Technology :: Power struggle: How to keep India's lights on

For many in India, when the largest blackout the world has ever seen struck last week, it didn't come as a surprise. Smaller, scheduled blackouts are a common way that the country copes with its explosive growth in demand for electricity.

As a result, many of the 600 million Indians affected were already prepared with their own systems – diesel generators or solar panels. Still, many millions were left in the dark, and infrastructure such as train networks ground to a halt.

Nature is partly to blame, in the form of a poor monsoon season. The Indian Meteorological Department says that rainfall across the country has only been 81 per cent of its average through June and July. That forced India's hydroelectric plants to run below full capacity, while farmers had to use extra electricity to pump water for crop irrigation – a sharp one-two punch to an already strained power grid.

Quick reactions

To stay online, any large-scale grid must be able to react quickly to power fluctuations – on the order of a few tens of milliseconds. This was likely a key failure in India as well. The sentinels of most modern grids are devices called phasor measurement units (PMUs). Situated mainly at power plants and high-voltage substations, they match the frequency of the alternating electric current to other locations across the grid, ensuring that the network is in sync using GPS timing. Drops or outages in power across any part of the grid cause the frequency to dip locally, and PMUs also make it possible to isolate the problem.

The Indian Central Electricity Authority (CEA) only produced its draft plan to install PMUs across the grid in April this year and, as of 31 May, there were just 14 operating in the country. By contrast, the US, which has a similar patchwork infrastructure to India's, has thousands, many of which were installed following a 2003 blackout that affected millions in the country's north-east. China has built thousands of PMUs to ensure its grid is similarly protected.

Such monitoring is important in an overtaxed grid like India's, where it would help prevent unscheduled blackouts. Scheduled blackouts would still be necessary though.

Central control

The ideal, says Arshad Mansoor of the Electric Power Research Institute in Washington DC, is to centrally control small reductions in load across the board – turning down the air conditioning across the country for example, or dimming public lighting by a small amount for a short period of time. This is the long-awaited "smart grid" that, despite much hype, has so far eluded widespread implementation, even in rich nations.

But progress is being made. CenterPoint Energy, a regional utility company based in Texas, is in the final stages of constructing a network of smart meters across the city and suburbs of Houston. By 2013, 2 million smart meters will track energy use in Texans' homes, and allow CenterPoint to turn off air conditioning units during times of high demand for instance, although CenterPoint admits it will need customer consent for this.

If smart meters are still a way off in the US and other rich countries, they will be even more difficult to deploy en masse in India, particularly in the short term, where the government remains focused on generating more power and better managing what it has. Until that time, the motto in the footer of every CEA monthly report rings true: "Energy saved is energy produced."