An Introduction To Solar Lighting
A straightforward guide to understanding, buying, installing and benefiting from solar lighting.
Where to begin? There’s so much choice and so many applications that are naturally suited to the latest generation of solar powered lights. This is largely thanks to huge technological advances in photovoltaic (PV) cells, more commonly called solar panels that convert sun light into electricity, the increasing availability of very low power consumption domestic lighting with next generation LED lighting and the unsung hero of the modern era of electronic devices, battery technology.
These technologies perfectly complement each other and between them may possibly prove to be the features that will define the beginning of this new century, as the world comes to terms with the combination of declining oil reserves and global warming.
Solar lighting is just one facet of solar power in general, with systems that have the capacity to power all your household electrical appliances, whether directly, by storing electricity locally in batteries, or by sending excess electricity back to the main electrical power grid (running your electricity meter in reverse) and allowing you to reclaim it back later.
But let’s not get all heavy now; you just want to know how YOU can install and benefit from solar lighting, right? Well, you’ve seen pocket calculators that have no replaceable battery, no on/off button in fact, and they seem to carry on working forever? They’re solar powered. You probably also come across solar LED garden lights. Now imagine how these could be scaled up to running bigger stuff, like domestic lighting.
This is no drippy-hippy eco pipe-dream: solar power works and in a world about to go cold-turkey from its addiction to cheap oil, its one of the few truly viable alternatives to maintain the living standards we have come to enjoy. So why did we not all buy solar lighting years ago?
The answer is economics. When oil was plentiful and therefore cheap it was more expensive to develop and deploy effective solar lighting. That relationship is now close to being reversed and in the very near future expect the gap between relatively cheap solar power and oil based energy to widen considerably, with the completely predictable consequence that domestic solar energy will one day become commonplace.
Main Components Of Solar Lighting Technology
So how does solar lighting (and indeed solar power in general) work? There are essentially three components: collecting and converting sunlight to electricity; storing the electricity; using the electricity.
Turning sunlight into electricity requires installing one or more PV (photovoltaic) modules or solar panels as they are more commonly termed. As the name suggest, these are able to convert light into DC (direct current) electricity. This DC electricity is then sent down electrical cable to the storage component.
At this point it’s worth noting that most indoor domestic electric appliances require AC (alternating current), whereas most outdoor lighting (outdoor LED lighting in particular) and other electrical appliances require (typically 12v low voltage) DC and crucially all batteries require DC.
The storage component can either pass the electricity straight on to whatever needs power there and then (this isn’t so common by the way) or store it one way or another. The two most common storage options are a) batteries and b) the main power company electrical grid. Either way, you need to decide whether to convert the DC current to AC using a device called an inverter or leave it as DC. You can of course also mix and match, which is most easily done by dedicating solar panels to certain applications (say 1 for DC and 2 for AC, or whatever).
The end usage part of the package depends to a large extent on the storage option(s) chosen, but assuming you have collected enough electricity (which is effectively determined by the number of solar panels installed) then you should be able to provide normal domestic level electrical power. Of course, if you additionally opt to reduce the end load on the system by for example installing low energy light bulbs then you effectively have more power to play with, or can do more with less depending on how you look at it.
Why Install Solar Lighting?
Lighting is such an obvious choice for solar power, not only because the power required by new generation quality garden LED lights is quite small and often low voltage (12v or less), but for the simple reason that during the day, when lighting is usually not required, the sun can fully charge the batteries that will power the lights and the stored electricity then used at night. It’s a perfect, free, pollution less power cycle.
So, the obvious attraction of solar lighting is that once you get beyond the initial capital investment, it’s effectively completely free to run, indefinitely. Which is great news since the true cost of lighting, it turns out, consists almost entirely of the cost of running it (even quite high purchase prices become dwarfed over time by electrical running costs)
Another compelling argument in favor of solar lighting is that because it is adopted by individual households as a “personal” lighting solution, it is intrinsically scalable. No-one has to wait for a government to “do something”; anyone who has a property that is exposed to some form of daylight (not necessarily bright direct sunlight) can install and benefit from solar lighting.
