FenTiger

Seems more people in our village are switching to solar power. A neighbour just had it installed. Local friends applied via a grant process but I'm still unsure if one does exist. Relatives are going down this path too. I do wonder if they really need to switch to solar power. Not everybody can afford solar power so there's going to be millions of people struggling to pay exorbitant electricity costs on top of gas, wood and other fuels.
Of the three above only one has external insulation (20cm) and triple glazed windows. Mind, they do need to replace their old gas boiler, two immersion heaters and other white goods. It does seem pointless switching if you don't go the whole way to make efficient use of solar power and update other hot water or heating appliances.
Hopefully, governments around the world get a grip on things to stabilise energy costs.

Jack_Russells4ever

I have been thinking about solar recently. I would get a completely off grid solar system because if it is grid tied when the grid goes down you lose your power along with your neighbours. If you do an off gtid solar system get the Lithium batteries if you can afford them because they require less maintenance required with them.

FenTiger

That's an interesting point about losing power when the grid goes down. I'm going to ask this question to friends and family who are having solar power installed. They probably don't realise. They haven't mentioned batteries. I can see our neighbours solar power is tied to the grid! Is there not an option to switch to lithium batteries?

Jack_Russells4ever

It is my understanding that off grid cpable systems are not allowed or at least they were not when I inquired back in 2018. If that has changed I am certain someone will chime in. I do not see the point in installing a solar system if it is not capable to provide power all the time even if the grid goes down. True you may save some money if you install solar that is grid tied but in the event the grid goes off having the power remain on would be nice especially if the power is down for more than a couple hours.

FenTiger

It just crossed my mind if our friends solar power system has lithium batteries where will they be stored? I can't see any safe place for them but family members can be safely stored in garage.

Jack_Russells4ever

Many people with an offgrid solar system make a small shed to house the battery bank, the inverters and other equipment from the solar system. I would not want them in my house or under it in a basement because of offgasing and being a potential fire hazzard.

FenTiger

Good point. I got a feeling there'll be no batteries!

wolfi

I haven't thought too much about solar yet because first we'd need to better insulate our house and think what to do under the roof first - can we use the extra space?
But I know from my sister that in Germany eg if you have solar power and a connection to the grid you can sell the extra power at a good price. Maybe this feature will be available here too, some day?

FenTiger

If we could sell back unused capacity I'd go down this route.
We have space in the roof. I think we could get two large bedrooms up there, probably an ensuite each or both sharing but I honestly wouldn't want to go up the steep stairs every day except when guests are occupying the downstairs WC or bathroom far too long. One side already has a window looking east but it's pretty low so ideally not suited to children. Other side zilch! Still have to insulate that space too if converted to living space. Think we'll leave that for whoever gets our house after we've dropped dead!

Peter_in_Hungary

Going off grid is expensive and when you consider the number of times you get a power outage IMO it is not worth the investment

Off grid systems are allowed, what is not allowed is hybrid systems that go off grid in the event of a power cut. The reason is that if a power cut happens it would be possible for your solar system to still be connected to the grid which would be dangerous to any electrician working on the grid. Yes you can build in an auto disconnect (from the grid) system but these are not fail safe so not allowed. Also this would add complexity (= expense) which also increases maintenance and the likelihood of a fault. And as per my comment above how much do you spend to avoid the occasional outage.

Most off grid systems today use lithium batteries which don't off gas but are expensive (1,000,000 huf or more). The problem is running something like a washing machine or dish washer which has a high current demand in the water heater, this requires a high capacity battery and you also need to have a battery big enough to cover the demand in the winter when you could (will) get several days of cloud cover with minimum charging capability from the solar panels.

