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Demand charges, demand response, & switching from gas to solar electric appliances

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  • Demand charges, demand response, & switching from gas to solar electric appliances

    Another view through my dusty crystal ball:

    Without solar power, it makes sense to prefer natural gas powered furnaces, water heaters, and clothes dryers over electric ones, since it probably generates less co2 than burning coal and running the electricity all the way from Wyoming or whereever. And the gas company offers incentives to buy more efficient models.

    But burning natural gas still generates co2, so if you're moving to solar to reduce your carbon footprint, you want to switch those three appliances away from gas and to electric (and install more panels to power them).

    Likewise, burning gas generates NOx, which can contribute to ozone pollution. Large parts of California have trouble meeting ozone standards, and state law requires AQMDs to implement "all feasible measures to reduce emissions of ozone precursors, including NOx". Encouraging a switch from gas heaters/furnaces to local solar electric powered heat pumps for HVAC, water, and clothes is certainly a feasible measure.

    But "demand charges", another energy efficiency incentive increasingly offered or required by local electric utilities, may be discouraging switching from gas to electric for those appliances, even for solar users.
    With demand charges, a possibly large part of your electric bill is set by your peak demand for power in the month. If your electric dryer, water heater, and furnace all happen to run at the same time just once in the month, you might get socked for a huge bill, even if you are net zero negative for the month.

    Effectively switching from gas to local solar electric for these uses will probably require a combination of fixes:

    1) Building http://en.wikipedia.org/wiki/Demand_response directly into appliances so utilities can directly reduce demand during their peak periods

    2) Enabling the solar inverter to track peak demand and issue its own demand response commands to appliances to reduce peak demand charges

    When selecting "smart meters" for wide rollout, utilities should try to make sure they can support
    this kind of combined local and centralized demand management. Some expensive combination of cellphone modem, zigbee, wifi, and customer-provided internet will, alas, probably be involved.

    I see that the hybrid water heater I was thinking of buying is internet-controllable ( http://www.digitaltrends.com/home/ge...s-at-ces-2015/, http://www.geappliances.com/ge/heat-...heater-faq.htm ), and the same vendor is rolling out internet-connected refrigerators etc.

    The most efficient heat pumps don't tend to be internet controllable yet (that I know - correct me if I'm wrong), but that will come.

    And inverters are already internet-monitorable. So it should be relatively easy in principle to implement local load management to match solar output.... as long as you buy internet-connected appliances, and an API is available for controlling them.
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