Saturday, 10 December 2011
CASE 369 - Self sustainability - Part 3 (Powering your home)
Generating your own power is not as impossible as it sounds. A large Off grid Solar or Wind installation might cost tens of thousands but for most people this would not be practical anyway. Insulating your home and saving electricity can reduce your bills significantly. To produce the amount that the average household uses is not practical. While fairly large amounts can be produced they could be matched by reducing consumption by the same amount without affecting your lifestyle. Some households could reduce utility bills to almost zero by using all three of these methods:
Use Less: Simple energy saving tips can significantly reduce the amount of waste you produce.
Efficient Use: Insulation is key to efficient use of energy, along with an efficient boiler, and energy efficient appliances. For smaller budgets, radiator reflectors and draught excluders can make some difference, and are usually cost effective.
Harvesting: Wind power and Solar panels can be cheaper than you think, Solar Thermal Water Heating and Biodiesel production are also possible on the smallest of scale
Generating energy from the wind is surprisingly simple, utilising a standard generator with a coil of wire turning around magnets like an electric motor in reverse. Home wind turbines are not as common in urban areas, as the winds speed and stability are compromised by surrounding buildings, but it is estimated that at least 2 out of 5 urban homes have the conditions needed to make home wind generation financially viable. When you consider some of the cheaper alternatives to a commercial installation, this number can increase to almost all, but it can be hard getting neighbours, the local authority or community members to agree on it.
Off grid wind power is quite unpredictable, producing hardly any power in low winds and far too much in strong winds. This makes it more suited to connection to a series of batteries rather than the mains. Grid connection installations are also less cost efficient, as the payback on a system costing thousands is often over 20 years. It is best to have enough battery storage for 2 weeks with no wind, which should be enough to store all the energy a heavy wind might give you.
While wind capturing technology has remained largely unchanged, the evolution of large batteries (mainly for the electric car) is in full operation. Deep-cycle batteries are becoming an increasingly viable alternative to selling excess power back to the grid, as new markets and technological advances bring down the production costs, older batteries can even be obtained for free from certain sources. Payback time on the costs of such a system can be significantly reduced compared to that of an expensive grid installation.
Generating energy from the wind is surprisingly simple, utilising a standard generator with a coil of wire turning around magnets like an electric motor in reverse. Home wind turbines are not as common in urban areas, as the winds speed and stability are compromised by surrounding buildings, but it is estimated that at least 2 out of 5 urban homes have the conditions needed to make home wind generation financially viable. When you consider some of the cheaper alternatives to a commercial installation, this number can increase to almost all.
While solar is not greatly viable on a commercial scale it can be extremely effective on a small scale, particularly when combined with other methods. Using both off grid solar power and wind power generation combined can offset the limits of each device, so that electricity can be derived from the wind at night and from the sun on less windy days. As with most generation methods the power travels one way (as opposed to our usual power supply which can travel both ways many times a second) so much of the cost of a full system is spent connecting the intake supply to the grid. You can bypass this by connecting the panels to some deep-cycle batteries and running appliances directly from them. This also offsets the major disadvantage of solar that allows you to only derive energy during the day when energy use is low in the average household. Deep cycle batteries can give about 12 hours of continuous power which is perfect for solar collection.
Biodiesel requires little or no modification to a diesel engine, and even runs more smoothly through your cars fuel system, requiring less servicing than diesel itself. Biodiesel can be bought from a few locations but is taxed in most countries at the same level as fossil fuels. As countries such as the U.K allow some production (2,500 litres) to be tax free it is possible to produce your own bio-diesel for less than half it's retail cost. Whilst some more extreme fuel products exist on the market which can enable you to make fuel cheaply and easily, these have not been officially tested and verified (by a thousand engines running for a thousand hours) to allow commercial sale of the fuel produced.
Biodiesel is extremely cost efficient if you can gain a regular supply of free waste oil. Many restaurants have a contract with the firm who supply their oil to take it away as well, and some use palm or tallow oil which is unsuitable for biodiesel production. Family owned restaurants, pubs and bistro's can be good sources of waste oil, as well as Italian and Chinese takeaways (although some chinese oil can block filters with tiny bits).
While it's entirely possible to build your own reactor for very little cost, there are many other processes (other than the main chemical reaction) that would make it a very involved and time consuming hobby. Biodiesel Processors require more investment initially, but can allow cheap bio-diesel to be made at home within hours, to a very high quality and with little technical knowledge. All biodiesel processors claim to do everything for you, but before purchasing one you should gain some knowledge of the process involved and ensure that your reactor will do all of these things for you:
De-Watering of the Waste vegetable oil.
Heating of the vegetable oil.
Taking the methoxide (Chemicals) into the process.
Reacting the vegetable oil.
Seperating the Biodiesel from the Glycerine and waste.
Dries and polishes.
Filters down to 5 microns, ready for use.
Alternative methods, unproven or supressed
CASE 020 - Self sustainability - part 1 (Introduction)
CASE 361 - Self sustainability - part 2 (Growing)
CASE 056 - Free energy