Re: integration of renewables (mostly wind), and the network effects this can have

[dave andrews]

Can anyone help this contact from Cornell?  His list of papers may be useful to you? 

 

Alberto, good to hear from you.  Don’t forget that for example Alstom are producing new CCGTs specifically designed for cycling without  loss of efficiency / start up penalties and presumably this will be installed over the time period in which new wind is installed, so any figures of contemporary balancing costs are likely to be pessimistic.

 

Kind regards

 

David Andrews

---

From: Alberto Lamadrid [mailto:ajl...@cornell.edu]
Subject: Re: Hi

 

Hi Herbert and David,

 

Glad to hear from you. This is very timely, as there is a question making rounds in my head. 

 

I am working in integration of renewables (mostly wind), and the network effects this can have, specially due to the intermittency of such resources.

 

Now I'm looking at the issue of ramping costs and the conventional generation capacity needed to counteract whenever the wind stops. From the formulation standpoint, I'm including the differences in dispatches from generators in two consecutive periods as an additional cost in the objective function to be minimized.

 

However, to calibrate this model I do not have any strong numbers, but some private studies with large ranges:

 

[1] Hamal, C. W., & Sharma, A. (2011). Adopting a ramp charge to improve performance of the ontario market. LECG, 1–53. Retrieved from
http://www.ieso.ca/imoweb/pubs/consult/mep/MP_WG-20060707-ramp-cost.pdf

 

[2] Agan, D., Besuner, P., Grimsrud, P., Lefton, S., 2008. Cost of cycling analysis for pawnee station. Tech. rep., Aptech.

 

[3] Condren, J., Gedra, T., Damrongkulka- mjorn, P., May 2006. Optimal power flow with expected security costs. Power Systems, IEEE Transac- tions on 21 (2), 541–547.

 

[4] Wang, C., Shahidehpour, S., Feb. 1995. Optimal generation scheduling with ramping costs. Power Systems, IEEE Transactions on 10 (1), 60 –67.

[5] XcelEnergy, 2008. 2008 wind integration report. Tech. rep., Xcel Energy.

 

My question is:

 

Do you know of a source with specific information on the cost of ramping for conventional generation to counteract such uncertainty?

 

Thanks for the lists, I went online and look at it, and saw some interesting conversations regarding the depression of energy prices - here they call this problem missing money, mostly an issue for conventional generation again.

 

Thanks for your help.

 

cordial saludo

 

Alberto

 

 

Alberto J. Lamadrid

PhD Candidate

Applied Economics & Management

Engineering and Economics of Electricity Research Group (E3RG)

250 Warren Hall

Cornell University

Ithaca, NY 14853, U.S.A.

+1 212.496.2492

http://www.pserc.cornell.edu/ajlamadrid/

 

On Nov 4, 2011, at 12:18 PM, Herbert Eppel wrote:

 

 

--

Dave Andrews

K.E.N.T.
+ 44 (0)  755 265 9166

+ 31 (0)  631 926 885
+ 44 (0) 1225 837978

 

 

[Chris Hodrien]

I’m very glad to see that Alberto J. Lamadrid is doing a PhD in this important area, and will open a direct correspondence with him. Could anyone providing him with info’/ref’s direct in this please copy me +Fred Starr in as well.

Alstom are not alone in supplying these ‘flexi’ CCGT designs (or necessarily the ‘leader’), GE and Siemens have them too, as per my detailed briefing notes on this very topic earlier this year.

