Engineering on the grid
Over some of the past blogs, we have talked about the different aspects of solar energy, its applications, the technological advances and the materials behind it. This week we concentrate on the storage capabilities of solar energy dependent upon on and off grid scenarios.
The electrical grid, also known now as the smart grid, is an interconnected network of electrical power plants, substations and the transmission lines that was developed to supply vast areas with electricity. Power plants are used to create great amounts of high voltage electricity using different types of energy sources of which we will discuss later in this blog. The electricity that is created is carried via transmission lines to smaller substations that are capable of reducing the voltage and redistributing it to households and commercial building applications. While the use of dams in hydro electric power plants has been a large energy supplier since the mass production of electricity was developed, a large number of power plants have used different types of combustible materials to generate the electricity such as coal and natural gas. With the push for energy independence and the desire to lower the impact these types of fuel usage have on the planet, engineers and scientists have been looking for ways to increase the impact of renewable and cleaner energy sources. Wind, nuclear and solar, in addition to hydro power are the main non-combustible sources in use to date.
As solar engineering technology has improved to maximize our use of solar, we have to understand that the greatest challenge is the fact that we only have access to the sun at limited intervals, so storage becomes a concern. Being attached to the grid is the most sensible and cost effective approach to storage as new technology has allowed us to put electricity back into the grid on large and small scales.. During daylight hours, any excess solar electricity generated can be fed back into the grid which helps lower the demand for electricity from combustible sources. As solar energy becomes more affordable and efficient, the amount of electricity pushed back into the grid will only reduce the need for other sources. As an individual home or business owner using solar power, this basically means you have the ability to receive credit back for unused electricity in the form of monetary savings.
Chemical electric energy storage is one option
In areas that do not have grid access, the method of storage is not quite as simple. Chemical electric energy storage such as batteries would seem to be the most logical method but they have limited storage capabilities and the materials such as lithium used for battery construction, is scarce and expensive. These are the main concerns for electrical engineers that are working to increase the efficiency of this type of storage. When a series of batteries are connected together, they create a storage bank from which electricity can be made available for emergency or back up applications. This is a solution that can be rather large or small in both size and cost depending on the application. As we discussed in previous blogs regarding the difficulties from disasters such as hurricanes, this could provide a viable solution to generate the power needed for pumps and emergency lighting during blackouts.
A type of mechanical energy storage that I find compelling yet simple is used on a more commercial scale is known as pumped hydro electrical storage. This method of storage uses the solar energy to run large pumps that transfer water from lower to higher elevated reservoirs in the daylight hours and allow for the hydro electric power station to operate and create electricity during the evening hours as needed. While this is not a direct storage application for solar, it allows for the operation of hydro electric stations in areas with less access to ample water supplies. While evaporation means you would have to have some sort of replenishment of water, the possibilities for being able to generate electricity in more barren regions of the world makes this solution appealing.
These are just a couple of the many different types of storage being improved and developed every day. In future blogs, we will discuss in depth some of the more intricate methods such as superconducting magnetic energy storage systems, as well as using more routine styles such as compactors and compressed air. We have certainly come a long way since the days of Edison and Tesla, but we have not slowed down on moving forward in ways to harness, store and utilize the different sources for electricity.