RENEWABLE ENERGY SYSTEMS


Renewable energy systems are defined as systems that produce energy using an environmentally sound, non polluting, renewable source of energy. The most common of renewable energy systems are:


Typical applications for renewable energy systems include:

Remote Homes & Facilities Telecommunications
Village Electrification Cathodic Protection
Water Pumping Irrigation
Utility Intertie Utility reduction

As we continue to pay the price both economically and environmentally for fossil fuel and nuclear generated power we realize that there must be a better way. Presently it is difficult to economically justify renewable energy systems at many utility connected sites. This is partially due to the uneven playing field and the heavily subsidized fossil fuel and nuclear power industries. We also need to remember that there is no expense for the fuel in renewable energy systems, nor do they produce pollution.

Hand in hand with utilizing environmentally sound power production is the careful use of and conservation of energy. Dollars spent towards conservation pays for themselves many times over when comparing them to the cost of producing ones own power. It is roughly a four to one ratio. For example spending another $500 for an energy efficient refrigerator would save you over $2000 on a solar system large enough to offset the energy consumption difference of the two refrigerators. Conservation is key to getting the best value.

Renewable Energy Systems can be either stand alone for remote power production, or utility intertie. Utility intertie systems are either utility intertie direct or utility intertie with energy storage. Direct utility intertie systems are the simplest and most efficient. They do not have any storage capacity, although the utility can in most situations be looked at as storage for your power system. However if the utility is not operating or down so is your renewable energy system. Direct utility intertie systems require the utility to produce power themselves. It is quite common to have energy storage, usually in the form of batteries, and still be tied into the utility. This type of system also provide standby power should utility power not be available. It is the most flexible system and also the most expensive.

Please note that for any utility intertie system you must have permission from and/or a contract with your local utility. Rules and regulations vary dramatically. There is a federal law that requires all utilities to buy your excess power generated from renewable energy. It does not dictate the price or terms of sale. Often utilities will pay "avoided cost" which is either their cost to produce power or the price they pay their supplier for electricity. In Wisconsin it is required by law that the public utilities pay you the same price that you pay them for power from renewable energy systems up to 20 KW. Your meter is usually allowed to run both forwards and backwards. This is called net billing and is an ideal situation. Contact your local utility for more information on their specific requirement.

Renewable energy system maintenance is something that needs to be considered, especially if you are not located near a qualified service person. As with all good system design, simpler is better. LMW&S offers service world wide, but this is not usually practical. Some systems inherently require more maintenance than others, and as with all mechanical systems the more moving parts equates to more maintenance. Photovoltaic Systems have no moving parts and can provide years and years of maintenance free power production. Solar hot water and air heating systems have very few mechanical parts and require period service similar to other typical mechanical systems found in residences and industry. Wind turbines are usually exposed to a very harsh environment and have more moving parts than most renewable energy systems. Some wind turbines require annual oil changes and semiannual greasing. Without this maintenance failure is eminent. Wind energy is a very good and reliable source of power and often referred to as getting the most "bang from your buck", but without the ability to provide service to the equipment it will not continue to produce power. The views from 120' towers are usually quite spectacular, as long as you are not afraid of heights. Most renewable energy systems are maintained by the owners or installing contractors.

We firmly believe that everyone should have a renewable energy system. At the same time not every type of system is for everyone. Wind energy can provide the most power most economically, but wind power is not for everyone. Solar photovoltaic systems on the other hand are quite maintenance free, and if the site has unshaded solar access then solar may be the way to go.

Selection of a renewable energy system is based on determining what best suites your application and what resources are most readily available. Quite often a combination of resources, such as both wind and sun, are used in make a hybrid system. The first step is to determine the load that you would like to offset by the renewable energy system. Step two is to determine how much of the resource is available using existing solar and wind data. Step four is to size the equipment, including any storage that is required. Keep in mind wind turbines only produce power when the wind is blowing, and solar systems provide the most useful power or heat when the sun is shining.

Environmental Impact of renewable energy systems is worthy of note. The following sample systems provide approximate values of the consumption of fossil fuels and pollution offset by use of renewable energy.

SYSTEM

OUTPUT*

COAL

OIL

TREES

CARBON DIOXIDE

SULFER OXIDE

30 Tube Solar Water Heating            
1200 Watt Photovoltaic            
1500 Watt Wind Turbine            
10 Kilowatt Wind Turbine            
20 Kilowatt Wind Turbine            
660 Kilowatt Wind Turbine            
             
*Output is based on an average of 4.3 hours/day of sunshine and 12 mph hour average wind speed.


For other systems the following approximate Equivalents can be used to evaluate the pollution offset by using renewables: