Facts & Thoughts about Electricity Generation

by Ginosar  

FACTS AND THOUGHTS ABOUT U.S. ELECTRICITY GENERATION

I. Electricity generation consumes 40% of US input energy,

II.  2/3 of this input energy is wasted!

Numbers are rounded up for clarity. All units are metric.

 

I. Total US PRIMARY energy consumption  100 Quads per year (in 2004), (equivalent to 30 trillion  kWh/yr.)

Total PRIMARY energy input to electricity sector is 40 Q  (12 trillion kWh)

Total electricity production is 4 trillion kWh/y = 4 x 10^12 kWh/yr [10^12]

Efficiency of total electrical system is low: 4/12 about 30%, almost 70% is wasted

 

II. We need to capture much of this waste. Not more than half of it is possible to capture

Not only that, central, thermal plants use huge amount of water to cool the steam for the next cycle. Most Solar Thermal plants have the same vast water needs and are now starting to compete in arid areas for scarce water supplies. (See below.)

 

II. Global Warming Gases - CO2 equiv. emission:

Total US GreenHouse Gases, GHG, emission: 7 Billion tonnes/yr

(1 B T is absorbed in US by nature, mostly by being captured by photosynthesis and stored in the net growth of US forests, for a net of 6B T , but that is a side issue)

 

Total electricity generation emit 2.4 B Tonnes GHG , 34% of all US GHG

 

Half US electricity is from coal, emitting 1.9 B T of GHG, 27% of all US total GHG;

 

1. The first step in the process of reducing GHG emission from electricity generation is reducing electrical consumption. This should be mandatory-not voluntary- voluntary has, at best, very minor penetration that takes decades to make any impact. Examples of successful mandatory measures exist: California's electric appliance efficiency standards, and new building permit standards for residential and commercial structures.

Steps:

A. High conservation levels of all new construction

B. Increasing appliance efficiency.

C. The best timely approach is using nationally the well- seasoned California Title 24 conservation and the appliance efficiency plans which proven their effectiveness for over two decades.

D. Conservation of existing structures. Most electricity is used in existing poorly insulated homes and businesses. Conservation should be mandatory at sales and upgrades. Voluntary programs are appealing, but insignificant compare to the need.

2. The search for CCS (carbon capture and storage), is a must since so much of global electricity comes from coal. And we will have to depend on coal for at least twenty years. The problem is that :

a. No CCS experience, no plant of the needed characteristics exists,

Therefore, WE DO NOT KNOW IF IT WILL WORK RELIABLY over time

b. The danger of major CO2 leak could be serious.

c. The cost estimates for production scale CCS are high, in the range of $50-$100 per ton of CO2.  At $100/ton CO2 would add 10 cents/kWh to the cost of electricity from coal, an increase of 100% to 200% from current costs of generating from a coal-fired power plant.

The cost paid by a residential customer is usually two to three times the cost of generation, because transmission, distribution, connection and administrative costs add to about twice the costs of generation in cents/kWh.

Because coal is an extremely polluting source and so much is dependent on CCS unproven technology, we must do all we can to reduce our dependence on coal. First we should prevent construction of any new coal power plants that do not capture and store most of their CO2 emissions, and as a minimum retire aging, low efficiency plants ASAP, and replace those we can by natural gas combined cycle (NGCC).  NGCC  can cut GHG emission to 40% of coal.

III. Some governmental impediments to increase electricity generation efficiency:

Most electrical production is controlled by local utilities which are mostly profit oriented, and regulated by each state's form of public service commission (PUC or PSC or other).

"Munis" (municipal utilities) are not so controlled but should be. Their local interests should be secondary to national needs.

Most PUCs require large, centralized electrical generation, far away from population centers, partially for safety and partially to reduce local pollution. This reduce the potential for CHP (combined heat and power), which uses the wasted heat of the power plants.  CHP is also called "cogeneration". Europe has considerably higher percentage of CHP than in the US.

We need a national law setting increasing percentage requirements for CHP, and appropriate compensation when applicable. This, together with conservation and efficiency measures at the points of electricity use, will be one of the lowest cost ways to reduce CO2.

CHP could reduce electricity generation costs.

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For comparison:

Germany generates 50% of its electricity from coal, and is increasing it rapidly; 23 % nuclear

China generates 80% of its electricity from coal, increasing it rapidly

France generates 80% of its electricity from nuclear power

 

I thank Dr. Evan Hughes for his review and comments on some of the content here.  However, the views and opinions expressed, and the responsibility for the facts given, are mine alone.

 

 

 

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