Solar ... In the news

cells

Solar PV can never provide more than a small fraction of a nations electricity (tops out at around 20% MAX for a nation like the uk or Germany) and even lower for total energy use. Overall solar PV would max out around 6-8% of a nations primary energy needs

That might sound good but it isn't becuase to get to those upper bound figures solar would need to write off nuclear and wind. If you have any nukes or wind farms the solar PV max figures are even lower.


Solar thermal can improve on this as it can supply a higjrr fraction of electricity and primary energy needs. Concentrated solar plus fibre optics imo offer the only way to utilise sunshine to surpass 10% of promary enerfy needs with an upper rabge of 30-50% which woild be tremendous.


For the UK and for Germany it would be better to invest in highrr capacity wind farms. The UK could go towards 50% of its electric from wind (solar MAX was 20% ) so wind can do a lot more.


Of course then there is the unpopular option. Nuclear can give 100% of electricity and some 20% of heating. Often its quoted that France gets 75-80% of its electricity from nuclear. Although true it should be noted that the french use a lot of electric for heating and effectively they actually produce 100% of their electric needs from nuclear and also about 15-20% of their heating needs from nuclear. Something wind and solar can not hope to achieve.

cells

For the idea of batteries making households independant from the national grid. Fantasy

To be grid independent you need to be able to store seasonal energy needs or over install PV such that in low producing months it produces enough and in high production months you ground the excess.

Also what ever solution you think will come to existence know that noting lasts for ever. Even a rock degrades. So if your 'cheap' £20k PV and battery system is great and giving you 'free' eletrocity know that in 20 years time you need to pay again for another £20k to install a new 'free' system. Meanwhile the national grid will continue to provide eleteicoty for £500 pa tp everyone else

cells

Martyn1981 wrote: »

PV momentum continues to grow fast in the US.

Now we have a former US Energy Secretary and Nobel prize winning physicist declaring that PV + storage could be:

Former US energy secretary Chu: Utilities need to respond to ‘disruptive’ solar-plus-batteries

PV - the little subsidy that could!

Mart.

Rich nations can afford expensive electricity production methods

The problem isn't from growing to 1% of electricity from 0%
Or from growig to 2% from 1% for PV

At those low levels the inbuilt ability of the hundred year old grid to handle variability makes it possible.

the problem is whwn you hit the wall where the grid can no longer provide the smoothing for a low/free marginal cost

that happens at around 10% solar PV for a nation like Germany or the UK

to go beyond 10% you need to then start investing in storage or start grounding your excess during periods of excess.

Storage is so expensive that you are more likely to start grounding soon after the10-15% max storageless limit. (The exact percentage dependants very much on the nations particular demand profile)

So even if solar pv could be produced at the same price as coal it would cost more as you need PV plus storage.



also the idea that storage will get exponentially cheaper is fundamentally wrong.
comouter chips can get exponentially cheaper becuase the SAME AMOUNT of silicon can be used to sketch on more and more transistors.

Storage is different. To store more you need more. There are only the fundamental forces you can use for storage no maxic exists today nor will it be found tomorrow. Gravity kinetic heat strong weak nuclear chemical electromagnetic ....these are your only options and no matter which one you choose to store more you need more. So storage cannot get exponentially cheaper like comoiter chips because the fundamental difference exists. Chips can be sketched with exponentially more transistors usig the same amount of materials whereas storage needs exponentially more to store exponentially more

ed110220

cells wrote: »

For the idea of batteries making households independant from the national grid. Fantasy

To be grid independent you need to be able to store seasonal energy needs or over install PV such that in low producing months it produces enough and in high production months you ground the excess.

Also what ever solution you think will come to existence know that noting lasts for ever. Even a rock degrades. So if your 'cheap' £20k PV and battery system is great and giving you 'free' eletrocity know that in 20 years time you need to pay again for another £20k to install a new 'free' system. Meanwhile the national grid will continue to provide eleteicoty for £500 pa tp everyone else

Please provide some reliable sources to back up your assertions as an opinion without evidence is worth little. I could assert that people are descended from giraffes, but without some evidence to support it my opinion would of course be worthless.

Shell for example predicts that solar will be the worlds main source of energy by 2070.

You also have constructed a number of straw man arguments and dubious assumptions. For example the main focus of energy storage, especially on the domestic front, is the ability to store energy for use at night or on dull days, not storage from one season to another. Your assertion that PV systems will need replacing after 20 years is highly unlikely given that degradation rates are negligible and panels from the 1970s are still functioning well, and your assumption of what grid prices will be like compared with solar prices is far out of line with most predictions.

Ed

Martyn1981

cells wrote: »

The problem isn't from growing to 1% of electricity from 0%
Or from growig to 2% from 1% for PV

that happens at around 10% solar PV for a nation like Germany or the UK

to go beyond 10% you need to then start investing in storage or start grounding your excess during periods of excess.

and

cells wrote: »

Solar PV can never provide more than a small fraction of a nations electricity (tops out at around 20% MAX for a nation like the uk or Germany) and even lower for total energy use. Overall solar PV would max out around 6-8% of a nations primary energy needs.

Actually, I'd have thought PV in the UK tops out at around 5 to 10% (not 20%) of annual leccy generation, assuming 20 to 30GWp of installs. So you seem to agree that it fits in OK, before storage is needed. In fact, if you look at our current generating mix, you will see that we already have a daily fluctuation of gas generation in the vicinity of 20GW.

Unfortunately you seem to be making the same mistake as many others when they choose to criticise one (or more) sources of renewable energy. That is to place it on its own, then point out that it can't do the whole job.

