March 7, 2012

Energy Self-Sufficiency? Still Just A Dream

One of our goals is to someday get off-grid by becoming energy self-sufficient. Of course, the term off grid typically implies electricity, so I suppose it would be possible to be off grid but not entirely energy self-sufficient. I could make my own electricity but still purchase kerosene, propane, natural gas, home heating oil, even candles. Our home is all electric however, so for us, making our own would make us basically energy self-sufficient as well.

About the only things we've done toward this goal (in all our spare time ;), has to been to observe sun and wind patterns throughout the year, and keep track of our electric usage. We've observed enough to know that there would be some limitations with either of these systems. We've kept track of our electrical usage long enough to know that even though we consider ourselves frugal in that area, we still have a long way to go.

One thing that's puzzled me, is how to figure out what size alternative energy system would meet our needs. Most things are rated in watts. For things like solar panels or wind turbines, this tells me how much electricity they can generate. But how do I know how much I'll need? When I look at my electric bill, it tells me how much I've used in terms of kilowatt hours. Things like appliances and light bulbs are also rated in watts. In this case, the wattage tells me tells me how much electricity is needed for the device to operate. However, I can run a 60 watt light bulb for 3 minutes, or for 3 hours. Obviously the amount of electricity I use won't be the same. Kilowatt hours are the actual amount of electricity I use to run that light bulb. I pay for what I use, so my electric bill specifies charges for kilowatt hours.

So how do I get to there from here? After a little research, here's what I've learned about using my electric bill to determine the size solar system I would need.

First I need to know how many kilowatt hours I use on a daily average. Last year we used a total of 10,751 kilowatt hours.

10,751 kWh / 12 months = 896 average kilowatt hours per month

896 kWh / 30 days in a month = 30 kilowatt hours per day

As an aside, I have to say that averages do have their limitations. The actual range for daily use was from 16 to 54 kWh in a given month, depending on the time of year (remember, we have an all electric home. The worst culprit are the auxiliary electric heat strips in our air source heat pump, which come on when the outside temperature it too low. Now that we have the wood cookstove to heat the back of the house, we can further decrease our electric during winter months. )

By looking at a solar insolation chart like this one, I know my area is rated at 4.5 solar hours per day. I divide that into my average daily kWh consumption

30 kWh / 4.5 solar hours = 6.67 kilowatts

Because solar panels are only about 20% efficient, that must be factored in as well. Actually, its the inefficiency that's factored in, so for this example, 80% or 0.8. This could be more accurately calculated from the information provided with a specific brand and model of solar panel.

6.67 / 0.8 = 8.3 kW

That gives me an idea of the size solar system I would actually need, assuming we made no other changes to our lifestyle.

There are numerous online calculators to determine the cost of installing solar systems. I used this one. It estimated my cost would be $71,040 for a system to cover 100% of our electric usage. The good news was that because of the government solar energy rebate, I'd be reimbursed $21,312, so that the system would actually only cost me $49,728. The problem with rebates of course, is that one must pay the entire cost upfront and then wait until tax time to get the rebate. That's great if one can afford it in the first place, but for those of us who can't, it would be more helpful to receive a grant to cover the $21K. Of course that's assuming I'd have the remaining $50K. Even at that, I figured it would take 42 years for the thing to pay for itself, assuming my electric bill remained the same. We don't do loans, but hypothetically, if I took one out to purchase the system, the additional interest would mean my energy self-sufficiency would cost me more than simply buying electricity from the power company. That of course was just one estimate, and if one can DIY, especially with used parts, the cost would be far more manageable.

Wind energy for us is even less feasible. According to the US Wind Resource Map, we live in a virtually zero wind resource area. From my observations I know that this is not specifically true, but I do know that the only time it gets truly windy here, is this time of year, in spring, or late summer, when we get hit with the remnants of a hurricane. In fact it's been so windy the past few days, that the chickens won't even go out. They all stay huddled on the lee side of the goat shed. Even so, this is not enough to justify spending tens of thousands of dollars on a wind turbine that would only be productive   a few weeks out of the year. (Unless of course I used my solar tax rebate ;)

So how close are we to actualizing energy independence? About as close as the man in the moon.


