DC takes the driving seat

Low voltage direct current has benefits for both developed and developing countries

By Morand Fachot

At the 2014 IEC General Meeting in Tokyo, the IEC Standardization Management Board (SMB) agreed to set up a Systems Evaluation Group, SEG 4: Low voltage direct current (LVDC) applications, distribution and safety for use in developed and developing economies. e-tech asked SEG Convenor Vimal Mahendru to explain what drew him to the LVDC domain, the global challenges and opportunities he anticipates for the technology, and the contribution IEC SEG 4 can make to its global adoption.

Vimal Mahendru. Convenor, IEC SEG 4
Vimal Mahendru, Convenor, IEC SEG 4: Low voltage direct current (LVDC) applications

Improving the lot of millions has been a driving force

My country, India, is a developing economy. For the past 25 years it has been liberalizing its economic system and has experienced a lot of wealth creation as a result. However, there are also great disparities between the ‘haves’ and the ‘have-nots’; these are magnified by today’s opportunities.

The ‘haves’ live in urban areas, have electricity almost around the clock, 24-hour access to telecommunication, Internet, mobile phones, etc. All this provides them with great opportunities.

At the same time there are 320 million people who have absolutely no access to electricity. This means that on a daily basis they rely on candles or kerosene lamps for lighting and on kerosene or burning wood for cooking. There is a huge environmental cost attached to this. Even if kerosene is subsidized, as it is in India and many other developing countries, it doesn’t help lift people out of poverty, but ensures they remain poor.

In the 21st century it is hard to believe that such a situation still exists. This has been a driving force for me and I am lucky to have the opportunity to work to help solve the problem.

Bringing electricity to people

I have been involved in an industry association, the Indian Electrical & Electronics Manufacturers' Association (IEEMA), which I headed until recently. During this period the government opened this debate: How do we bring electricity to the people? They started addressing this issue in 2003 and their immediate reaction was: “let’s build more power plants!”.

Coal-fired and hydropower plants were built, but then it was realized that power lines had to be installed to bring power across regions.India is a big country with 32 states; you have to take the lines across several states and each one has to give permission. The environmental policies of each state may be different and so may the regulations. So even though a power plant may be built and operational, it may take five years to install transmission lines.

Around 2010, although many power plants had been built, it was recognized that something more radical had to be done: we could not wait 15-20 years to bring electricity to people. This is already a political issue, but if it cannot be effected rapidly, it becomes a social issue.

Discussions started in government circles about a model with big plants, powered by coal or hydro, and extensive networks of 2 000-3 000 km-long power lines to transport electricity. Subsequently this has to be transformed down in stages: from 650 kV to 440 kV, then to 66 kV, to 11 kV, down again to 440 V and eventually to 220 V to enable a bulb to be lit. It will take 20 years to build this network and bring electricity to villages. And if there is any incident along the line, the whole system will come down, as happened two years ago in India and during the 2003 Northeast blackout in the US and Canada.

Solar answer

There is growing awareness of environmental issues and of the need to bring electricity to people rapidly. At the same time the price of solar panels has come down a lot and the Indian government embarked on a big solar power mission in 2010. The plan was to produce 22 GW of solar electricity by 2022.

The new government, led by Prime Minister Narendra Modi, which came to power last year, pledged to increase this to 100 GW by 2019. As a result India is now one of the hottest markets in the world for renewables. The government has embarked on a new policy of incentives and liberalizing investments to provide 200 GW of solar power by 2024. This has become the driving force in India, and this is what got me involved.

DC is the answer

When you think about it, solar generation is in DC and modern power consumption is nearly entirely in DC. In the room in which we are sitting, the telephone works on DC; the computer, the TV screen and the audio system all operate on DC.

Since it’s solar, it’s local: no long transmission lines are needed. You don’t need gigawatt-scale systems, you can have smaller scale. You can put installations on rooftops. This has been the main reason why we see this widespread renewed interest in DC.

At an SEG 4 meeting in Princeton recently, it was mentioned that today we may have 35 use cases in which LVDC is being employed. There are those who say it may be even more. When we looked at these cases, we didn't come across a single one where we said: “Unfortunately this cannot be done with DC but only with AC”.

There is now a global realization that, almost without being aware of it, we've been using and generating in DC. Now we need to put a system around it and that's where the IEC has a leadership role to play in bringing all this together.

Voltages as a system

By definition LVDC means up to 1 500 V; LVAC is up to 1 000 V. The moment we are below 1 500 V we're looking at voltages as a system. It's pretty obvious that a desk telephone works best at a certain voltage, a laptop or a desktop computer at a certain voltage, the strip lights or a video projector at different voltages. The reason is that the power to drive that equipment efficiently could be different. Even if all these are DC applications, ideally they may work at different voltages.

