School me. I know nothing about them and the more I research the more confused I am (which isn’t hard)!
I am buying a small 2 bed farm house which will be 100m2 (1075 square feet) when renovated. I think I would need a small electric water balon for water (assume instant draw would use too much electric) and will be using a pellet burner cooker/bottled gas hob. The rest is lighting and normal daily life. From what I know the biggest usage would be boiling a kettle? Not having dishwasher but will need a washing machine. I know A++ grade appliances and LED lights are a must.
Got no idea how much power I would need, how many batteries etc. It is €15,000 to connect to grid, which I think makes pursuing solar viable. I would save €1,000 a year in standing charges plus usage. There is +10,000m2 of attached land south facing so not short of space.
Would be good to know experiences from people who have done it. Was it a good decision? The pellet burner would heat the house as well as cooking. Total renovation so modern insulation and double glazing etc is a given.
Well-achievable, especially if you’re looking at $$$ to get a grid connection.
Total non-starter w/o batteries, thankfully don’t need to convince you of that.
Hot water will be your biggest electricity demand by an order of magnitude. Feasible to have a wetback off the pellet stove to help? Or an instant gas water heater if you’re really in a pinch? That’s relatively cheap insurance. Timer for the cylinder will be a godsend, too.
There’s some discipline/planning in making the most of excess PV when you’ve got it: run the washing machine when the sun’s out, or don’t run it in the evening before a forecasted 3-day storm, etc. etc.
Since you’re going to be fully off grid you get to skip all the gamification of min-maxing import and export and all that other baloney.
It may take a year or two to really understand your usage and to discover whether your installed system is throttled by panels, inverter, or battery (or some combination). Ideally you’d be scalable enough to add whatever you may be lacking in without tearing other shit apart.
Kettle might be high draw but it’s short duration, just so long as you are boiling only the water you need My Irish wife has this genetic compulsion to always have 1.5L of freshly-boiled kettle just in case the entire neighborhood pops in, but I have learned to pick my battles.
As an extra for charging at night or in poor weather, a helical vertical wind turbine is a thought. They’re a bit less efficient but don’t need adjustment for wind direction.
It’s not normally something I’d suggest but for off grid - and a farm house with lots of open area, worth a look. This would be in addition to solar, not in place of it.
The first step is to get the best estimate of your daily power needs in winter and summer. For our large house with gas heat and gas water heater but electric A/C and electric dryer we run about 20kWh in the winter and 40 kWh in the summer. Heating and cooling of the house and water are going to be your biggest electric draws with refrigeration, pumps, lighting and other electronics as secondary.
The other big question is the climate the farm house is located at. What latitude? Can you go days without sun? Do you get snow? Big difference between a Scottish farmhouse and one in Greece. In June my panels will max out at 50kWh on a crystal clear day, less than 10 kWh if it is raining. 15 kWh on a sunny December and have put out 0 for a week after a heavy snow.
Then you need to look at the max load for your inverters and batteries. The latter probably isn’t an issue if you have enough batteries to carry you for multiple days without input from your panels.
Also be aware that sometimes the system will just go down. I have gone through multiple inverters. All covered under warranty, but I have had to wait a few weeks for them to get replaced. Also was down for a few weeks after some squirrels got under the panels and chewed through all the cabeling. I could have probably got fixed faster if I was off-grid and it was more critical.
What’s the up front cost for the solar, battery plus the redundancy meeded? Also don’t forget the inconvenience of having to ration your electricity usage in the cost.
Not your question but its likely feasible to do both, connect to the grid and do the solar install.
If you are doing a complete reno anyways, the extra cost of the grid connection will not be significant.
Add in increase in resale value plus the £1000/year in savings.
Plus eliminates the risks already mentioned if solar is down due to weather, failure etc.
Here is a cheap and easy solution for hot water that you often see on the off the grid houses in Dalmatia and on the islands, but also at the everyday houses to save on electric bills. We had this too.
Take a big metal barrel, paint it black and install in at the sunniest place on the roof. For increased capacity, my dad attached to it’s lower end a long black hose, coiled it horizontally on the roof and covered it with transparent plastic sheet. If I remember well, it was about 2” or 3” in diameter, and to this was attached a narrower pipe that led to the shower. During the sunny days, the water was piping hot.
The issue of course is where do you get the water from. We had a well near the house that would collect rain.
You need to estimate how much power you use daily. Heating uses the most power. House heat, hot water, oven, stove, clothes drier. Lights, electronics, fridge, they don’t use very much.
You need that number first.
Then you need to size a battery pack to last a minimum of 24 hours with that load, from one solar peak to the next. It’d be a good idea to bump that up a few hours, let’s say 28 hours to increase the margin and account for batteries degrading over time.
Then you need to size the solar panels to charge those batteries in about 5 hours. That’s the length of a solar maximum at midday. Not only in full sunlight in the summer, but also the dark days in the winter too. That’s the no 1 problem with solar. This would work just fine in tropical regions, and not very well at all in northern Europe. Solar is working for me in Auckland NZ, but it did not very well in Seattle. Was getting just 10-20% of rated power midday because it was so dark.
Where are you?
Edit: the obvious workaround duh just buy 5-10x the solar panels than you need is incredibly expensive and you will probably not have enough space to do it. Then what to do with excess power on a sunny summer day?! This is why grid connected solar is great. The grid is your battery. If its windy there maybe add a wind turbine?
This dude is my favorite version of useful autism on Youtube. He’s awesome. All you’d want to know about solar, batteries, and electric systems delivered with incredible thoroughness and great energy (pun intended).
I could have a hydro pellet burner stove which would heat the whole house but it would be a minimum of 9kw.
No gas for cooking or heating unless it is bottled. I would have a small gas 2 burner hob as back up and use for cooking outside of colder months.
The turbine is a brilliant idea and something I hadn’t even considered. Will do some research.
No getting away from the electric water balon but I have found a new 65l Ariston one that uses a lot less electric.
Kettle - thinking about it I could ditch an electric kettle and use the gas hob. In the colder months the pellet stove would boil the kettle.
Yes one concern is having to watch electric consumption, but I think after a period of adaption that probably wouldn’t be a huge burden.
The quote for connection to water and installation of a fosse have both come in a lot cheaper than anticipated (600%) so I have a bigger budget than anticipated. I have a meeting at the end of the month to see if I qualify for grants for insulation and going green.
Fun note - the electric meter is dated 1933 and the property was last connected 63 years ago. Before I was born!!!
I researched inexpensive residential wind turbines at one point. Basically what you can buy online and setup yourself, then pay an electrician to hook up the HV side to your electrical panel. (Yeah don’t touch that!) Most of the turbines were made in China, and all of those lied on their specs by comical margins. 1000W was a code word for 100W. Divide by at least 5, sometimes 10, to get the real specs.
My Irish wife has this genetic compulsion to always have 1.5L of freshly-boiled kettle just in case the entire neighborhood pops in, but I have learned to pick my battles.