Ngo Family Farm said...

Oh, sometimes the truth (especially in dollar amounts!) hurts. We're thinking of a solar hot water heater somewhere down the line, but would certainly need to do more research and crunch the numbers like you have :)

Prairie Cat said...

Thanks for this post, I had been wondering about the kwh and watts conundrum, too.

That is a ton of money, though. Also taking into account the lifespan of a solar panel makes it even more costly in the long run. I am hoping that by the time we attempt to start going off-grid that it will be a little more popular and hopefully bring the cost down some!

Sunnybrook Farm said...

I have been looking at the possibility of a wood pellet mill and using the pellets in a wood gasification reactor which generates a gas with 1/7 the energy of natural gas and can run a generator or any motor including the one that makes the pellets. So far we have heated our house completely with wood since 2008 and use propane as a backup. It is probably not worth the trouble to go completely off the grid at this time but it needs to be thought about.

Florida Farm Girl said...

There are so many ways to reduce the amount of electricity used. Extra insulation in the house is a bargain. Good windows and weather stripping on doors. Don't use the electric heat unless absolutely necessary. Now that you have the wood stove, that should drop your heating costs significantly. As for summer, open windows and ceiling fans. Adjust your waking hours to closer resemble the natural light hours. Early to bed, early to rise.

Our local power company will come out and do an assessment of our house and give us recommendations for how to make it more efficient. I bet your's will too.

Good luck. I might be able to survive off the grid (so long as I can use a computer), but I don't think DH could handle it.

Renee Nefe said...

I recently read an article on zero energy homes. I couldn't find that article, but I googled it and found others...even a website. But that's to build a new home. However, I think that you could incorporate some of the ideas they use into your home. I've always wanted to get that spray foam insulation and that article showed how they had used it in the attic along the floor AND for the "ceiling" (inside of the roof).
Here we aren't allowed to have solar panels due to our HOA but I wonder with all the hail we get how long they would last anyway. We do get enough sun here to actually be able to sell back our extra electricity to our power company. The AF Base is trying out different energy sources including geo-thermal, but hubby doesn't feel as if that will ever pay for itself (he is working on that project.)

Sue said...

It can be depressing when monetary realities slap our dreams about the head and shoulders. It would be nice if we could all afford to be totally self sufficient, but even baby steps in the right direction are helpful.

I definitely get enough wind to go that route, but the cost of the equipment is prohibitive, and there are zoning issues with a nearby airport.

Nina said...

We've lots of solar installations around here, due to the gov't mandated high prices paid to alternate energy producers. Windfarms are going in as well, although they are quite controversial. As much as I'd love to pop solar panels on our south facing roof, it's still too pricey an investment for us as well!

Funny about the differences in chooks. My chooks go out in the wind. They go out in most weather, staying inside only when there is heavy snow falling, heavy rains or it's bitterly cold combined with snow too deep for little chook legs. The rest of the time, they'd rather be outside.

Susan said...

It's nice to dream, but the reality usually costs a great deal more than most of us can afford. It helps if you can find used equipment (in good working order, of course) and you have the ability to hook it up and get it running yourself. I agree with the rest of the comments, that a step in the right direction is to cut electrical use as much as possible in your existing systems. Having the wood stove will be a big help.

Leigh said...

Jaime, there are actually plenty of DIY plans for solar water heaters. Just google it. Many of them are with parts you can find easily. That will be one of the things we will do too down the road. It's a passive system and no need for batteries!

Prairie Cat, that was a puzzler for me too. Good point about the life of solar panels. Batteries too, have a limited lifespan. All things to think about.

Sunnybrook, my DH is actually very interested in wood gasification. We have ton of pines here, which aren't good for the wood heat stoves, but we could use the way you're talking about. I looked into wood pellet mills once and wow are they expensive. I think they are very energy inefficient to make commercially, but if one had a resource to make them, might be a good way to go.

FFG, good suggestions all. Our first winter here we froze with just the one wood heater. I refused to use the old oil furnace but this old house was terribly inefficient. When we bought our heat pump, we debated on whether to get that or put the money into insulation. In the end we reasoned that we could do the insulating a little at a time (as we could afford) so we got the heat pump, mostly for the AC. It's a lousy heat source, but now with the wood cookstove in the back of the house, plus the insulating we have done, I'm expecting much lower electric usage over the next year.

