XYLENE POWER LTD.

ELECTRICITY INTRODUCTION

By Charles Rhodes, P. Eng., Ph.D.

ELECTRICITY:
Our society has become highly dependent on reliable grid supplied electricity.

Electricity is electromagnetic field energy that is generated, guided by transmission lines over long distances and then used to do work. Grid supplied electricity is widely used to provide power on demand when and where needed.

Grid supplied electricty is used to power socially critical applications such as fresh water pumping, sewage pumping, lighting, communications, signalling and electric transit. Grid supplied electricity is also routinely used to control other energy sources.

It can be shown that at any point along two parallel guiding conductors that have identical currents flowing in opposite directions the instantaneous energy flux is equal to the product:
(instantaneous current through the conductors) X (instantaneous voltage between the conductors)

The energy propagation velocity along a transmission line is dependent on the exact materials, geometry and frequency but is usually close to the speed of light.
 

EFFICIENCY:
The end to end (generator shaft to motor shaft) efficiency of a low frequency (~ 60 Hz) electricity system is typically in the range 60% to 90%. An issue that is not adequately appreciated is the role of reflected power in AC power systems. If reflected power is present the electrical energy delivery capacity of a transmission system can be severely reduced.

Measurements of delivered electrical energy indicate the capacity of the delivered electrical energy to do work.
 

CENTRAL GENERATION:
During the 20th century most electricity generation in Ontario was done at large central plants. Electricity was transmitted to customers via high voltage AC transmission lines that fed local distribution networks.

After Ontario Hydro developed the large easily accessible hydro-electric resources in southern Ontario, it built large coal and nuclear thermal generation plants that relied on direct lake water cooling.

For safety and environmental protection reasons it is anticipated that future nuclear generation plants will rely on use of dry cooling towers for heat dissipation. The problems at Fukushima Daiichi demonstrated the inherent dangers of building nuclear power stations at close to the level of a large body of water. Earthquakes and related tsunamis are rare, but when they do occur they can cause extensive damage.
 

EMISSIONS:
Nuclear electricity generating stations are more expensive than the coal fired electricity generating stations but the coal fired plants emit carbon dioxide and toxic products of combustion.

Excess carbon dioxide in the atmosphere and in the oceans is an increasing threat to the continued existence of mankind. The toxic products of combustion of coal are also a major public health problem. The soot resulting from combustion of fossil hydrocarbons contributes to melting of both glaciers and floating ice.

IPCC CO2 emission data from electricity systems around the world shows that the lowest emission large electricity systems (< 40 gms CO2 / kWh) contain a high penetration of hydroelectric and/or nuclear generation. Electricity systems with a high penetration of variable renewable generation (wind and solar) have much higher average CO2 emissions (~ 228 gms CO2 / kWhe for natural gas backup to ~ 557 gm CO2 / kWhe for coal backup). Purely coal based electricity generation emits about 973 g / kWhe.

The reason for the higher average CO2 emissions from electricity systems containing variable renewables is that in most jurisdictions zero emission storage technologies are too expensive and too inefficient to provide the backup electricity generation required at times when the variable renewable generation cannot meet the electricity load. The energy source for the backup electricity generation used with variable renewable generation is usually a fossil fuel. The result is much higher average CO2 emission levels in electricity systems with variable renewable generation than in electricity systems that rely heavily on hydroelectric and/or nuclear generation. Exceptional situations exist in British Columbia, Quebec and Norway where due to local geography much of the electricity comes from hydroelectric power and where mountain valleys have permitted construction of large amounts of seasonal hydraulic energy storage.

The recent average CO2 emission levels of a few large electricity systems are tabulated below.

ELECTRICITY    SYSTEM	YEAR	CO2 EMISSION    (g / kWhe)	DATA SOURCE
Ontario	2015	40	P.24 https://www.ospe.on.ca/public/documents/.../2016-ontario-energy-dilemma.pdf
PJM	2016	450	fig. 3 http://www.pjm.com/~/media/library/reports-notices/special-reports/20170317-2016-emissions-report.ashx
MISO	2015	800-1,000	P.20 https://www.misoenergy.org/Library/Repository/Communication%20Material/EPA%20Regulations/MISOEPACO2EmissionReductionAnalysis.pdf
Germany	2011	557	https://www.eea.europa.eu/data-and-maps/figures/co2-electricity-g-per-kwh/co2-per-electricity-kwh-fig-1_2010_qa.xls/at_download/file

To achieve rapid and deep (>80%) carbon dioxide emission reductions, the most cost effective solution using currently available technologies is to increase the penetration of hydroelectric and/or nuclear generation, especially for base load (24 hour a day) energy requirements. That is just one of many inconvenient engineering facts about climate change mitigation that many people are reluctant to accept.
 

