A new City Council car park in Nottingham is claiming the solar panels installed on the roof are enough to power 50 homes all year round. In a sister article in their magazine claims enough to power the building all year around (not it also states the building has 81 vehicle charging points).
The output is expected to be 190,000 kW/h over a year.
Not too far out.
720 panels at say 250W each at average 10% output over year = 18kW18kW * 24 hours * 365 days = 158 MWh per year.
In the realms of possibility.
720 panels 330-350Wp per panel, let's say 350 720*350 = 252kWp
Capacity factor 10%
-> Average output 25.2kW
8760 hours per year-> Total 220752 kWh per year
Average home electricity consumption (according to Ofgem): 3100 kWh pa
-> Enough to power 71 homes
Sounds about right. I didn't correct for orientation or location, just took a ballpark 10% figure (as previously discussed here).
Of course it won't provide energy 24/7/365. But the car charging should help here - when it's sunny, energy goes into the cars. Which means they don't need to charge from grid power in the evening, when it isn't sunny. Not much help in the winter, though.
Theo
3,800 kWhr/year. Seems perhaps a little low, unless there's other energy in the mix...
190,000 kWh in a year is equivalent to a power of 190,000/(365x24)kW = 21.7kW, or 21700 watts. There are 720 panels, so each one is producing 21700/720 = 30.1 watts on average, over the year. If that takes into account a 10% capacity factor, then each panel is capable of producing 301 watts maximum. Most conventional solar panels have an output of between 225 and 350 watts, it says here
So unless one of my assumptions isn't justified, I'd say their claim was realistic. Amazing! An honest claim about renewable energy. Maybe I've made a mistake somewhere in my calculation!
pessimistic?
panels could be 330-400W, lets say the lower
the article claims optimum slope (which would be 40°) but they look shallower than that, lets say half that.
Canal street runs pretty much E-W, so lets say they're facing due south.
plug in the numbers
and it says 215,000 kWh/year, that calculator agreed pretty well with the logged output of jharrison's system.
Thw rating (in Wp) is for when the solar irradiance is 1kW per m2. That's approximately the peak sunlight cast per m2 on the Earth's surface at the equator. Obviously at other latitudes and seasons the sun is at an oblique angle, so you get a fraction of that 1kW per m2. In theory if you were to concentrate the sun with a mirror you could get more, but there would probably be other limits to how high you could go with a particular panel.
you can average 100W/sq m annually... So 21kw average = 210 square meters.
that looks realistic for the panel size.
Very few hones run at less than 1kW so I'd say 21 homes on average, in winter about 2 homes and then only during the day.
So the claims are misleading and ought to be reported
The linkg says: "? enough to supply energy to over 50 domestic homes all year round. "
Where are these homes that don't use electricity in the dark and only use energy that can come from solar panels, rather than gas coal or oil etc?
What happens at night in the winter on cloudy days? Do they have some huge batteries somewhere? Brian
Before the pigeons shit all over them. Brian
That's the problem with expressing the outputs of renewable electricity generators such as solar panels and wind turbines as averages. I see that the average yearly domestic electricity consumption in the Nottingham area is 3,326 kWh (lost the link, sorry), meaning that those panels could actually provide enough electricity for 56 homes, _on_average_. But try cooking your evening meal by solar power at 6pm in February! It's the same with global temperatures. Averaging cleverly hides important detail, and is never to be trusted.
Isn't it the case, though, that electricity from all sources just goes into the grid? It's only when electricty generated is wasted (that is, not stored or used) that a problem arises - and AFAIK that doesn't happen.
So that solar array does, overall, meet needs at times it doesn't actually contribute directly?
exactly ! While welcoming the solar panel installation, enough generation or storage capacity is still needed to provide power when the sun doesnt shine and the wind isnt blowing especially for the peak evening demand.
I think expressing the output in terms of daytime EV car chargers would be far more relevant.
At the end of the day the wind and solar generates what it can, and then gas/coal/nuclear/hydro/etc covers the rest. By putting N kWh into the grid you displace N kWh of (probably) gas. You can burn that later when the solar isn't generating. It's only in rare circumstances that there's too much wind and solar that are we burning zero fossil and the solar is 'wasted' (or the local grid connection is overwhelmed)
Also here it's powering car chargers, which are inherently an energy storage system. If you charge the car now, you don't need to charge it later. So it's not fair to say it doesn't contribute when the sun isn't shining - it does by time-shifting the load.
Of course it's much reduced in the depths of midwinter. But, if it displaces gas in summer, we can keep the gas in the well and burn it in winter. So it does help that way as well.
Theo
often wind turbines are paid not to generate
until you try and run a grid with *all* renewables and realise just how many windmills you need to cover a cold windless sunless sub zero winter evening...and how much it costs.
In terms of carbon emissions to manufacture, and service and install them.
The short answer is that in the UK grid, renewables save little or no emissions overall. And an all renewable grid is actually *impossible* without bankrupting the nation.
Well, yes of course, at the moment. But there is a sub-text there: it tries to give the impression to the uninformed of powering the houses all the time, as do all claims of that general nature, whether solar, wind or tidal generators ('enough electricity to power N homes'), trying to boost the credibility of renewable energy in general to replace fossil fuels.
Yes, I get that, and I would add the wider environmental impact of renewables and other sources such as biodiversity. But it wasn't my question.
Short answer to your question. We are were we are, and I was asking about a scheme in use.
In fact you don't.
In particular that massive fall off of solar in late afternoons leads to massive amounts of fuel bing uses to get gas powerstations up to temperature, all of which is lost when they shut down again.
And also, the temptation to build gas guzzling OCGT stains which are cheap just to cover peak demand, means you are back to where you started in terms of gas - renewable energy barely displaces *any* .
Add in the amount of diesel burn to service windmills out at sea, and the amount needed to install them for a service live of only around 12 years, and the whole issue turns out to be a f****ng expensive waste of time, that does almost nothing for global emissions.
You can burn that later when the
On tey other hand, if its night time, and you need the car tomorrow, and the battery is flat you have no option but to charge it
No it f****ng doesn't.
You have to think of the system as a basket of generation methods - not just solar and gas. They're probably not perfectly complementary but that shouldn't stop anyone trying.
No. I doubt you'll bother but take a look at:
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