At its most fundamental, energy comes in various basic forms; including chemical,
electrical, thermal, nuclear, radiant, and others. For humans to actually use any of it,
though, we need to transform it into something that we specifically require - like, for example,
electricity. And this, in general, is where engines come in, as essential facilitators of
that magic. And here, we’ve relied on the steam turbine for a long time, before some upgrades
in the twentieth century… but now, an even better engine might finally be on the horizon.
This is Unveiled and today we’re answering the extraordinary question;
have scientists already invented the engine of the future?
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Our world runs off of engines, but for the most part we still use the same ones we invented a
long time ago. Steam turbines were introduced by the engineer Charles Parsons in 1884 and,
really, they’re still the standard. Designs do differ, but they generally work via the
burning of fossil fuels, which evaporates water, which builds pressurized steam,
which builds up and up in an enclosed system until it pushes the blades of a turbine. In doing so,
heat is transformed into mechanical energy, which can then be used for electricity,
etc. But, despite their historic success, steam turbines aren’t without problems. On average,
they transform only about 35% - at most 60% - of the total heat energy they’re
subjected to into electricity. The rest is lost, making them very inefficient.
One of the base problems with steam turbines is that they themselves have many moving parts,
meaning a long list of stages and drop off points from the start to the finish of the process. The
many moving parts limit the temperatures that steam engines can handle, too, because each part
can only take so much heat before warping. And this is a major issue, considering an engine’s
entire purpose is to transform heat energy: steam turbines are inevitably, physically limited. As
such, contemporary research has instead grown around what are known as solid-state engines.
Solid-state engines have no moving parts, which is then a potentially huge benefit.
In 2022, researchers from MIT and the National Renewable Energy Laboratory in the US published
a study in the journal “Nature” detailing fresh experiments with a new type of solid-state engine.
From the very beginning, reports were that it averages at a 40% energy transfer rate,
which is already better than most steam turbines... although all hopes are that
its eventual performance will far, far exceed even that. The new engine runs
via a tweak on an emerging technology called a Thermophotovoltaic cell (or, TPV cell). A TPV
cell functions similarly to how solar panel cells, or photovoltaic cells, work. They take
photons (i.e., energy) from, say, the sun and turn those base particles into electricity.
What’s especially great about TPV cells, however, is that they can operate at temperatures much
higher than what’s possible with a steam turbine… meaning more heat and energy and
power passes through them from the outset. More than that, though, TPVs can be used to store
wholly renewable energy, as well. This is perhaps the most revolutionary part of them. According
to the study, and others since, by attaching TPV cells to a thermal battery, heat energy
can be held indefinitely… and later turned into electricity by the same TPV cell. This means that
even when the sun isn’t shining (or, perhaps, in another setup, the wind isn’t blowing) TPV
engines (backed up by thermal batteries) should continue to run and run, entirely unobstructed.
Thermal batteries aren’t a new technology, but their use in this way is still innovative. As is
the setup of the TPV engine itself. In short, the team behind it placed a thin gold sheet underneath
the TPV cell, to act as a mirror. That mirror then reflects any passing (but missed) photons
back into the cell, to be reabsorbed again and again… which then increases the efficiency of
the wider engine, ensuring that less is lost. But it’s hoped that the design can be made to be even
more efficient, still. Previous research in 2020 revealed a specific material that can (under the
right conditions) reflect back up to 99% of photons that reach it - much more than the
standard gold sheet. And so, if that material can be merged with this TPV technology, then we could
be on the brink of another major uptick in the engine’s performance. It’s already impressive,
but it could soon be even more so. Add into the equation that this new kind of solid state setup
has generally lower maintenance cost projections, too, and it’s easy to see why it could have a big
impact on the energy sector. According to one of the lead researchers, Professor Asegun Henry, TPV
cells were “the last key step toward demonstrating that thermal batteries are a viable concept”.
Before, despite their promise, the practical applications for thermal batteries appeared
to be limited… but now, with TPV cells bridging the gap, the possibilities open out and out.
At the top end of the scale, there are early talks of redesigned whole
power plants. Not just smaller, individual facilities, but entire,
socially and economically crucial energy bases. At present, most major power plants are in
some way dependent on fossil fuels to provide their energy. But fossil fuels are, of course,
non-renewable and destructive to the environment. Incorporate TPV engines, however, and all plants
could soon be humming along on the reliability of stored renewable energy, instead. At least,
that’s one potential (and exciting) direction in which the team behind this new engine believes
we could soon be headed. Especially as it’s also hoped that the new technology shouldn’t
be overly difficult to manufacture on a large scale, either. As TPV cells are fundamentally
similar to solar cells - and as we already have a growing number of factories to make those - a lot
of the early legwork has already been completed. On the face of it, this wouldn’t require a total
reinvention or a radically new process… it would only need some slight tweaks here and there.
If TPV engines are successfully implemented into modern life, then, what happens next? What
kinds of differences could they realistically make? Again, Professor Henry is optimistic. In
an accompanying MIT article for the original study, he says that; “the technology is safe,
environmentally benign in its life cycle, and [it] can have a tremendous impact on
abating carbon dioxide emissions from electricity production”. For those on the outside looking in,
then, could this finally be the missing piece needed to properly move away from
limited and damaging fossil fuels? Could this finally be the technology to convince the rest
of the world that renewables aren’t only a better idea, but that they’re feasible
and capable of meeting our needs, as well? What might the future look like?
In a best case scenario, perhaps we’ll see thermal battery powered TPV engines that are
actually powerful enough to provide energy for whole streets, towns, or communities. Or personal
TPV vehicles that never need to be filled up, but instead are kept running based on wholly natural
means - like the sun’s light, but also the winds and perhaps the tides of Earth, too. At present,
and even with renewable energy, there’s often a major mid-point through which all energy passes
as a commodity, from provider to consumer… but, with TPV, perhaps that midpoint will itself be
bypassed, as well? If nothing else, then the prospect of an engine and battery that can
store and use energy indefinitely… means that, beyond the manufacture of the actual engine,
users should be much less reliant on bigger companies for their energy needs. Quickly, energy
bills could be a thing of the past, with an engine that’s at once relatively easy to make, simple
to scale up, reasonably low-cost to maintain, and limitless in terms of its energy potential.
That said, converting an entire planet’s entrenched energy structure is no mean feat.
Redirecting an entire civilization’s long-held energy habits is more easily said than done. And
perhaps there are yet technical reasons as to why we aren’t already all enjoying the benefits
of TPV engines? What’s your verdict? Is this technology the holy grail for our collective
energy needs? Are there other reasons as to why it hasn’t been more widely pursued before
now? Is the energy sector perhaps unwilling to change, or is there actually still just a
long way to go before TPV properly takes off? Let us know your thoughts in the comments.
For now, though, we are at something of a crossroads for the issue. Fossil fuels have
to be replaced; renewables need to be able to do the job. One thing that is clear is that TPV
cells plus thermal batteries could be another vital step towards a new,
improved and limitless tomorrow. A tomorrow that we’re getting closer and closer to
realizing. And that’s how scientists may have already invented the engine of the future.
What do you think? Is there anything we missed? Let us know in the comments, check out these other
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