In a way renewable energy will be more and more linked to homes and cars. And not just as users of renewable energy, also as storage.
I mentioned in my previous posts that storage is crucial to take full advantage of renewable energy since we cannot control the source, as we do with other forms of energy. Hence we need to immediately use it as it becomes available, unless we have some way to storage it for later use.
There are several ways to store energy, by creating fuel (solar fuel: hydrogen and oxygen) and storing it in tanks, by spinning a big, heavy, wheel converting electricity into motion and then making use of that motion to create electricity and by using batteries (there are also other ways but these are the most practical).
Rather than creating huge batteries (energy density in battery is relatively low when compared to fossil fuel) it could be more practical to have many, distributed, batteries, a few per each home, as proposed by Tesla.
Their Powerwall is designed to provide back up power for a small medium home (up to 3 bedroom) in a well designed package (see figure) whose cost, installation included, is around 7,000$. The idea is to make every house energy self sufficient by capturing solar energy through photovoltaic shingles and a battery to store the energy for later use when the Sun goes down.
Electric cars may also become, potentially, a huge reservoir of energy. Imagine a world, like the one in 2050, when all vehicles will be electric vehicles.
In Germany the plan is to have electric cars taking the upper hand in sales in 2030 (regulation is pushing for that) with an estimated sale per year (in 2030) of 5 million electric cars. That is about the total number of cars sold each year in Germany (there are 45 million cars in Germany as of 2016, and the average life per car is 9 years, hence 5 million cars are replaced each year). By 2045 all cars in Germany should be electric cars.
Now, that is to say that there will be 45 million batteries, most of them standing still (our cars are parked most of the time) that can be used as buffer storage for the electric grid. This is called V2G, Vehicle to Grid technology. However, although there have been studies to make use of this large expanse of batteries the feasibility (and cost) is doubtful.
More recently, a Bloomberg report analyzed the electric car forecast with a 2040 horizon and pointed out that there will be a growing stack of second hand batteries.
The reasoning is that once a battery has degraded to a 70% of its full functionality it will no longer be fit for a car (that car will no longer cover the miles you expect it to run between charges) and it will be disposed. Hence, why not use this growing pile of disposed batteries to provide energy storage for the grid. They expect that already by 2025 the available, usable, storage capacity provided by these disposed car batteries will reach 26GWh. By 2050 that figure should be big enough to cover the needs of electrical storage for the grid.
Clearly the “space” needed to stack all these batteries will be significant and possibly will give rise to new urban architectures and landscape.
Also important, whilst the drive towards self sufficient homes (in terms of energy) can be reached with a micro production of energy (the one provided by PV shingles on each home roof), the drive towards electrical vehicles is much trickier. In practice, one needs to generate sufficient power to replace the power provided by the billion of liters of gasoline that the electricity will replace. As an example in Germany every day 420,000 barrels (66,780,000 liters) of gasoline are consumed. This is equivalent to 714MWh. In a year this means 260.6GWh. This is about ten times as much as the current PV power installed in Germany.
As it can be seen from these numbers a huge investment is required to move to renewable sources. Most estimate put the contribution of renewable around 40-50% by 2050, if one takes into account all energy needs. And to achieve that we will need plenty of technology, including ICT, and even more commitment at political and social level.