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A Comparison of Wood Chip and Oil-Fired Power Plants

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The Vermont media site, VTDigger, had a recent comment: “Just a single 25 megawatt (MW) wood chip plant could provide some 4 percent of Vermont’s consumption, 24/7/365, and would contribute to the Vermont economy in the form of jobs and money in circulation from the wages, taxes — wealth created in the state that stays in the state.”

Special Report: New Renewable Energy Standard Would Revolutionize Energy Use in Vermont

The comment is correct about jobs, wages, taxes, etc., but are wood power plants:

  • Efficient? NO. The efficiency of wood power plants is about 25%, fuel oil power plants about 33%.
  • Producing low-cost energy? NO. The plant owners likely would sell the electricity at about 10 c/kWh*
  • Requiring public subsidies? YES. Federal and state up-front cash grants, and a subsidy of about 5 c/kWh.
  • Increasing CO2 emissions? YES. See below explanations and URLs.
  • Increasing health-damaging air pollution? YES. See below explanations and URLs.
  • Negatively impacting forests? YES. See below explanations and URLs.

* The owners of the Ryegate, VT, 20 MW, wood chip power plant receive about 10 c/kWh for electricity fed to the NE grid (156 million kWh in 2015), under Vermont’s SPEED program. NE wholesale prices have averaged about 5 c/kWh for the past 5 years, and likely will not be increasing, due to an abundance of domestic, low-cost, natural gas.

http://www.vermontstandardoffer.com/ryegate-production/

Vermont Needs Low-Cost Electrical Energy: Vermont has a near-zero, real-growth economy. It needs to have more low-cost energy to make ALL sectors of Vermont’s economy more viable, so they can expand, be profitable, create good, steady, full-time jobs, that pay good wages and have good benefits. Those private businesses and their workers usually pay more income and other taxes, than subsidized, non-profit and government/private partnerships and their workers.

Vermont, one of the poorer states in the U.S., with a fragile, services-dominated economy, cannot afford to turn over a major part of its economy to expensive renewable energy production. With more and more of such subsidized, renewable energy projects, Vermont’s entire economy would be facing an increasingly stronger headwind for many years.

Increased energy efficiency, plus increased supply of low-cost (6 – 7 c/kWh) hydro energy from Hydro-Quebec, would REDUCE energy bills of Vermont’s already-struggling households and businesses, add practically no CO2, and no pollution!

Countries with higher wind and solar energy on the grid invariably have higher household electric rates. Figure 7 of this URL shows Denmark and Germany having the highest rates; France, 75% nuclear, has one of the lowest.

http://euanmearns.com/an-update-on-the-energiewende/

Wood Burning Plants and CO2 Emissions: A wood chip power plant or heating plant adds CO2 through: 1) Logging soil disturbance, vehicle transport, equipment use, refurbishments and replacements, diesel fuel burning; 2) Plant construction; 3) Plant O & M, refurbishments and replacements; 4) Plant decommissioning. Those CO2 emissions would require a forest area up to 15% greater than the wood burning CO2 to reabsorb it over up to 60 years.

http://www.theenergycollective.com/willem-post/2392251/wood-for-fuel-logging-increases-co2-and-damages-forest-health

http://www.theenergycollective.com/willem-post/2390703/a-comparison-of-wood-chip-and-oil-fired-power-plants

http://www.theenergycollective.com/willem-post/2225851/economics-and-co2-emissions-montpelier-district-heating-plant

CO2 Emissions and Sequestering: Vermont CO2 emissions are about 8,370,000 Mt/y*, of which Vermont forests sequester about 8,230,000 Mt/y, 1.82 Mt/acre/y*. The remaining 140,000 Mt/y becomes an annual addition to the atmosphere. Vermont forests cannot sequester all of Vermont CO2, i.e., there is NO spare forest area in Vermont, or elsewhere, to sequester ANY CO2 from wood burning.

*The 1,603,737 Mt of CO2 from wood burning is improperly excluded, due to the historical myth “burning wood is CO2-neutral”. See Note.