Although SEG 4 is still debating the issue, it seems to me that there is a consensus among all the global experts that we need a whole system of voltages, rather than a single voltage.

Another area involves the total energy that must be drawn to drive a system. In India, for instance, a typical use case is pumping water from wells for farming. Of course the solar panels are DC, and DC pumps are available. But how should the pumps and the solar panels be rated? Ratings are dictated by the head of water [height of the water level]. The deeper you need to draw, the more energy you need.

It is when more energy is needed that a system of voltages gets critical. That means that deciding on a system of voltages is essential and this is where a consensus is emerging.

Deciding on a system of voltages is a critical first step

Another thing that is emerging in SEG 4, less than six months into its existence, is that deciding on a system of voltage levels is a critical first step. Once we have decided the system voltage levels, then this can have a cascading effect: here are the voltage and energy levels; now what level of protection is needed? This has to do with the distribution system, with installation rules that can be developed.

So we have a consensus within the global community. The good thing is that we have a bit of a head start; in less than six months we have accomplished quite a lot, we are heading in the right direction.

I am amazed to see that since the IEC decided to create SEG 4, at the IEC General Meeting in Tokyo (November 2014), SEG 4 already has some 90 experts from all over the world. The single largest contingent is from the US; we also have Canadians, Latin Americans, a large number of Europeans, a very large pool of Asian experts and there are also African experts. There is a great need in Africa for LVDC because in Africa some 750 million people are without electricity. At the second SEG 4 meeting in Princeton recently, Zambia had specially sent one expert to make a presentation about what Zambia is doing to try to provide electricity access.

Dark rooms, but not the dark ages

Even in places where there is no electricity – and this is particularly true of India and Africa – people still have mobile phones. This means that they are resourceful; they don’t mind spending on the right solution, on charging. It also means that they are aware; while they may live in dark rooms, they are not living in the dark ages. However this awareness is leading to increased frustration. If I were living in a dark place and I was unaware of the existence of the Internet, maybe I would be happy in my little corner. But if I knew that things like the Internet and electricity existed, I’d be frustrated. 

This is the key to the matter: LVDC is seen as an enabler of social change. My personal motivation is that I see SEG 4 as the platform for meaningful change.

Opening the way to standardized plugs and sockets

Once we have decided on the voltages, we get into the installation, protection and distribution issues. So the plugs and sockets issue is essential.

It is interesting to see that some US IT hardware manufacturers have started building DC sockets in computer systems. They have the same physical dimensions [as AC sockets], but are fail-safe as it’s impossible to connect an AC cable to them. If you want to use DC, there will be a DC-DC converter since there is a need for some kind of conversion within the system, but there is no loss of energy with DC-DC conversion, unlike AC-DC conversion. So when you have DC-DC conversion the only thing you need is a DC plug and work is already under way to define a system for DC plugs and sockets.

I believe that in 20 years or so, this question of AC/DC will be fully settled. You may have DC meters, DC cables running through buildings and DC-DC converters per room or per device, but that’s how the network will be.

This means that as things evolve in the future there will be standards both for new-build and for retrofitting buildings [to DC].

Three things will be responsible for most of the changes: LEDs, battery storage and proliferation of solar PV. All are DC and are converging. Manufacturing costs are dropping for all three. While they may have been around for a long time, they have been expensive. Now costs have come down dramatically.

In many places you now have local generation, through solar PV, and local consumption; this will raise questions regarding the future of AC transmission lines.

Different needs, same excitement for LVDC

The needs of countries are completely different.

In India, for instance, there is a need for electricity everywhere, but the transmission infrastructure doesn't reach all places.

In developed economies such as Germany, Switzerland, countries throughout Europe and many other places, the infrastructure exists and there's electricity everywhere. So why does LVDC arouse excitement in all countries?

In developing countries where there is not enough electricity for everyone, we're talking about electricity access. In developed economies, people are getting more conscious about their environment, green energy, energy efficiency and reducing carbon footprint. These countries are ‘greening’ their technologies.

All of these, plus trends that see a global growing demand for LEDs, solar PV and associated storage, come together and require a comprehensive DC system.

The IEC is on the scene at just the right time to bring everybody together. I'm very optimistic about the capabilities of LVDC for bringing together a lot of things. I also believe that for the first time we will have a solution for the multiple plugs and sockets problem because, before national standards can be decided, the IEC is saying: “we are going to look at global standards for DC plugs and sockets”.

So the question is not: “do we want AC or DC?” but "when are we getting DC?"

Vimal Mahendru. Convenor, IEC SEG 4 Vimal Mahendru, Convenor, IEC SEG 4: Low voltage direct current (LVDC) applications
EV charging Electric vehicle charging can benefit from LVDC distribution networks
Rural off-grid lighting Off-grid power access brings electricity to rural communities, even in remote locations (Photo: The SASSI blog)