PV is there as an additional tool in our energy toolbox, call it a gas reducer if you like. It is not a singular solution, so judging it on that basis is worthless. The ability to source 5 to 10% of our electricity from PV in the medium term is actually an impressive figure, especially given the rapidly falling costs, with large scale PV already cheaper than off-shore wind, and due to match on-shore wind and nuclear by the beginning of the next decade.

On a smaller scale, PV is already cheaper, as it doesn't suffer the same large diseconomies of scale as wind, thus allowing demand side generation with its far easier breakeven target (socket parity v's busbar parity). Obviously nuclear doesn't even register on that scale.

cells wrote: »

Rich nations can afford expensive electricity production methods

Yet another advantage of PV, is that often poorer countries are also sun rich (S. America, Africa, Asia etc). Thanks to the work of the richer countries, PV is now on the brink of viability in these countries. In fact a quote from a Ministry in India last year said that PV was cheaper than domestic coal.

Moving on to storage, we already have compressed air and the production of methane and hydrogen. These are not highly efficient, but show other forms of storage.

Regarding domestic storage, I'd hardly call it a fantasy, the PV/energy news (dare I say on a daily basis) is full of articles on such storage, with initial tests/rollouts happening in Japan, Germany and the US already.

In the UK, just chat with some off-gridders, or consider Island type GTI's for on-grid storage. Add in a charge controller and about 5kWh of FLA's and at 40% DoD you have about 3kWh of daily capacity.*

With some generation back-up, electric cars, and localised storage (yes, that's being tested too at around 1MWh), just 2kWh of storage per household, could knock 20GW (or so) off peak demand from 5pm to 7pm. But now I'm waffling into the long-term.

*Yes I know that looks like 2kWh, but consider 1kWh of micro discharges/charges through the day as demand and supply don't match, then perhaps 2kWh of evening and nightime use.

Mart.

digitaltoast

Solar rentaroof schemes have just been discussed on You and Yours on Radio 4- surprise surprise, it's turned out to be a disaster and left people with a paperwork and legal nightmare. Gosh, no-one saw THAT coming(!) Listen again later: http://bbc.co.uk/youandyours

silverwhistle

Martyn1981 wrote: »

Unfortunately you seem to be making the same mistake as many others when they choose to criticise one (or more) sources of renewable energy. That is to place it on its own, then point out that it can't do the whole job.

PV is there as an additional tool in our energy toolbox, call it a gas reducer if you like.

That's exactly what I was thinking, although I still think that 20% of electricity demand (and less for primary energy needs) is pessimistic. We've not long had this as a source of power, and if my microcosm experience of getting PV on my roof is any guide, we're still tweaking usage and learning and investing (I'm looking for some more LED lights..).. I admit I've got the gas CH on tonight, but have hardly used gas for hot water this year, and for the following 7/8 months it would be nice to think the gas companies were storing gas whilst rates were low... Strategically a good thing too?

Martyn1981

silverwhistle wrote: »

That's exactly what I was thinking, although I still think that 20% of electricity demand (and less for primary energy needs) is pessimistic. We've not long had this as a source of power, and if my microcosm experience of getting PV on my roof is any guide, we're still tweaking usage and learning and investing (I'm looking for some more LED lights..).. I admit I've got the gas CH on tonight, but have hardly used gas for hot water this year, and for the following 7/8 months it would be nice to think the gas companies were storing gas whilst rates were low... Strategically a good thing too?

Hiya silverwhistle. It's hard to know where PV will peak at. In the short to medium term it will depend on what the grid can handle.

This briefing note is very interesting, suggesting an upper limit of 22GW (generation) on a sunny summer Sunday. Though the actual GWp may be more. Not sure what 22GW of generation means in GWp terms, but would suspect it's close to 30GWp taking other factors into consideration such as warm weather panel efficiencies, varying pitch and orientation, redirected water heating etc etc. And in the future the possibility of sizeable EV (electric vehicle) charging.:

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/65683/7335-national-grid-solar-pv-briefing-note-for-decc.pdf

To establish how solar PV output would vary, assumptions have had to be made about where the panels are, the angle they are installed at and which way they face. This note has been based on analysis of the effect of the varying angle of the sun’s rays, rather than experimental results.

Also the advice does admit:

It is also assumed that there is no means of controlling output of solar PV

and Germany has already solved this issue by requiring that inverters have a shut down facility (by monitoring grid frequency) so that maximum generation can be controlled (capped) when demand is too low.

This briefing note is a little old but still interesting, and the key factor in the long-term will of course be storage (in its many and varied forms).

Although personally I think there may be another key factor, and that is entrepreneurship, or the 'Field of Dreams' factor (if you build it, they will come).

Oversupply will cause spot prices to plummet, even go negative. I'm pretty sure it won't take 'the clever people' long to spot this opportunity and find ways to capitalise on it, even if it is something relatively inefficient like methane or hydrogen production at perhaps 20% efficiency. Or the use of expensive batteries, to purchase leccy at minimal costs, for re-sale during peak prices later that day/week.

Mart.

Martyn1981

Salmon-scented solar panels set for UK rooftop trial

The fish-flavored modules are designed to attract cats, their saliva helping keep the panels clean and performing at optimum efficiency.

British scientists at the Institute of Scientific Studies have developed a salmon-scented solar module coating that they claim can help improve PV efficiency by as much as 5%.

In laboratory tests, researchers applied their special fishy coating to a small rooftop-size array and observed how their two test cats – Lirpa and Lofo – were inextricably drawn to the module's scent, licking the face of the panels for hours at a time.

Mart.

groovyf

Haha, excellent