Cars workplace charging demand response

Published on February 17th, 2015 | by Tina Casey

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Heads Explode As Workplace Charging Meets Demand Response (CleanTechnica Exclusive Interview)

February 17th, 2015 by  


If you’re not familiar with workplace charging and demand response, we’ll get to that in a minute, but first, imagine if you stop at a gas station on your way to work, and you get a discount for not filling up your whole tank. To sweeten the deal, let’s say you can just glide straight on to work without even stopping at a gas station, because your parking spot at work has a gas pump. I know, right? If your head is not exploding yet, that means we’re ready to talk about a new pilot program that will study how electric vehicle owners respond to a discount for charging up their EVs at work.

The project is being conducted by the global EV charging company Greenlots, in partnership with the EV charging manufacturer EVSE LLC and Southern California Edison. Greenlots CEO Brett Hauser was nice enough to sit down with CleanTechnica for a phone interview last week, before the official announcement, so we could bring you the big picture.

workplace charging demand response

 Workplace EV Charging & Demand

We’ve talked about the convenience of workplace EV charging before — that’s where you can just park at work and charge up your EV while doing other things.

However, we haven’t really dug into what that all means for the companies that host workplace charging, and the utilities that provide the juice. Mr. Hauser clarified it for us: your EV now becomes part of the company’s demand on the electrical grid.

According to Hauser, the rule of thumb is that adding an EV charger to the grid is like adding another home, so workplace EV charging is more than a drop in the bucket, even for relatively small companies just putting in one or two spaces.

The numbers can really add up for large companies that host their own EV fleets while also making charging stations available to employees and visitors.

The question is, how to meet that demand, and how to pay for it.

The traditional solution is to build more power plants and upgrade the grid to meet peak demand, but that’s a pricey solution, even if you only consider grid-related costs, as Hauser noted:

…from a utility perspective, as the proliferation of electric vehicles becomes greater, there are certain service constraints, and upgrades are very time consuming and expensive.

So, there’s a big incentive for both utilities and customers to work within existing grid resources. That means shifting demand around to shave down those peak electricity use points.



Workplace EV Charging & Demand Response

Demand response refers to reducing or delaying the customer’s electricity use in response to a preset schedule, ad hoc requests, or emergencies, all with an eye toward improving overall grid performance and reducing the need for new power plants.

Electric vehicles are bringing a new twist into the whole equation, primarily because they don’t sit in one place like a building: they go from place to place, and they have different uses, so their place in the hierarchy of electricity users can change on a dime.

The flip side is that, with workplace charging, EVs provide utilities with an opportunity to build more flexibility into the grid, by engaging individual consumers both at work and at home charging stations.

That’s a win-win all around: the consumer gets a discount, the workplace gets to ease its peak demand, and the utility gets to avoid major new infrastructure investments.

The New Demand Response Pilot Project

According to some Greenlots press materials sent to CleanTechnica, this is among the first large-scale pilot tests of EV charging based on the open-standards automated demand response platforms OpenADR 2.0b and OCPP 2.0 for EV charging (think Wi-Fi open standards, and you can see why open standards are critical for mass-market EV adoption and effective demand-response programs).

As for hardware, the pilot will 80 Level 2 EV chargers recently installed by SCE at several of its facilities.

The idea is to see how EV owners respond when they are offered a variety of discounts off the base rate.

For this project, there will be a base or “premium” option, which guarantees the vehicle owner a full charge at the workplace charging station, the only exception being an emergency.

Owners who prefer to get a full charge but will settle for less, when necessary, will receive a discount.

An even bigger discount will be offered to EV owners who indicate that they don’t mind if they sometimes get less than a full charge.

In support of this arrangement, Greenlots cites Navigant studies indicating that home charging stations top the list for EV charging in the US, but workplace charging is also becoming popular as a convenience and a range extender.

In that context, it does seem likely that a fair number of EV owners with access to workplace charging also have a home charging station, which would translate into a high degree of flexibility.

The question is, will it make difference?

By the end of this year, Greenlots expects to have enough data from the SCE charging stations to do a deep dive into the ins and outs of demand response EV charging at the workplace. Here’s a laundry list of what they’ll be looking at:

  • Evaluating the impact of EV charging on peak load and the effectiveness of managing the peak through automatic load curtailment.
  • Enabling consumers to opt-in or out of a demand response program.
  • Evaluating consumer response to a variety of pricing and DR strategies.
  • Identifying cost-effective strategies related to system development requirements.
  • Directly engaging customers in demand response programs through Greenlots applications.
  • Evaluating DR as a means of mitigating local transformer overload risk in areas with EV clusters.
  • Evaluating the potential for creating accurate load plans through site and region specific demand response management of EV charging.
  • Lowering system costs via open standards.
  • Enabling and evaluating charging system response to day-ahead and hour-ahead pricing and load curtailment signals.