Ontario has now taken its coal fired electricity generation plants out of service, has replaced them with a mix of natural gas combined cycle gas turbines (CCGT) and simple cycle gas turbines (SCGT) and is building further electricity generation using non-fossil fuel technologies. Ontario needs to develop sufficient new non-fossil electricity generation capacity to both replace existing natural gas fired electricity generation and to displace fossil fuels in the transportation and heating sectors.
 

DISTRIBUTED RENEWABLE GENERATION:
As compared to solar and wind generation nuclear thermal generation has the disadvantage that about two units of heat must be dissipated at or near the reactor site for every unit of electrical energy generated. Provided that the thermal electricity generation facility can efficiently track the instantaneous electricity load this heat dissipation can be mitigated but not prevented through use of distributed renewable energy generation. Thus, in future nuclear power plants thermally efficient load tracking may be an important performance feature. In practise high thermal efficiency is best achieved using multiple step controlled steam turbines, so that each steam turbine operates at a high energy conversion efficiency. This control methodology requires automatic pre-synchronization of the next steam turbine to be loaded.

An issue not appreciated by many people is that most existing solar and wind generators couple electrical energy to the grid via static power inverters. These static inverters do not provide either the moment of inertia or the VAR compensation capacity inherent in a steam turbine driving a synchronous generator. In essence each static inverter has to borrow both moment of inertia and VAR compensation capacity from other firm generation. This constraint limits the ratio of interruptible power to firm power.
 

POWER MATCHING CONSTRAINT:
Electricity systems operate under the constraint that total instantaneous power generation must always equal total instantaneous load power. If some portion of the total generation is intermittent then complaince with this power matching constraint requires energy storage and/or load control.
 

ENERGY STORAGE:
Distributed energy storage must be added behind both generator and load electricity meters to smooth outputs from wind generators and to improve the utilization of the generation, transmission and distribution systems. Large reservoir dammed hydraulic energy storage, dispatchable synthetic liquid fuel production and dispatchable electro-chemical processing are required to provide efficient daily and seasonal balancing of intermittant renewable electricity generation.

An electricity rate with a low marginal cost per kWh when there is surplus non-fossil power is needed to financially enable energy storage and cost effective fossil fuel displacement. The electricity rate at other times should be primarily based on the registered peak kW or kVA damand during each billing period.
 

ELECTRICITY SYSTEM EVOLUTION:
A balanced one hour presentation relating to the optimal electricity system evolution in North America is: Jesse Jenkins April 2019 Video.

In order to completely displace fossil fuels and hence limit global warming, the per capita installed non-fossil electricity generation and corresponding transmission capacity must be increased several fold. Of particular near term importance is prevention of real estate development along corridors that in the future will be required for energy transmission or in river valleys that in the future will be required for hydraulic energy storage.

The electricity generation, storage, transmission and distribution infrastructure must be sufficient to allow rapid population growth in Ontario to accommodate people who are forced to migrate to Ontario from other countries due to rising sea levels, drought and conflict resulting from CO2 triggered climate change.

The change from an electricity transmission and distribution network based on central generation to an electricity system containing significant distributed electricity generation requires changes to the metering methodology, electricity rates, voltage regulation methodology, fault isolation switchgear and system control. The output variability of wind, solar and hydraulic generators requires additional investment in electricity transmission and energy storage.

The present use of dispatched natural gas fired combustion turbine generation for load following must be replaced by dispatch of load used for: displacing fossil fuels, charging energy storage and production of synthetic liquid fuels.
 

FUTURE RATE STRUCTURE:
The generator compensation rate structure should contain strong financial incentives to encourage every distributed generator to maximize capacity factor and to contribute to grid voltage stabilization.

To enable behind the meter energy storage and to minimize transmission/distribution costs electricity rates applicable to both generators and loads must financially reward parties that normally input or output electricity at a nearly constant rate.

In order to financially enable energy storage there must be public certainty that for at least a decade into the future the marginal on-peak electricity rate per kWh will be at least three times the marginal off-peak electricity rate per kWh. Absent that minimum daily rate swing behind the meter energy storage is not economical for its owner and hence will not be built. Absent energy storage intermittant renewable electricity generation is not economic due to its unreliability and inefficient use of transmission / distribution resources.

In order to financially enable construction of required transmission/distribution, transmission connected generators should pay for transmission costs at the same rate as LDCs and distribution connected generation should pay for distribution at the same rate as retail load customers. Otherwise electricity rates are distorted and the required transmission/distribution is not built when and where required. Unless generators directly pay for the transmission/distribution that they use the generators lack sufficient influence over transmission/distribution planning and lack financial incentive to operate at a high capacity factor.
 

LACK OF POLITICAL WILL:
Ontario politicians have repeatedly demonstrated lack of political will to impose a fossil carbon tax. The availability of low cost natural gas fuelled electricity generation presently prevents the wide daily swings in electricity price that are required to financially enable behind the meter energy storage. Absent energy storage most renewable electricity generation does not make economic sense because it does not reliably meet the instantaneous power requirements of the firm load. This politically absurd situation makes Ontario overly dependent on nuclear power.