Dave, for the record, there is (and probably never WILL be) no such thing as ‘a CCGT (or OCGT, or other fossil plant)  without  loss of efficiency / start up penalties for cycling’, all the new ‘flexi’ designs do is reduce (maybe halve at best) the penalties. They are no ‘silver bullet’.  The penalties are not just for start/stop and ramping, they are also for part-load operation most of the time.  There are also significant economic as well as technical penalties. And in any case, for many years yet ,the bulk of the combined fleet will consist of older CCGT units that were designed with no such features.  The Poyry Intermittency study makes clear that the impact of intermittent wind (the 30GW [rated] fleet) by 2030 is so severe that all fossil plant will have to be doing this all the time , inc’ the surviving older unabated  coal plants. They are completely different ‘kettle of fish’ in terms of losses and pollution, not to mention extra ‘wear-and-tear’ servicing costs for the entire fossil fleet, all of which will have to be paid for somehow.  Even the nukes will have to be backed-off on a few occasions annually – just look at the Poyry charts.  This is a very severe potential grid system operating and stability problem (witness the Danish 2005 national-level ‘near-miss’), and I wish that you and the entire ‘pro-wind crowd’ would cease trying to ‘wish it away’, ‘own’ it  and start ‘engaging’ with it.  If I had my way, all the renewables operators would be directly charged on a per-kWh’ formula for these additional costs (net of normal system-wide daily balancing costs), and made to formally ‘account for’ (as a debit to their claimed savings)  the extra CO2 (+NOx,SO2 etc) emitted, because it is inequitable, especially windfarm owners then ‘moaning’ to DECC and OFGEM about ‘how much extra pollution’ is going to come out of these inefficient fossil ‘balancing’ operations for their benefit.

Just in case you are wondering, the UK Nat’ Grid  ‘Grid Codes’ re. flexibility are  no help in this :

1)     They do not retrospectively apply to older plant,

2)     All they require is that new plant can meet the technical (power output ramp-rate) flexibility standard, irrespective of how inefficient and polluting it is doing it!

I really do wish (given your considerable influence) you’d stop spreading ‘mis-information’ by naive over-simplification of your ‘magisterial’ statements – I am fed up of having to correct them, and so I imagine is Fred.

Regards,

Chris Hodrien

Principal Technical Consultant,

Expansion Energy Ltd

[star...@yahoo.com]

Dear Chris

 

The costs of having to use CCGTs in an intermittent fashion to supply back up for wind are not too difficult to to estimate. They break down into five main groups.

 

1. Extra fuel in starting up plant from zero output......since CCGTs can be brought up to 100%  load in just over an hour, we can estimate an efficiency loss by assuming that no power is used in that hour. Hence over a 12 hour cycle, this equates to about a 10% increase increase in fuel use.

 

2. Extra fuel used in load following.......CCGTs are getting better at this. Older sets are okay down to 85% of load. I would guess that at 60%, the efficiency is still around 45%.  The reheat sets from  Alstom  and new gas turbines using four stages of variable incidence guide vanes will be keeping plus 50% efficiency down to 50% of load

 

3. Maintenance costs.......A full start up is about equa; to 20 hours of normal running

 

4. Amortisation and interest charges.......As plant is used less the capital costs etc have to be spread over less output ......The implications of running the plant for 80, 70, 60% of the time can be readily explored

 

5. Manpower costs........For a typical CCGT manpower levels are very low.....3 to 4 men per shift. 

 

By the time we have 33GW of wind I would guess that average CCGT fuel efficiency would be 45%, rather than 60%  which would be the nominal fleet efficiency.

 

33 GW of wind would supply on average 10 GW of power or 10GW of CCGTs . If the 10 GW of CCGTs was running at 60% the fuel use would be 10 GW./0.60  = 16.7 GW of gas. However since the CCGTs are running at 45% efficiency the fuel use is 22.2 GW. So the presence of wind energy costs 5.5 GW in extra fuel.

 

But 10 GW of CCGT running at 60% would have used 16.7 GW of gas. However after substract the intermittency losses of 5.5 GW, the actual fuel savings of  33GW of wind capacity are 11.2 GW of gas.

 

Fred     

 

 

 

From: Chris Hodrien <chod...@blueyonder.co.uk>
To: large-power-conventional-power-...@googlegroups.com; ajl...@cornell.edu; 'Claverton AB MAIN GROUP' <energy-disc...@googlegroups.com>; 'Claverton Supergrid group' <grid-supergrid-in...@googlegroups.com>
Cc: ajl...@cornell.edu
Sent: Tuesday, 8 November 2011, 19:46
Subject: RE: integration of renewables (mostly wind), and the network effects this can have

I’m very glad to see that Alberto J. Lamadrid is doing a PhD in this important area, and will open a direct correspondence with him. Could anyone providing him with info’/ref’s direct in this please copy me +Fred Starr in as well.

Alstom are not alone in supplying these ‘flexi’ CCGT designs (or necessarily the ‘leader’), GE and Siemens have them too, as per my detailed briefing notes on this very topic earlier this year.