NOTE: Conversion factor for carbon sequestered by 1 acre of average U.S. Forest = – 0.29 Mt C/acre/year x (44 CO2/12 C) = -1.06 Mt CO2. Vermont claims 8.23 million Mt/y/4,511,000 forest acres = 1.82 Mt/acre/y; Maine claims 0.3 x 44/12 = 1.1 Mt/acre/y.

https://www.epa.gov/energy/ghg-equivalencies-calculator-calculations-and-references

http://www.forestecologynetwork.org/climate_change/sequestration_facts.html

Forests and CO2: It was previously thought old-growth forests ceased to accumulate carbon. As a result, they are not protected by international treaties. But, due to research, it is now known such forests still continue to add biomass and sequester and store enormous amounts of CO2, i.e., they serve as a global CO2 sink, and should be protected.

http://www.nature.com/news/2008/080910/full/news.2008.1092.html

In the US Northeast, almost all forests are in the “infant to prime of life” stage, generally aged 0 – 80 years, well below old-growth stage, and adding much biomass and absorbing much carbon. Logging for burning, or fires, both immediately release this absorbed CO2, which gets very slowly reabsorbed by new forest growth, if allowed to proceed.

http://www.maforests.org/NewEnglandBiomess.ppt

Logging a forest for burning offsets net forest growth, thus reducing, or eliminating, the net forest CO2 sequestration benefit. Leaving a forest undisturbed, instead of logging it, is always better for net CO2 impacts, even if including forest growth and carbon storage in wood products, such as lumber. As CO2 levels in the atmosphere are the result of CO2 added to, or subtracted from, any lost, or reduced net forest CO2 sequestration, increases overall atmospheric CO2 levels.

http://www.maforests.org/Keeton.pdf

No Logging Provides Highest Forest Carbon Storage: http://www.maforests.org/Keeton.pdf
Logging Destabilizes Soil Carbon: http://www.eurekalert.org/pub_releases/2014-12/dc-ldf120214.php
Massachusetts Forest Watch: http://www.maforests.org/Links.pdf

Burning Wood is Not Renewable: A forest regenerates from the harvesting activity (which also disturbs the forest floor, releasing CO2), by absorbing CO2 from the atmosphere, and storing C as hydrocarbons in new biomass growth above and below ground, and releasing O2. That process may take up to 100 years in New England, up to 50 years in the US southeast, such as in Georgia. See below URLs.

Proponents simply declare, “burning wood is CO2-neutral”, which creates political “feel-good”, because it conjures up the APPEARANCE of meeting CO2 targets, etc. However, it perpetuates uninformed thinking by lay people and others. Proponents purposely forget to add: “over a period of up to 100 years in New England, up to about 50 years in the US southeast.”

“CO2-neutral” is not close to true. Even if the logging were “sustainable”, i.e., no more cutting than biomass growth, there would still be a large carbon impact, due to lost carbon sequestration from the biomass growth now being used to “offset CO2 emissions”, instead of that biomass growth reducing atmospheric CO2.

All of the harvested land area must be allowed to regenerate biomass to its former state, instead of being used for development. A further burden would be the CO2 from activities mentioned under above section “Wood Burning Plants”. In New England, adding wood chip power plants, which typically get much of their wood by clear-cutting, would be a 100-year “save the world solution”.

https://ampd.epa.gov/ampd/
ttp://www.pfpi.net/wp-content/uploads/2011/04/PFPI-biomass-carbon-accounting-overview_April.pdf
https://ces.williams.edu/files/2011/02/Mary-Booth-Wiliams-Talk.pdf
http://www.globalchange.umich.edu/globalchange2/current/lectures/deforest/deforest.html
http://www.maforests.org/Timberspeak-Timber_Industry_Propaganda.pdf

Burning Wood is Not Clean and Not Green: Usually, it comes as a surprise to lay people, wood burning has at least as much CO2/kWh and particulate/kWh as coal. Exhausts from wood chip-fired plants, which are used around the clock in some communities, likely increase the air pollution of nearby areas, due to volatile organic compounds (VOCs); carbon monoxide; and particulates, which cause diseases of respiratory systems.

http://www.maforests.org/MFWCarb.pdf

“Small” biomass facilities have high pollution rates, so the combined impacts of “small” facilities can create a “big” problem. In the below table are the pollution rates for modern institutional, or commercial-scale, wood burning plants, particularly school-sized wood chip boilers, compared to fossil fuels plants, as provided by the Biomass Energy Resource Center (which promotes biomass) for the MA Department of Energy.

