Speaking of GHG emissions

Piece on the CBS News this evening about a few cities in the US that have banned nat gas appliances in new construction. Not surprisingly, the nat gas industry is against it. Several states with certain reputations have also outlawed nat gas appliance bans.

As offered on this board before, changing the vehicle fleet is the most awkward and, probably, most expensive, way of reducing GHG emissions, because of the requirements for batteries and charging points, to replace the existing liquid fuel infrastructure. Changing stationary facilities, which are already connected to electricity, over to non GHG equipment, and changing the generation fleet to non GHG power, would reduce GHG emissions more than changing the vehicle fleet.

Steve

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The average heat rate for a natural gas-fired power plant in the US is 7732 BTUs of heat to produce 1 kilowatt-hour (kwh) of electricity. Assuming a 100% conversion efficiency, that 1 kwh of electricity could produce 3412 BTUs of sensible heat with standard resistance heating.

Therefore, you need to burn 7732 BTUs worth of natural gas in the power plant in order to get 3412 BTUs of usable heat in some customer’s house. In reality, there are transmission and distribution losses in the electric grid of, as I recall, about 7% on average. The longer the transmission distance, the higher the losses will be. The 3412 BTU of usable heat could be more like 3200 BTU. Why not just burn that gas right in your house?

Most of the heat produced in the power plant is lost to the environment. Gas stoves and hot water heaters are more efficient, as most of the heat is used for the ultimate purpose.

Power plant heat rates from the EIA. There might be an error message in the box, but the link works for me.
https://www.eia.gov/electricity/annual/html/epa_08_01.html

  • Pete
8 Likes

A couple thoughts. Resistance heating is pretty rare in new construction. The world has moved towards heat pumps. Depending on the climate and type of heat pump, electricity use will be around 50% lower than resistance heaters.

But there’s more. Pretty much everywhere, some percentage of grid electricity is carbon free (~20% nationally, IIRC), but 100% of natural gas furnaces emit CO2. Add up those savings and in many places heat pumps are already the low carbon solution. And it is reasonable to assume that the grid will become less carbon intensive in the future. That’s certainly the way things are headed.

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If one gets their electricity from renewables then burning gas in appliances is stupid. I get all my electricity from renewables.

Jaak

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In 2021, 40% of the electricity produced by the electric power sector was derived from non-fossil fuel sources.

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As specified in the OP, change the generation fleet to non-GHG generating sources.

According to the EPA, 25% of US GHG emissions come from power generation. 27% comes from transportation. Commercial and residential use generates 13%. Convert everything at both ends of existing wires to non-GHG generating technology, and you reduce GHG emissions more than converting the entire vehicle fleet, and it’s supporting infrastructure.

Steve

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Steve,

There is a major argument against this, “it costs money”, always said with zero regard that what were have been doing costs a lot more money over the next decade if we do not change.

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Your calculations are flawed becaue over 40% of our electricity is carbon free. You also ignore the energy needed to pump all that natural gas in millions of pipelines from storage tanks to homes.

Jaak

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Currently with fossil fuels some 8% of the energy from the fuel hits the end point usage. The rest is on mining, refinement, processing, generation, transport etc…

8% is a low bar. 8% is an ultra expensive bar. 8% is an inflationary statistic with no merit.

Yes, indeed. I wonder how the auto and oil industries ended up being “burdened” with compliance, rather than the utility companies? The goober controlled states outlawing building codes requiring non-GHG generating appliances are an entirely different vector of Shinyness.

Of course, the cynic says transportation was fingered for bearing the compliance costs, because it is the most likely to fail. Converting the US generation and appliance fleet to non-GHG technology is too feasible with existing technology and infrastructure.

Steve

3 Likes

It costs about 1% - 3% of the energy being pumped to pump NG, depending on the season and distance pumped.
Electricity line losses are about 5% - 7% depending on distance
(Edit: but much less if you have solar on your roof)

Mike

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I do not believe your numbers on natural gas pumping. Where is your reference for energy required to pump natural gas from Canada and Texas to California?

If you have solar on the roof, then line losses are zero.

Jaak

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See here:

“line” losses may be zero but the relatively small inverters have an efficiency of about 85% - 95%
Bigger grid scale inverters generally have a higher efficiency

Mike

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That is the hope, but the methods we are using to achieve that will ensure fossil fuels continue to be burned in power plants well into the future. The low carbon sources being added are mostly solar panels and wind turbines. Solar panels and wind mills are not consistent, dispatchable energy sources. The capacity factors of wind and solar are so low (less than 40% for wind, less than 30% for solar), they need to be backed up with power plants that can be ramped up and down, as required, to maintain a stable grid frequency.

