Solar ... In the news

Cardew

The electricity grid in Minnesota presumably shuts down when the sun sets! - or it gets cloudy!

spgsc531

https://www.gov.uk/government/publications/uk-solar-pv-strategy-part-1-roadmap-to-a-brighter-future

Strategy to be published Spring 2014

silverwhistle

Cardew wrote: »

The electricity grid in Minnesota presumably shuts down when the sun sets! - or it gets cloudy!

I suspect you'll find that peak demand is during the day, when factories, shops and offices are all in use. Plus the demand for air-conditioniong in the US in a continental climate will also be majorly during the day.

Seems a good solution not to meet peak demand by burning a finite fuel when cost-effective and environmentally better alternatives exist.

ed110220

silverwhistle wrote: »

I suspect you'll find that peak demand is during the day, when factories, shops and offices are all in use. Plus the demand for air-conditioniong in the US in a continental climate will also be majorly during the day.

Seems a good solution not to meet peak demand by burning a finite fuel when cost-effective and environmentally better alternatives exist.

It always amuses me when a non-expert imagines he has spotted a flaw that the experts have missed, when in reality they couldn't possibly have failed to account for it.

It's a bit like telling an aircraft engineer his plane won't fly because it's heavier than air or telling an evolutionary biologist that evolution couldn't possibly have happened as no-one has observed a monkey turning into a person at a zoo. :rotfl:

spgsc531

ed110220 wrote: »

It always amuses me when a non-expert imagines he has spotted a flaw that the experts have missed, when in reality they couldn't possibly have failed to account for it.

It's a bit like telling an aircraft engineer his plane won't fly because it's heavier than air or telling an evolutionary biologist that evolution couldn't possibly have happened as no-one has observed a monkey turning into a person at a zoo. :rotfl:

Gotta love cardew continually making a fool of himself

3+ years and running....

zeupater

ed110220 wrote: »

It always amuses me when a non-expert imagines he has spotted a flaw that the experts have missed, when in reality they couldn't possibly have failed to account for it.

It's a bit like telling an aircraft engineer his plane won't fly because it's heavier than air or telling an evolutionary biologist that evolution couldn't possibly have happened as no-one has observed a monkey turning into a person at a zoo. :rotfl:

Hi

You'll probably find that most 'experts' are self proclaimed anyway. Most climatologists and environmentalists have no engineering, or more importantly 'practical engineering', background and are far too focussed on their own fields and careers to take a step back and look at an integrated solution ... as such most just see energy out 'for free' from sources such as pv and wind turbines as being the ultimate panacea and jump on the 'expert' bandwagon, completely missing the need for associated mass energy storage schemes in order to allow anything near a significant level of renewables technology contribution to the energy mix.

I agree with silverwhistle's view about Minnesota's continental climate being suited to pv. It might be a state bordering Canada, but what most people don't realise is that it would be an a similar latitude to central France. I spent quite some time in the area (Iowa, Michigan, Illinois & Indiana) a few years back and it really does tend to get a little warm and humid during the summer, just when aircon becomes a necessity for those of us from parts of the globe with far less extreme temperatures. However, pv being suited to the peak demand usage profile within a central USA Minnesota summer does not necessarily mirror that of a central England Birmingham winter, which is usually Cardew's point of debate regarding efficiencies & contribution .... three years or not, when a point is valid, it's valid - just consider how many posts on this forum are related to efficient use & storage of 'own generation' via automated diversion to domestic hot-water etc ... without storage it's simply a case of 'use it or lose it' which applies in a similar way whether on a domestic, national or global scale ....

HTH
Z

silverwhistle

Indeed! I've laundered the bedding today which I've been putting off for various (mainly obvious) reasons, done some baking, and have topped up the hot water tank. Haven't used much gas for hot water even in these winter months, and the heating isn't on. As I'm sat at a desk doing job application related work I've put on an extra fleece.

So the power that is produced in Hampshire (or Birmingham) is used efficiently and also reduces peak loads at other times, so has a more beneficial effect on the network and its efficienceies than the raw figures may suggest.

Martyn1981

Sorry Zeup, but I just can't agree with that defence of Cardew's post.

To suggest the Minnesota grid wouldn't be able to cope with 'dark' if they install PV, is laughable.

As you'll be aware, intermittent generation contributes to demand, and needs balancing, be it by flexible generation like gas, or storage. But all generation needs to viewed as a package, rather than the somewhat cowardly approach of divide and conquer taken by the anti-renewables crowd of singling out each technology to point out it's weakness (wind turbines - no wind, PV - no sun, etc).

That's an easy (but pointless game) eg coal is extremely harmful plus CO2, gas is expensive plus CO2, nuclear goes bang ..... and so on.

Of course PV generation is greater in the summer, but wind generation is greater in the winter. Looking at Gridwatch you can see how gas in particular is used to meet varying demand and varying generation. It varies by 15GW or so most days. Coal also varies somewhat, but as it's cheap, tends to be used more as baseload. These variations existed before wind generation, and at present, wind generation is still relatively small (varying typically between 1GW to 9GW).

Also, your points about UK demand (ok, you were addressing Cardew's tired old point) and PV are not that valid. Electricity demand in the UK is high during the daytime (daylight) (summer and winter), even if peak demand is during the winter around 5pm to 7pm. So PV generation always matches higher demand, even if higher demand doesn't always match PV generation. So the 'PV and winter peak' argument is just a red herring. Taking that argument to its extreme would mean that a generation source that worked 22hrs per day 7pm to 5pm would be dismissed on similar grounds.

