Deciding whether to invest in solar power for home use has never been as tempting as it is today. There are currently so many ways to implement residential solar power that the sheer magnitude of the choices themselves become somewhat overwhelming. Solar power for home use is a large, multi-faceted subject so I thought I would offer some advice about how I think you should approach the subject.
First of all, regardless of whether you are into D.I.Y. or prefer hiring experts, you first want to read some of the available material about solar power systems. Knowledge is power when selecting products and materials, or when discussing your project with a contractor. This works both ways; a knowledgeable customer is, for a true professional installer, a better customer. Contractors who come across as reticent, or who are otherwise less than forthcoming with information should be avoided.
Making the switch from grid power to solar power is a commitment, regardless of the approach you take. It is important that you not let yourself be ‘sold' a system by an eager installer, who may himself be sold on the idea of solar power for home consumption, but who lacks sufficient communication skills to interpret and implement the wishes of you, the property owner. After all is said and done, it is you and not the contractor who must live with every choice and decision made about your system.
A poor match between professional and homeowner leads to the installation of an inadequate system that ends up being overkill, under kill, more maintenance than anticipated, and overall disappointing and discouraging.
Residential solar power installation in the United States is on pace to double over the next five years to 15 Gigawatts annually. This means that by 2024, 15 Billion watts (!) of new solar electricity will be installed. That translates to 15 to 20 million homes turning to solar for electrical power!
My point in bringing this up is to illustrate the kind of growth that is happening with solar power, and with growth comes all kinds of people participating in it, some good, some bad. By ‘bad' I don't necessarily mean dishonest, but in a broader sense that includes those who are aggressive salesmen or women, peddling inferior products based on price alone, and basically, anyone willing to take advantage of a customer's lack of knowledge of the industry and its products.
Where Do I Start?
The last thing I want to do is talk you out of considering solar power for home use. As PV module (solar panel) and storage (battery) technologies continue to improve, as well as management electronics (inverters, controllers etc), it eventually becomes imperative that the homeowner invest in solar power production, however limited.
When you own the means of production (Paging Adam Smith), you are in control. When the power company, a monopoly, is in control, you will pay whatever rate they determine they need. If that means a 36% sudden rate increase, as recently happened in parts of California, then that's what you pay. You cannot get bids and move to another provider…. or can you?
Solar power, being a growth industry that is a long way from maturity or saturation, gives you a compelling advantage in control. Prices for PV modules and supporting electronics are falling, the technology continues to improve, and when your current setup requires updating or repair, the components you replace years from now will likely also be less expensive and more capable than those you're using today.
Once you commit to the concept, you will want to start reading, and this is where I think you should start:
- Read my earlier post, Residential Solar Power Systems, to get an overview of the concepts you will be tackling.
- Visit Energy.gov (U.S. Dept of Energy) and spend time studying their article: Planning a Home Solar Electric System, which has good info likely geared more to someone planning to hire a professional installer, but still something you should check out.
- Buy this book from Amazon: Install Your Own Solar Panels: Designing and Installing a Phtovoltaic System to Power Your Home , even if you plan on hiring a pro, because if was written by industry insiders who have designed and installed hundreds of systems and you will quickly see what goes into a system and what to focus on, and more important, why.
- Visit Solarenergy.org, and check out their training courses and the wealth of information this non-profit brings to the table
- Check out the Resources Page of SEIA (Solar Energy Industries Association), which is basically an active blog about solar projects and case studies, and a student of the industry will find interesting and instructive.
These links and the book, with measured amounts of time and effort, will make you a knowledgeable participant in the design and implementation of your home solar power system. This is something to take on in pieces and you will notice that in a couple of months, the terms and concepts are becoming comfortable and even more interesting.
At this point, when you begin discussing your general plans with a professional installer, you will be working from a position of strength, and you will be able to focus more on nuance and in general, have to tools and knowledge to get what you want and need, rather than a system that a sales rep, someone who will never have to live with their recommendations, wants to sell to you.
Spending two or three months in study will likely translate to many years of increased utility, and even pleasure, from an adequately sized and capable solar system.
You Will Move Toward One of Two Big Choices
I like to have at least a fuzzy picture of the end result in mind when I start a big project. With solar power for home use, that means ultimately a choice between two types of systems: off-grid solar power and grid-tied solar power.
Choice #1: Grid Tied – otherwise known as ‘On-Grid' solar is by far the most common type of residential solar power system and is the one I prefer. Basically, with the use of a Net Metering Agreement with the power company, the grid tied system feeds excess power produced by your solar system back into the grid, which lowers your electric bill. You are thus using the grid to store your excess electrical power.