Pollution

Wood

No. 2 Fuel Oil

Natural Gas

Propane

lb/million Btu

lb/million Btu

lb/million Btu

lb/million Btu

Particulates

0.100

0.014

0.007

0.004

Carbon Monoxide

0.730

0.350

0.080

0.021

Nitrogen Oxides

0.165

0.143

0.090

0.154

Sulphur Dioxide

0.008

0.500

0.001

0.016

The particulate emissions from above wood burning data are 7 times worse than oil, 14 times worse than natural gas, and 25 times worse than propane. Even if better pollution control technologies were used, the wood emission profile remains worse than other fuels that use similar pollution control.

http://www.maforests.org/doer_pellet_guidebook.pdf

NOTE: Recently, the EPA proposed reducing the particulate emissions of NEW residential woodstoves by 80%. The proposal covers woodstoves, fireplace inserts, indoor and outdoor wood boilers (also called hydronic heaters), forced air furnaces and masonry heaters.

http://yosemite.epa.gov/opa/admpress.nsf/0/e3175e041784cf6485257c550059ca4c?OpenDocument

CO2 from Wood Burning: In the US northeast, the industry standard is burning one ton of green wood (7.6 million Btu/green ton; 45% moisture; 7.6 million/1100 = 6,909 Btu/lb, dry) creates a little more than one ton of CO2, and dry wood consists of 50% carbon (by weight). See table.

Green basis

C

H2

O2

H2O

Ash

Total

%, by weight

27.5

3.3

22.8

45.0

1.4

100.0

Lb.

550

66

456.5

900

27.5

2000

Dry basis
%, by weight

50

6

41.5

0.0

2.5

100.0

Lb.

1000

120

830

0

50

2000

The CO2 is calculated as follows:

C = (1 – 0.45) ton dry wood/green ton x 0.5 = 0.275 ton/green ton

C + O2 = CO2.  By molecular weight = 12 + 32 = 44; 1 ton C + 2.67 ton O2 = 3.67 ton CO2; 0.275 x 3.67 = 1.01 ton CO2/green ton.

http://mha-net.org/docs/v8n2/docs/WDBASICS.pdf

NOTE: Below is a comparison of the combustion CO2 of various fuels in latest-technology power plants; excludes other CO2 contributors:

Super-critical coal plants, 220 bar and 600/600 °C, efficiencies of 42%; ultra-super-critical, 300 bar and 600/600 °C, efficiencies of 45% to 48%.
CCGT gas plants, “H class”, 60% efficient at ISO conditions. See URL
Wood-chip plants 50 MW, 30% efficient. See URL

Untitled

http://www.eia.gov/tools/faqs/faq.cfm?id=73&t=11

http://www.brighthubengineering.com/power-plants/72369-compare-the-efficiency-of-different-power-plants/

http://www.aet-biomass.com/en-GB/Home/References/Biomass-Fired-Plants/Western-Wood-Energy-Plant.aspx

NOTE: Vermont’s wood-for-fuel harvest was 1,216,167 ton in 2014, of which 868,825 for space heating and 347,342 for electrical generation. About 347,342/719,033 = 48% of total electrical tonnage was harvested in Vermont. See URLs.

VT Harvest

Space heating

Electrical

Electrical

Total Electrical

Total

Fuel

In-state

Out-of-state

All-state

VT Fuel

ton

ton

ton

ton

ton

ton

Wood

1,216,167

868,825

347,342

371,691

719,033

1,587,858

CO2

1,228,329

876,065

350,237

374,789

725,025

1,601,090

http://fpr.vermont.gov/sites/fpr/files/About_the_Department/Library/Library/FINAL_2015 Residential Fuel Assessment Report.pdf   Page 14

http://fpr.vermont.gov/sites/fpr/files/Forest_and_Forestry/Forest_Based_Business/Library/2014 HARVEST SUMMARY_final.pdf

http://www.maforests.org/VermontBiomassBiomess.pdf

NOTE: Below are listed the wood tonnage and combustion CO2 tonnage of Vermont’s wood chip power plants in 2015.

