Anyone Can Go Off-Grid and Satisfy Their Power Needs with Solar.
California recently passed legislation mandating that all new homes have a solar capability that provides a certain percentage of solar power. Solar is emerging as a necessary and intelligent approach to power generation and is particularly suited to anyone pursuing self-sufficiency.
Many solar systems are designed to provide a small percentage of power for a few lights and appliances, while some more sophisticated systems are connected to the grid to earn energy credits when the power is on, and as a power backup in the event of a blackout.
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We’re going to explore a third option that is designed to provide whole-house power while off the grid on a full-time basis. This option will still allow you to run on the grid, but the goal is 100% self-sufficiency with solar.
This article will serve as an introduction for anyone interested in getting their home off the grid and onto solar power. We’ll start by going over the equipment you’ll need.
Solar Power Parts and Pieces
There are four primary components needed to generate and store electricity from solar power.
1. Solar Panels
Solar panels are about 2 feet wide and 4 feet long and about a half-inch thick. They weigh anywhere from 10 to 15 pounds. On average, one panel is rated at 100 watts of generating power. But be careful when you try to calculate the total power output.
The watt rating on any panel assumes that the panel is perfectly placed at a 45-degree angle to the full sun. The angle alone will decrease the wattage as the sun passes across the sky. Clouds passing by the sun or an overcast day will also decrease wattage output. And then it gets dark and at varying times of year, the amount of darkness varies depending on the season.
It’s rare that you’ll see only one solar panel on a roof unless it’s to power a lone, attic fan or light in a chicken coop. Solar panels are usually arrayed on a rooftop in a long series with each panel interconnected to provide power to a main cable leading to the Charge Controller.
2. Charge Controller
The cable or cables from the solar panel array leads to the charge controller. The controller can display the amount of power currently being generated by the solar panels. It might even have a way of recording the history of power generated by day, week, month or year, and identifying the current charge in the batteries.
The most important feature on any charge controller is the ability to switch off or redirect the power when the batteries are charged to their maximum. If your system is connected to the grid, this is when the power you generate runs your electric meter backward to either reduce the amount of power you are drawing from the grid or in some instances, earn you an energy credit that will either reduce your energy bill or get you a check in the mail. How you are compensated varies depending on your local utility.
3. Storage Batteries
There are fundamentally two options for battery storage of solar generated power. Wet Cells or a new innovation from dry Lithium cells.
Wet Cells or Lead-Acid Batteries
Wet cell batteries or Lead-Acid Batteries have been around a long time and your car battery is probably the best example of how these batteries look and work.
Wet cells consist of a plastic box that contains metal plates suspended in a solution of water and sulfuric acid. This acid solution allows the battery to store power and distribute it through a positive and negative terminal on the top or top-side of the battery.
Wet cell batteries require routine maintenance to ensure the water levels are consistent over time, and a measuring tool is used to evaluate the acidity of the solution requiring the addition of sulfuric acid. Handling any kind of acid is dangerous and if you ever have to add acid to a battery, remember that acid should be added to water -never add water to acid or the acid will cause the water to rapidly evaporate in a cloud of acidic steam.
Wet cell batteries also can give off small amounts of sulfur dioxide gas, so they should be stored in a vented area outside of the house but with sufficient heat to keep the batteries at maximum output. If you’ve ever tried starting a car outside on a below-zero morning, you’re familiar with the effects of cold on a battery.
Lithium Ion Batteries
Lithium batteries are a form of dry-battery for long-term power storage. They require no maintenance and are safer than traditional wet cells. They can be installed indoors and they take up less space than a bank of wet cell batteries. They’re also more expensive.
At the top-of-the-line of dry cell battery storage is the Tesla Power Wall. It also does not require maintenance. It can literally be built into a wall in the house with monitoring gauges on the outside of the wall. It’s the new alternative to long-term power storage in batteries and is being used for both home solar and for industrial uses. It is also very expensive.
4. AC (Alternating Current) Inverter
This is often referred to as a “Power Inverter.” It inverts or “converts” direct current (DC) to alternating current (AC). It’s necessary for powering any traditional light, appliance, electronic device, or tool that plugs into a standard 110/120-volt household socket.
Understanding the AC/DC Dilemma
DC power or “Direct Current” is the type of power generated by Solar Panels. What’s good about DC is that it can be easily stored in batteries. Unfortunately, we live in an AC “Alternating Current” world and most lighting, appliances, electronics and tools depend on electricity delivered with an alternating current. That’s why you need a power inverter.