Before we leave the topic, let’s note that demand response is just one in an expanding toolkit for utilities to avoid new power plant construction. On-site energy storage, distributed energy generation, and “smart” metering can all come into play, too.

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Photo Credit: Workplace charging stations in Malaysia, courtesy of Greenlots.






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About the Author

specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.



  • Brooks Bridges

    I’m surprised the possibility of the car supplying electricity to the grid isn’t mentioned.

    There will be a high percentage of workers with far more range than needed for a work commute who have home charging capability. Why does the article only see EV’s as a range of demand power?

    • Bob_Wallace

      Because grid storage batteries will be a lot cheaper than ‘renting’ storage from EV owners.

      • Brooks Bridges

        I’ve read your posts. You are far more knowledgeable than I am. I genuinely don’t understand. I thought what I suggested was, a very short time ago, proposed as a yet another big reason for going with EV’s – load balancing. Charge EV’s at night, use excess EV battery capacity during the day for load balancing. Why duplicate capacity?

        Let me expand on what will be the case for a large percentage of EV owners: It’s 5 years from now. I’m one of millions of EV owners with a car that goes 200 miles on a charge. I charge my car at home at low night rates. Monday I have a full charge from SP over weekend. Friday I just have to get home and wait for Sat morning to charge on SP. I have a 40 mile RT commute so only use 20% of battery capacity. For one thing, I don’t normally need to charge at all.

        So all my office has to pay me is something more than my night rates but much lower than their day time rates. I’ve got plenty of charge for the trip home and running some errands then I again recharge at low rate time or free from SP.

        At the very least, it seems to make a lot more world-wide sense to use excess EV battery capacity instead of using scarce resources to duplicate that capacity building grid-storage batteries for any business (that has a worthwhile number of employees, etc.)

        • Bob_Wallace

          I understand V2G, using EVs as storage. But I’m also watching what is happening with grid storage.

          A couple years back the battery/storage industry bifurcated. EVs and grids have different needs. EVs need light weight and small batteries because they have to be hauled around in the car. Utilities care relatively little about size and weight since they can be parked on cheap real estate and remain stationary.

          Making small/light batteries is likely to always be more expensive than making batteries that don’t have the same restrictions.

          EOS is selling a complete battery system for $160/kWh and stating a cycle life of 10,000. Tesla is paying $180/kWh for just the cells and cycle life is likely a small fraction.

          To use the EV driver’s batteries the utility would have to pay the owner both their battery cost plus enough profit to get them to agree. It’s likely to be much cheaper for the utility to install its own batteries.

          • Brooks Bridges

            Thanks. Point about diff in life cycles could be major.
            The world has big problems scaling up renewables and efficiency fast enough. Be an interesting next 5 years.

    • EV owner will then to use the first 30% of a batteries capacity life (ie: from 100% at new until about 70% for an under 100 mile EV). Since use of batteries in vehicles is optimized for reduced weight and reduce volume, the cost per kW is high vs. stationary energy storage.

      To be of value to EV owner, the utility payment much be greater than the charging cycle cost of lost capacity. Typically overage on a lease is billed at 10¢ to 15¢ per mile which would imply 30¢-50¢ per kWh as a comparative reference. Note: shouldn’t just compare directly to utility rates of 10¢-12¢+ per kWh as cost of equipment needs to be factored in. This is similar to why the cost per kWh at a DC Level3 charger is higher than a home electric rate.

      Once a battery pack has pasted it’s useful life in an EV it value will have decrease, but with ~70% usable capacity remaining, will make ideal on-sight energy storage. Likely to have a secondary life than it did traveling in an EV.

  • Brooks Bridges

    I’m surprised the possibility of the car supplying electricity to the grid isn’t mentioned.

    There will be a high percentage of workers with far more range than needed for a work commute who have home charging capability. Why does the article only see EV’s as a range of demand power?

  • RobMF

    Now to make heads explode by deploying EV charging stations at apartment and condo complexes.

  • No need to explode heads by adding complexity to EV charging options.

    EVs charging at a workplace will always add to the business location’s electric demand, never reduce demand. The only flexibility is ability to time shift charging demand during the work shift period.

    The article overlooks that overall grid demand is almost always lower overnight vs. during workday hours. While grid demand follows an annual pattern, the commute distance is fairly constant.

    The assumption that many EV owners have the ability to charge both at work and at home is not valid. Many reside in appartment, or other multi resident facilities that don’t offer dedicated charging/parking spots) Workplace charging maybe the only soure for a significant number of EVs. For other EV owners, home charging meets all their needs.

    Demand for charging for an individual EV is combination of distance driven and time spent commuting. With larger capacity batteries, there will be less need for workplace charging unless: 1) workplace charging offer at a discount, 2) EV driver has limited options on locations to charge.