Vermont Wood Power Plants

McNeil

Ryegate

Total

ton

ton

ton

Electrical, wood

2015, McNeil

469,190.0

249,843

719,033

Electrical, wood CO2

EPA, McNeil

473,100.4

251,925

725,025

http://www.maforests.org/McNeil Emissions 2015.pdf

http://www.maforests.org/RYEGATE TECHNICAL.pdf

NOTE: Below is a comparison of CO2 /MWh for various base-loaded plant types; variable solar and wind energy are supplementary energy sources, i.e., not base-loaded. The wood combustion CO2 gradually diminishes (not to zero) over at least 5 decades, if the deforested area is allowed to regrow itself to its before-harvest status.

Base-loaded plant type

Combustion CO2, ton/MWh

Wood

1.500

Coal

1.000

Gas

0.500

Nuclear

0.012

Hydro

0.010

NOTE: The Vermont Comprehensive Energy Plan (CEP) stated goal is to have 90% RE of ALL energy by 2050, not just electrical energy, which is only 35% of all energy. The plan includes proposals that would increase cutting and burning of Vermont’s forests. See table.

ton/y

Electrical

300,000

Combined heat power, CHP

400,000

Space heating

900,000

Total

1,600,000

This would increase the VT wood harvest for fuel by more than 1,600,000/1,216,167 = 132%, mostly from in-state forests. Add to that the clearing for access roads and 500-ft-tall wind turbines and those forests, with hundreds of clear-cut areas, will look much different from today. It would immediately add to the atmosphere 1,616,000 ton of CO2/y, due to burning, plus prevent the forest, which is in “infant to prime of life” stage, from absorbing CO2, if it were left alone to grow new biomass, instead of being developed as a “working landscape”. Increased logging likely will cause decreased overall growth and sequestration, causing a double whammy of increased CO2 stack emissions and decreased forest sequestration.

http://www.maforests.org/Biomass%20Assumptions.pdf

NOTE:

  • The most valuable portion of a tree is the straight trunk.
  • Forest residue consists of branches, tops, areas with splits or sweep, crooks, or portions of a tree with rot; moisture 40% – 50%; fuel value 4,625 Btu/lb.
  • Sawmill residue consists of bark, sawdust, chips; moisture 50%; fuel value 4,500 Btu/lb.

NOTE:

  • Forest residue usually is chipped for burning. Much of forest residue is left to rot.
  • Loggers, in sustainable-harvesting mode, often say they take only sick, near-dead trees and other “waste” wood, but, in almost all cases, that is not close to the truth.
  • Loggers, in clear-cutting mode, take almost all there is to take. See Figure 4, 5, 6 of URL.

http://www.stlawu.edu/green/sites/stlawu.edu.green/files/reports/INRS Final Report.pdf

NOTE: There is other biomass, such as corncobs, cornstalks, various grasses, bamboo, etc., that can be harvested each year, or every few years. Those crops require much land area. In Vermont, most of that land area would need to be created by eliminating open spaces, meadows, etc., to ensure biomass would be available in the quantities required by Vermont. In that case, biomass could be claimed to be PARTIALLY renewable. However, the soil likely would become less useful for other agricultural purposes, due to depletion. Taking, taking, taking from the land, without giving back, is not a long-term, sustainable option, as any farmer knows.

Wood Chip Plants Heating Energy-Hog Buildings: Some people advocate for wood chip central heating plants, or wood chip combined heating/power (CHP) plants, with thermal distribution systems to heat buildings. However, any new central plants likely would be connected to energy-hog buildings, which make such systems uneconomical, especially with higher energy prices.

Such central plants systems may appear attractive to people, who are not familiar with the numbers, but as energy-efficient building design has significantly advanced since the oil price shock of 1973, the economics of NEW central plant systems became unfavorable, except in Europe, Japan, etc., which have higher energy prices and more energy-efficient buildings.

It would be far less costly to pay some additional money to have zero-net-energy or energy surplus buildings with heat pumps and PV solar systems, instead of central plant systems. Trying to convince decision makers, including legislators, etc., to let go of their ingrained, uninformed thinking is quite an uphill battle.