The wattage that is delivered by the inverter varies in range from 100 watts into the thousands depending on the size of the inverter and the amount of DC power you are generating and storing. As you would expect, the larger the inverter, the larger the price. For a whole house installation, you’ll have to think big.
When you look at it from a component standpoint, it seems fairly easy to put together, but there are a number of considerations to evaluate before you jump into solar. The best way to get solar off the ground is to start putting together a plan.
The Solar Power Plan
Your planning process for implementing a solar power solution for your home begins with a series of very good questions. You’ll have to do a bit of homework to answer many of them, but the end result will give you a very good idea about your energy needs, feasibility, costs, options, tax breaks, and a schedule for implementation.
1. Your Home Energy Assessment
The first key decision you have to make is with regards to the energy needs of your existing home. This decision may contradict the advice you’ll sometimes receive from solar suppliers and installers. They’ll typically ask you to look at your electric bills and estimate the amount of Kilowatt Hours or kWh’s that you use on a monthly basis adding up to a yearly basis. They’ll then base their estimate and recommendation for equipment and installation on that.
The flaw with this logic is that it assumes you will make no changes to your current power usage. Something as simple as buying an energy efficient appliance could make a difference. You also can and should buy energy efficient light bulbs. LED light bulbs are the most energy efficient and provide significant light for their size.
You may also consider options for heating water and heating the house that use natural gas or propane, or a wood burning stove or pellet stove. Passive floor tiles, a double-check on home insulation and timers on certain electronics can also reduce your monthly kWh usage.
Make sure to account for these energy improvements before you total your monthly energy needs. Otherwise, you’ll end up with a system larger and more expensive than you need.
Home Power Hogs
Certain appliances in our homes burn a lot of electricity. We often don’t notice or take them for granted. Here’s a short list of the top power hogs that can put a real burden on electricity demand provided by solar power:
- Central Air-Conditioning
- Refrigerators and Freezers
- Washing Machines and Electric Powered Dryers
- Electric Powered Furnaces, Furnace Fans and Other Heat Sources
- Sump Pumps
- Well Pumps
- Electric Powered Hot Water Heaters
- Electric Oven and/or Range Top
The point is, it’s not just about keeping the lights on and watching TV. We’ve become accustomed to many of these appliances and some–such as refrigerators, well pumps, and furnaces–are necessary. That’s why you have to prioritize as you evaluate your on-grid lifestyle.
- If air-conditioning is critical to your health or location, consider individual window units rather than whole house central air. Fans are another consideration and use little electricity relative to any type of air-conditioner.
- If you must have a dehumidifier to keep the basement dry, consider a smaller, more energy-efficient model, or repair the source of the dampness.
- Think about a wood-burning stove or two as an alternative heat source. A pellet stove is another option, but they also require some electricity to power the pellet auger.
- It’s expensive and complicated, but you could switch to natural gas or propane to power your water heater, furnace, stove & range-top, and clothes dryer.
- Any time you replace an appliance, buy the most energy-efficient appliance available.
- Downsize your refrigerator and/or freezer. And while you’re at it, get rid of that old fridge in the garage. Some utilities will pick it up for free and pay you for it.
- Get rid of all of your incandescent light bulbs and replace them with energy saving bulbs. They cost more but they last much longer and use 1/5 of the power to deliver the same number of lumens.
The Power Draw Problem
Some appliances have motors that draw more electricity when they start up and then level off to a lower wattage. Examples include well pumps, sump pumps, refrigerators and freezers, air-conditioners and furnace fans.
That initial power draw can present some unique challenges when you have a fixed amount of stored electricity to draw on. That’s why you have to build in a cushion when evaluating your total power needs, and it’s another reason why it makes sense to prioritize what you use and what you can replace, downsize, or do without.
2. Effects of Home Location and Geography
The telegram here is simple: The amount sunlight your house receives on a daily basis throughout the year will determine the efficiency of your solar power system. Here are some of the key considerations:
Ideally, solar panels are mounted on the house rooftop. This allows the power to be easily directed to the house, and the same applies for solar water heaters. If you’re planning on installing a new roof anytime soon, you’ll want to do that before any solar installation.
If you’re in the Northern hemisphere, southern exposure for your solar panels is ideal. The sun travels across the southern sky and will deliver the most energy to your solar panels, solar water heaters, and solar tiles. A westerly or easterly exposure can still work to some degree, but a northern exposure may require you to rethink solar as a solution or improvise a location for your panels if your rooftop won’t work.
