Comment

Comment by Willem Post on February 15, 2021 at 9:59am

ECONOMICS OF UTILITY-SCALE BATTERY SYSTEMS FOR DUCK-CURVES

https://www.windtaskforce.org/profiles/blogs/economics-of-utility-s...

 

Solar systems have their highest electricity production at midday.

The surge of production from near-zero to maximum causes disturbances on the grid, aka DUCK-curves.

Southern California and Southern Germany, with high MW of installed solar, have major DUCK-curves on sunny days.

At present, mostly gas-fired, combined-cycle gas-turbine (CCGT) power plants are used to counteract the DUCK-curve surges.

 

In California, the shutdowns of 15 of 19 coastal, CCGT plants led to rolling blackouts during a multi-day heat wave covering a large area of the US southwest, followed by forest fires.

 

Climate fighters want to shut down the CCGT plants and replace them with utility-scale battery systems.

Climate fighters accused the plants of heating the Pacific Ocean!

https://www.windtaskforce.org/profiles/blogs/the-vagaries-of-solar-...

 

NOTE: In case of Germany:

 

- Whenever it has excess wind and solar electricity (which has high, subsidized costs/kWh), it usually spreads the excess into grids of nearby countries at very low, even negative, wholesale prices (excess supply lowers the price).

 

- Whenever Germany has very little wind and solar electricity, these countries sell to Germany at higher wholesale prices (shortages increase prices). That procedure avoids having utility-scale battery systems, which would be off-the-charts more expensive, as shown in this article.

 

Solar Electricity Production and Midday Duck Curves

 

The image is of electricity demand, MW, versus time of day, due to various levels of installed MW DC of solar systems producing electricity, mostly at midday. Solar dozes off in late-afternoon/early-evening, when peak electricity demands occur, and does not reappear until about mid-morning the next day.

 

 

The image is of solar electricity production, during variable cloudiness, at various US Postal System area codes in California. Southern California has much greater DUCK-curves than northern California.

 

 

Wind Electricity Production

 

The image is of the calculated wind electricity production, during very windy conditions, of future, 1600 MW-offshore wind turbine systems, located south of Martha’s Vineyard Island in Massachusetts, New England.

 

- The top flat areas indicate production curtailments during strong winds to avoid damaging the wind turbines. Curtailment payments would be made to Owners.

 

- The huge up/down, weather/season-dependent, output variations would need to be counteracted by up to 3200 MW of CCGT plants varying their outputs, 24/7/365.

 

- Typically, CCGT plants operate near rated capacity to maximize production and revenues. However, with higher levels of wind electricity on the grid, they would have to vary their outputs from about 50% to 100% of rated capacity to counteract the variations of wind; operating below 50% needs to be avoided, because CCGT plants tend to become unstable.

 

- Payments would need to be made to CCGT plant owners for forcing them to: 1) Generate less electricity, than without wind, i.e., operate uneconomically, and 2) Provide counteracting services, 24/7/365.

 

 

NE Grid Conditions at End 2019

 

The energy sources of electricity in New England were 40% from gas, 25% from nuclear, 19% from net imports, 9% from renewables, 7% from hydro, 0.4% from coal and 0.1% from oil.

 

Generators fed about 125.5 TWh into the NE grid, customers (mostly utilities) drew 119 TWh from the NE grid, i.e., losses due to transmission from generators to utilities was 6.5 TWh, or 5.2%. This excludes distribution losses within the service areas of NE utilities.

 

Wholesale electricity prices have remained consistently low, due to low-cost gas and low-cost nuclear. The average annual price to utilities was $42.02/MWh in 2009 and $30.67/MWh in 2019.

https://www.iso-ne.com/static-assets/documents/2020/02/2020_reo.pdf

 

Proposed New Generating Capacity to be Connected to NE Grid

 

Proposed NE generating capacity is 20,927 MW, of which wind is 14,256 MW. The annual production is shown in table 1.

 

The production of all generators fed to the NE grid, aka grid load, would be much greater in 2035 than in 2019, because the increase in heat pumps and electric vehicles.

 

Because wind speeds continuously vary in a random manner, the production would vary as well; if wind speeds increase 2 times, say from 10 mph to 20 mph, the production would increase 8 times.

 

The production likely would be about 15% of the average of that time of year, during a multi-day wind lull

The production likely would be about 80% of nameplate rating, during very windy weather; some areas with wind turbines likely would have output curtailments.

 

The production could not be fed into any grid, without the existing generators counteracting the wind output variations, 24/7/365, i.e., wind could not exist/would be totally dependent on the other generators.

 

The alternative would be to have sufficient battery storage capacity (MW/MWh, delivered as AC) to provide electricity when winds are low and to absorb electricity when winds are high.

 

However, the turnkey capital cost, CAPEX, of custom-designed, site-specific, grid-scale battery systems would be exorbitantly high, even if prices /kWh, delivered as AC, would decrease. See URL.

https://www.windtaskforce.org/profiles/blogs/reality-check-regardin...

