Day in, day out you are using one of the biggest
machines in the world and may not even know it. It’s in your home, it lines the streets
and it’s powered by gigantic engines across the country. The biggest machine in the world isn’t this,
or this, or even this. It’s the electrical power-grid or more specifically
the US power grid. In the United States alone the grid contains
enough high voltage wiring to wrap around the earth 6 times over and that’s not including
all the low voltage wiring running through our streets and into our homes. This entire system was built in a little over
100 years and since then we have become very accustomed to having electricity available
to us at the flip of a switch, but before this machine existed our only sources of light
by night were lanterns and candles and nearly all our daily chores needed to be done by
hand. This giant machine started pretty small with
the world’s first central power station built on Pearl Street, Manhattan in 1882. Thomas Edison, the ever present American businessman,
saw an opportunity to not only sell more of his lightbulbs, but to sell the electricity
to power to them. So he built an electric generator driven by
a coal powered steam engine to create electricity at a cost that would allow his light bulbs
to compete with lanterns. The station contained 6 of these generators
each produced 100 kilowatts, enough to power 1200 of edison's lightbulbs, allowing edison
to sell 7200 lightbulbs, which needed to be replaced regularly, as these early bulbs lasted
about 1200 hours. Even then the project ran an operating loss
for it’s first 2 years. Setting up this system was a bold business
move. The machines, the conduits and the 30 kilometres
of wiring needed for it were expensive at a cost of 300,000 dollars or about 20 million
dollars in today’s money. The expensive Lower Manhattan real estate
didn’t help either, but Edison’s placement of the Pearl Street Station was vital to the
success of his idea, as it had the population density to make the project financially viable,
but he also made one of his first customers The New York Times. Who published a story about the historic event,
reporting that the light was “soft, mellow and graceful to the eye…without a flicker
to make the headache.” This was all the marketing Edison needed and
demand for the system grew, but this pointed out one of the systems major flaws. It couldn’t scale economically without installing
more power stations nearby, because it generated a low voltage direct current and to efficiently
transfer power over long distances we need to transform the low voltage to a higher voltage. The power loss equation states the power lost
in transmission equals the current squared multiplied by the resistance of the wire and
so to reduce power loss we really need to minimise the current. This equation describes the relationship between
power transmitted and the voltage and current. The community demand fixes the amount of power
required and so to decrease the current we need increase the transmission voltage. Alternating current’s main advantage over
direct current isn’t that it loses less power over long distance, but that it can
be transformed from low voltage to high voltage much more efficiently than direct current. Thus as demand for power grew across the nation
the famed argument between Edison’s idea to have many smaller generators located near
population centres and Nicolas Tesla’s idea of having one large efficient engine located
far from population centres grew. Of-course we know who won and today we have
hundreds of gigantic power stations located far from population centres generating gigawatts
of power. So what would a map of the current US electrical
grid look like? Let’s create a map showing the largest power
plants across the US. In areas where rainfall is high like Washington
state on the west coast and Alabama in the south there is a high volume of electricity
generated with hydropower. Where wind speeds are highest in central America
there is a growing number of wind turbines and states that get the most sun like california
and Arizona have the highest percentage of solar power, there are several high power
nuclear power plants located in areas where water is plentiful, which is needed for the
steam turbines and to cool their cores. Coal power plants tend to be close to coal
mines as its a very heavy fuel, but The largest percentage of energy in the US is generated
from natural gas, as it is the cleanest of the fossil fuels. Let’s zoom in on one of these power plants
to get an idea of how this energy is delivered to population centres. As I mentioned earlier it is vital that electricity
is transmitted at high voltage, so the first step as the electricity exits the power plant
is to pass it through a step-up transformer, the electricity is then delivered across these
high voltage power lines that you see stretching across the country. These power lines feed into local step-down
transformers for local distribution in neighbourhoods and gets stepped down again by these transformer
drums on poles outside your house. The electricity you consume in your home is
measured on a meter like this that reads the power running through the wire that enters
your house. So let’s say after a long day’s work you
come home and decide you want to watch the premiere episode of Game of Thrones. You plug in your viewing device of choice
and that meter starts to tick a little faster, along with millions of other meters across
the nation. Suddenly the biggest machine in the world
just got a little bigger and the engines powering it have to work harder to keep up with that
demand. This is one of the huge disadvantages of the
current power-grid. During low demand hours we have a number of
always on power plants called baseload plants, that are powered by reliable energy sources
like coal and nuclear. These maintain the baseload requirements of
the country, but what happens if one of these power stations fail? Suddenly the system doesn’t have enough
energy to meet demand and if we don’t have the ability to meet it power stations will
begin rolling blackouts where they cut the electricity to certain areas to prevent a
larger blackout. One of the largest of these rolling blackouts
to ever occur was the 2003 north-eastern blackout that left 50 million people without electricity. Rolling blackouts like this should usually
never occur in a country as advanced as the US. Modern countries will have many redundant
power sources that can be brought online when power demand surges or power stations go down
and excellent communication between all parts of the grid to ensure problems can be fixed
immediately. But as renewable sources like wind and solar
become more popular this micro-management of the power-grid is becoming even more difficult. We cannot command the weather to make these
power sources work harder when needed and the more likely scenario is that we have to
shut down these power sources while they could be generating energy, because they are generating
energy that is not needed, which can overload the system. It’s unlikely that we will be able to rely
on renewable energy without still having many baseload power plants running on natural gas,
coal or nuclear, unless we create an efficient way of saving this energy during peak performance
for later use when the demand is there. Currently the largest energy storage method
worldwide is hydro-electricity at about 80%. On some days of the year Denmark generates
so much energy from Wind that they have enough to export to countries like Norway, who often
use the advantage of their mountainous terrain to buy this cheap excess power to pump water
to the top of mountains. This water can then be released to power hydroelectric
turbines when it’s needed. Of-course this leads to some power loss, but
it is better than shutting down the wind turbines while they are at peak performance. This issue is only going to grow as solar
energy becomes more and more popular, which is why Tesla’s Powerwall is such an integral
part of making widespread home installed solar power a reality. If we cannot store the excess energy generated
by these panels during the day, for use when there isn’t sunlight, then we are still
going to depend highly on those baseload power plants using fossil fuels or nuclear energy. As the price of manufacturing solar panels
decreases it is inevitable that all countries will begin to move away from the current model
of the powergrid. We are at the brink of world changing moment
and the largest machines in the world are going to drastically change for the better. Large fossil fuel power-plants generating
AC electricity are quickly becoming out-dated and will be gradually decommissioned over
the next couple of decades and a new model for the power-grid will rise in it’s place. We will be gradually moving towards Thomas
Edison’s early vision of having many local low voltage power generators creating DC power,
but with a modern twist. They will all be powered by nothing more than
the energy we can draw from the ever replenishing pool that nature has provided us.
