Unit 2 - A Little Bit of Background: Energy, Electricity, and the Grid.
Energy is all around us in tangible and intangible forms. Energy can power cars, raises tides, gives you sunburns, launches rubber bands, gets you through gym class and even pushes space ships out of the solar system. Humans use energy in many ways, almost always to make life easier. As such, the flow and use of energy as used by an entire city, province, or country, is a very important field of study.
Energy can exist in many different forms (heat, mechanical, kinetic, electric) and can in many instances be converted into one form from another. Some forms of energy are more useful to humans than others and much technological innovation has been put toward the conversion of energy into useful forms. As an industry term, “energy” usually refers to the forms of energy that make humanity progress. These forms of energy propel cars, trucks, boats, and planes, they heat or cool matter (like water), they facilitate chemical reactions, and, above all, they provide useful work.
Electricity is special in the energy field because it lends itself relatively easily to conversion between different forms. A power plant burning coal 400 km away can convert chemical energy to heat and motion, which generates electricity, that is transported into your home where it can be converted (by your water kettle) back into heat or (by your coffee grinder) into motion. Electricity is sort of like a form of energy currency that can be bought using, and sold for, different types of energy.
The electric grid as we know it is an invention of the 20th century, but it has its beginnings in the late 1800’s. The electric grid is the complex infrastructure behind the generation and transmission of electricity. This includes power stations, power lines both large and small, substations that increase or decrease voltage or even convert electricity between alternating and direct current, and even the transformer outside your house. The electric grid wasn’t planned out from the start, like the way you would build a bridge, for example; it arose in response to the needs of the time, it has developed as technology and processes developed. Because of this, the grid can be inefficient in certain ways, can be easily disrupted, and can be very hard to understand!
The basics work like this:
- Electricity is generated in power stations, which are rated based on their power output (where power - in Watts - equals the flow of energy per unit time). Large power plants produce electricity on the mega Watt scale (1MW = 1,000,000 Watts). As example, 1 MW can power between 800-1000 homes at one time).
- The electricity is modified to make it fit for long distance transport and incorporation into the frequency of electricity already on the grid. These modifications involve increasing the voltage and sometimes conversion into direct current from alternating current.
- The electricity travels through power lines to ‘end users’ like homes and businesses (being lowered in voltage along the way) where it can be used at 120 volts, 60 hertz. A really important point to remember is that there is no stopping or storage of electricity in the system (with some minor exceptions – not discussed here, but e-mail us at The Gaia Project if you want to learn more).
- As soon as electricity is produced in a power station, it is consumed by an end user. Therefore, the amount of electricity in the system isn’t determined by the power plant or grid manager, it’s based on the demand of end users like homes, businesses, and industry. This last point is a key challenge in the electricity industry, all the electricity that could be needed has to be immediately available (even though it isn’t needed all the time).
Key things to remember are that:
- Electricity is produced based on demand. Generation follows demand.
- The system doesn’t store electricity.
NASA's Incredible Video showing the year in the life of Earth's CO2 (greenhouse gas) concentrations.
A very important aspect of energy creation is the emission of greenhouse gasses. Burning carbon-containing materials like coal, wood, natural gas, oil, and living organisms, releases carbon dioxide (CO2) - a known greenhouse gas. As CO2 and other gases accumulate in the atmosphere, they interfere with solar radiation that has reflected off planet earth, effectively trapping it with the atmosphere. You’ve probably heard of this causing climate change/global warming, and may have heard it referred to as the greenhouse effect. An easy way to think about it is to think about a greenhouse. Why do plants like greenhouses? Because they are sunny and warm – the glass or other transparent covering lets light into a greenhouse and traps heat inside. It’s the same thing as sitting in your car with all of the windows rolled up on a sunny afternoon – it gets hot because the heat is trapped in your car. Greenhouse gases do that for the earth – trap heat inside of the atmosphere. We need them, but are releasing lots of them through various things we’re doing, like producing electricity from fossil fuels like coal, oil, and natural gas.
Impacts of climate change vary by region (by the climate), but some impacts could be more/less flooding, more/less drought, rising sea levels, shrinking ice sheets and glaciers, changes in plant growth patterns and animal habitats, acidified oceans, among many other unknown changes. Energy planners carefully consider CO2 emissions in planning new power generation because too much CO2 in the atmosphere will lead to irreversible climate change.