Types of alternative power systems

There are many ways to build an alternative power system. Some such as Wind and Hydro are very site-specific. Here are some of the more commonly encountered types:

• Solar Panel Power System only
• Hybrid Solar Power System & Generator
• Wind Power System only
• Hydro Generators
• Generator only
• Generator w. Battery Bank & Inverter
• Hybrid Solar & Wind Power System
• Hybrid combination of any of the above Power Systems

Solar Panel Power System only

Usually reserved for specialised communications or security applications where small power supplies are required. I have built systems for such applications such as these to supplies for electric fences and dc lighting for small houses. Other possibilities include water pumping where batteries are not necessary.
NOTE: Hybrid Solar panel power system & a small backup generator probably the most common system here in Northland and is what I would recommend 99% of the time

Pros

• Practically maintenance free, apart from batteries (if installed)
• SILENT power generation (once you have had any exposure to a NOISY generator for any length of time you appreciate this attribute!)
• Very GREEN, sustainable energy option.

Cons

• Expensive for large house size installations with no back up generator. A small generator can significantly reduce the size of battery bank and PV array needed N.B. some people simply hire a generator when necessary

BACK TO TOP

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Hybrid Solar Panel Power System & Generator

My personal favourite because I know it will work almost anywhere with predictable results.

Pros

• If a 230 volt alternator / generator is used in conjunction with an inverter running off batteries, two sources of 230 volt power are available ensuring security of supply. I.e: should the inverter fail, (rare with quality equipment installed correctly) the generator is there as backup, as is the case if the sun does not co-operate for a few days or times when power consumption is higher than usual:
  1. large quantities of produce making fridge or freezer work harder than normal
  2. using T.V for entertainment when weather is bad
  3. extended runs of washing machine for new babies or vacuum cleaner for spring cleaning
  4. friends visiting
  5. parties (experience talking with these last few points!)
• Great if the solar array can provide say 80-90% of the normal power consumption reducing fuel consumption and cartage of fuel
• Maintenance intervals of the generator are extended (less wear and tear).
• Less fuel used than a stand alone generator. The more PV panels, the greater the reduction.
• Maintenance intervals for genset increased as running hours reduced.
  My recommendation, after having been off grid myself for almost 12 years & speaking with many others who have been offgrid much longer, assuming that hydro and wind generation have been ruled out, is buy as much PV as you can afford. This is the most user friendly generation one can find in my opinion. The more I install PV the more I appreciate its silent hassle free generation. please see note below regarding the cost of PV
• More PV solar panels can be added over time as finances permit.

Cons

• Some NOISE (from the genset) at times of unfavourable weather or unusually high power consumption
• Still needs some Fuel, more PV panels = less fuel
• Produces fumes
• Produces waste heat though sometimes this can be harnessed especially in the case of a water cooled machine

BACK TO TOP

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Wind Power System only

JUNE 2010: WITH THE PLUMMETING PRICE OF SOLAR (PV) INTHE LAST 12 MONTHS I am now recommending people invest in solar panels rather than wind turbines. For the price of a good quality windturbine install one can now build an array of PV in excess of 1400 watts and for alot of homes this is sufficient. (I run my modest dwelling on 1100 watts) There are the added benefits that solar is more user friendly (little or no maintenance) and will last longer. Solar has always been the easiest option the only problem has been price! that has all changed now!!

There may be instances where a wind turbine is still a good bet but I think they will be few and far between now

2012 the price has continued to fall! Solar is most often the cheapest way to go now when you take into consideration all the other engineering factors

Pros

• Turbines can be built by the keen DIY' er (for this approach, see scoraigwind.co.uk the best site I know of) The commercial ones we deal in have the benefit of extensive research and testing.

Cons

• Quite rare to find a standalone wind system as the wind can be a bit fickle.

• Turbines must be sited correctly i.e. somewhere that gets copious quantities of wind, free of turbulence. I can't emphasise enough how important this is for a successful installation.