The electricity system needs a combination of fast neutron reactors and interruptible loads to enable non-fossil generation tracking of uncontrolled load. The lead time for fast neutron reactor development and deployment is likely close to 20 years. The lead time for large scale deployment of interruptible load is comparable. The politicians have totally failed to face this energy system planning reality.
 

IRRATIONAL PUBLIC RESPONSE:
There is a large segment of the public that for irrational reasons is unwilling to face three major electricity grid related problems, all of which can be solved by intelligent application of nuclear power. These problems are:
a) Seasonality of renewable electricity generation;
b) Inability of renewable electricity generation to fully displace fossil fuels;
c) Moment of inertia

(a) SEASONALITY
A fundamental problem, true almost anywhere on Earth's surface, is that there are significant time periods (about two weeks) when the wind is too low and it is too overcast for significant renewable electricity generation.

The only technology that can efficiently and economically store and then supply sufficient electrical energy to bridge these time periods is the large hydroelectric dams that hold back enormous lakes. There are only a few places in the world with the required geography. Even then this energy storage technology is limited because during the period when it must supply electricity the downstream water flow is enormous whereas at other times the downstream water flow is very low. Since these situations are exceptions rather than the rule they are ignored herein.

There are only two ways of supplying clean energy during extend periods of low renewable power output. One is with nuclear reactors or large hydraulic systems. The other is with very long electricity transmission lines. The fundamental transmission problem is that wind is generated by atmospheric absorption of solar radiation. It may be necessary to transmit electricity 2000 miles to obtain it from a zone where there is significant wind. The cost of sufficient transmission for implementing this strategy is prohibitive.

Once society faces the need for sufficient nuclear power to bridge periods of low renewable generation, then there is little need for either extensive transmission or renewable generation. At that point these promoters get all excited about loss of employment, etc. without facing the reality that they should go back to school and study physics and nuclear engineering.
 

(b) FULL DISPLACEMENT OF FOSSIL FUELS:
The second problem that renewable advocates fail to face is that displacement of existing fossil fuel generated electricity solves only about (1 / 5) of the atmospheric CO2 problem. The other (4 / 5) is mostly energy used by industry for mining, smelting, production of base metals (aluminum, sodium, nickel, steel, chromium, zinc), production of ammonia (fertilizers), production of cement, production of paper, powering ships, fueling airplanes, etc. None of these major industrial processes lend themselves to economic use of intermittent renewable electricity. While at great effort and expense society might provide convenience electricity with renewables, that strategy does not begin to solve the atmospheric CO2 problem. Solving the CO2 problem requires fuel sustainable nuclear reactors for industry, so preventing use of similar reactors for supply of public electricity makes no logical sense.
 

(c) MOMENT OF INERTIA:
Back in 2007, when wind generation was in its infancy in Ontario, I could already foresee problems that would occur due to deployment of current source inverters with wind and solar generation. I represented to the then regulatory body, the Ontario Power Authority, that Ontario should force the use of voltage source inverters (grid forming inverters), to preserve grid stability. My representation was denied because the high cost of such equipment was politically unacceptable. Similar decisions have been made by virtually every other electricity regulatory jurisdiction.

Flywheel action can be electronically simulated. In normal synchronous electricity system operation very little power flows into or out of a synchronous flywheel. However, when there is a sudden grid frequency or phase change enormous amounts of power are emitted or absorbed by the flywheel. This action can be electronically using nickel metal hydride batteries (such as are used in hybrid vehicles for acceleration and braking), but the required battery bank is large and the required solid state switching devices are expensive. The average heat dissipated by these switching devices is small, but on a grid transient all of a sudden they must switch megawatts. If the peak thermal dissipation rating of these devices is exceeded they will fail within milliseconds. The result is an expensive battery and solid state switch that seldom operates at its rated capacity and that potentially emits high power switching spikes.

Such solid state voltage source solutions involve a compromise between performance and cost. A flywheel can be electronically simulated, but a full flywheel simulation is prohibitively expensive. It also does not make global economic sense, particularly when it is also necessary to solve problems (a) and (b) above which generally provide the required moment of inertia using a steam turbine.

One of the operational difficulties is inadequate generator compensation. In some jurisdictions, such as ERCOT, the existing generation compensation is all based on delivered energy. When there is a high penetration of renewables no private party will finance new dispatchable generation because the average power load seen by that new generation is too low. Remedying this problem requires new legislation which in Texas is contrary to present republican government policy. Fundamentally generators must be adequately paid for providing grid stability and transmission efficiency, even if they supply relatively little energy.

A related issue is VAR compenstion. Real electricity loads, such as motors, have an inductive component which causes reflected quadrature power measured in Volt Amps Reactive (VAR). One of the features of a synchronous generator is that it can perform VAR compensation, thus maximizing transmission capacity, whereas VAR compensation is beyond the capability of most static inverters.
 

This web page last updated June 28, 2025.