NOTE: With enough “free” money, i.e., cash subsidies, anything can be made to appear economical, such as the recently built, much-praised, wood chip District Heating Plant, Montpelier, VT, which:

Received 100% of its $20 million construction cost as federal, state and city cash grants to heat energy-hog buildings, and
INCREASED CO2 emissions compared to No. 2 fuel oil, that would take about 100 years to be reabsorbed, and
Is operated at a loss, because heat users are paying at rates too low to recover all O&M and refurbishments costs, and
Had that been a privately financed plant, i.e., without subsidies, it would lose at least $2.5 million per year, including paying real estate taxes.

Repeating such a folly throughout Vermont would be irrational energy policy. That $20 million should have been spent on increased energy efficiency.

http://www.theenergycollective.com/willem-post/2225851/economics-and-co2-emissions-montpelier-district-heating-plant

Evaluated Alternatives: Two alternatives were evaluated:

Alt. 1: Wood chip power plant
Alt. 2: No. 2 fuel oil power plant

Results of Evaluation:

  1. Alt. 2 has about 40% less capital cost than Alt. 1
  2. Alt. 2 has much less staffing, maintenance and other operating cost/y than Alt. 1
  3. Alt. 2 produces electricity at a much lesser cost/MWh than Alt. 1
  4. Alt. 2 emits about 54.3% less CO2 emissions/y than Alt. 1*
  5. Alt. 2 requires much less area than Alt. 1

* The percentage gradually diminishes over 50 – 100 years, as the forest recovers, i.e., reabsorbs the combustion CO2. The total CO2, due to activities other than burning wood, would require a forest area about 20% larger than the harvested area.

Summary of Alternative No. 1: Wood Chip Power Plant

Assumptions: Capacity 25 MW; capacity factor 90% (base-loaded mode); 25% efficiency; 7.6 million Btu/green ton (45% moisture); 3,413,000 Btu/MWh; cord weight of low-grade, green wood chips = 5,000 pounds = 2.5 tons; 0.5 cord/acre to conform to sustainable forestry practice; 32 ton/truckload; 250 hauling days; 640 acre/sq. mi.; a ton = 2000 lb; a metric ton = 2204.62 lb.

http://www.biomasscenter.org/pdfs/Wood chip-Heating-Guide.pdf

Turnkey capital cost = 25 MW x $2,500,000/MW = $62.5 million
Electricity, gross = 25 x 8760 x 0.90 = 197,100 MWh/y
Electricity, self use = 22,675 MWh/y
Electricity, net = 197,100/1.13 = 174,425 MWh/y
Heat input = 197,100 x (3,413,000 Btu/MWh)/0.25 = 2,691 billion Btu/y
Wood chip supply = 2,691 billion Btu/y/(7.6 million Btu/ton) = 354,054 ton/y, or 1.8 ton/MWh
Truckloads = 354,054/32 = 11,064/year, or 44/day
Cords = 354,054/2.5 = 141,622/y
Area* = 141,622/0.5 = 283,243 acre, or 443 sq. mi

*In the real world, the plant would get its wood from an area with a 30-mile radius, or 3.14 x 30^2 = 2,826 sq. mi., about 6.4 times greater, or which about 15% would be used for clear-cutting. As a result, Vermont could have only a few additional 25 MW wood-burning plants.

NOTE: The 40-year clear-cutting for a McNeil-size power plant would be 13000 ton/MW x 50 MW x 0.75, CF in 2015 x 1/(78 ton/acre x 1/3), usable fraction x 40 y, time between harvests = 0.75 million acres. McNeil gets its wood from an area with a 50-mile radius, or 3.14 x 50^2 x 640 = 5,024,000 acres, of which about 15% is used for clear-cutting.