Renee, I heard about those too, but also discovered they were talking about new builds. We've used the spray foam in a number of places (around windows and doors and in other cracks) and find it works very well. I'd highly recommend it. Another good point about the solar panels and hail. We looked into geo-thermal too, but it was outrageously expensive, plus the units still required auxiliary heat sources for really cold weather. After I learned that, I couldn't figure out the point of getting one.

Sue, so true! I doubt though, the government or big corporations would like us all to become individually self-sufficient. No profit in that LOL. If I could get a wind turbine for free or cheap, I'd put it up! The zoning issues are another matter though.

Nina, I think you all have better government support for solar. Wish we had that. I have to admit nothing usually deters my Buff Orpingtons, but I reckon they don't like being blown across the lawn. :)

Susan, Jane at Hardwork Homestead and her husband got used equipment and are making a go of being off grid. She is so interesting to read! And it's true that it is so much about lifestyle. We are a flick-of-the-switch society and I doubt most folks actually realize how much electricity they use.

Jane @ Hard Work Homestead said...

A few suggestions. First get a killawatt meter that you can hook to individual appliances or your electric meter and it will tell you your per minute, day, month, or yearly usage. That will help in your figures. And a killowatt is 1000 watts.

Now are you talking a grid tied system or off grid? A grid tied system is not considered off grid. I think from your quotes and the fact you say there is a rebate, is you priced a grid tied system. Off grid is a battery system with no hookup to utility lines at all, so if you are off grid, you really are energy independent. Now we are talking apples and oranges in considering the size of your system. Also remember that some of these figures you are reading are abstract approximations and not in application. For example solar is considered 95-98% efficient today. And under the right conditions a panel can be 110% efficient and produce over the amount of watts it is rated. Where you lose efficiency is what size wire you use from panel to inverter, the distance the panels are to your inverter. The type of inverter, the temperature-cooler is better for electrical transfer, If you tie your system in 12, 24, or 48 volt (this can be a biggie). How many strings you have in your battery bank. If you wire your panels in sequence too. Etc. So your installation will also determine how efficient your system is. I have no idea where the figure 20% efficient came from, but I can tell you that is not true. And remember you lose power to convert D/C power (what is coming from the batteries) to A/C so if you keep your home A/C wiring, you will have a small loss of power there too. Also you make power with a solar system from sun up to sun down. Those figures you have are for daily maximum solar exposure, but you will make power other times of the day, so that is not an accurate way to figure in real life application. A sun tracking system will increase your maximum exposure also, but they are costly.

If you truly are off grid, you do not need as large of a panel system as you do with a grid tied. You only need enough panels to keep the charge in your batteries. In that case, to figure the size of your system you need to take your daily KW and convert to amps. Then you will know how many amp hours you will need to have in your battery bank and plan the panels accordingly. You really want a battery bank large enough to hold 3 days worth of power.

If you do want to be off grid and on a battery system you are going to need to cut down on your KW per day substantially. 30 KW per day is considered high when considering going off grid. Electric heat, electric hot water, air conditioning are no-no's if off grid. If you want to keep those appliances you will need a grid tied system. You would drain your batteries so quick running an all electric house I dont think it would be possible. A grid tied system will allow you to draw grid power to run all those appliances after the sun has gone down. So also consider that if you purchase a grid tied system you will possibly be paying an electric bill monthly too. If you have a grid tied system and the grid power goes down, you also will have no power. Even during the daylight hours since your grid tied inverter goes through the utility meter. All things to consider.

I can tell you when considering any alternative energy system, unless you are independently wealthy, you need to reduce, reduce, reduce. Once you find the absolute minimum you can live with, you can then size a system. I hope this helps a little.

The Stay @ Home-Gardener said...

Thank you Jane. :)

Poppy said...


You've written yet another incredibly information article! It is unfortunate that the system that we would need to be completely self sufficient is way out of our price range as well.

It would make so much sense to me if the government were to award grants as you propose. Unfortunately, the powers that be likely have vested interested in our society remaining dependent on energy other than solar or wind powered.

