How long does a renewable energy system take to pay for itself?
There are five factors which determine payback of a system:
Average length of solar day (5.5 hours in Wyoming)
Average wind duration and speed (for wind turbines)
Current cost of electricity (payback accelerates as rates increase)
Available Incentives (Federal, State, Utility)
Cost of the installation
Renewable energy is one of the few purchases you can make which not only pays for itself but increases in value over time.
How much does a renewable energy system cost?
Every installation is different. Here are just a few reasons why price is tough to generalize: size of system, which affects excavation and electrician expense; ground mount vs. roof mount; distance of system from meter; ability of customer to help with installation.
The cost of solar electric panels is coming down; cost of wind turbines is going up.
Which is a better buy, wind or solar electric?
Depends entirely on your location. A wind turbine can be a better buy, but ONLY if the wind resource is very good – 12+mph for at least an average of 6-8 hours per day. Many people overestimate their wind resource. Other factors which must be considered are zoning regulations, neighbors, noise, covenants, soil type, and physical obstructions to the wind.
Solar electric works well in neighborhoods where noise or space might be an issue. Solar requires an unshaded southern exposure, either on a roof or on a ground mount. A solar installation can also be sized to fit your budget and space and can be expanded over time.
Can I have some shading on my solar panels?
Definitely not between 10 a.m. and 3 p.m. It’s certainly a huge loss to allow ANY shade on the panels.
How many kilowatts of renewable energy do I need to power my whole house?
Use this calculation:
Look at your utility bills for 12 months and calculate the average kilowatt-hours (kWh) per month which you consume; divide that number by 30 to get your daily consumption; divide the daily answer by 4.8 (5.5 average solar hours per day adjusted for wire and inverter loss, dust, etc.). The answer you end up with will be the size in kilowatts of a solar array you would need to completely power your home.
Please keep in mind that you don’t have to offset 100% of your consumption. You can offset any amount of your consumption, and add more renewables later if you choose. Whatever you install will reduce greenhouse gas, will move us toward energy independence, and will reduce your electric bill.
How difficult is it to install a solar or wind system?
Conceptually it is easy to install. However, with a system which is connected to your utility, you have to know National Electric Code and UL rules, government regulations and limitations, zoning, and the requirements of utilities and individual inspectors. Many of these factors are moving targets, subject to change on a frequent basis.
Off-grid (battery-based) systems are a different story. There is no State inspection, but some counties require building and/or electrical permits. The NEC and UL should be followed. Battery sizing and number of kilowatts of renewable energy need to be computed so energy production and consumption loads are matched and provide the desired hours or days of autonomy. Miscalculations or incorrect installations have resulted in fires and ruined refrigerator contents.
I can’t afford to do the whole off-grid installation right now. What can I do?
As a point of reference, it takes about three 240w solar panels to run a refrigerator. For starters, you should by a high-end inverter, maximum power point tracking charge controller and control center. Buy cheap local deep cycle batteries (we call them starter batteries) and plan on replacing them. You will also need a DC generator (required in Natrona County). A generator is a great idea for back-up power, but it’s too expensive and noisy to run all the time.
We recommend a wind turbine (if it’s in the right location) because the wind blows at night and in the winter. Solar works great in the summer and is a very consistent energy producer.
How much electricity does a solar panel produce?
Three 240w panels will power an Energy Star refrigerator. If the sun shines on the panels for five hours, these panels will produce enough electricity to run your refrigerator for 24 hours.
There is about a 7% loss in efficiency in solar panel wattage after it is connected to an inverter and then travels through wiring.