Average New England Standing Biomass = 78 green tons per acre.

http://www.maforests.org/STANDING%20BIOMASS%20CALC.xls

CO2 Emissions:

Below is the lb CO2/million Btu for No.2 fuel oil or diesel fuel.

lb CO2/million Btu

Production

12.5244

Transport

0.6262

Combustion

161.3000

Total

174.4506

CO2/gal

24.2922

Harvest, process, transport = 2.09 gal diesel/ton x 24.2922 lb CO2/gal x 354,054 ton wood/y = 8,988 ton CO2/y

Combustion = 1.01 x 354,054 ton wood/y = 357,594 ton CO2/y

Total = 366,582 ton CO2/y

NOTE: The CO2 due to building the plant, land disturbance, O&M, and decommissioning the plant is omitted

Summery of Alternative No. 2: No. 2 Fuel Oil-Fired Power Plant

Assumptions: Capacity 25 MW; capacity factor 90% (base-loaded mode); 35% efficiency

The turnkey capital cost = 25 MW x $1,500,000/MW = $37.5 million
Production = 25 x 8760 x 0.90 = 197,100 MWh/y
Heat input = 197,100 x (3,413,000 Btu/MWh)/0.35 = 1,922 billion Btu/y

CO2 Emissions:

ton/y

Production

12.5244 lb CO2/million Btu x 1,922 billion Btu/y x 1 ton/2000 lb

12,036

Transport

0.6262 lb CO2/million Btu x 1,922 billion Btu/y x 1 ton/2000 lb

602

Combustion

161.3000 lb CO2/million Btu x 1,922 billion Btu/y x 1 ton/2000 lb

155,010

Total CO2

167,648

NOTE: The CO2 due to building the plant, O&M, and decommissioning the plant is omitted.

Photo Credit: Jori Samonen via Flickr

Willem Post's picture

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Discussions

Simon Friedrich's picture
Simon Friedrich on Oct 21, 2016 12:09 pm GMT

Willem,

You have provided a detailed account of greenhouse gas emissions resulting from promoting wood as an energy source in Vermont. There are adverse impacts of this policy on the biomes because of clear-cut lands. Unfortunately, the consumption of wood for energy is not included in greenhouse gas emissions inventory totals by the states, EPA, EIA and other nations. These governments are following the politically driven guidelines of the International Panel on Climate Change (IPCC). Effectively, by not counting these emissions it is easier for all to reach their greenhouse gas emission reduction goals.

PS: If/when we have a carbon tax, bioenergy will most probably be exempted.

Willem Post's picture
Willem Post on Oct 21, 2016 1:19 pm GMT

Simon,

That would have to be a worldwide carbon tax levied at wells and mines to maintain a level playing field.

Wood is shipped, as pellets, from the US southeast to Germany and the UK for burning in coal plants to reduce CO2 emissions, all with the blessing of the EU in Brussels.

Another CO2 obfuscation is the balancing CO2 of wind energy. That balancing CO2 is also ignored by the US, EU, etc.

Because wind energy output is variable, like the wind, they require the traditional generators to provide the balancing of that wind energy to meet the demand, 24/7/365; that balancing causes these generators to operate less efficiently, i.e., more fuel/kWh, and more CO2/kWh. In NE the balancing inefficiency is still small, because wind energy is only about 5%.

Balancing inefficiency at 5% wind energy is about 0.15 x 5% = 0.75%, at 10% about 0.30 x 10% = 3%, at 17% about 0.528 x 17% = 8.94%; the latter condition existed in Ireland a few years ago, i.e., 17% wind energy on the Irish grid did not reduce CO2 by 17%, as claimed by pro-wind lobbies, but by only about half of that, i.e., 8.94%. See URL.
http://www.theenergycollective.com/willem-post/2264202/reducing-us-prima...

Helmut Frik's picture
Helmut Frik on Oct 21, 2016 2:54 pm GMT

Willem, your calculation is not correct. you can not deduct from the poor performance in part time load of irish CCGT to e.g. german plants which are optimised for part time load ald loose only a small amount of efficiency. And you can not conclude from small grids, where the few exisitng plant shave to run in partial mode to a huge grid like the european grid, where whole plants can be run from zero to full power according weather forcast of the next 48 hours without operating in partial load. E.G even a block like Moorburg usually either runs at maximum load or not at all, while balancing residual load. It conributes just around 0,3% +/- to the power generation in the synchronus grid when it starts from being offline to full operation, and less than 0,1% if you look at all interconnected grids.

Willem Post's picture
Willem Post on Oct 21, 2016 6:40 pm GMT

Helmut,

Optimized for part load?

