Distribution grid in B.C.
BC Hydro generates power by harnessing the power of moving or falling water to produce mechanical/electrical energy. BC Hydro generates over 43,000 gigawatt hours of electricity annually to supply more than 1.6 million residential, commercial and industrial customers. This power is delivered using an interconnected system of over 73,000 kilometres of transmission and distribution lines.
So how do we generate this power? The process begins before electricity even reaches customers. The steps to generating electricity from a dam and how it is transported are outlined below.
- Hydro dam: There is potential energy stored in a water reservoir behind a dam. It is converted to kinetic energy when the water starts flowing down the penstock, from the dam. This kinetic energy is used to turn a turbine.
- Generator: The falling water strikes a series of blades attached around a shaft which converts kinetic energy to mechanical energy and causes the turbine to rotate. The shaft is attached to a generator, so that when the turbine turns, the generator is driven. The generator converts the turbine's mechanical energy into electric energy.
- Step-up transformer: Voltage is the pressure that makes electricity flow. Generators usually produce electricity with a low voltage. In order for the transmission lines to carry the electricity efficiently over long distances, the low generator voltage is increased to a higher transmission voltage by a step-up transformer.
- Grid high voltage transmission lines: Usually supported by tall metal towers, carry high voltage electricity over long distances.
- Terminal stations: Control power flow on grid transmission lines and reduce the grid voltage to sub-transmission voltage.
- Sub-transmission lines: Sub-transmission lines supply power from terminal stations to large industrial customers or distribution substations.
- Customer use: Electric energy can be sold at transmission voltage to users of large amounts who own and operate their own substations. Most customers, however, are unable to accept energy at transmission voltage, and require that it be stepped down in a transformer.
- Distribution substation: A system of transformers, meters, and control and protective devices. At a substation, transmission voltage is reduced to lower voltages for distribution to residential, commercial, and small and medium industrial customers.
Energy can be stored in a variety of ways, including (excerpt from EPA electricity storage):
- Pumped hydroelectric: Electricity is used to pump water up to a reservoir. When water is released from the reservoir, it flows down through a turbine to generate electricity.
- Compressed air: Electricity is used to compress air at up to 1,000 pounds per square inch and store it, often in underground caverns. When electricity demand is high, the pressurized air is released to generate electricity through an expansion turbine generator.
- Flywheels: Electricity is used to accelerate a flywheel (a type of rotor) through which the energy is conserved as kinetic rotational energy. When the energy is needed, the spinning force of the flywheel is used to turn a generator. Some flywheels use magnetic bearings, operate in a vacuum to reduce drag, and can attain rotational speeds up to 60,000 revolutions per minute.
- Batteries: Similar to common rechargeable batteries, very large batteries can store electricity until it is needed. These systems can use lithium ion, lead acid, lithium iron or other battery technologies.
- Thermal energy storage: Electricity can be used to produce thermal energy, which can be stored until it is needed. For example, electricity can be used to produce chilled water or ice during times of low demand and later used for cooling during periods of peak electricity consumption.
Learn more about the Tŝilhqot’in solar farm.
B.C. is powered by water
In B.C., we have a unique advantage. The province’s natural landscape has allowed us to generate and deliver clean, renewable power to B.C. residents for decades. And as we look to the future, BC Hydro has an ambitious goal to do more.
Our plan to electrify B.C.
BC Hydro will be instrumental in building a sustainable economy in B.C. We’ll continue to support conservation efforts, while also offering new programs and incentives to help British Columbians make the switch from fossil fuels to clean hydroelectricity to power their homes, businesses, and vehicles. We’ll also help to attract new energy-intensive industries to B.C. and offer programs to reduce the time and costs for new customers to get connected to our grid.
Our goal is to reduce greenhouse gas emissions in the province by 900,000 tonnes per year by April 2026 – that’s around the same as taking 200,000 gas-powered cars off the road for one year. Our Electrification plan outlines how we’ll get there.