Science & Technology in Action

15th Edition

Transforming the grid for the next generation

Eirgrid

Between 2019 and 2024 smart meters will be installed in homes and businesses throughout the country in place of the older electromechanical meters. The new meters will provide live data on the use of electricity to both consumers and suppliers. The data will enable suppliers to manage the network more effectively.
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Contains the full lesson in 2 formats A4 and A3 along with a supporting toolkit, including a powerpoint slide deck and teachers’ notes.

Lesson excerpt

What is the ‘grid’?

The electricity grid is the network of high voltage overhead lines and underground cables that transmit electricity from power stations, or other sources, to local distribution networks. In Ireland the transmission network (‘the grid’) operates at voltages above 110,000 volts while the local distributions networks generally operate at lower voltages (from 230 volts to 110,000 volts). A map of the grid can be downloaded from http://www. eirgridgroup.com/the-grid/

Matching supply and demand

Demand for water, oil and gas varies throughout the day and indeed throughout the year. However, enough of these resources can be stored to meet the country’s demand for days, weeks or even months. Demand for electricity varies from minute to minute but the energy cannot be stored to meet the total demand for more than a few minutes. Instead, most of the required electricity is generated as required and stored energy is used – in the form of batteries or pumped water storage – to meet short term peaks in the demand.

It takes many hours to start up coal-fired power stations and get them to full capacity. For this reason they are generally left running at low levels as much as possible. Gas-fired and hydroelectric power stations can get to full capacity in minutes and so they can be used to meet anticipated peaks in demand.

The supply of electricity from renewable energy sources (particularly wind) can be forecast to some extent and where possible it is added to the grid so that the use of non-renewables (especially gas) can be reduced.

Balancing the supply and demand for electricity for the whole island is therefore a complex task which requires constant adjustment. This is carried out jointly by the National Control Centres (NCCs) in Dublin and Belfast where electronic systems process large amounts of data in real-time. Ireland and Northern Ireland have agreed an ambitious target of meeting 40% of the electricity demand from renewables by 2020. Targets for 2030 are more ambitious, with an expected 70% of the electricity demand coming from renewables in Ireland. As fossil fuel systems are increasingly replaced with renewable power plants, the task of matching demand and supply will become more complex. Smart technologies will provide part of the solution.

True or False?

  1. The electricity grid consists of low voltage overhead lines and underground cables. false
  2. Electricity is generated in power stations. true
  3. It is difficult to store large amounts of energy in a reusable way. true
  4. Gas-fired and hydroelectric power stations can get to full capacity in minutes. true
  5. Renewable energy sources are very predictable. false
  6. A Smart Grid provides greater control to both electricity consumers and suppliers. true
  7. Smart meters can share data with mobile phone apps. true
  8. Synchronous generators must be run at constant speed. true
  9. In future we will be less dependent on renewable energy. false
  10. Ireland’s total electricity requirement is expected to rise at least 10% in the next 10 years. true

Glossary of terms

50 Hz
fifty complete cycles per second
alternating current
electric current whose direction is reversed at a fixed frequency known as the mains frequency; the mains frequency in Europe is 50 Hz
data centre
A facility housing computer systems and associated components. 
fossil fuel
coal, oil or natural gas that result from the fossilisation of ancient plants or animals
frequency
the number of complete oscillations or cycles per second
greenhouse gases
the gases that contribute to the greenhouse effect including carbon dioxide, methane, nitrous oxide, ozone and water vapour
high voltage
generally taken to mean voltages above 110,000 volts
hydroelectric
the production of electricity by a flow of water
in phase
In satellite navigation terms 'in phase' means that the appropriate parts of two signals coincide
Internet of Things
networking of physical devices such as domestic devices by using smart electronics
intermittent
stopping and starting at irregular intervals
power station
an industrial plant in which electricity is generated
non-renewables
fuels such as fossil fuels that are not replaced naturally at the rate they are used
non-synchronous generation
generation of alternating current at frequencies that are not fixed and so do not match the frequency to the national grid (50 Hz)
pumped water storage
a means of storing energy by pumping water to a higher elevation for later use in generating electricity
renewable energy sources
energy sources that are not used up or are replaced naturally; wind, hydro, solar heating panels, photovoltaic
synchronous generation
generation of electricity at a rate that is synchronised with the frequency and phase of the national grid ('the mains')
TWh
terawatt-hour; a thousand million watt-hours; 3.6x10^12 joules
transmission network
the power lines used to transfer electrical energy from a generator to a substation
wirelessly
without wires