Forum newbie & home worker needs advice re solar panels

Martyn1981

marchesini46 wrote: »

No shading until well after 4pm. In the absence of being able to show a picture or post a aerial image of the house location, I would estimate that the roof faces approx 10 degrees off due south (towards the east) - if that makes sense??

Popping -10 in the azimuth box, changed generation from 4,120 down to a miserable ....... 4,110kWh pa. Hardly worth bothering now!

Not that I'm jealous with an annual target of 4,200 from 5.58kWp of panels in sunny Cardiff.

Mart.

marchesini46

Martyn1981 wrote: »

Not that I'm jealous with an annual target of 4,200 from 5.58kWp of panels in sunny Cardiff.

Mart.

Again from my limited knowledge on the subject, a 4kW system is the norm. Would my good fortune on my location make sense for me to go for a larger system or are the incremental costs not worth the extra expense?

Martyn1981

marchesini46 wrote: »

Again from my limited knowledge on the subject, a 4kW system is the norm. Would my good fortune on my location make sense for me to go for a larger system or are the incremental costs not worth the extra expense?

Good point. Normally myself or tunnel try to sneak in a mention of going 'large' as we are fans (see our auto-sigs).

Have a read of the FAQs section 10, about the various issues of going bigger. It actually gets cheaper as you go bigger. Some of the costs are fixed, or will only increase a little bit, such as internal wiring, scaffolding, inverter etc. So if you went to 5kWp, it wouldn't add 25% onto the 4kWp price.

However, the FiT bands are upto 4kWp and 4-10kWp, so you'd get the lower FiT. It's only 10% less, but applies to the whole install, so it would be daft to install 4,001Wp.

Also, if you want to generate more than 3.68kW then you need permission from the DNO for an inverter that can output more than 3.68kW. However, even 5kWp wouldn't lose too much to capping in the UK, as panels rarely generate more than 90% of their rating once warm. And spend a lot of time in less than ideal weather.

Given your very high leccy consumption, it might be worth you trying to go bigger. Using multiple rooves that have differing orientations also works well, as they won't all be peaking at the same time, so a lower max cap doesn't matter as much.

Have a read of section 10, and a good thunk about your options, as in your circumstances it would at the very least be worth considering before ruling it out.

Mart.