Solar Lighting And Government Policy
The extent to which solar power in general and solar lighting in particular gain acceptance (which in turn affects the pace of development and price of solar technology) is quite heavily influenced by government attitudes toward solar energy.
Where governments are either indifferent to the issues or prone to determined lobbying by fossil fuel interest groups, then take up of solar power solutions has been understandably slow because the increase in the price of oil hasn’t yet started to seriously bite.
However, in countries where government policy is favorable to the widespread adoption of renewable energy supplies for a variety of reasons, for example Germany, Japan and India, it’s a very different story. Taking Germany as an example, there the Renewable Energy Sources Act compelled the existing power companies to buy all surplus energy produced by solar power systems at a fixed, above-market price, for 20 years. This immediately prevented the established power companies in Germany from undercutting the value of the surplus electricity from renewable solar sources and led to a huge surge in installation of solar power systems across Germany.
Germany now produces about 1/7th of its energy needs from renewable sources, well ahead of the EU target of 12.5% by 2010. The success of German legislation to promote the adoption of solar and other renewable energy sources is now being emulated by Spain, France, Italy, and Greece. Even in the USA, Californian Governor Arnold Schwarzenegger pushed through similar though slightly less aggressive legislation that limits the potential liabilities to power utility companies.
The problem with the German legislation is that because the power companies were forced to pay a rebate for surplus renewable energy without any limits, they responded by first passing on their drop in profits as price increases to their traditional non-renewable customers and then lobbying government to reduce incentives for solar power using the twisted logic that this was making electricity too expensive for their traditional customers.
The real argument is in fact centered on the fact that solar generated power is intrinsically decentralized and something therefore over which big power utilities are, ironically, powerless. Even more ironic is that so long as the German government stands firm on its renewable energy policies, the more the power companies hike the price to recover their lost profits the more people will abandon them in favor of solar energy.
How To Use Solar Lighting
Outdoor solar lighting is the place most people begin with because it is low cost and incredibly easy to install. This covers garage and solar shed lighting (and even low power consumption 12v tools) and courtesy or security lighting as well as more traditional solar garden lighting. Because these are small scale, well defined applications, it is usual to find outdoor solar lighting systems sold as more or less complete kits (these outdoor solar kits usually provide the solar panels, necessary connections between components and light fixtures, but do not normally include light bulbs or batteries – most people simply supply a car battery)
Once you have gained some familiarity with installing solar lighting outdoors and got to grips with how and where best to site solar panels, how to store the electricity, how to distribute and use it, what to expect from solar power in general, and so on, then its time to consider the move indoors.
Indoor domestic solar lighting is in principle little different to its outdoor cousin. As a rough guide, the same components are integral to the system: collection of sunlight, storage of electricity, and distribution to required appliances. And similarly, the use of low power consumption electrical appliances and LED lighting will help any domestic solar lighting system deliver to its full potential, thereby saving you, the householder, a great deal of money. Who said that green credentials have to come at a price anyway?
Installing Indoor Domestic Solar Lighting
The first decision to make when installing domestic solar lighting is concerned with the storage options: the power utility grid or batteries. Frankly, unless you have a compelling reason to opt for batteries (such as being in an especially remote location or otherwise unable to connect to the main electricity supply grid) then using the grid is the recommended choice.
Connecting a domestic solar power system to the grid is cheaper and in many ways easier than buying (and maintaining and disposing of) batteries. It also provides far more flexibility in that you can sell surplus electricity back to your power supply company, offset this surplus against what you actually use, and if/when the need arises use (and pay for) more electricity than your domestic solar power system is capable of providing. You might experience sharp peaks in your use of electricity for example, or simply suffer a run of particularly short and gloomy days.
Connecting your solar power system to the main grid also means you don’t have to fiddle about with any internal wiring in your home; the electricity still comes out of the meter like it always did but now with an inverter attached that causes the meter to run in reverse when the solar panels are producing more electricity than is currently being consumed by all the appliances and lights in the house.
