Posted: Fri Dec 27, 2024 8:20pm
Solar energy for beginners (this fools guide)
There are 2 types of solar energy 1) Solar Thermal to heat water at 86% efficency
2) Solar Photo-Voltaic at 26% efficiency.
For water heating use No.1 (ABSOLUTLEY THE BEST VALUE)
For energy, this is where it becomes difficult to work out, but here goes.
Panels (465W+) cost only €70 each, an inverter (battery capable) about €1000 and batteries start about €1500 for 5kwh and ancillaries like mounts and cables etc add another €1000.
The biggest cost will be labour and the profit for the installation company.
Where Spain differs from most other EU countries is the dynamic pricing of electricity (price changes every 30min to reflect demand). In Ireland for example, with smart meters being pushed, we only have 3 time tariffs, 11pm to 8am (night) 5pm to 7pm (Peak) and 8am to 5pm And 7pm to 11pm (Day) BUT you can also sign up for a special Electric Vehicle tariff (from 2am for 2/3/4/5 hours, depending on company.
Now comes the simplistic juggling where you try to outwit the electric companies.
Bigger is always better but mind the cost
In Ireland the biggest inverter you can install is 5.5kw (NI is 4kw I think), Spain allows bigger. This means in Ireland the max number of panels is 22-24 (voltage calculations and math) and the max number of batteries is 3 (before you need to add more BMS (control units which cost as much as batteries).
Now the idea is that you fill as many batteries at night (where costs can be as low as 5c per kw) and use this stored energy throughout the day (so you do not pay for any electricity at up to 40c per kw) and use your panels to generate electricity that you sell back to your electric company (in Ireland rate is 20c per kw).
The maths are where you have to concentrate. Work out your initial costs, see where you can save or make a profit and judge if it is for you.
You really need to start with 1 full years readings of your usage to be able to make any headway (if high usage you need more batteries therefore more charging at cheap rate but your batteries can only charge at a set rate (varies by battery) so 2/3/4 hours may not be enough to fill your batteries and you will have to forgo some of your sell-back energy to top them up (rate depends on your number of panels and the size of your inverter)
So how was that for starters?
Welcome to Solar PV for beginners