Renewable Energies and How They Work

The first thing to understand about renewable products, they all produce electricity in one form or another. Without going into great detail to all of these renewable energy forms and not having to be an electrical engineer (we will leave that up to the experts in their fields), the electricity they produce simply comes from a renewable energy source.

The one thing that you need to understand is the measurement of electricity. It is on your power bill monthly as the kWh that you use. KWh stands for Kilowatts an hour, just as it sounds, one kWh used or produced in one hour. Breaking that down there are 1000 watts in 1 kW. Think of it in this form, 10, 100-watt light bulbs equal 1000 watts or 1 kW. If you turned on all 10 bulbs for one hour, you will have consumed a 1000 watts, or 1kwh. The average home consumes 1000 to 1500 kWh a month.

Most power providers have this information on your power bill. Perhaps a graph shows your usage over the course of a year. If your home is all electric, you may see a spike in your usage in the winter months; I am sure that you notice it on the dollar amount! You may have a gas fired heating with central air, and notice a spike in your usage in the summer months. Whatever your situation is, you need to add up the total kWh that you use for the year. As an example, if you use 1000 kWh a month, your total is 12000 kWh for the year. This annual figure is your benchmark for what size of renewable energy producing product you need to purchase; you’ll want to at least offset your consumption by 100%.

Now that you have determined the size of unit that you need, you need to assess what type of renewable energy product will produce the most for your area of the world. You may live in an area that is sunny, windy or abundant with water, or all three. Combining all of these renewable products is commonly known as a Hybrid system. For determining your most abundant resource, there are numerous web sites that you can go to for help or ask your local renewable energy supplier.

One of the figures in determining the production of your renewable energy is the number of hours in a year, 8,760 hours. If you had a renewable energy unit that was 1kWh and it produced 24-7-365, it would produce 8,760 kWh per year. Out of the three renewable energies, hydro is the only one that has the capability of producing 24-7-365, with the exception of tacking in climate conditions such as icing. Sunlight is a bit more predictable, we know that it comes up every day and sets every evening. What we do not know is the intensity each day. However, there is a history of average sun days per area. This will help determine if solar will work for you. Wind is quite unpredictable, however there is history for areas of the world, if you think wind is good for you. The wind averages are based on percentages. A good safe number for calculating wind in most areas is 30%, in other words 2,628 hrs a year that may be productive.

Each one of the renewable resources mentioned above presents it owns challenge in putting it to work for you. Hydropower may require extensive permitting issues in manipulating waterways or tributaries. With wind, once again, you may also be faced with extensive permitting issues and zoning. There are a number of products on the market today that help avoid some of these issues. One thing to keep in mind is that the higher you go from the ground, the more productive the wind unit is. Solar may be the easiest renewable energy product to install, with little permitting issues and a relatively easy installation process. However, at this time it is one of the most expensive renewable per kWh products.

The other side of renewable energy is inverters and controllers. These are the electronics that convert your renewable resources to productive power. This is the part that gets little to no recognition, mainly because you don’t see it, until you own a renewable product and experience the issues of the inverters and controllers. Don’t get me wrong, these things aren’t bad, but just like any other product, especially electronics, you get what you pay for. Look for products that offer warranties and extended warranties.

Now that we have covered the basics of renewable energy, calculated your annual kWh usage, determined what renewable fits for your part of the world. Now you need to contact your local power provider, find out what their criteria is for connecting to their system. This is referred to as a grid-tied system and is the most productive and economical method. The grid is the power lines running to your home at the meter base.

An off-grid system usually involves batteries, in which they would store the excess energy until you use it. Batteries may also be used in a self-sustainable situation for the event of primary power failure. In a grid-tied system, the grid is used like batteries; you tie into the grid and it turns your meter backwards, this is called net metering. For example while you are asleep at night, the wind is blowing and your wind unit is spinning like crazy, your producing kilowatts turning your meter backward so that when you wake in the morning you can use the credited kW.

Some of the myth around net metering is that the power company will buy your power back. In some cases or power districts this is so; however, you will not be paid what they charge you. Rather, you’ll be paid at the wholesale price around less than .2 cents per kW. In most cases this is annually returned, so if by December 31st you have not used your credits, they will purchase them at the wholesale price. Again, this is in some power districts, so be sure to check with your local power provider. In co-ops, they make their own criteria and may pay nothing. Another critical fact is that in every power district they have their limit as to the size of kW unit that you can tie to their grid. I have found it to be from 10kw to 50 kW, you may be able to apply for larger units, but it is based on their criteria.