Solar PV advice sought

[Eric The Viking]

.....
Incidentally, does anyone know where the smallest, but arguably most dangerous British reactor was sited? It's not there any more, but I once walked past the window, none the wiser...

Sellafield?

Nope.

Much closer to the seat of gummermint.

 

[Yetty]

Queen Mary College London, Department of Nuclear Engineering ?

 

[Eric The Viking]

It's unlikely that everywhere in Europe will all have a peak demand at exactly the same time so some power trading would sort out any problems.

Peak demand often occurs at exactly the same moment over large parts of the planet, because of the televising of international sporting events. The classic examples are the Superbowl and the World Cup final. The moment the whistle goes for half time, several tens of millions of kettles go on.

The joke in the BBC about Dinorwig was that it was built to counteract the commercial breaks in Corrie. Back in the late 1970s I remember seeing the demand graphs that showed this. This type of synchronised demand is what pumped storage excels at covering. IIRC, Dinorwig can come on stream within seven seconds if the turbines are already spinning, and 16 seconds to full output (1800MW), although I think it's only got less than an hour at full output**.

I would have said probably the most dangerous nuclear plant in the UK is Dounreay as it is getting old and was designed for nuclear experimentation at a time when we didn't fully understand the risks. Decommissioning it is certainly going to be a real challenge. It's a close call between that and Windscale though.

I think it's already in hand. One thing is that the plant's capacity is considerably smaller than later 'production' reactors. As I hinted earlier, we've already decommissioned and fully cleaned-up after what was probably the riskiest one of all. It can be done.

You've got to admit that setting fire to a reactor is the mother and father of all bad days at work

When the CEGB HQ was in Bristol in the 1980s, one of my friends worked as a metallurgist on the 'local' nuclear stations (apparently radioactive particles do funny things to the physical properties of metals over time). He was a great fan of our AGR (Advanced Gas-cooled Reactor) design, on the basis that the half-life of the radioactive products from the CO2 primary coolant is very short (tens of days). Thus, in the event of a catastrophic primary containment leak, one stratagem is simply to leave the secondary containment sealed and come back in a few months. This is in contrast to the US PWR designs, now prevalent, that are not 'inherently safe*' in the same way. Or so I was told...

I was also told that Magnox had similar safety advantages, but I believe both it and AGR development were dropped because of their higher costs compared to PWR and derivatives. There is presently talk of a new class of Thorium fuel-cycle reactor, which might be both cheaper on fuel and safer.

If you're interested, http://www.angelfire.com/extreme4/kiddofspeed/chapter1.html has a lot of pictures of present-day Chernobyl.

Cheers,

E.

*for rather odd values of 'safe', admittedly!

**I checked Wikipedia before writing this. I think it's article is a little disingenuous in that the 6 hours it claims probably isn't at full output. I'm fairly certain I was quoted a 30 mins full load run time and 7sec warm start by an engineer on a visit in the early 1990s, but I may be wrong. My memory plays tricks on me at the moment.

 

[Eric The Viking]

Queen Mary College London, Department of Nuclear Engineering ?

Theirs isn't/wasn't in the capital, IIRC. But I stand to be corrected (often am).

 

[RogerS]

Slight OT. but relevant to green energy.....I have two books for sale as a pair:

Choosing Windpower £7.99

Ground Source Heat Pumps £19.99

Yours for £17 including postage

 

[Eric The Viking]

The reactor I was thinking of was "Jason". It was constructed in one of the original buildings of the Royal Naval College, Greenwich. It was very small, used for training submarine engineering personnel. The spec. listed the output at around 3kW, "about enough to boil a kettle." [edit] Wikipedia gives the output at 10kW, but I've heard 3kW quoted as typical - that may have been generative capacity rather than heat though).

It was decommissioned in 1999: http://en.wikipedia.org/wiki/JASON_reactor

Apparently, it caused us to be sued by the European Union!

 

[miles_hot]

Misterfish

Many thanks for sharing all the data etc - very interesting. One thing that confuses me a little is that you said that it cost 19K to put in and you "made" 220 in the last two months. This suggests a payback period of around 14 - 15 years which whilst better than the 20-25 years it was when we looked at it 5 years ago still isn't a great return on investment.

Have I got something wrong here?

Miles

 

[misterfish]

We're not actually doing it purely for financial reasons - we have a fairly green ethos, though the return on expenditure is still an important factor.

We did a fair bit of investigation before going ahead and found the 'Solar Electricity Handbook' by Michael Boxwell a useful and informative guide. It contains some useful tables of 'insolation' levels on a month by month basis taken from data collated over a 22 year period upto 2005 - data was collected every three hours for 24 hours a day and then 'crunched' to give an average of solar radiation in kWh per square meter for each month of the year.

These are the figures for Portsmouth and Aberdeen so you can see the potential differences between the two locations of me and dickm, bearing in mind that Portsmouth is at latitude 51 north and Aberdeen is 57 north

Although not a definitive amount of 'energy' this does give a (hopefully realistic) comparitive value of what we may expect from month to month allowing for the vagaries of the British weather. I'll have a play with Excel to get some 'what if' type totals based on our experience so far and then add the results.

As one of the early adopters of PV we have to accept that we are guinea pigs and taking a risk. We wouldn't have taken the plunge if we weren't comfortable with the finances. SWMBO and I were brought up to be financially aware/responsible and we both have company pensions as well as AVC pensions we also purchased as well as the State pensions we have both contributed to throughout our working lives (in my case I don't actually get my State Pension until I turn 65 in a few years time.

Misterfish

 

[SEOaaron]

Swindon receives more insolation that Aberdeenshire, as shown in the graph above. Also, 5 years ago, there was no government backing, such as the Feed-In Tariff.

A modest system that might cost in the region of £11,000 (retro fitted) should in theory allow you to gain a ROI of up to 9% depending on your roof tilt and orientation, resulting in a paybakc period of just over 10 years.

The optimum tilt is around the 30 degrees mark, and the orientation is obviously Due South!

 

[misterfish]

Yes, quite true for Swindon which shows a record of

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
0.75 1.37 2.31 3.57 4.59 4.86 4.82 4.2 2.81 1.69 0.92 0.6

Reports from others indicate that there are a number of 'less knowlegeable' installers around who lack either the skill, analytical equipment or experience necessary to accurately analyse any potential PV siting location and who are just interested in a quick buck.

Any installation should be a considered decision and not a spur of the moment whim.

So far, our system is producing a bit more than expected and predicted by the NASA historic records - despite the miserable weather.

Misterfish