• Some Turbines can be noisy, though the latest models we are selling are very quiet
• The turbine site then needs to be within a reasonable distance of the battery bank
  1. or large capacity expensive cabling has to be used
  2. or the voltage has to be raised and the lowered again for the batteries, which raises all the safety issues associated with that technique
• Turbines need to be mounted up a tower requiring some rigging skills or the employment of people with the skills and can be expensive for large machines
• Turbines definitely require a maintenance routine or spectacular destruction is almost certainly assured!

BACK TO TOP

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Hydro Generators

If you have a viable hydro site at your place, you are very lucky. To qualify as a good site, a general "rule of thumb" is that you need a fall of 10 metres or better and a flow of 2 litres/second or better. As with wind turbines, the site then needs to be within a reasonable distance of the battery bank or else large capacity expensive cabling has to be used, or the voltage has to be raised and then lowered again for the batteries (which raises all the safety issues associated higher voltages).

Good Hydro sites are extremely hard to find. The main factors I look for are

1. Good all season flow in the stream 
2. Safe (and preferably easy) access to the head of the penstock and the turbine site
3.  Length of cable run from turbine to batteries

Pros

• Potentially the cheapest of all power systems $$/Watt output on an ideal site
• Can be DIY'edthough some advice from someone with experience is recomended
• As power production is 24/7 Size of battery bank needed can be relatively small compared to solar power and wind power options

Cons

• Some noise
• Maintenance required cleaning out nozzles and clearing water intake. The Mainland model I recommend and sell I have seen run for 10 years or more with no actual maintenance to the turbine itself
• An eel can really mess up your day (joke but it has been known to happen)
• Sooner or later you'll probably get wet
• Floods can trash the turbine if it has not been sited so it's protected (installation issue)
• You don't even want to think about droughts

Having said this a properly installed well sited quality turbine with a good water resource is a very reliable system type.

BACK TO TOP

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Generator only

I.e. petrol or preferably diesel generator

Pros

• Cheap and easy, buy it, DIY it? take it home, plug in and start her up: Job done.

Cons

• NOISE, NOISE, NOISE
• Constantly needs fuel
• Produces fumes
• Produces waste heat though sometimes this can be harnessed especially in the case of a water cooled machine
• Inefficient to run an xx kVA machine to power a load such as a light bulb
• Needs to be started every time you need a light in the middle of the night, and if you didn't buy the remote start option, it's probably raining.

BACK TO TOP

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Generator with Battery Bank & Inverter/Charger or stand alone Battery Charger and Inverter

The vastly more efficient way of utilising a generator. Generator charges batteries, at convenient times, which provides power (230 volts via an inverter) silently at the flick of a switch in the middle of the night or any other time.
More user friendly as the generator is not required just to power a tiny load like a fluorescent light.

More efficient as generator is more effectively put to use to do the real work of keeping the battery charged which is a better load for it.

The generator may not even need to be run every day depending on the load on the system and the storage available in the battery. Great basis for the start of a hybrid system!!

Pros

• Relatively cheap and easy to set up quickly depending on size

Cons

• NOISE, NOISE
• Needs fuel and...
• ...frequent regular maintenance
• Produces fumes

BACK TO TOP

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Hybrid Solar & Wind Power System

Assuming that a reasonable amount of wind is available, combining a wind turbine with your solar panel energy system can be a really good combination as the two sources of energy tend to complement each other in terms of seasonal power output.

Pros

• Also a very green option as no fossil fuels are consumed (or at least vastly reduced ).
• Relatively quiet

Cons

• Still very reliant on mother nature, and overcast / windless days do occur
• Some maintenance required for turbine and tower

BACK TO TOP

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Hybrid combination of any of the above Power Systems

This is what most people end up with in the long term. Some systems tend to evolve as their owners get a "feel" for what will work for their particular situation.

BACK TO TOP

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .