Wind turbines and solar panels

When you live in a ‘normal’ house with an unlimited supply of electricity, you don’t even stop to think before you plug something in – at least, we never did. I was a great lover of lamps – we had so many around the house, all on timers so they went on and off automatically. Kettles, irons, microwaves, telly, stereo, hairdryer, food mixer, coffee machine, slow cooker, computers, bread machine, toaster … the list of electrical items we use is endless, and nearly all are probably considered necessary for daily life.

So when you live on solar panels you have to totally re-think what you use, and not just what you use, but when you use it.

The biggest enemy of solar power is ‘the heating element’. Heating elements drain power at an unbelievable rate – I was really taken by surprise by the amount of power they use. So that rules out an awful lot of things – the kettle being the big one for me (being a tea lover!). No iron, no microwave, hairdryer, coffee machine, bread machine, heaters or a toaster – they’re all a huge no no! Instead, we have a stove top kettle, and do the toast in a griddle pan (my new cooker has a grill, which I was quite excited about, but was totally underwhelmed the first and only time I used it). As for the other stuff, well we just don’t have them anymore!

When we were learning about solar systems it became obvious very quickly that it was not as easy as it looks. There are different parts to a system, and balancing out the different parts and calculating what power you think you might need had us producing pages and pages of mathematical equations, and we spent several months of planning before we attempted to install anything.

The house had a very simple control panel, one 100 watt panel, a 150 watt inverter and six 2 volt batteries to store the energy. This set up was used by the previous owner to run the tv for an hour once or twice a week. We were clearly going to need more! We found the original paperwork for the installation of this original system and discovered that everything was 15 years old. Only five of the batteries were working, and the rest were bulging, and definitely at the end of their life. So, we were starting from scratch basically.

On the Internet there are lots of methods of calculating how big your system needs to be. We started by listing what electrical equipment we NEEDED (not wanted!). We needed to know the wattage, voltage and amps of each item, and estimate how long we would use each item each day / week / month / year. Once this calculation is done, you then look and see what items might need to be on at the same time, and from that you can calculate what amount of power you need in any given day. Now, as you can’t discharge the batteries by more than 50% you have to build a system that gives double what you actually need.

So step one – we bought a 2000 watt inverter. We have a 12 volt system here and so we need the inverter to change the current from 12 volt to 240 volts. That was around €800 – wow! You can get much bigger ones, but we calculated that we could run what we needed on this. The big problem with most electrical items is, it might say it’s 5 amps, but to get the item going it actually needs triple the amps. So something you think is pretty light on power can still cause a problem.

The inverter converts the power from 12volts to 240 volts.

The power coming into the inverter from the solar panels is controlled by … the control panel. Now there are two main types of control panel – MPPT and PWM. We chose an MPPT controller as it’s more flexible. MPPT stands for maximum power point tracking. This type of controller looks after the life of the batteries better as it gives just a little more power than you need for what’s on, and the rest is used to maintain the batteries. That may be over simplifying it a little, but you get the drift! When you turn something else on in the house, it diverts the extra power you need to the inverter. The control panel wasn’t too expensive – around €140. You can also buy a combined inverter and control panel all in one now.

The control panel tells you at a glance what state the system is in, and what power is coming in and going out.

So then there’s the solar panels. There are two ways to connect the panels to the controller – in series or in parallel. Always so many choices to decide on when installing a solar system! We have three solar panels totaling 745 watts. The maximum we could have for our controller was 760 watts. Solar panels have come down in price massively and so this part cost around €400. Again, there are different types of solar panels – polychristaline or monochrystaline. The big problem with solar panels is how quickly they lose their effectiveness – we’re probably looking at replacing the panels every 6-7 years.

Lastly, you need batteries to store the energy so you can have power when it’s dark. These are expensive, and need changing about every 8-10 years. We bought 6 batteries which cost about €1100, but they are a decent size. Again, there’s a huge amount of choice of type and size of battery. The control panel’s job is to maintain the batteries – when to pull in power, when to stop, when to stir the batteries to refresh them etc etc.

The batteries are stored in our bedroom – it’s sometimes disconcerting when the fizz and bubble!

Now at this point, I will say that Rog did 98% of the research, and all of the installation! I just couldn’t get my head around volts, amps and watts, so was sitting there chipping in ‘can I run a food processor then?’

All was well, and as we’re in Spain we get a decent amount of sun for much of the year. It is harder in the winter – it gets dark at 5 o,clock and so the batteries get drained much more than in the summer. This is where the candles, oil lamp and solar lights come into their own! We have fitted low energy LED lights in the house, but they are still a drain, and so only use them briefly when we need to rather than leaving them on all evening. We can charge up the solar lights in the day and bring them in the evening. We also have a light we can charge up in the day via usb to use in the evening, which has been more successful than the solar lights! We have to plan what needs charging in the winter on cloudy or rainy days as we can’t have everything plugged in together like we can on a summers day!

So last winter we asked ourselves what we could do to boost our power on cloudy days – and of course, the solution was a wind turbine! It was surprisingly cheap at €130 from Germany. Now, this is where it got complicated. Solar panels output DC power which comes into the control panel and is then converted to AC by the inverter. Wind turbines produce AC power! We wired the wind turbine into the solar panels (I can say we here ‘cos I did actually help!) so all the power from both the solar panels and the turbine combine as they come into the house. This meant fitting a small controller between the wind turbine and the solar panels. This changes the current from the wind turbine into DC to join up with the solar panels, and then the controller / inverter changes it all back to AC. It makes your head hurt doesn’t it!!

We stabilised the pole that the wind turbine sits on with metal wire – it wobbled alarmingly without these!

The net result is that we have enough electricity to live a simple life. We can produce about 7 amps. The average house in the UK has a supply of at least 50 amps to put that into perspective! Most of Roger’s power tools need to run on the generator as the solar system simply can’t handle them, but much of what we do is manual so this doesn’t need to happen often. We are fortunate to have satellite WiFi so I can work, and if we do have a bad weather day, there’s always the generator (a back up is a must have in our situation) – it costs about €1 an hour to run so not too bad. There are days when we literally turn everything off during the day so that we have some power after dark, but the benefit of living in a sunny country is that we don’t have too many days like that!

So, that’s all there is to installing an alternative power system!

Living with solar power… a year on

Having completed just over a year of being off grid, I really think we have this licked now! Not really knowing what the climate would be like across a whole year meant we had to try and anticipate what we would need to get through winter.

We have three decent sized solar panels, a 2000 watt inverter, charge controller and six big batteries to store the energy in here.   We replaced the ancient system that was here when we moved in as it was just 1 x 100 watt panel, very old batteries and a 150 watt inverter!  What we have now gives us enough electricity to run the compost loo fan 24 hours a day, for charging phones, the toothbrush, battery packs, running the WiFi and the radio / speaker. We can also run the computer when I work in the day as long as it’s not really cloudy. We have to be careful how many things we have going at once, so try to stagger the usage.  On bad winter days we turn the wifi off for most of the day so we can have it on in the evening for a few hours – running the compost loo fan is way more important than having wifi!!  We added a wind turbine last autumn to try and boost the power on cloudy days and overnight – I wouldn’t say it’s been a roaring success, but it helps to maintain the batteries rather than add to the stored power.

We can have lights on, but they’re quite a drain on the power even though they’re LED, so we have a couple of solar lights that we charge up outside during the day, and another we can charge on the usb in the day, which is a great light in the evening.  Worse case scenario, we always have a stock of candles. It all comes down to finding other ways of achieving your goals, and prioritising what’s most important.  We can use the light in the bathroom in the evening as it’s not on constantly, but we do find these days that our eyes don’t like bright artificial lights!

On cloudy days we really limit our usage. We both have battery packs that we can charge up on sunny days to use on cloudy days so we don’t need to draw on the power, and we have the all important back up petrol generator so I can work in bad weather.

But it’s funny how quickly we’ve got used to living like this! It just takes a little juggling and organisation, but we do it now without really having to think about it!

In the kitchen though, I didn’t want to be beholden to having sunshine to be able to cook, wash etc, so opted for as few electrical items as possible. I did bring my food processor, but this has been resigned to the back of the cupboard as it will only work on the generator – it’s too powerful for the solar on start up.  I can use it if I really need to, but its a bit of a pain to turn on the generator, run a lead into the house just to blitz something for 30 seconds!  I have a spiralizer and have just treated myself to a pull cord mini chopper / processor, and I have to say it’s brilliant!  But other than those, everything is just done the old fashioned way by hand with a wooden spoon or knife – it actually feels like real cooking again!

We have a fridge with a small freezer, which runs on butane gas – we go through a gas bottle every 3-4 weeks, which costs about 13 euros, so an effective way to run a fridge.  We have a small camping oven with two gas rings, which is ok for cooking on – this also runs on gas, and a gas bottle lasts 6 weeks, so pretty efficient.  I simply avoid cooking things that take hours – lots of dishes that take 20-30 minutes works well on so many fronts!  For most of the summer it’s too hot to eat anything other than salads anyway! Our hot water is on gas too – in the summer a gas bottle lasts nearly 3 months – all you want are cold showers when the temperature doesn’t drop under 26 degrees at night and averages 36 in the day!  In the winter we get 6-8 weeks on a gas bottle.  So we average 2 gas bottles a month – about 26 euros – I wish my gas bill in the UK had been that low!

I’ve got the clothes washing down to a fine art now.  I have a small hand crank washing machine in the house for clothes and a larger one outside that Rog built for duvets, towels etc.  When we got here there was an old fashioned sink outside with a washboard (you can actually still buy these new here!). Rog has done it up, added a pipe to drain away the water etc and this is brilliant for getting really dirty work clothes clean.  Now that the weather has gone back to normal at last, the washing dries in no time outside, and with the afternoon breeze it doesn’t need ironing – in fact, I haven’t ironed a single thing since we moved to Spain! It’s been a revelation!

We weighed up putting in a bigger solar system so we could run things like a fridge, but the cost was pretty steep – it would only break even after ten years compared to what we spend on gas, and at that point, parts of the solar system would need replacing, so not a cost effective option.

We bought a decent generator when we moved here – being able to work to earn a few bob is essential, but we also use this for some of Rogers’ power tools for doing jobs outside – there are times when you just need to use beefy tools for some jobs!  We bought a rechargeable drill with a spare battery pack, so one on and the spare charged up as a back up, and this does for most jobs.

Our only source of heating for the winter is the wood burning stove, but as our house is tiny this pretty much heats the whole house.  We have a fan that sits on top of the stove to maximise output, and this is powered solely by the heat from the fire – an excellent purchase! We tend to only use this in the evening – if it’s cold in the day it’s warm clothes and move around (difficult when I’m teaching, so out of view I have a hot water bottle and a blanket!).

We don’t have air conditioning here – some people think we’re crazy to live in Spain without it, but the house stays pretty cool in the summer, and we do have a tiny fan just to keep the air moving in the day. We found last year that we opened all the windows in May and they stayed open until September! We have mosquito nets up at all the windows to stop the critters otherwise leaving them open just wouldn’t be an option!

We use strimmers outside for weed control, a rotavator and of course the wood chipper, and these all run on petrol. As they aren’t in constant daily use they don’t cost us much at all – we rotavate a couple of times a year, strim every couple of months in autumn and winter but more often in the summer (almost a constant job like the forth bridge!) and wood chip maybe 6 – 8 times a year.

Back in the UK we never gave a second thought to using gas and electric – just turn it on, and the direct debit goes out each month.  Now we have to be more careful, and prioritise what jobs to do and what to use, but it’s really no problem at all.  I would imagine that living off solar in colder or cloudier climates would be harder and more of a challenge.

I can honestly say that with the set up we have, living off the grid is pretty easy and less of a compromise than I ever thought it would be.