In 2015, more than 196 world leaders committed to 17 Sustainable Development Goals, commonly known as SDGs, to end extreme poverty, fight inequality and fix climate change. Of these 17 goals, number seven is about ensuring access to affordable, reliable, and clean energy for all by 2030. Twelve of the 17 SDGs are directly impacted by electricity or the absence of it. For this reason, SDG Seven is recognized as the key enabler for most of the other Sustainable Development Goals.
However, this is easier said than done! Connecting each and every hut, dwelling and home to a stable electric grid is expensive, time-consuming, mired with too many regulations, as well as the challenges of rough, remote terrain. Given the urgency to enable electricity access, nations are seeking innovations which help reduce the time required to electrify rural areas in an affordable and sustainable manner.
The solution is direct current, or DC: electricity for the 21st Century! Today, in most countries electricity is produced in large power plants as alternating current – also known as AC. More often than not, these power plants operate on fossil fuels and add to global pollution, degrading the environment. These plants are located far from cities or areas of consumption and so electricity has to be brought in via long transmission lines.
Innovation for 21st Century electrical systems
In direct current, the electric charge (current) flows in one direction - plus to minus. That is why you see the (+) and (-) symbols on all batteries. Electric charge in alternating current, on the other hand, changes direction periodically. Alternating current is better for transmission over long distances, while direct current is great over short distances.
Ironically, Thomas Edison discovered electricity as direct current, and in 1887, installed the first DC network in Manhattan, New York. However, due to the nature of the technology, polluting and noisy power generators were installed right next to the homes of the wealthy who could afford electricity. Nicola Tesla invented the transformer which enabled moving the polluting power plants, which used fossil fuels, away from the cities, bringing electricity into the cities via transmission lines.
There are three main reasons why direct current is now considered the key innovation for 21st Century electrical systems:
- Most consumption devices have electronic components these days, and all electronics simply run on DC. This is the reason why we get AC in our homes and offices, but use transformers, adapters or drivers to adapt electricity from AC to DC. Each time we make this conversion, adapters lose up to 20% electricity as heat energy. That is why your phone chargers or laptop adapters heat up.
- From generating power at large utilities in the middle of open spaces, we are now generating power much closer to where it is used, on roof-tops via solar panels, as well as small wind turbines or micro hydro installations. This saves space and brings power generation close to power consumption, thereby reducing the need for power transmission lines across long distances.
- The last and perhaps most significant reason is that politicians and administrators are under pressure to address climate change, increase energy efficiency and provide electricity to the millions who do not have it. Locally-produced renewable energy is the only answer to rapidly moving away from fossil fuel-based electricity to green electricity for all. This means that especially for rural areas not connected to the grid, small-scale direct current grids, or solar home systems are key to providing affordable and clean electricity to all.
DC is everywhere
Everything we love and like, is already using DC, we just don’t realize it. DC is evidently the solution for the future, but how do we get there? When will it replace AC, if at all?
Adoption is rapid and as we speak there are in excess of 600 000 homes in India alone which are already powered by direct current. Bangladesh today has over five million DC-powered home energy systems, providing light, comfort and livelihood. The numbers are growing. As with many legacy systems, however, there is a huge amount of global investment and reliance on the existing AC infrastructure. These are long term investments which are good for several decades to come. It may not be prudent to reduce these investments to junk, just because we want to change to DC.
You might ask if DC is only relevant in the context of supplying electricity to those homes which do not have it. The answer is the opposite: it is equally and perhaps more relevant in those areas where electricity may be in abundance.
Direct current is impacting data centres. There are about 125 DC data centres worldwide. It is not hard to imagine why: all computers work on DC. In data centres, which are densely packed with computers, DC is more efficient and affordable. In fact, Facebook and Google are also now experimenting with DC in complete racks in their data centres. I recently visited a data centre in Texas, in the United States, which was generating power through solar panels on the parking lot and supplying it right there for direct use, achieving instantaneous savings!
It is the same with greenhouses, which are now beginning to generate electricity on the roof, and grow plants and flowers below. DC is consumed locally at the same greenhouse for light, heating, ventilation and irrigation. This reduces the total electricity consumed and avoids reliance on the electric grid. The savings add to the profits of the greenhouse.
Electric vehicles carry batteries which require DC for charging. You must have already noticed that LED is powered by DC and used in streetlights, traffic signals, roadside hoardings and airport lighting, among other uses. I am discovering new applications and uses of DC almost every day.
The question is how to create genuine momentum to trigger a universal movement toward DC?
The next step is to develop a complete set of global Standards so that DC can finally energize electricity-deprived homes and provide clean, affordable electricity. All applications which consume conventional electricity must begin to reap the benefits of clean, sustainable and affordable energy that can be used directly, without conversion losses, from the solar panel on the roof to the appliance in your kitchen.