Wattvision (YC W09): Catching the Power Company's Mistakes | Hacker News Reader

Wattvision (YC W09): Catching the Power Company's Mistakes

blog.wattvision.com

41 pointssavrajsingh10 comments

A standard household ammeter watches the electrons sashay back and forth in the wires and totals that up. e.g. you get billed for both current you use and current you produce (since they never imagined that when they built the meter).

A "net-metering" ammeter determines if the electrons are cycling back and forth because you pushed them, or because the power company compelled them and tallies them appropriately.

Does anyone know how they determine "why" the current moved? At a first crack, I'd check the voltages very carefully on either side of the ammeter and decide which was bigger, but this is going to be complicated since there will likely be different answers across the complete cycle.

All power meters work by measuring both voltage and current and multiplying. Even without local generation, power periodically (60/50Hz) flows back into the grid (except when the load is purely resistive aka power factor of 1).

http://en.wikipedia.org/wiki/Power_factor

The mechanisms in old meters were just designed with the assumption that the net flow was always into the house (perhaps in response to the various tricks people would use to artificially slow their meters). A modern digital meter doesn't have to do anything special to measure the direction for net metering.

To elaborate on this: assume the sine waves of voltage difference and current are fully in phase when the house is net-consuming. Multiplying the voltage and current functions and integrating over time gives you the total energy consumption.

When the house is net-producing due to solar panels, the current will be 180° out of phase with voltage, i.e. "negative" AC current. Multiplying and integrating yields negative energy consumption.

Note that current is directional, so "negative" current isn't anything special - if you reverse the meter, the sign will be inverted.

With these stories Wattvision is doing an excellent job of positioning their device as 'something that pays for itself'.

Really, keep it up, super marketing! Have you considered a 'the device will pay for itself within a year or your money back' guarantee?

Yes, we could have that -- not sure exactly how we'd quantify it though. ;)

Gather stats about your users electricity consumption by asking them to participate in an experiment where they get an anonymous ID, then they enter their old electric bills and the ones after they bought wattvision.

Next you get to do a lot of datamining and analysis to figure out which reports are outliers. You'll need a control of people that do not use wattvision.

Once you've done that you can compare the two and figure out how much of the drop is attributable to the device and how much to other influences (season and so on).

That should give you an idea based on the current price per KWh how long on average it takes to earn back the value of the device.

You'll have to add a safety margin. In order to qualify for a refund people would have to send you their actual before and after stats for a 12 or 24 month period, so scans or PDFs of their electrical bills.

I'm sure there are lots of details to be worked out but that's the approach that I would take and before making any public claims you'd have to make sure the whole process can't be gamed in any way.

No point in becoming another cue-cat ;)

Thematically, I am excited about technologies/businesses which shift the balance of power between consumer and large corporation. That the man whose story was reported in the blog entry implicitly was burdened with the requirement to prove he was being cheated is a fundamental problem in his relationship with his "business partner" (a term I chose because each party sells power to the other). How many other common consumer relationships are like this?

I am angered that almost all consumer-grade laptop providers drop driver support only a few months after discontinuing a particular model. There's no easy way to prove that stability issues which crop up later are the result of interaction effects between, say, a Windows 7 update and a particular revision of my video driver. How could someone make HP, etc. accountable? This is merely one example of how consumers are hurt from information asymmetry.

How does one go about auditing his mobile phone bill and ensuring that it actually adheres to the stipulations in his plan "contract" (quotes because there often seems to be no official written statement of terms for a particular plan)?

I love these stories. Must feel great to have a real impact on real customers. Keep it up!

This ia a great way to meter energy usage. Definitely need to get my hands one of their products.

I'm looking forward to hearing similar stories as we deploy Gridspy. Well done.

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