Tesla CEO Elon Musk unveiled the company's new foray into the energy market with energy storage devices for residential and commercial buildings at an event in California on Thursday night. 

"Our goal here is to fundamentally change the way the world uses energy," Musk said. 

CBC News answers five questions about the newly announced batteries. 

What is it?

The wall-mounted Powerwall is a rechargeable lithium-ion battery that can be used to store electricity in homes.

There are two models, a 7 kWh version that sells for $3,000 and a 10 kWh one for $3,500. However, those costs do not include installation. Up to nine of them can be used together. 

Musk also said there is a commercial version called the Powerpack that delivers 100 kWh for use by electric utilities and companies. He said the unit is "infinitely scaleable" and one utility wants a 250 megawatt-hour facility which would consist of 2,500 Powerpacks.

What could you run using Powerwall?

It really depends on what kind of electrical devices you plan to use, as each draws a different amount of power. 

Tesla-Battery Power For Homes

There are two models of the Powerwall, a 7 kWh version that sells for $3,000 and a 10 kWh one for $3,500. (Ringo H.W. Chiu/Associated Press)

A kilowatt-hour (kWh) is the most common unit when measuring electricity consumption, according to BC Hydro. It is equivalent to 1,000 watts of energy used over the course of one hour. 

A 100-watt lightbulb running for 10 hours would use 1 kWh, for example. 

According to the Ontario Ministry of Energy, a typical family of four uses about 800 kWh a month, or about 27 kWh a day.

So a single 10 kWH Powerwall could conceivably power a home for several hours (depending on what sorts of devices were being used) but is unlikely to last the whole day without limiting your electricity usage. 

What does it do? 

Musk said the Powerwall is designed with home solar units in mind, giving owners the ability to store energy when the sun is shining but energy consumption is low (in the middle of the day, for example) for use during the evening. 

"The obvious problem with solar power is that the sun does not shine at night," he joked during the news conference. 

In Tesla's view, such storage systems could become part of a fossil-fuel-free lifestyle in which people can have solar panels on their roof generating electricity to power their home.

The unit can also be used for load sharing -- storing energy during off-peak hours when energy prices are low for later use during more expensive periods. 

In Ontario, for example, electricity prices vary depending on the time of day. During the summer months, each kWh of electricity used during the off-peak hours (7 p.m. to 7 a.m.) costs eight cents. Rates are more than double during the on-peak period of 11 a.m. to 5 p.m.

The Powerwall can also work as a backup during power failures. 

Some analysts have questioned the cost savings of the unit through load sharing given its high initial price tag, suggesting that its primary benefit is as a backup power source. 

When will it be available?

Tesla plans on shipping a limited number of Powerwall batteries in the U.S. beginning in the summer before expanding into international markets next year. 

The company is building a factory in Nevada that will begin churning out batteries in 2017.

Although Tesla is making the Powerwall, it will actually be sold by a number of other companies.

Is this the start of an energy revolution?

It's obviously far too early to tell what impact this will have. 

Some analysts have questioned whether the battery is too expensive for most consumers, which could discourage widespread adoption. 

Research firm IHS CERA, however, expects huge growth in the energy storage industry over the next few years, from $200 million in 2012 to $19 billion in 2017. 

Deutsche Bank estimated sales of stationary battery storage systems for homes and commercial uses could yield as much as $4.5 billion in revenue for Tesla. 

With files from The Associated Press, Reuters