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On Are Rebound Effects a Problem for Energy Efficiency?


I like to look at it another way, because this is what actually happened based on the emperical data.

In 1800, the Gross World Product, GWP, was $175.24 billion; population 1.0 billion.

In 2012, the GWP was $71,830 billion, 407 times greater; population 7.0 billion.

GWP/capita in 2012 = 407/7 = 58 times greater than in 1800.

In 1800, world energy consumption per capita was 20 GJ. In 2010, 80 GJ.

With 4 times the energy use per capita, 58 times the GWP/capita is achieved, i.e., energy/capita is used about 14.5 times more effectively than in 1800.

GWP multiplier from 1800 to 2010 = 4 x 7 x 14.5 = 407; an indication of environmental impact.

NOTE: The wildlife animal population decreased 50% from 1970 to 2014, while the human population and GDP/capita, and CO2/capita increased!!

NOTE: Steam engines were 3% efficient, modern CCGTs are 60% efficient; Dutch wind mills were 2-4% efficient, modern wind turbines are about 35% efficient, wood/peat OPEN fireplaces of 1800 had negative efficiency. Lay people usually do not get that point, as they know little about the efficiency of engineered systems.

Because of the present effective use of energy, much more goods and services can be produced for consumption and more damage is done to the environment that debilitates the fauna and flora.


October 22, 2014    View Comment    

On Are Rebound Effects a Problem for Energy Efficiency?


I think that if energy efficiency is built-in there is no rebound effect.

If I drive a Prius at 50 mpg, instead of a standard light vehicle at 25 mpg, am I going to drive 2 times the number of miles? Heck no, I have better things to do with my time.

If I live in an off the grid house, my energy bills will be near zero, versus living in a standard energy hog house with energy bills of about $4000; about $5500 before tax, am I going to run out and stock up on other goods and services, or pay off some debt, or save for a rainy day, or take more time off?

Regarding off the grid living, here is how that may be done for a free-standing house oriented towards the sun:

Off the Grid, in Near-Zero-CO2 mode, With an Energy Efficient House: My starting point is a house, NOT grid-connected, that uses about 80% less energy for heating, cooling, and electricity than a standard house, a la Passivhaus.

In winter it will be challenging, as several days may pass with near-zero electrical and thermal energy generation. At least a week's consumption of electrical and hot water storage will be required.

For living off the grid, in a near-zero-CO2 mode, the house would need to be equipped with:

- A roof-mounted, PV solar system + a lead-acid battery system + a hot water storage tank with DC electric heater + a system with DC pump and water-to-air heat exchanger.

- A gasoline-powered, 2 kW DC generator with 50-gallon fuel tank to provide electricity in case of too little PV solar energy during winter, due to fog, ice, snow, clouds, etc.

- Any excess electricity would bypass the already-full batteries and go to the electric heater in the DHW tank. Any excess thermal energy would be exhausted from the DHW tank to the outdoors.

- A whole house duct system to supply and return warm and cool air, with an air-to-air heat exchanger to take in fresh, filtered air and exhaust stale air at a minimum of 0.5 ACH, per HVAC code.

- For space cooling, a small capacity, high-efficiency AC unit would be required on only the warmest days, as the house will warm up very slowly.

- For space heating, a DC electric heater, about 1.5 kW (about the same capacity as a hairdryer) for a 2,000 sq ft house, in the air supply duct, would be required on only the coldest days.

NOTE: Because PV solar systems have become much less costly, it would less complicated and lower in O&M costs to increase the capacity of the PV solar system to also provide electricity for DHW, instead of having an $8,000 roof-mounted solar thermal system for DHW; no tube leaks, freeze-ups, less moving parts, etc. With a properly insulated, large capacity DHW tank, say 250+ gallons, there would be enough DHW for a week.

NOTE: About 70% of battery nameplate rating is available, as batteries are typically charged to a maximum of 90% and discharged to a minimum of 20% of capacity to prolong their useful service lives beyond about 8 years. Usually the charging and discharging is much less than 70%.

NOTE: Battery charging loss is about 10% and discharging loss is about 10%, i.e., in 100 W in, store 90 W, out 81 W. DC to AC has a loss of about 10%, and AC to DC has a loss of about 10%, i.e., minimizing conversion by using DC devices (fans, pumps, etc.) avoids losses.

NOTE: As space heating and cooling would be required for just a few days of the year, an air-source heat pump would be overkill and too expensive in this case.

NOTE: A future plug-in vehicle could be charged with DC energy from the house batteries by bypassing the vehicle AC to DC converter, provided the house batteries have adequate remaining storage capacity, kWh, for other electricity usages. During some winter days, this may not be feasible, as not enough PV solar energy would be available; public chargers would be needed.

NOTE: The PV solar system needs to be oversized to ensure adequate electrical and thermal energy during winter when the monthly minimum winter irradiance is about 1/4 - 1/6 of the monthly maximum summer irradiance. See below URL of monthly output from 2 monitored solar systems in Munich; 1/6 is about right in South Germany. Whereas, the daily or weekly maximum solar output may be up to 60% of installed capacity, kW, during a very sunny period, it may be near zero, due to fog, ice, snow, clouds, etc. The same is true in Vermont.