Next you need to decide what size PV solar panel(s) to purchase and install (most commonly mounted flush to a roof). The following illustration based on average UK power consumption figures as a guide should help. The average UK annual electricity consumption is just over 3000kWh (kilowatt hours). Solar panels are rated according to kilowatt peak (kWp), where a system rated at 1kWp is capable of producing 750 to 1,000 kWh annually.
To provide the average UK home with all its electrical power needs then would require solar panels capable of delivering between 3kWp and 4kWp. In practice, depending on the size of the house, number of occupants and lifestyles, a solar power system of between 1kWp to 5kWp covers most normal domestic situations.
Once installed, a domestic solar power system such as this would provide free electricity not just for lighting but for all typical electrical power demands such as fridges, cookers, laundry, computers, TVs and so on.
This is a characteristic feature of renewable power technologies and low energy appliances such as LED lights: the cost is entirely up front capital investment and the pay back comes from decades of virtually free running costs.
It’s also worth noting that in the UK for example, it is possible to obtain grants up to 50% of the cost of installation of solar power through the Low Carbon Buildings Programme, administered by the Energy Saving Trust, with the possibility of further grants from local authorities.
The Low Carbon Buildings Programme also handles applications for grants towards other renewable energy initiatives such as wood burners which are proving popular due to the significant energy savings to be gained and sustainability with regard to supply of resources and CO2 emissions. Whether such incentives exist in your own country will depend upon your government’s attitude and policies towards solar energy.
From Domestic Solar Lighting To Full Solar Power
Like most things, the most effective way to learn how to apply and benefit from solar lighting technology is to just use it. Make a start; something small, inexpensive and simple, such as using solar power to run lights and tools in your garage (if you have one, of course), or install a basic solar powered security lighting system around the entrance to your property. This useful solar lights guide has further information.
Buy a basic solar lighting kit that contains most of what you need. Learn and build on that experience to guide you; soon enough you will have the expertise and confidence to scale up to larger solar power systems; all the while discarding your dependence on power utility companies and saying goodbye to rising fuel bills. Oh, and don’t forget to switch to LED home lighting to really squeeze the energy savings out of your domestic solar lighting installation.
A compact set of photovoltaic solar panels delivering between 1kWp to 5kWp covers the range for most domestic needs and is quite capable of delivering ample power not just for lighting but for fridges, cookers, laundry, computers, TVs and so on. It also opens up further possibilities such as installing electric radiant heat which is probably the most effective way to heat a floor (the luxurious warmth of a heated floor is arguably among the nicest forms of space heating ever devised – those Romans knew a thing or two). The usual downside to electric radiant heat is the cost of electricity to run it; obviously this becomes a non-issue if your electricity is free.
Of course, cutting the electricity utility bill out of your life is only one way that providing your own domestic energy with solar electricity helps; by heating water with thermal energy and switching to electricity for cooking means you can save gas money also. Why pay for gas and oil to power boilers and kitchen hobs when you have ample free electricity to do the same thing?
Once you get to the point where you have installed (or had installed, if DIY is not your thing) a full domestic solar power system that both meets all your household lighting, heating, cooking and other electrical power demands for free and massively reduces your carbon footprint, you might get to wondering: well, what next?
You have a system that provides all the electricity you require to run your home, but you’re still paying for gasoline to run your automobile? Move up a gear; add another solar panel if need be or squeeze some more spare capacity by replacing old domestic appliances with modern low energy equivalents; ditch the gas guzzler and get an electric or hybrid car.
Whether you might opt for purely electrical or hybrid depends on your travel requirements. If you need to drive more miles than the car batteries have capacity for, then you need a hybrid, but otherwise an electric automobile will get you where you need to go and back; simply recharge it with your free mains electricity overnight and enjoy virtually cost free motoring.
Who would choose to be eaten alive by the inevitability of rising energy prices when the route to a free future is right there already? Buy a simple solar lighting kit; it won’t cost the earth, but it might help save the earth and who knows where that first step might lead you?