Trees in close proximity to your home will block sunlight. So will other geographical features like buildings, hills, and mountains. You could cut some trees down if necessary, but moving mountains may be more than you want to pursue.
Some places receive more sun on an annual basis than others. Places like California and Florida are known for their sun. In fact, there’s a swath across the U.S. known as the sun belt.
However, other state–particularly in the Ohio Valley and the Pacific Northwest–don’t receive as much sun on a consistent basis. The way to compensate for that is to increase the number of solar panels and batteries to store more energy for those dark and cloudy days and places. Or move.
Various communities have varying laws and policies related to solar power systems. Generally, the attitude towards solar is positive and growing, but some municipalities and Homeowner Associations have restrictions on the placement of solar panels and their size, and may even require inspections. Make sure you understand the benefits or restrictions on solar in your area.
There are also tax benefits to consider. Federal tax deductions are available for solar power solutions and some states and municipalities offer funding and grants for solar expenditures or tax benefits as well. All states and most municipalities have a website ,and you can easily find more information there.
Currently, there is a 30% federal solar energy tax credit through 2019. The tax credit decreases to 26% in 2020, then to 22% in 2021, and expires December 31, 2021. Some states like Arizona even offer tax incentives for installing wood-burning heating solutions.
A whole house solar installation will be expensive. The standing argument is that the system will pay for itself over the years due to the cost savings, but the initial investment can be sizable. Most people hire a professional solar installer to help with a home evaluation, energy evaluation, location assessment, and an estimate for materials and labor. Do research on the background of any solar contractor you consider in the same way you would evaluate any contractor doing significant work on your home.
Grants for solar installations are available from the federal government across a variety of solar applications from homes to businesses to communities.
If you are tempted to do this yourself, you have quite a bit of homework to do. Amazon.com should be your first destination for books on installing solar power solutions for your home.
There are also many resources from organizations and government websites that can guide and direct your decisions and installation of solar power.
It’s easy to assume that solar power is all about solar panels and the generation of electricity, but there are other solar solutions to satisfy needs ranging from the generation of hot water using the sun to home heating solutions that do not require electricity, gas or firewood. If you’re going to consider solar as a solution, you should take the time to understand the other ways that the sun can keep you comfortable off-the-grid.
1. Hot Water Generated by Solar Power
Most water heaters are powered by electricity or gas. A traditional off-grid exception is a wood-burning cook stove with a large water chamber attached to the side. This was the primary source of hot water in the log cabin days and still works today, but the sun can deliver hot water and requires no logging, sawing, wood stacking or ash shoveling.
The typical configuration for a solar generated water heater is a series of pipes located in a box frame with a glass cover with exposure to the sun. The interior of the box frame and the pipes are painted black to absorb more heat from the sun.
It’s usually located on a roof to not only give the solar water heater better exposure to the sun, but to allow gravity to provide water pressure for delivery to rooms in the house. Cold water needs to be piped up to a water tank on the roof to keep the water flowing, and hand pumps can allow you to refill the tank when needed. Or you can install a small, 12-volt solar powered water pump.
The temperature of the water varies depending on various weather conditions and time of year, but it typically falls in a range from warm to very hot.
2. Heat Generated by Solar Power
There are a variety of ways to generate and capture heat with the power of the sun. A passive approach involves the installation of tiles on an indoor floor that has steady exposure to sunlight. The tiles are a dark color and designed to absorb and retain heat during the day and give off heat at night.
Another approach is similar to the solar water heater using pipes in a glass covered box, but in this instance, the pipes are larger, typically made of a thin foil painted black, and simply cause the air to be heated. The bottom of the pipe is open to the outside and as it snakes its way upward through the box, warm air exits into the home through a vent leading inside.
Many homes that depend on solar power use all of these approaches to generate electricity, hot water, and heat. The benefit is that the electricity generated by the solar panels can be conserved for other uses rather than trying to use solar generated electricity alone to power a furnace, baseboard heating, or a hot water tank.
Natural gas or propane gas can fulfill a role, but if a natural or manmade disaster strikes and the grid goes down, the sun will always be there to keep things going.
Putting it All Together
What we’ve covered here may seem like a lot of information, but we’ve really only scratched the surface. A whole house solar power installation is complicated, but if you take the time and consistently work on your plan, it will become easier to understand and implement.