The American company Tesla will launch in early 2016, Powerwall, high performance batteries that integrated into the production system of electricity through solar energy or wind power allow a house to be self-sufficient and work off-grid.

The price announced for the American market is $3500 for batteries with weekly cycles of 10 kWh. There is another model that will have daily cycles of 7 kWh, but the price has not yet been announced. For both products, the Tesla gives a 10 years warranty.

For most houses, a 10 kWh battery is enough to suppress all daily consumptions. Obviously it has to be done a study on a case-by-case, but the matter needs bigger, Tesla’s solution allows the batteries to be connected in series at the ceiling of 90 for the 10 model kWh and 63 for the 7 kWh.

As a reference it is considered that the normal consumption of a House is 30 kWh per day, but to have an idea of consumption consider the image below as a reference.

In the case of a solution by power generation with a solar panel, how does it work?

The Solar System consists of solar panels, electric inverter and battery to store the excess solar energy for later use.
The Solar panels installed on the roof converts sunlight into electricity. The battery stores the surplus electricity generated during the day, or inserts on the utility network when linked on-grid. Already the inverter transforms direct current generated by the solar panels into alternating current for the use of various appliances and lighting.

According to studies, the daily consumption in housing is higher during the morning and evening, and during the day when solar energy is more abundant it is precisely when the power consumption is lower.

From what you can see in the figure above, the production of energy to be higher than the consumption during the day, allows that there is a build-up of energy for the period of greatest consumption.

In a system without accumulation and off-grid a solution, this excess energy is wasted.

On-grid, when the battery is charged by the electric energy of solar panels (or farms), the release of this excess energy, is injected into the network and sold to the power company. In the classic model, without the Tesla battery or any battery that accumulate the energy, the owner will buy energy back to your night consumption and the next morning.
In the case of households, this business is called Microgeneration and in most countries it works in auction system, so it is not always possible to make this contract with the dealership, causing the current energy matrix becomes dependent on the economic interest of the dealers or the State for this trade.

Powerwall fills this gap between renewable and conventional energy market, providing a “battery” of energy in which the owner produces for use when you need it, at your discretion, put (or not) on the public network the energy created in excess.

Within the same concept but applied to the commercial and industrial market, where the installation capacity of power generation equipment is greater, the Tesla has a similar solution, but with the name of Powerpack, where each module has 100 kWh. It can also be coupled in series as the Powerwall.

Tesla announces that they will make their patent available to who may wish, aware that the global interest for this product will never be answered in an effective way, if it stays just with their company.

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