than solar thermal panels and they deliver less than half the energy. The question then is whether hot water (low grade energy) is more practical for your situation compared with electricity (high grade energy). Some manufacturers now produce ‘combined’ systems that deliver both hot water and electricity, but this comes at a premium price on SunlineEnergy
My advice to anyone considering going solar would be to study the claimed saving estimates by the manufacturers very carefully with trusted organisations data and material, it varies hugely according to where in the world you are living. There is a wealth of information available out there but do your research thoroughly and seek valuable knowledge from others who have already installed solar systems in your area.