ECN Forum Forums General Topics of the Trade General Discussion Area Is somebody pulling my leg?

They still use seperate meter plans around here for all electric houses. (IE boiler ripped out and heat pump and water heater installed.)

Trailer park is that way too, phasing out oil and gas for two-meter electric houses, not as many connections for the park goons to make.

Ian A.

Most off-peak schemes use a time base. The idea is to get demand smoothed by offering incentives for consumers to run stuff in low-demand periods by a price reduction. This is supposed to reduce generation plant needed on standby and increase the base load for fuel efficiency. There is no reason why a poco could not use outside temperature to decide when to switch tarifs, but how does that smoothe the base load or incentivise the customer? Sure increases the bottom-line though, or am I getting cynical?!

The only other tarif switch-method I know of is that in France it is possible, if you consume enough, [ say with electric central heating ], to go onto a 100% off-peak tarif 24/7! The catch is, 15 days in the year you pay an astronomic figure - about a dollar per kwh. This is supposed to allow EDF to shut down hydro-electric and other plant for maintenance. I thought "Wizard idea! I'll just bugger off back to the UK on holiday in the peak period!"
No such luck! You only get 24 hours notice of a peak period and it's in single days, so you can't plan ahead!

That's similar to a plan over here Alan for industrial. Our Company is billed by either A,B or C Tariff. C is very cheap per KwH, B is twice C rate and A is 25 times C rate. They have a Winter period and Summer period, but are only allowed to bill us for 26 days per year. You have to call or view(internet) the next days tariff, after 12 o'clock the day before.

HECO in Hawaii (and maybe others?) offers reduced electric rates for customers with standby generators if they agree to go on generator if/when demand or casualties puts the grid into a brownout situation. Honestly, it's win-win for the customers because if the grid is browning out, we'd all be going on generator anyhow...

Our house is on the "time of use" plan here in Phoenix. For the most part it costs me more. For people with normal working hours the on peak periods are guess when? When you're getting ready for work or when you're getting home. Right now the winter on peak hours are 5-9 am and 5-9 pm.Weekends and holidays are all off peak. So just when you want a hot shower, morning coffee, warm morning house, make dinner, do laundry it's all on-peak and you pay a higher rate and a demand charge. It's a lousy idea unless you work from home or work odd shifts. I try to do what I can by turning down the T-stat and the W.Heater is on a timer, but that savings is more than offset by the penalties. It was easy to get on the plan... now I have to try to get off of it!

Cheaper off-peak electricity tariffs have been used in the U.K. for decades for water heating and for space storage heating. For anyone who has missed previous discussions about storage heaters, they are usually individual heating units in each main room which have one or more elements set inside large thermal bricks, so that the bricks can be "charged" with heat at night and release that heat gradually during the day, often controlled by simple thermostatic dampers. (Some large, centralized storage heat units with forced ducted air around the house were also installed in the 1960s/early 1970s.)

One of the original schemes had a completely separate meter to record the cheap rate usage, with a timeclock-controlled contactor which turned on power to a separate distribution panel at night. It was commonly referred to as the "white meter tariff," because the second off-peak meter was in a white casing to identify it instead of the usual brown-black. All 24-hour circuits were still charged at the normal rate on the regular meter.

These days though, the general Economy 7 tariff is the norm. There is still a timeclock and contactor to feed power to a separate panel for storage heating, but just a single meter with dual registers. As well as energizing the contactor at the appropriate time the clock also switches the meter to so that all usage during the off-peak hours is charged at the lower rate. It's usually midnight to 7 a.m. in winter, 1 a.m. to 8 a.m. in summer, or thereabouts (hence "Economy 7" -- 7 hours cheap rate each night).

We have some more options now which aren't quite so common, such as Economy 10. This gives the usual 7 hours per night cheap rate but also provides 3 hours afternoon boost for heating at an intermediate rate.

Also, in place of the conventional timeclock some systems now have remote radioteleswitch systems which change rates (and close the off-peak contactor) in response to signals from the PoCo.