Who is the manufacturer of such CCGTs?

Siemens and GE both make 60% efficient CCGT systems that have lesser efficiencies at lesser outputs. Look at the performance curves.

Such systems are required to operate at lesser outputs due to wind having priority, and are required to ramp up and down, as needed, to offset variations in wind output.

In case of excessive wind, excess wind energy is curtailed or exported to nearby grids, if such grids allow it.

In a big system the inefficiency is spread over many units, so it is hardly noticeable. As wind increases, it will become more noticeable.

In a small system, the inefficiency is highly noticeable, and easily quantified.

Helmut Frik's picture
Helmut Frik on Oct 21, 2016 10:03 pm GMT

Willem read what I write. The power stations do not have no loss of efficiency but they have a much smaller loss than the (technical)old power staions in Ireland which just are efficient in baseload mode.
Ramps due to wind generation changes are in average miuch smaller than ramps due to load changes, and much better predictable. which means that there are nearly no power stations running in partial mode, at least not significant more than without wind power, the power stations are eithe running at full load or are switched off. Its known several days in advance when wind arrives and as wind power rises the blocks go offline one by one. It is not the case that all power stations remain online and reduce ooutput, this would be uneconomic and unneccesary.
If there are 1000 blocks in the grid, and you need 40% output, you don’t run 1000 Blocks at 40% output level, but 400 Blocks running at full load, and 600 block switchen of, if load is static. Naturally it is not static, so you have e.g. 20-50 blocks ramping up or down, most hthen either heading for full load or switching off,. Only when the valley in the residual load is very short, a significant number of power stations go in partial load. No matter weather the cause is Load change or wind or whatever else. Power station operators are not stupid and run their systems efficient.

Willem Post's picture
Willem Post on Oct 22, 2016 12:56 am GMT

Helmut,
I suggest you talk to grid operating personnel to learn from their experiences.

Helmut Frik's picture
Helmut Frik on Oct 22, 2016 10:14 am GMT

Thats part of my work, along with discussions with the ones writing the software to control the grids. But maybe you start with learning the basics sometimes, instead of developing your own theorys of reality in your texts.

Willem Post's picture
Willem Post on Oct 22, 2016 1:40 pm GMT

Helmut,

In that case, you should share your expertise with others, including real-time scheduling of units and operating data of such units, on the German grid, during higher wind energy.

I look forward to your TEC articles on that subject.

Helmut Frik's picture
Helmut Frik on Oct 22, 2016 2:57 pm GMT

That would be very boring articles since these are well known facts. It does not make any sense to let 2 blocks run at 50% if one can do the job, and there is enough capacity online wich can do the ramping. When ramping is required is known in advance, the biggest uncertaincy is the load prediction.
If you do not believe there is a article online about the question weather Moorburg is switched of during high wind. As a side effect it shows that Moorburg either runns at full load or not at all, and just in rare cases in partial load (ramping) And thats one of the power plant suited best for ramping and partial loads.

Engineer- Poet's picture
Engineer- Poet on Oct 22, 2016 5:28 pm GMT

It does not make any sense to let 2 blocks run at 50% if one can do the job, and there is enough capacity online wich can do the ramping.

You contradict yourself.  The whole reason that units run at 50% is specifically to provide the on-line ramping capacity (and spinning reserve).  When you add non-dispatchable generation which can either increase or decrease output by itself, you need more ramping capacity to match generation to load.

When ramping is required is known in advance, the biggest uncertaincy is the load prediction.

Even if that was true, it would not mean that wind and solar would not increase the requirement for fast-ramping generation, meaning regular operation at part load.

Helmut Frik's picture
Helmut Frik on Oct 22, 2016 7:40 pm GMT

No no contradiction. You just show you have not enough knowledge about what is big and what is small, and waht increases ramping and waht decreases ramping.

– avereage ramps of wind are mulitple times less steep than ramps induced by load changes.
– Solar reduces neccesary ramping during somer months to nearly zero, and does not increas the need for ramping in winter.
– German power plants can ramp up and down much faster than load changes require it. This could be shown in practice during the solar eclipse where 14 GW of solar went offline and came online again within minutes. (Ramp rates up to 400MW per minute), which could be handeled without problems.

