by Dan Bihn, Enerdynamics Instructor
Aftershocks are still being felt in Tokyo more than two months after the magnitude 9.0 earthquake and tsunami that devastated the coastline of northeastern Japan. But the repercussions of the subsequent meltdown of the Fukushima nuclear power station are being felt even further away and will likely persist a lot longer.
The Japanese government recently announced plans to update its long-term energy policy “starting from a blank piece of paper.” There’s lots of talk about shifting to more renewable energy. Since less than 2% of Japanese electricity comes from non-hydro renewables, this shift would definitely be a long-term policy. Currently, Japan is the third largest consumer of nuclear power in the world just behind the United States and France, according to the EIA.
The short-term policy is to get through this summer with as few rolling blackouts as possible. At the beginning of 2011, the summer peak load was projected to exceed 55,000 MW. But this summer’s peak load will only be about 45,000 MW – even if it turns out to be a very hot summer. That’s all the generation Japan has; load will be limited.
The only question is, will the load be limited by a few substation breakers or by millions of household switches and thermostats? I’m betting on the people. They’ll be motivated by a compelling price incentive: reduce peak demand and your company will have power. That’s the big stick the grid operators have. But little carrots are starting to pop up everywhere, and some are even candy-coated. It’s not just about rewarding people for their energy efficient behavior. It’s about giving them something cool to buy and show off while positively contributing to a national energy solution.
Such “cool” things include energy-efficient products like LED light bulbs, intelligent powerstrips and LCD TVs with a “Peak Shift” feature that charges an internal battery at night and then, with a click of the remote, disconnects from the grid during the peak hours of the day. On May 11th, Mitsubishi unveiled a prototype ‘model home’ that features rooftop PV (photovoltaic solar electric), a Home Energy Management System (HEMS), and a host of smart appliances. And this could be exactly how Japan rebuilds its infrastructure – one smart home at a time.
So, how can such innovations make a difference? With a traditional system, if you just put PV on your roof, you’ll reduce your peak most of the time. But when a cloud passes overhead, your air conditioner will still think it’s hot out and keep running. The net effect is that for a few minutes your house will put a big load on the grid. But Japan no longer has enough capacity for that kind of peak. So PV panels by themselves don’t help much.
That’s where the HEMS comes in. When a cloud passes overhead, your PV generation still drops dramatically, but now the HEMS immediately turns off your air conditioner compressor and maybe the refrigerator compressor. Result? Smaller peak. If the sun comes back out, things return to normal. If the sun doesn’t, the house will start cooling off naturally, so the air conditioner won’t be needed as much. Still no peak.
So the grid stays on – and Japan doesn’t need to build a lot of new fossil fuel power plants that run on imported fuel. And there is a big increase in consumer spending to help the economy through these challenging times. Of course, a smart grid with dynamic pricing and a lot of price-responsive loads can achieve the same basic load-flattening results. But somehow a PV system connected to a home energy management system seems a lot simpler. And consumers respond MUCH faster than bureaucracies.
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