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

Electricity is electromagnetic field energy that propagates along guiding conductors at close to the speed of light.

Due to future constraints on use of fossil fuels, electricity must become the primary means of efficient medium distance transmission of energy.

Clean electricity is electricity that is generated without use of a fossil carbon fuel.

Sustainable electricity is electricity generated by use of fuels which have sufficent abundance that on the time scale of modern human existence the fuels will never be exhausted. Examples of such fuels are hydrogen and deuterium which fuel solar fusion reactions, deuterium and lithium which might potentially fuel fusion reactions on Earth, and U-238 and Th-232 which can fuel breeding type fission reactions in nuclear reactors. Hydroelectric generation, wind generation and solar generation are all means of capturing energy from solar fusion reactions.

Fossil fuel generated electricity is not sustainable because this electricity source is energy limited both by existing fossil fuel geologic reserves and by accumulation of CO2 in Earth's atmosphere.

Grid supplied electricity can be divided into two portions, dependable power which is reliably available and interruptible power which is intermittently available.

Dependable power is generally supplied by multiple parallel connected electricity generators which do not have common mode failure mechanisms. A dependable power source has at least a 99.7% probability of meeting the consumer controlled electricity load at every instant in time.

The main sources of dependable power are large hydroelectric generators, nuclear thermal electric generators and fossil fuel thermal electric generators. Generally, the total available dependable power generation capacity should be at least 15% greater than the peak consumer controlled electricity load in order to meet the required electricity supply reliability criteria.

Energy derived from the sun via hydropower, wind power or solar power is referred to as renewable energy. Wind power and solar power are intermittent and hence are unsuitable for supply of dependable power. Smaller hydroelectric sites usually exhibit seasonal intermittency whereas very large hydroelectric storage dams can provide dependable power.

Interruptible power is electricity which is centrally dispatched to the extent necessary to usefully use the instantaneous clean electricity generation capacity which is surplus to the electricity grid's instantaneous dependable power load. At each consumer premises the interruptible load should be automatically enabled/disabled in real time by a consumer specific control signal from the LDC (Local Distribution Company) or IESO (independent Electricity System Operator). The interruptible load enable/disable signals should be computer generated to fairly share the total available interruptible power over all the interruptible power users.

The main sources of interruptible electricity are intermittent wind electricity generation, intermittent solar electricity generation, energy storage and unused dependable electricity generation.

Dependable electricity provides the dependable power required by most existing electricity applications, but bears a premium price per monthly peak demand kW measured at times when interruptible power is not available to the consumer, as well as a low price per kWh consumed.

Interruptible electricity intermittently provides clean energy at the same low price per marginal kWh consumed but bears no peak demand charge.

Interruptible electricity provides consumers clean energy that would otherwse be discarded. The benefits of proper use of interruptible electricity include:
a) Reduced overall energy system costs;
b) Reduced fossil fuel consumption;
c) Reduced overall CO2 emissions;
d) Better alignment between electricity rates and electricity system costs.

Energy storage of interruptible electricity provides dispatchable power that is conditional on prior charging of the energy storage. Energy storage needs dedicated transmission and may need synchronous capacitors. Bulk energy storage is primarily used in power systems that have favorable geography for hydraulic storage. Short term (4 hour) energy storage can be achieved with batteries, but that energy storage is insufficent for handling seasonal load variations. In many circumstances it is less expensive to provide dispatchable nuclear power than to provide sufficient renewable generation and energy storage to meet worst case seasonal load variations. The main purpose of energy storage is to minimize short cycling of consumer loads.

In order to efficiently distribute interruptible power it is necessary to divide the electricity loads at each consumer premises into two categories, loads which require dependable electricity and loads for which interruptible power is sufficient. Appliances that use interruptible power, such as hybrid heating systems, often need an alternate energy source such as a stored liquid fuel in order to operate during periods when interruptible power is not available to a particular consumer.

The apparatus that measures the consumer's monthly dependable power peak demand in kW actually senses total power but ignores the power measurements during periods when the control signal from the LDC or IESO indicates that the consumer is permitted to draw interruptible power without financial penalty.