Thanks again for such a great piece!

Have a great day!

Woolly Bits said...

wow, that's a lot! we only use 3.700 kwh a year, but we could probably lower it down to 3000 a year. we've changed our fridge and freezer to very energy efficient ones. we changed all the light bulbs bit by bit, took out the electric water heater (which of course means that we only have hot water when one of the ovens is on.) I don't have many e-gadgets anyway, but of course in our climate we don't need AC anyway, which probably uses a lot. cooking is with gas (bottled, not piped) and so on. I don't think we could ever be totally self-sufficient, but we'd have better chances with a small turbine than solar panels anyway! not sure that it makes sense to install solar panels for that price - I doubt they'll last for over 40 years without replacement! it's one of those things that are very difficult to do on a small scale - and unfortunately you come to a point, where trying to save more is pretty much impossible, if you want to keep fridge, computer etc.

Leigh said...

Jane, everything you write on this subject is always a tremendous help because you do so from the user's perspective, not from having something to sell. I wasn't sure about the pricing calculator, but assumed it must be grid tied because it asked what percentage of our bill we wanted to cover. I gather that tax rebates are only for grid tied systems(?) Why am I surprised. :o It made an interesting exercise but of course we would never go that route. In fact Dan is actually skeptical that solar would be the best way for us to go. Our first winter here we had no sun for three months. We know the panels can still make electricity, but we realized there would be limitations. He's interested in researching other systems, but in the scheme of things, it's still a ways down the road.

Poppy, that's true. Our culture is not set up for anyone to become independent of it, and is in fact against it. That's one of the reasons everything is so expensive, I think.

Bettina, having an all electric house is definitely a disadvantaged place to start from. I'm not sure there even a way to compare total energy usage with a home that is able to utilize other fuels for cooking and heating. And it's true that in the end it's not about saving money after all. Like you, we're working on it a little at a time. It will be interesting to see how far we actually get!

Freedom Acres Farm said...

Everything Jane said - I am in perfect agreement with. Her experiences are SO similar to ours. It can be done. Her family and ours proves that. However, lifestyle is a deciding factor. If a 21st century home wants all the switches, automatics, and such... then it probably isn't a good choice. I just worry about the time when the grid is not trustworthy. I'm guessing we all will be wishing we had changed and adjusted our lifestyles before that happens. Kinda scary. Keep doing your research, you've learned a lot already. If it's something that your family really wants and it's a priority then you'll be willing to change your lifestyle and adjust. I know for us we LOVE it!!!

Laura said...

This is one thing I've always wanted too. We live in a very warm climate and our house faces semi the right direction so I think we could do it if we made some changes to our life style and changed out a few appliances. My husband has become sudddenly against it though :(

Leigh said...

Freedom Acres, that's a fact. One thing I lament about getting such a late start in life, is wondering whether or not we'll accomplish everything we'd like. So far our priority has been 1)repairs and upgrades to the house, which include much needed insulation as well as things like the wood heater and wood cookstove. 2) Food and food self-sufficiency. We've lived without electricity before so we know we can do that. We also know we can't live without food. :) I only hope we live long enough to accomplish it all.

Laura, well, I'm sure he has his reasons, have you talked to him about them? We struggle sometimes with the decisions we have to make in doing repairs and upgrades. Some of them seem silly if our goal is to ultimately get off grid. I wonder too, if it would be better to try to do that or try to pay off our mortgage. Either one would take awhile considering our financial circumstances.

Clint Baker said...

Great post, I know one day you will be off the grid. I believe that we are starting to see the importance of it as well. Thank you all for such wonderful topics of discussion.

Anonymous said...

That is the problem with alternative energy....we all want it, the experts all tout it, yet the people who really need/want it cannot afford it. Sad state of affairs. Great post on how you came to the actual cost breakdown, thanks for sharing.

Theresa said...

And that;s all the pity, until good cheap,efficient and affordable alternative energy choices are available few will be able to cut their usage. It's a chicken or the egg thing. For a time, it will cost more than traditional sources until the tipping point when it becomes desired enough that it's profitable on a mass produced scale.Oh woe that in the gas embargo of the 70's we didn't use that to our advantage as a country, but kept on the same course of energy usage.