Dave, for the record, there is (and probably never WILL be) no such thing as ‘a CCGT (or OCGT, or other fossil plant)  without  loss of efficiency / start up penalties for cycling’, all the new ‘flexi’ designs do is reduce (maybe halve at best) the penalties. They are no ‘silver bullet’.  The penalties are not just for start/stop and ramping, they are also for part-load operation most of the time.  There are also significant economic as well as technical penalties. And in any case, for many years yet ,the bulk of the combined fleet will consist of older CCGT units that were designed with no such features.  The Poyry Intermittency study makes clear that the impact of intermittent wind (the 30GW [rated] fleet) by 2030 is so severe that all fossil plant will have to be doing this all the time , inc’ the surviving older unabated  coal plants. They are completely different ‘kettle of fish’ in terms of losses and pollution, not to mention extra ‘wear-and-tear’ servicing costs for the entire fossil fleet, all of which will have to be paid for somehow.  Even the nukes will have to be backed-off on a few occasions annually – just look at the Poyry charts.  This is a very severe potential grid system operating and stability problem (witness the Danish 2005 national-level ‘near-miss’), and I wish that you and the entire ‘pro-wind crowd’ would cease trying to ‘wish it away’, ‘own’ it  and start ‘engaging’ with it.  If I had my way, all the renewables operators would be directly charged on a per-kWh’ formula for these additional costs (net of normal system-wide daily balancing costs), and made to formally ‘account for’ (as a debit to their claimed savings)  the extra CO2 (+NOx,SO2 etc) emitted, because it is inequitable, especially windfarm owners then ‘moaning’ to DECC and OFGEM about ‘how much extra pollution’ is going to come out of these inefficient fossil ‘balancing’ operations for their benefit.

Just in case you are wondering, the UK Nat’ Grid  ‘Grid Codes’ re. flexibility are  no help in this :

1)     They do not retrospectively apply to older plant,

2)     All they require is that new plant can meet the technical (power output ramp-rate) flexibility standard, irrespective of how inefficient and polluting it is doing it!

I really do wish (given your considerable influence) you’d stop spreading ‘mis-information’ by naive over-simplification of your ‘magisterial’ statements – I am fed up of having to correct them, and so I imagine is Fred.

Regards,

Chris Hodrien

Principal Technical Consultant,

Expansion Energy Ltd

 

 

From: large-power-conventional-power-...@googlegroups.com [mailto:large-power-conventional-power-...@googlegroups.com] On Behalf Of dave andrews
Sent: 08 November 2011 09:17
To: ajl...@cornell.edu; Claverton AB MAIN GROUP; Claverton- Large Powerplant Web-Group; Claverton Supergrid group
Subject: Re: integration of renewables (mostly wind), and the network effects this can have

 

 

Can anyone help this contact from Cornell?  His list of papers may be useful to you? 

 

Alberto, good to hear from you.  Don’t forget that for example Alstom are producing new CCGTs specifically designed for cycling without  loss of efficiency / start up penalties and presumably this will be installed over the time period in which new wind is installed, so any figures of contemporary balancing costs are likely to be pessimistic.

 

Kind regards

 

David Andrews

[David Milborrow]

As far as I can see the analyses discussed so far do not take into account the "sum of squares" formula for determining the total uncertainty in an electricity network with wind:

 

(total uncertainty) squared = (generation/demand uncertainty) squared + (wind uncertainty) squared.

 

That enables the extra reserve needs to be derived; then, knowing their costs (which allow for reduced efficincies), the extra costs associated with wind can be calculated

 

The formula was first quoted by Farmer at Al – "Economic and operational implications of a complex of wind-driven generators on a power system" – IEE proceedings, A, volume 127 number 5 (June 1980).

 

It is also quoted by Hudson, Kirby and Wan – "The impact of wind generation on system regulation requirements", Oak Ridge National laboratory report 110830, 2001.

 

It also appears in a report by the Enernex Corporation for Xcel Energy and the Minnesota Department of commerce – "Wind integration study – final report". September 2004.

 

These and other studies mostly conclude that the extra balancing costs do not add more than about 10% to the generation cost of wind energy. The abatement of emission savings is also small.

 

David Milborrow