Applications of low cost interruptible power include:
a) Displacement of combustion fuels in heating systems;
b) Charging of battery electric vehicles;
c) Charging of thermal energy storage systems;
d) Production of green hydrogen by electrolysis of water;
e) Charging energy storage for routine daily time shifting of interruptible power generation.

This website section examines practical aspects of the public electricity system including:
electricity: generation, storage, transmission, distribution, measurement, control, dependability and rates.

An overview of Ontario Electricity System related environmental matters is contained in a 2018 report titled Making Connections by the then Environmental Commissioner of Ontario Ms. Diane Saxe.

This website section includes energy distribution via buried district heating piping systems.

This website section also includes synthetic liquid fuel synthesis for energy storage and energy transmission via fluid hydrocarbons moving through pipe lines.

The basic of electric power is a watt (W) where:
1 W = 1 joule / second = 1 J / s

The basic unit of electric energy is a watt-second where:
1 W-s = 1 J

In the case of electrical energy a joule is a unit of directed kinetic energy where:
1 J = 1 kg m^2 / s^2
If this directed kinetic/electrical energy is dissipated as heat it becomes 1 J of thermal energy.

Most electricity billings are expressed in kW and kWh where:
1 kW = 1000 W
1 kWh = 1000 W X 3600 s = 3.6 X 10^6 J

The outputs of large electricity generators are usually expressed in MW and MWh where:
1 MW = 1000 kW
1 MWh = 1000 kWh

The outputs of large electricity systems are usually expresed in GW or GWh where:
1 GW = 1000 MW
1 GWh = 1000 MWh

In situations where there might be confusion between units of electric power or electric energy and units of thermal power or thermal energy the subscript e is used to indicate an electrical unit and the subscript t is used to indicate a thermal unit.

There are many electricity related web pages, so please scroll down.

1. Electricity Introduction
2. Electricity Dependability
3. Ontario Electricity System
4. Electricity System Expansion
5. Displacement of Fossil Fuels
6. Electricity Regulatory Bodies
7. Conference Short Presentation (20 minute)
8. Conference Short Presentation Slides
1. Electricity Generation
2. Synchronous and Asynchronous Electricity Generation
3. Electricity Generation Constraints
4. Environmental Considerations
5. Distributed Electricity Generation
6. Wind Energy
7. Equipment Financing
8. OPA Feed-in Tariff
9. Generation Valuation, Grid Stability and Black Start
10. High Power Electronic Component Review
1. Energy Storage
2. Seasonal Hydraulic Energy Storage
3. Liquid Metal Electro-Chemical Energy Storage
4. Electrolytic Hydrogen
5. Synthetic Liquid Hydrocarbons
6. Synthetic Liquid Fuel
7. Nitrogen Fertilizers
1. Electricity Transmission
2. Electricity Transmission Black Start
3. Energy Transmission Planning
4. Distribution and Distributed Generation
5. District Heating
6. Pipeline Basics
7. Pipeline Corrosion
8. Letter To Premier Wynne
9. Electrically Accelerated Pipeline Corrosion
10. Natural Gas Pipeline Safety Setback
1. Existing Electricity Rate Problems
2. Electricity Rate Issues
3. Electricity Services
4. Retail Electricity Rates
5. InterruptibleElectricity.com
6. Interruptible Electricity
7. Interruptible Electricity History
8. Interruptible Electricity Opportunity
9. Interruptible Electricity Service (IES) Implementation
10. Interim IES Implementation
11. Electricity Regulatory Hurdles
12. Electricity Market Problems
13. Historical Electricity Rates and Introduction of Smart Meters
14. Variable Electricity Rate
15. Transmission/Distribution Cost Apportioning
16. Capacity Factor
17. Electricity Rate Derivation
18. Electricity Rate Structure
19. Low Overnight Rate Plan
1. Electricity Metering
2. Electricity Power Transducer
3. Electricity-Three Phase Metering
4. Electricity Meter Program
1. Smart Grid
2. OPA Integrated Power System Plan (IPSP)
3. Energy Vision
4. Letter to Ontario Minister of Environment
and Climate Change
5. Letter to Mininster of Environment
and Climate Change, Canada
6. U of T 17-02-09 Slide Presentation
7. U of T Presentation
8. Energy Policy

This web page last updated August 14, 2023.

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