Unknown said...

Oh, good luck to you figuring it all out. Hopefully, you will reach your dream! I'm finding a lot of great advice in the comment area, hopefully you have too. :)

Beth of the Rocks said...


I just read your post. I really have to sit down when I'm looking at the numbers, write it down and figure it out. I am not mechanically blessed, and electrical systems fall under that. (GREAT spatial reasoning, though, so it's really good for building a house.) :))

Maybe instead of focusing on the fact that your house is all electric, figure out what you actually need to live. For example - can you make do with 2-3 low-wattage bulbs in high-traffic areas of your house, such as living room, kitchen and possibly bathroom, and try to use natural light or lanterns during the winter months for the others? Try unscrewing the light bulbs and see if you can do it. Can you go with a propane refrigerator and a gas stove? No microwave? No coffeepot? (I'm sorry I don't remember if you use a coffeepot or not...) How about those energy sucking appliances - e.g. my flat screen 20" TV only uses 50W/hr. If you can really cut out electricity use then your system might only cost you a couple of thousand. (Although propane refrigerators are expensive, it may be far better to put $$ into one of those instead of paying for the electricity you would need to make to keep one running 24/7.)

Now I don't even have a couple of thousand, so I won't be able to set up a complete system right away when I build. But I can probably handle 3 lights, tv, computer, and charging up the phones etc on a couple hours a day of generator power. (In fact I know I can, my parents did it and I lived with them for a while when they were doing it.)

On the plus side, if you're not grid-tied you will have electricity when everyone else's power goes out! Bad side? You also have to repair everything yourself.

I really hope you get to do this. Good luck!


Beth of the Rocks said...

P.S. Can you put in a big south facing window to harness natural warmth during the winter?

OK bye. :)

Leigh said...

Clint, thanks. It's a goal, though we realize that every step helps along the way.

Theresa, so true, so true. I actually doubt though, that alternatives will ever be affordable for us commoners. Even when the power companies use them, the savings seems to be passed on as profits to stock holders rather than customers.

Rugratmommy, that's the beauty of blogging, isn't it. :)

Beth, that's actually what we've been doing for a number of years. I should probably do a blog post on that sometime. Actually we've never been big on appliances, time savers and gadgets, and have always done a lot by hand. Of course, to go into all that here, would make this post longer than anyone would care to read. ;)

I made a specific point about our house being all electric, because another figure I find misleading, is "average" national usages. Many, many folks have lower electric consumption, but on the other hand, use fossil fuels for cooking, furnace, and hot water heater. Or course, all electric homes are practically unheard of in the north, but common in the south. If I could subtract our electric stove, water heater, and heat pump from our total usage, our figures would be much lower too. On the other hand, purchasing propane or natural gas would still not be energy self-sufficient. It would just be substituting one commercial source for another. Does that make sense?

Megan said...

WOW! That's a lot of money! I hope you find something worthwhile in all of that research.

Leigh said...

Megan, definitely. It confirmed that this isn't the route to go, LOL

Andrew said...

Yes, I keep coming out with 25 years + on the most optimistic guesses about when the solar power will have paid for itself. Like shingles, I have a gut feeling the resin that the photovoltaic crystals are made out of will break down from regular exposure to sunlight well before you break even. Much sooner if you account for wind, snow, unidentified flying objects and the like. Simply, solar needs to be profitable within about 10 years to be useful. So, based on your estimate, it is about 7x too expensive for what you get. I agree.

Leigh said...

Andrew, I suspect you are absolutely correct. Of course the businessman needs to sell in order to make a profit. If we're self-sufficient, we aren't buying and they make zip. It's in their best interests to keep it expensive and imperfect. Dan has pretty much abandoned the idea of solar. It's not time in the scheme of things for us to seriously pursue energy independence but still, it's something to continue to research.

Kaat said...

As a happy owner of a solar array that provides all our electricity needs (and then some) while being more North than you are those numbers seem excessive. I'll try to get back to you on this soon!

Leigh said...

Kaat, I would appreciate that. It seems that a lot of what I'm seeing advertised on the internet is awfully expensive and I can't help but think way overpriced. It makes DH say, "forget it."