Posted By: Ed DaviesWe need to replace them as quickly and economically as possible.

...the people you mean, I shouldn't worry Ebola will sort things out. My I must be feeling unusually crass tonight.

Posted By: fostertomIt's the places in the world where disease and war are rife, that produce population explosion

Not any more, that is such an old imperial view.
https://en.wikipedia.org/wiki/Total_fertility_rate

What the uk fits does do is create this 4kwp (3.68kwp) restriction on array size. Even with the 3.68 inverter limit.
If there's room on the roof much better design to max out panels to inverter DC input limits

The idea of pointing panels west has only arisen since PV became so cheap. Previously you would never get payback unless you went for maximum kWh regardless of time of day.

I tend to think that economical storage technology will come along before this becomes a serious dilemma.

Meanwhile, in the English climate, I would recommend pointing panels somewhere eastward of south. The typical English summer day starts out cloudless and is overcast by 11 AM.

Nearly all the countries in the African continent have not had a war in the last 20 years.
War, like disease tends to put a 'blip' in the line somewhere.

What causes a higher fertility rate is wealth inequality. Wealth inequality is caused by political policies.
If war caused population growth then the UK and the USA would be expanding rapidly, we seem to have had our fair share in the last 30 years. Though I am not sure if occupation counts as war.

Posted By: SteamyTeaHas anyone got a West facing array and do they have data for it?

Over on Navitron some people post figures every month. The monthly summary doesn't (now) include location, slope or orientation, but if you look at the posts you'll find that some people provide that data (a few years ago there was a sort of "standard format" for data submission but not everyone uses it).

http://www.navitron.org.uk/forum/index.php/board,33.0.html

Agree with 5% for SW but it's probably more like 20% for west.

PVGIS for arbitrary spot east of Birmingham (just east of the M1/M6 junction) with low obstruction to the east and nothing to the west but for a little blip to the NW: Location: 52°24'30" North, 1°7'9" West, Elevation: 107 m a.s.l., with default 35° roof elevation. 1 kW panels with default performance and efficiency. Should be very typical of the middle of the populated areas of the island, I hope.

Orientation, annual production, December production:

S (0°) 957 kWh 31.9 kWh
SW (45°) 900 kWh 26.2 kWh
W (90°) 757 kWh 13.7 kWh

So 5.95% and 20.89% reduction on annual production, more than 50% for mid-winter west.

Definitely shouldn't put people off having panels if they can't get exactly south but given the choice between the same panels facing due south and due west I still think due south wins.

I rather expect that the US will do a lot with storage as well, given how poor their "mains" power is. so as soon as storage becomes practical, but may get used just to ad void "brown outs".

"Our current carbon emissions will very likely result, directly and indirectly, in a lot of deaths in the 3rd world over the next few centuries mostly via climate change. We need to replace them as quickly and economically as possible."

I think the main problems with carbon emissitns will come from China, India and other emerging nations, the UKs emissions will pale into insignificance. Having said that I am doing my bit.

PVGIS is generally pretty good compared with, for example, the Navitron forum figures Skyewright mentioned above. I haven't run the numbers but my impression is that it's slightly conservative; typically actual results beat PVGIS about 3/4 of the time. However, those comparisons are usually for fairly conventional systems so I don't know of validation for more unusual cases like Renewablejohn's. Still it'd be my suggestion for a best guess.

For 12 kW pointing north (-180°) at 15° elevation near Shrewsbury it says a round 8000 kWh/year.

Average is 21.9 kWh/day with the peak in June being 44.70 kWh/day and the lows in December and January of 2.67 and 2.95 kWh/day respectively but note that November is 4.08 and February 7.46 kWh/day; it's a quite sharp dip.

The real problem is knowing what to measure against. Should it be 'per capita' as this does not take into account wealth or income distribution. So if half of China is at subsistence level and use very little fossil fuel based energy, should they be included.
If you measure against land area, how do small countries with high densities, like Monaco, fair. And what if they import all their energy.
Then you get the quirky ones like the Netherlands, where 83% of the population are urbanised.
Or France with a lot of nuclear but it also imports and exports more than most.
Also what happens if a large multinational moves into a country, raising the per capita emissions and then moves out?

It is a really hard thing to sort out. I think people like the per capita measure as they can relate too it easily, but very few people think about all the social benefits they get, they just stick to their own usage, and generally never include transport.
My transport energy usage is horrendous, about 4.5 times my house usage. Good job that diesel costs the same as electricity at the moment (about 13p/kWh).

Right - but I was talking about how well PVGIS can be validated then going on to point out that validation doesn't fully apply in renewablejohn's case, rather than responding to Steamy.