Bloom Energy – Not Replacing the Grid Any Time Soon

Date February 25, 2010

Bloom Energy just announced their Bloom Box today.  The Bloom Box is a fuel cell that consumes air and fuel (natural gas, methane, etc.) to produce electricity.  The box is apparantly cheap to produce (key component is sand used to make ceramic plates) and produces a lot of energy for its size (25W per plate).  A segment on 60 Minutes shows Bloom pimping the technology as the cure for power in homes across the world.

According to Bloom, one fuel cell plate produces 25W, one stack is 1kW.  Multiple stacks are combined to produce modules, which can be combined to produce larger systems.  It’s a beautifully simple and modular system that can scale easily.

But don’t believe all the hype.  Their claim that one stack is sufficient enough to power a typical US home 24 hours a day, seven days a week is a bit of a stretch.  According to the US Department of Energy (excuse my lack of Canadian data, but this is a US company and they’re talking US numbers), the typical US home consumed 936kWh of energy per month in 2007.

To see how Bloom’s claims are over-inflated, let’s do a little simple math.  There are roughly 720 hours in a month.  The average home consumes 936kWh per month.  936kWh / 720 hours = 1.3kW or 1300W of power consumed on average for every hour over the entire month.

Bloom’s claim that 1kW is sufficient for a typical US home falls short by 300W per hour.  Doesn’t sound like much, but that’s the average over a month, and it adds up.  The point they aren’t making clear is that their basic system is somewhat capable of sustaining the average power demands of a home, but it does not come close to meeting the actual usage of power in a typical home.

A typical home these days has minimum of 100 Amp service from the grid (new homes commonly have 200A service) or about 12kW.  This is sufficient to power the appliances, lights, heating, etc. that we don’t think twice about using, even simultaneously.  To put it into perspective, a typical microwave draws about 1000 W of electricity at full power, a powerful hair dryer could use 1500W, 5 incandescent light bulbs will draw about 500W, and your desktop PC might draw about 300W.  The total of these examples is already 3.3kW, but under certain circumstance it is entirely possible that much more power is consumed at any given time.

To be truly free from the grid, which Bloom is suggesting their technology will enable users to do, users will need to buy more expensive Bloom modules that supply 25kW of power.  These boxes are about the size of a fridge, and are likely much more expensive.  As well, these fuel cells likely produce heat and will need to be installed outside, which could be problematic for some.

Bloom seems to have a good product and interesting new technology, but they need to be a bit more realistic with what the true energy demands of the typical home really are.  Users should be aware that smaller systems will likely help offset electricity consumption from the grid, and could realize some cost savings over time, but the grid will still need to be connected to cover peak usage scenarios or for redundancy if the Bloom module fails.

All-in-all, I think this is good technology and I’m excited to see where this will take us in the future.  Perhaps it will be common for homes to have their own supplemental power generation from such systems.  Using such systems to remove homes from the power grid, however, is not likely due to cost and reliability factors.  Bloom will likely try to overcome these issues either through clever marketing, or innovation, but until then we will need to continue to rely on grid power.

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