To be clear, I'm not belittling the UK's winter peak, but just pointing out, that since PV didn't cause it, nor makes it worse, it should not be judged on this irrelevant point. However, previous articles I've posted suggest that PV can displace some demand from the peak, though I suspect many of the actions, such as running large white goods during the day, could be done regardless of PV, it's just that PV incentivises such actions.

At the end of the day, we need to change the way we generate electricity, but we also need to change the way we store it, transport it and use it too. PV is part of the solution, but wrongly gets labelled by some 'spin doctors' as part of the problem.

Mart.

Cardew

Martyn1981 wrote: »

The decision marks the first time that unsubsidized solar energy has gone head-to-head with natural gas and come out on top as the best option, both economically and environmentally.

A judge in the U.S. state of Minnesota ruled last week that solar energy was a more economical and better environmental investment for the state than gas producers.

The PV magazine quoted, not unexpectedly, puts a slant on the judge's ruling.


'the best option, both economically'? Well it may be for the State of Minnesota as they(the State) pay no subsidy.


However the solar firm(Geronimo Energy) will get a Federal subsidy.

That could help Xcel toward its requirement to get 1.5 percent of its power from the sun by 2020 under a new state energy law. Xcel also is counting on rooftop solar systems, community-owned arrays and its own large projects to meet that goal

.

Obviously to meet that target they have to use solar when possible. However until solar finds a way to generate at night it simply ain't going to replace 'conventional' generating capacity.

So not exactly the simple picture that the PV magazine published.

On the subject of Minnesota's climate; I also know that area quite well. It is one of the coldest States in the USA(obviously leaving out Alaska). Like all the mid-West States it can get stinking hot in summer - particularly the South of the State. However I doubt if air-conditioning is used more than 2 or 3 months in the year. My brother lived in NW Wisconsin(on the border) and his up-market house didn't even have A/C.


In any case latitude is not the main determinant of a location's climate - isn't Moscow south of Glasgow?

P.S. Nice to see Martyn bit again.

zeupater

Martyn1981 wrote: »

Sorry Zeup, but I just can't agree with that defence of Cardew's post.

To suggest the Minnesota grid wouldn't be able to cope with 'dark' if they install PV, is laughable.

As you'll be aware, intermittent generation contributes to demand, and needs balancing, be it by flexible generation like gas, or storage. But all generation needs to viewed as a package, rather than the somewhat cowardly approach of divide and conquer taken by the anti-renewables crowd of singling out each technology to point out it's weakness (wind turbines - no wind, PV - no sun, etc).

That's an easy (but pointless game) eg coal is extremely harmful plus CO2, gas is expensive plus CO2, nuclear goes bang ..... and so on.

Of course PV generation is greater in the summer, but wind generation is greater in the winter. Looking at Gridwatch you can see how gas in particular is used to meet varying demand and varying generation. It varies by 15GW or so most days. Coal also varies somewhat, but as it's cheap, tends to be used more as baseload. These variations existed before wind generation, and at present, wind generation is still relatively small (varying typically between 1GW to 9GW).

Also, your points about UK demand (ok, you were addressing Cardew's tired old point) and PV are not that valid. Electricity demand in the UK is high during the daytime (daylight) (summer and winter), even if peak demand is during the winter around 5pm to 7pm. So PV generation always matches higher demand, even if higher demand doesn't always match PV generation. So the 'PV and winter peak' argument is just a red herring. Taking that argument to its extreme would mean that a generation source that worked 22hrs per day 7pm to 5pm would be dismissed on similar grounds.

To be clear, I'm not belittling the UK's winter peak, but just pointing out, that since PV didn't cause it, nor makes it worse, it should not be judged on this irrelevant point. However, previous articles I've posted suggest that PV can displace some demand from the peak, though I suspect many of the actions, such as running large white goods during the day, could be done regardless of PV, it's just that PV incentivises such actions.

At the end of the day, we need to change the way we generate electricity, but we also need to change the way we store it, transport it and use it too. PV is part of the solution, but wrongly gets labelled by some 'spin doctors' as part of the problem.

Mart.

Hi Mart

I don't know why everyone needs to consider things in such a B&W way. The point at hand was a Minnesota judicial ruling in that "The decision marks the first time that unsubsidized solar energy has gone head-to-head with natural gas and come out on top as the best option", which seems to suggest that Cardew's point was correct.

Without a significant energy storage medium the questions posed in the article should have been "invest in gas" -or- "invest in gas+solar" -or- "invest in solar+storage". The 'best' option would be to ensure that the energy supply is maintained 24x7 and that includes nighttime and when the 'wind don't blow', therefore the 'strategic' cost comparison is flawed as there's no cost comparison allowance for either backup generation or storage .... all this suggests to me is that judges are also prone to be "far too focussed on their own fields and careers to take a step back and look at an integrated solution ". If the state has decided that it needs additional generating capacity and "seeks the most cost-effective projects to deliver an extra 150 MW of new capacity by 2017", I would have thought that they would be estimating 150MW as being the increase in gross demand, something which couldn't possibly be satisfied by a "100 MW project consisting of 20 arrays in 17 counties in the state budgeted at a total of $250 million." .... what they will do is spend the $250million then have to spend just as much on gas plant as they would have done without the pv arrays and that's the case whether peak demand occurs during night-time, summer or winter if the weather's bad on a particular day ..... as such, from a strategic viewpoint (investment based), the entire Minnesota article, as written, makes absolutely no sense at all ...

HTH
Z