Since you are fully tied to the national grid, this is the easiest system to live with because you haven't constructed limitations to the amount of electrical power you are able to consume. Whenever your solar production setup falls short of your needs, the grid seamlessly compensates.
Keep in mind that the average homeowner will likely never get rich selling excess power back to their utility. Your power company ultimately needs to make a return on investment so that payroll can be met, equipment can be repaired etc. They will be charging you something like 3 times more for the power you use than the power you produce. Also keep in mind that there is a natural conflict here as the utility is likely keeping constant pressure on regulators to limit or reduce the amount they are required to pay you for your excess power. Residential solar power production is, understandably, a rival to their business model and they work diligently to limit its affect.
The law requiring your power company to purchase your excess power is the federal Public Utilities Regulatory Policy Act, also referred to as PURPA. This law creates the requirement, but the actual compensation is set by the various state regulators.
My state and area are handled by Duke Energy, which has a up beat net metering page which I highly recommend you check out no matter where you live. Duke has done a good job providing links to PV Watts and other resources, as well as providing details about Tier 1 systems (Facilities generating less than 10kW) it will be interacting with.
Also keep in mind that with a grid-tied system, when the power grid goes down, you are lighting candles just like everyone else in your neighborhood. Your system requires isolation, referred to as ‘islanding', from the utility for safety reasons when they are offline. You can install backup power systems to compensate for this, however that adds a level of complexity that I find not worth the hassle. Personally, for short outages I would rather resort to a backup generator than a battery bank for temporary, emergency power.
The exception would be a solar backup power generator of the type I have reviewed here.
Choice #2: Off-Grid – The total novice to solar power tends to assume that all solar systems are off-grid. However, this is actually less common than grid-tied and for good reason. It is significantly more difficult to implement and maintain because you are living with a system that provides all your power, and you must store and maintain your power in a battery bank.
While no-doubt easy for some, this is actually a deceptively difficult task. Battery capacity is an extremely dynamic thing and significant attention and care must be given to the battery bank if longevity and capacity are important – and they always are.
A big plus here is the rise of the lithium battery as an alternative to the flooded or wet cell lead acid battery. Lithium batteries are more forgiving, meaning less likely to be damaged during repeated deep discharging, than their lead cousins. However, an improperly sized battery bank either works too hard, resulting in premature death, or is over sized for the job which means wasted expense. Over sizing a lithium battery bank to the anticipated load is somewhat unlikely because they are so expensive to begin with.
The point is, that with an off-grid system, your power storage requirement, handled by your battery bank rather than by the power utility, takes center stage (or should), and your daily power consumption is wholly dependent on its relative health.
For most, this tends to become quite a behavior modifier, which may actually be a good thing. Personally, I get a little ‘antsy' when we oven-roast a chicken in august and I realize that my 600 watt plasma TV has been on all day for background noise, and I also discover I left a triple bathroom light on upstairs along with a couple ceiling fans, and we've been drying clothes we are about to donate all afternoon. This while my 4-ton first floor and 3.5-ton second floor AC systems work overtime along with everything else that gulps power.
Just maybe, had we been responsible for producing and storing 100% of our power on that, or any given day, we would have been a little more careful? I think the answer is clear.
Going off-grid for us would be an order of magnitude different in terms of planning and commitment. It is an interesting challenge but for now, for our main residence, is a bit over our heads so to speak. I personally would rather implement solar in small, incremental steps that eventually deemphasize the grid component and provide a slow, less noticeable transition from total grid reliance to consumer-producer of electrical power.
Take a Step Back Before Launch
As you read from the resources listed in this article, keep in mind that one of the neatest things about creating and implementing solar power is how scalable it is. You can start with a solar attic fan or solar water heater and later ramp up from there with additional solar projects. Some people go all in from the beginning and implement a completely autonomous, off-grid electric production and storage system. Their budget, pain tolerance, energy level, goals etc, may be quite different and thus the all-in approach works for them. That's great, but don't let that affect your decisions about your system.
There is a solar system for home power production that is the right size and complexity for you. You just have to determine what that means to you, and what is your comfort level. Buying based on price alone without careful thought about usability may lead to a system that functions poorly and fails to meet expectations. There are so many choices and products that it becomes tempting to delegate the design of the system to someone with experience and that is fine. However, it really does pay to learn what is out there, because solar is such a rapidly evolving industry.
Take your time to learn about the many options available from our modern solar power industry, and when the time is right to pull the trigger on your system, you will know it. Good luck!