If you want to know how much power you can expect from your solar panels in your location and roof orientation look here
https://re.jrc.ec.europa.eu/pvg_tools/en/
It is an EU produced tool. Zoom in on the map to your house, enter the size of system you intend to install and the slope of your roof and 'visualize results'. When you have done that you can adjust the 'azimuth' using the compass rose to see the angle (south is zero) The graph obtained gives expected panel output by month. (winter is typically 1/3 of the summer output)

If you are thinking of getting solar then don't delay because at the moment you can get annual reconciliation which means that summer solar output can balance against lower winter output. The plan is that next year this will change to monthly reconciliation which means that summer over production won't be able to support winter under production and this change will extend the pay-back time of solar and put up your winter electricity bill. Contracts started now will stay on annual reconciliation. (unless you get the current government grant which allows the electricity co. to vary the contract at their discretion)

Oh and you are only allowed 2.5kWp on single phase. To get more than this you will need a 3 phase supply (most houses need 3 -4 kWp to supply the annual power usage or more if the hot water is electric).

FenTiger

Reading all the above I am wondering if all those having it installed or already have are fully aware of the limitations, especially due to cloud cover. October onwards when the sun's gone into hibernation isn't going to produce much solar power. The investment.... is it going to be worth it.
Think I'll hang back until there's something better and more cost effective.

FenTiger

https://re.jrc.ec.europa.eu/pvg_tools/en/ ... posted by Peter_in_Hungary is quite technical. I'll have to look at that another day after I've done some homework.

Peter_in_Hungary

They should have been told what to expect by the company installing the system. One thing that is not often mentioned is that shadowing the panels can have a big effect. E.g. If one panel is shadowed by a tree or chimney pot then the whole set of panels output is reduced by that one panel getting shade so the whole output is reduced to the level of the lowest panel.

The prediction for my house for a 4kWp system gives 4524 kWh per year with expected 556 kWh in July and 153 kWh in December. Which is why it would be important to get annual reconciliation now rather than monthly next year.

My roof faces SW. If my roof faced S then I would get 4786kWh and for a SE facing roof then 4462 kWh. So the difference in roof orientation is about 1 months electricity over the year i.e. more panels would be needed.

It is not really that technical. Once you have zoomed in to your house on the map enter the 'installed peak power (kWp)' then the slope of the roof (typically 45 deg.) (Oh ensure you have selected 'roof added' and not free standing). Then click 'visualize results). Then scroll down to see the results. The important line on the left is 'Yearly PV energy production [kWh]' . The graph to the right shows the monthly amounts.
At this point you can see the compass rose next to the graph and use the cursor to see the azimuth angle number for the direction of your roof, enter this in the azimuth box and 'visualize results' again

kWp is the term use for the power of your panels e,g, 4 kWp system produces a peak power of 4 kW. ( kWp = kiloWatt peak)

FenTiger

The neighbours have a large walnut tree. It's been chopped back. When I read that part I suddenly thought .... oops .... will we be blocking any sun with our new raised terrace .... bottom line the roof is lower than the three trees that were along the boundary but basically can't see how the trees which were there before would have affected their solar power system because their house is some distance from ours. Their roof is higher too.

Jack_Russells4ever

Peter, you make good points but my concern is more about the volatile prices that could visit us here in Hungary in the future.

In my village usually once a year EON schedules (2) days of scheduled power shutdowns to repair and upgrade the power lines which means about 8 hours per day of no power and ocassionally during a bad thunder storm the power has been off a few times for 2 or 3 hours due to a fallen tree branch etc. So, by itself power cuts would not justify the outlay for solar.

I think if prices skyrocket the investment in an offgrid solar system would be worth considering.

I have 3 phase power already and would install a 3 phase offgrid system were I to go down that route.

True the payback time for the equipment and batteries would probably be a long time. But given the state of things in our current world it would be worth it to me if prices for power escalate.

About transfer switches and on/off grid system capability ALL manual and automatic transfer switches break not only the phase conductors but also the neutral leg so there will be no system backfeeding possible if the installer hooks up the transfer switch gear box properly. In every instance I am aware of outside of Hungary the power provider will not re-install the meter until they come and verify the proper wiring inside the meter and transfer switch box. The automated transfer switch boxes have built in failsafe sensors that shutdown all current in the event of any issue with incoming and outgoing power and the neutral leg. IMHO EON does not want to allow them because it cuts into their power sales. Again just my opinion.