NOTE: The above example shows to provide standard houses (energy-hog instead of a la Passivhaus) with PV solar systems, they would need to be of such large capacity that the costs would be prohibitive, if zero-energy/near-zero CO2 is the goal.



October 21, 2014    View Comment    

On High Renewable Energy Costs Damage the German Economy


"Norway saves a little money and Denmark does as well".

Definitely not true. How can you make such a statement without backup?

The amount to the benefit of Norway and Sweden has been estimated by DANISH energy systems analysts at about 1 billion euro in 2012 and about the same in 2013, and growing. Just google on non-RE sites.

I lived and worked in Norway for 3 years.

Energy engineers I spoke with think Danish wind energy is a loser for Denmark and a winner for Norway and Sweden, for the reasons described in above comments.

October 19, 2014    View Comment    

On While Critics Debate Energiewende, Germany is Gaining a Global Advantage


Professional, reliable, knowledgeable reference?


October 15, 2014    View Comment    

On While Critics Debate Energiewende, Germany is Gaining a Global Advantage


You are talking in circles. Stick to the topic.

I was talking about wind energy in Denmark, and how it is so dependent on the foreign hydro plants, and I explained how it is an ECONOMIC negative for Denmark, despite rah rah propaganda.

Somehow, you drag Norway, etc., into this.

BTW, I used to live in Norway for 3 years.

October 15, 2014    View Comment    

On While Critics Debate Energiewende, Germany is Gaining a Global Advantage


German willingness to put in solar is declining, because subsidies are declining.

When it was lucrative at the higher subsidies, they were all for it, when it was not, they were not all for it. Germans are no different than any other people. Special admiration is not warranted.

October 15, 2014    View Comment    

On While Critics Debate Energiewende, Germany is Gaining a Global Advantage


You continue talking the type of nonsense typical of RE afficionados. Check your statements with a power systems designers and analysts before making them here.

"Why not adapt the normal cost allocation method?" What kind of blather is that?

$6+ billion to bring energy from the Panhandle to population centers falls under the "normal allocation method"?

Germany likely will be spending about 50 b euros over the next 10 years for north-south grid extensions (much of it underground) to accommodate wind and solar generators.

Remember, before 2000, Germany had the most reliable grid in the world. It did not need those north-south connectors. It is largely the wind and solar build outs that require the additional grid investments.


October 15, 2014    View Comment    

On Offshore Wind Power Can Save U.S. Billions On Electricity, Recent DOE Study Finds


It is all so simple to the handwaving layperson, but very complex to the experts.

Have you heard of levelized cost? O&M is one of them.

Offshore O&M happens to be about 3-4 times onshore O&M.

Upfront capital cost is at least 2 times onshore, not counting grid adequacy, and generating capacity adequacy.

October 15, 2014    View Comment    

On Offshore Wind Power Can Save U.S. Billions On Electricity, Recent DOE Study Finds


Thank you for adding your insider knowledge to debunk this article based on a fluff "study".

I am surprised people with no experience in power systems design and analysis get their articles approved for the TEC site.

October 14, 2014    View Comment    

On Offshore Wind Power Can Save U.S. Billions On Electricity, Recent DOE Study Finds


I think your article is based on wishful thinking by starry-eyed bureaucrats listening the RE promoters.

Germany's offshore wind plants have huge cost overruns, as do Denmark's, as do the UK's. There is not much offshore wind energy elsewhere.

If these three have huge cost overruns, the US will magically not have them?

As a result, the cost of generating wind energy is well over 15 c/kWh, not counting the capital investments for grid extensions for grid adequacy and more flexible/balancing generators for capacity adequacy.

Many of these costs are hidden from the public by "socializing" them.

The State of Texas spent over $6 billion to bring energy from the Panhandle to population centers. Without that outlay, the Panhandle wind turbines would be useless.

This article explains all in detail.

October 14, 2014    View Comment    

On While Critics Debate Energiewende, Germany is Gaining a Global Advantage


Your statements show a lack of understanding, which means you are commenting on a complex subject you know little about.

Here is what physically takes place. Verify it with an power systems engineer with about 10 - 35 years of experience.

When wind turbines generate energy at night, and it is not consumed in Denmark (people are sleeping), and it is balanced by foreign hydro plants, that means these hydro plants operate at less output and modulate at that lower output, i.e., less water is used.

During those times grid prices are very low, i.e., foreign owners of hydro plants are smiling, because they will use the saved water (courtesy of the wind turbines) to generate DAYTIME energy for Denmark when grid prices are much higher.

How can that possibly be a good deal for Denmark, especially if the wind energy is generated at about 10 c/kWh, plus the "socialized" costs of grid adequacy, plus generation flexibility adequacy.

The latter two are significant, if hydro plants are unavailable.

The latter two usually are not included in the cost of wind energy, i.e., the cost of wind energy is understated.

The Irish wind energy export plan was cancelled, because of too much opposition.

October 14, 2014    View Comment