As skeptics we should be guided by data and evidence wherever possible. This leads us to acknowledge there are some facts that will be the same today they were yesterday, and will be again tomorrow – such as that the earth is an oblate spheroid. However, we also have to acknowledge that some facts that were true yesterday may not be true today or tomorrow.
For instance, for over a hundred years, Alternating Current (AC) has won the current war; even though the Direct Current (DC) generator was invented nearly fifty years before the AC equivalent, AC still triumphed. AC equipment was cheaper to manufacture, cheaper to maintain and less complicated to operate. Plus, patent holders for the DC transformer set a high price for its use, restricting development of the technology for decades, leading it to lag behind AC. This, along with the need for significantly more DC generators to provide sufficient power for industry and consumer use, meant it just wasn’t a financially viable option compared to AC.
That was the past. Are the variables that led to us favouring AC still relevant, today? And do we still need such centralised generators or is localised generation now a viable option?
The vast majority of the energy we use today comes from power stations that are often extremely harmful to the environment, but that is starting to change. There is now a variety of commercially available sources of microgeneration that are essentially DC generators for the twenty-first century. These include photovoltaic (solar), hydro, and wind generators. Each of these methods have their strengths and weaknesses, but they all have the serious drawback of requiring consistent natural resources (which aren’t always as reliable as we would like) or mass storage requirements.
While we have the ability to store sufficient power in battery banks for consumers (home owners/occupiers), they are currently extremely expensive – though it is worth pointing out that some hospitals (such as the Nightingale hospital during Covid) do rely on battery banks as an emergency backup.
With the number of electric vehicles expected to rise from less than 1 million today to over 37 million by 2050 (according to reports from the National Grid), and as the Grid system itself hasn’t been fully upgraded since the 1950s (proposals have been made to make £58 billion worth of upgrades to be completed by 2030), it’s clear we do need to start considering alternative options.
With regards to solar power, we currently need relatively flat, south facing areas to position panels for optimal generation. Much of the housing in the UK consists of terraces aligned north to south rather than the optimal east to west. Also, office and high-rise buildings have a smaller footprint on which to place panels to be effective.
These problems are being addressed in 2 major ways. Researchers from the Korea Institute of Energy Research are developing semitransparent panels, and a team at Michigan State University are developing transparent panels (with multiple nations and the EU directly funding research). These designs are intended to replace windowpanes. Imagine, if you will, that all of the windows from the southeast to southwest of the shard were replaced with one of the new electricity-generating options. During the day, these new panels could generate enough electricity to power a large amount of the city of London’s businesses.
For perspective, the city of London consumes approximately 103 Gigawatt hour (GWh) electricity per day. A standard solar panel can generate 1.5 Kilowatt hour (kWh) of electricity per day. If every household in the city had a conventional solar panel array (ten panels), each house could generate 15 kWh per day – and with 3.7 million homes in the city of London, that would equate to 55.5GWh generated per day. If we then conservatively estimate a quarter of these homes can also be fitted with semi-transparent panels as windows, we could add an additional 5.6 GWh of electricity per day, covering more than 60% of London’s energy usage.
If homes around the country replaced their windows with these new solar panels, they could further offset their energy costs by selling excess energy generated back to the grid, which in turn will reduce the carbon footprint of the nation.
There are currently some major drawbacks, though. Firstly, the technology isn’t quite there yet. Development is still in the R&D phase and hasn’t been tested at large scale. The energy output for transparent panels has been recorded at 5% less than standard panels (a maximum of 1.425kWh per day based on above figures), and 3% less for semitransparent (so, a total of 1.455kWh per day), though it is still unclear whether this will scale up as expected.
Also, as with all new technologies, the cost would be beyond most consumers and the return for businesses would currently take too long to be cost effective.
For commercial use, if UK businesses want to make alterations to a property, they must gain planning permission, and this includes the installation of microgeneration units such as solar panels. This barrier could be removed relatively easily by an act of parliament, were it not for one major obstacle; a powerful and well-connected fossil fuel lobby. With oil and gas companies reporting record breaking profits, they have a vested interest in ensuring renewable energy sources are made as difficult to embrace as possible.
So, considering these drawbacks, why would solar potentially shift the balance of power in the current war between AC and DC?
Solar power generates a DC power supply, which we then convert to AC via an inverter. However, many of our daily electronics actually run on DC – including laptops, phones, microwaves, vacuum cleaners – and most of the rest can either be easily altered to do so, or could be manufactured in the future to use a DC supply. Anything that is, or can be, battery operated is powered by DC. There also currently isn’t much difference in price or running costs between AC and DC motors, and there isn’t much difference in potential application, either.
With current design trends aiming towards sustainability and mitigation of environmental impact, it is reasonable to conclude that DC is likely to become the new norm in our day to day lives, bringing about the vision of the future that Thomas Edison had over a hundred years ago, but in ways he could never have dreamt possible.