 

Table 1A/State	Type	MW	CF	Production	NE grid load	NE grid load
					2019, act.	2035, est.
			%	MWh/y	MWh/y	MWh/y
MA	offshore	8460	40	29664144
RI	offshore	880	40	3085632
CT	offshore	4160	40	14586624
ME	onshore	751	28	1843314
MA	onshore	5	28	12272
Total		14256		49,191,987	125,500,000	140,000,000

 

Comment by Art Brigades on February 13, 2021 at 10:53pm

CMP is an easy scapegoat, especially these days. But CMP (and others) warned legislators about the very real downsides in a willy-nilly infusion of solar power. Seth Berry and the other ideologues in the legislature, buoyed by NRCM, Sierra, Maine Conservation Voters, Acadia Center, et al didn't want to hear about facts, math or science -- and didn't care.  "It's about sending the message that we are doing the right thing" they said over and over. 

The difference between the wind weasels and the solar swindlers is smarts.  The wind weasels infiltrated the Baldacci administration with well placed operatives like Kurt Adams, David Littell and others. They secured the getaway car (MPRP) and put it in place long before the heist (The Wind Act). The solar dopes jumped without a chute.  Now the chute is hitting the fan.  Boo hoo.

Comment by Penny Gray on February 13, 2021 at 1:31pm

They need to put all these solar panels and wind turbines at the fast charging stations being built all along the I95 corridor.  That way there won't be any need to connect anything to the grid, all they'll be doing is charging EV's when the sun is shining and the wind is blowing.

Comment by Willem Post on February 13, 2021 at 11:47am

THE VAGARIES OF SOLAR IN NEW ENGLAND

https://www.windtaskforce.org/profiles/blogs/the-vagaries-of-solar-...

 

VAGARIES OF SOLAR  

 

In summer, expensive, weather and season-dependent, highly subsidized, variable, intermittent solar dozes off in late afternoon/early evening, during peak electricity demands, sleeps all night, and does not wake up until about mid-morning the next day, becomes very active around midday creating DUCK curves, especially on sunny days, then dozes off again in late afternoon/early evening, during peak electricity demands.

 

In winter, solar dozes off in late afternoon, sleeps all night, and does not wake up until about mid-morning the next day, becomes very active around midday creating DUCK curves, especially on sunny days, then dozes off again in late afternoon.

 

Variable Cloudiness: In New England, the output of solar systems varies up and down with variable cloudiness, throughout the year. That creates disturbances on distribution grids, which become more severe with increased deployment of solar systems.

 

Those disturbances can be mitigated/attenuated, if owners of larger solar systems (the major disturbers) would be required to install battery systems. Politically, this may not be feasible, because it would increase the already-high price of solar electricity. See image.

http://www.windtaskforce.org/profiles/blogs/cost-shifting-is-the-na...

 

 

VAGARIES OF WIND 

 

In New England, throughout the year, wind is very often near zero from late afternoon to the middle of the next morning. That includes peak demand hours.

 

Combined Wind/Solar Lulls: In New England, combined wind/solar lulls occur throughout the year, and can last 5 to 7 days.

 

Grid and Generating Capacity: The grid (poles, wires, transformers, substations) and traditional generating capacity must be designed to serve peak demands, whether solar and wind electricity exists or not, because both very often are near zero during peak demand hours. Shutting down traditional generators is not an option. See note.

http://www.windtaskforce.org/profiles/blogs/vermont-is-going-to-hel...

 

Utility-Scale Battery Systems for Electricity Storage: Some people claim utility-scale battery systems could take the place of combine-cycle, gas-turbine, CCGT, plants.

However, the batteries would add a significant cost to the cost of any electricity passing through the batteries, as explained in this article.

http://www.windtaskforce.org/profiles/blogs/economics-of-tesla-powe...

 

NOTE: US CO2 emissions from electricity generation are down to 1980 levels, mostly due to fracked gas, and wind and solar, replacing coal. It is likely the CO2 reductions of wind and solar are overstated by the EPA and the EIA.

 

https://wattsupwiththat.com/2020/11/11/eia-us-co2-emissions-from-el...

https://www.windtaskforce.org/profiles/blogs/world-total-energy-con...

 

NOTE: Near-zero means less than 15% of what normally could be expected at that hour of year. See URLs.

 

DUCK CURVES IN VERMONT 

 

VELCO, Inc., is the manager of the Vermont high voltage grid.

The below graph shows the grid load (electricity fed to grid by generating plants) on an overcast day (blue line) and a sunny day (red line).

 

The grid load difference between an overcast day (small Duck) and a sunny day (big Duck), due to solar generation, was about 236 MW, about a 236/655 = 36% drop, which is far from trivial.

 

NOTE: The installed solar capacity of 306.30 MW ac, or 369.04 MW dc, at end 2018, could have had a peak output of about 290 MW at 2 pm.

The grid load, without solar, would be about 680 MW.

The grid load, with solar, would be about 680 – 290 = 390 MW.

See URLs and below graph

 

http://www.windtaskforce.org/profiles/blogs/vermont-solar-market-pa...

https://www.iso-ne.com/static-assets/documents/2019/04/final-2019-p...