Most people don’t understand how the grid needs to be constantly balanced between supply and demand. Dispatchable power plants are the key to keeping everything stable.

Before anyone brings it up, batteries are not the solution to the entire problem. Batteries can be used for a few hours a day to shave down the generation required at the peak demand time of day. But batteries can’t supply 24/7 power like a real power plant can.

So, we will continue going down the same path. More solar panels, more wind farms, and more natural gas power plants to supply the dispatchable power. We could adopt the French model, which has a power system around 90% carbon free. But instead, we will go with the German Energiewende model, and continue to burn fossil fuels to keep the lights on. I’ve heard part of the Nord Stream gas pipe might still be functional.

  • Pete
1 Like

Your reference on crude oil flow energy losses is not what you said before. Also you should be looking a nat gas flow energy requirements with compressor stations every 50 to 100 miles. Each compressor is rated at 1000 hp or 2000 hp or up to 30,000 hp powered by natural gas or electricity or other fuels. Some compressor stations have multiple compressors. There are thousands of compressor stations across the country. The energy requirements for these compressors: 1 MW for 8 inch pipelines to 15 MW for 42 inch pipelines.


WRT roof top solar inverters being less efficient than utility grade transformers: The homeowner does not even know the difference and their EV charging is still very efficient.

Jaak

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Wind and solar should always be the first priority in power generation to reduce pollution and GHG emissions. Nuclear is too expensive, to hard to build, and has nuclear hazards and waste problems. Wind and solar are backed up by biomass (24/7), geothermal (24/7), and hydro (24/7). Of course nat gas and coal will be used in emergency situations until renwables reach their maximum capability.

France has shown that nuclear power plants can not provide reliable power when they have to be repaired so often. The people in France are paying higher prices for electricity than Germany because they have to import lots of electricity from their neighbors.

There are batteries and other energy storage systems being developed for 24 hour and more operation.

Jaak

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Data from the EU shows the French pay somewhat less for electricity than do the Germans, as of the second half of 2021.

Germany: 0.3234 euro per kwh
France: 0.2022 euro per kwh

Also, from the BP energy database, Germany emitted more than twice as much CO2 from the consumption of energy in 2021 compared to France.
Germany: 628.9 million tonnes CO2
France: 273.6 million tonnes

Germany has a slightly larger population, but not that much larger. Calculating per capita CO2 emissions, Germany still has higher CO2.

  • Pete
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:rofl: :rofl: :rofl:

Pete are you nuclear engineer? I have been assuming you were all along.

Pete, That data 2H21 has nothing to do with now after the war started. Jaak is talking now.

But worse you gave that link and chart but did not read the heading? Or missed what the heading said? It said in brackets taxes included. The French taxes MIGHT be less since the government controls the generating plants. I do not fully know that.

But in the mean time by the end of 2021 the French nuclear plants many were in trouble. The costs have soared in France. Jaak is correct.

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A couple things. First, it is a complete disconnect from objective reality to suggest the US is pursing the Energiewende model. In the US, new nuclear gets the same producer tax credit renewables get, plus nuclear gets federal loan guarantees, plus existing nuclear is subsidized on the state level in many states, PLUS the IRA allocates federal dollar to further subsidize existing nuclear to prevent existing nuclear plants from shutting down.

You realize this is the opposite of Energiewende, right?

We could follow the French model, but that is also by far the most expensive and by far the most time consuming way to build out carbon free energy. Even the French aren’t following the French model going forward. Instead, as a matter of policy France intends to shut down aging nuclear reactors and replace the energy with renewables.

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I said French are paying more currently in 2022 - not last year before the war. Look at the numbers below from ⚡️ Day ahead electricity prices in Europe :
10/17/22: France 174 €/MWh Germany 151 €/MWh
10/16/22: France 125 €/MWh Germany 93 €/MWh
10/13/22: France 260 €/MWh Germany 257 €/MWh
10/10/22: France 208 €/MWh Germany 157 €/MWh
10/01/22: France 123 €/MWh Germany 83 €/MWh
9/15/22: France 437 €/MWh Germany 369 €/MWh
9/01/22: France 636 €/MWh Germany 586 €/MWh
8/17/22: France 553 €/MWh Germany 552 €/MWh
7/30/22: France 398 €/MWh Germany 381 €/MWh
7/13/22: France 447 €/MWh Germany 352 €/MWh
6/30/22: France 362 €/MWh Germany 325 €/MWh
5/30/22: France 226 €/MWh Germany 226 €/MWh
4/13/22: France 238 €/MWh Germany 223 €/MWh
3/01/22: France 270 €/MWhGermany 241 €/MWh

Jaak