How can solar energy fit our needs when the sun doesnâ€™t shine? These two innovations in battery technology could be the answer.
So long as the sun is shining, solar energy is an abundant source of renewable energy which can be relatively cheap to deploy. It can also have a relatively low impact on the environment, as we can set up solar fields on sites thatÂ areÂ unusable for things like home development or farming. This approach has led to a solar energy boom in places like Spain, and China is currently racing ahead of the West in terms of solar energy innovation.
However, one of the greatest obstacles to creating energy networks based on solar is keeping that solar energy in long winter months when we donâ€™t have access to an abundance of sunlight. Itâ€™s a problem that has shadowed solar power innovation and been used as one reason why we need to keep on using fossil fuels. It is a reasonable point, even if fossil fuel companies and their supporters are using it to perpetuate their dying industry.
Photovoltaic solar panels, whichÂ are what we use today, require exposure to sunlight in order to start off the reaction that gives us electricity. In places where the sun doesnâ€™t shine all year round, that can be a major headache, as no sun means no reaction and thus no power. There are some solutions to this, and they are important to understand as we move towards a future where solarÂ power is a leading candidate for our energy needs.
Tesla, among other companies, is developing domestic â€śsolar batteriesâ€ť that can store solar energy. These batteries would allow us to essentially stock up on solar energy during the daytime andÂ use the surplus throughout the night.
They would be particularly useful for homes with their own solar panels, for example in states like California that now require all new builds (with few exceptions) to have solar panels.
On a macro level, serving the wider energy gridâ€™s needs is actually more complex.
Individual houses may have spikes in their general usage,Â but those are relatively easy to deal with on a house-by-house basis. However, unlike burning fossil fuels, which we can do toÂ match increases in demand, we canâ€™t as easily increase solar and wind energy to serve energy demand spikes, say after a big football game or even more sustainedÂ energy spikes resulting from weather like the Polar Vortex.
We need large energy storage facilities to overcome this obstacle and to manage the flow of electricity demand. It is possible to do this now, but it comes at a cost, and not just a high price tag. Like most large-scale battery storage solutions, there are risks.
The current crop of lithium-ion storage batteries could deliver a reasonable level of energy efficiency, but they also present a major fire hazard. Remember the exploding Galaxy Note 7 batteries? Imagine that but on a significantly larger scale, andÂ you can quickly see why this isnâ€™t necessarily an attractive option for utility-scale batteries.
Indeed, itâ€™s somethingÂ thatÂ cities like New YorkÂ already want to guard against before they consider how to scale these kinds of batteries for general utility use.
But what if we could side-step the conventional battery and find another solution? There are a couple of excitingÂ innovations in the pipeline.
One such innovation relies on â€śbottlingâ€ť heat via what is known as a â€śthermal batteryâ€ť. Essentially, any material that can get warm when exposed to sunlight qualifies as a thermal battery, but obviously not any old household item will do for actually storing and delivering usable energy.
Scientists atÂ the University of Massachusetts believe they have a plastic-like material calledÂ AzoPMAÂ which switches between energy forms depending on environmental conditions. When exposed to sunlight, the polymer will absorb heat in a high energy state. When later triggered, it will adopt a different state and expel the heat energy has been storing.
The applications for this are obvious.Â Thermal batteries could be ideally suited for powering individual units in the same way Tesla is forging ahead with its electric cars but reportedly with much greater energy storage capabilities, at some 200 times that of water.
MOSTÂ relies on much the same principle of exposing a materialâ€”in this case a special fluidâ€”to sunlight via a solar thermal collector (a kind of solar panel) and then using the liquid to store energy. That liquid can be stored at room temperatureÂ andÂ holds onto the heat it has collected. Then, when it is passed over a catalyst the fluid will warm and release its stored heat.
The added benefit of this process using a specialized fluid is that it can be looped, meaning that once installed the fluid could go through this process again and again, capturing and delivering heat with very little degradation and no carbon output.
Obviously, there is a lot of complex science behind this and a number of obstacles still to overcome. What it does mean is that, in theory, the MOST system could work to heat our homes in much the same way as a gas-fired central heating system.
Thereâ€™s a long way to go before we have an all-encompassing solar energy solution, if that is ever possible. What recent progress on finessing solar energy storage and usage shows clearly is that, while fossil fuel companiesÂ and the Trump administration may like to say fossil fuelsÂ are a crucial a part in meeting energy demand, solar energy and other renewables are closing the gap fast.Â That gap is closing not just in terms of energy generation potential, but also in how they can integrate into our homes and into the wider utility gird.
Photo credit: Getty Images.