Engineer- Poet's picture
Engineer- Poet on Oct 23, 2016 2:14 pm GMT

We’re fed up with your lies, Helmut Coal.

– avereage ramps of wind are mulitple times less steep than ramps induced by load changes.

This graph shows the wind curve sloping just as steeply as the load curve.  If wind was scaled up to be on the order of the size of load, it would be several times as steep.

– Solar reduces neccesary ramping during somer months to nearly zero, and does not increas the need for ramping in winter.

Three words:  “duck belly curve”.

You just show you have not enough knowledge about what is big and what is small, and waht increases ramping and waht decreases ramping.

Talk sense to an idiot, and he calls you idiotic.

German power plants can ramp up and down much faster than load changes require it.

And Germany will continue polluting the atmosphere with massive amounts of carbon until it gets rid of all of those plants.

Helmut Frik's picture
Helmut Frik on Oct 23, 2016 8:34 pm GMT

So you start insulting once again and the produce a pile of trash.
Can somebody explain the word “average to out engineer’s pet? And deven in your examles the ramps in load are much steeper than the ones in wind.

And there is noc duck bally in germany. REsidual load in summer is simply flat threwout the day. Discussion is about germany, but thats propabely to complex for our engineer’S pet.

And further just isnults without any sense. MAybe some moderator could give him some rest for a while to calm down and start behaving like a normal person.

Engineer- Poet's picture
Engineer- Poet on Oct 24, 2016 4:01 am GMT

So you … produce a pile of trash.

Your half-truths and evasions are trashier than anything I could write even if I tried to make porn.

you start insulting once again

You insult our intelligence every time you come out with your propaganda and misleading references.  Nobody here has time to translate and pick through your German-language stuff.  Use English references; there are more than 3x as many native speakers of English as German, more than 2x overall.  You come across like a Gymnasium activist well-trained in rhetorical talking points which work well on the ignorant, but next to no factual knowledge… and your rhetoric doesn’t cross the language barrier.

It would help if you could learn and follow a few rules about having a rational discussion, particularly the second box from the top.  When you violate that rule, you are ONLY worthy of insults because you have given up reason.

And deven in your examles the ramps in load are much steeper than the ones in wind.

I was trying to scale the wind portion of that graphic to match the peaks of wind and load, but there have been enough tweaks to Gimp that I can’t even find the control for the paintbrush size any more, let alone stretch a selection of an image vertically.  I’m afraid that simple graphic proof is going to have to come from someone else.

Helmut Frik's picture
Helmut Frik on Oct 24, 2016 9:21 am GMT

We discuss the german grid, so you have to come along with references in german, as I have to come along with references in english when discussing the U.S. Grid.
And you sittl just go on insulting while having no facts to tell.
Here a random picked time from german grid in summer. The red line is the load, the coloured areas are the residual load. Try to find the duck curve.

Willem Post's picture
Willem Post on Oct 24, 2016 12:41 pm GMT

Engineer,

The graph indicates no wind for four days.

It is good, ALL the TRADITIONAL generators were ready, staffed and fueled to take over, when wind was absent.

Two complete energy systems to do one job.

That, by definition, just HAS to be more expensive than having just one system.

The hydro production is used for balancing. It is larger, because, much of it is exported to California.

The exports should be subtracted to get a better picture of its balancing function of wind energy.

Also, when wind was Absent, thermal generation (and CO2) increased.

It good hydro is doing the CO2-free balancing, as is the case for Denmark.

Germany has had NO decrease in CO2 for about a decade.Se graph in URL

http://euanmearns.com/an-update-on-the-energiewende/

German household electric bills are the SECOND highest in Europe, about 28.69 eurocent/kWh in 2015;

Denmark is the leader with about 30 eurocent/kWh. Both are RE mavens.

France, about 80% nuclear generation, has one of the lowest.

See line items on German household electric bills in this URL.
https://www.bdew.de/internet.nsf/id/DC9ABD3F2D97604DC1257F42002E5075/$file/160122%20BDEW%20zum%20Strompreis%20der%20Haushalte%20Anhang.pdf

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