    Time shifting of demand is not free. There is a cost to add the capability. wether it will be used, or not. For a business, the cost needs to be less the the demand savings that electric utility can offer.

    For a workplace, its facilities are likely to remain the largest shift in demand over a year related seasonal heating and cooling. Onsite energy storage, and solar are ways to balance out these larger demand shifts. EV energy demand at workplace will be fairly constant from month to month.

    For workplace charging, the cost for added flexibility to shift demand during the day, may not offer as much saving as minimizing demand loads over a month, or the year. Managing EV charging locally is only a small part of monitoring local energy demand.

    The first priority of workplace charging is to offer charging access to potential EV drivers that have limited charging options as without EVs at the workplace, there is no need to manage charging demand. Smart EVSE that is aware of the workplace demand and charges during periods of lower demand should be all that is needed. There is little need to shift charging between home and workplace. Most likely the choice for EV owners will be either home, or workplace charging; not both.

    • jeffhre

      “EVs charging at a workplace will always add to the business location’s electric demand, never reduce demand. The only flexibility is ability to time shift charging demand during the work shift period.”

      And then again – never is such a very long time to ponder.

    • isitso

      Almost always lower overnight…
      Ever heard of the duck curve?
      California, like Germany, is about to have a daytime solar surplus.

      • Yes, aware of the so called duck curve. Tends to form in mid-spring and mid-fall with good clear solar days and moderate temperatures. True to cuck form it migrates with the seasons. The duck curve fades in summer as A/C loads follow daily solar cycle. In winter the duck flattens and goes south as solar power is less and the solar day shorter.

        The overall daily pattern tends to have a consistent low period overnight, but there are periods of some days in some months that have similar mid-day low. Charging an EV overnight is a easy pattern to follow, when and where a duck will land requires a bit more work.

        The best way to take advantage of a duck curve period is to have on-sight energy storage … store power when the duck in total power occurs (ie: cook the duck) and make use as the sun goes down on the day. A demand only system can also feed on a duck curve, but relies on being able to increase demand correspondingly. Using EVs to generate time-based demand as location (if connected) of EVs tends to follow a different pattern on weekends vs weekdays.

        Once EV batteries are not able to provide a useful range, eg: 70% of new capacity, they will make ideal candidates for on-sight energy storage. This is because weight of needing extra batteries for a fixed location is not a limitation, as it is when in a vehicle. So EVs can complement solar both during normal EV life, then again in a secondary life cycle.

        • Bob_Wallace

          I’ve been following the <80% capacity EV batteries for grid storage idea for a while. I'm losing faith in it.

          Perhaps when the cars are sent to the crusher, but I'm not so convinced that many batteries are going to get replaced in cars.

          Consider a 200 mile EV. After 150,000 to 200,000 miles capacity drops to 70%. That's a 140 mile range EV in a older car, the sort of car that people with limited budgets buy to get to work. These are not people who take off for 500 mile drives on weekends. There's going to be a market for EVs with less than 50% capacity left. "Junked" batteries with 70% capacity should find a market for EVs with 30% capacity.

          Then consider that capacity will likely continue to increase. At the historical rate of 8% per year we could be driving 300 mile range EVs a decade after 200 mile range EVs hit the market.

    • Ronald Brakels

      In Australia, things are easier. In South Australia sometimes electricity demand is sometimes lower in the middle of the day than in the wee hours of the morning thanks to our rooftop solar. And it won’t take too long before this becomes normal. And then, in the state of Queensland, businesses are limited in how much solar electricity they can export to the grid. It’s funny how South Australia, a state with twice as much solar capacity per person and almost no coal industry, doesn’t need to do this. Anyway, this child drowning policy means that some businesses will have free electricity during the day. And finally, there is no need for special chargers. Here a normal everyday power point can charge a battery pack with about 100 or so kilometers of range over eight hours.

      • Bob_Wallace

        Giles on RE posted an interesting idea. How about a company that buys surplus electricity from home owners and businesses and sells it on if the utilities don’t want to pay a fair price?

        • Ronald Brakels

          Interesting. How that would actually work, I don’t know. It’s one of those things that we’d need a properly functioning market for it to work, because otherwise vested interests will block it, but if we had a properly functioning market we wouldn’t need it. I might go have a look at what he has written.

        • Ronald Brakels

          Okay, it’s like this. This summer electricity prices have been horrible for generators. And wholesale electricity prices have been low despite the cost of natural gas soaring as a result of increased natural gas production that has resulted from coal seam gas and fracking. (Yes, we can’t even get supply and demand right here. If you like you can pretend it’s because we’re down under.) And it’s not going to get better. As Australians install more rooftop solar and hopefully build more wind capacity, the average market price of electricity during the day is going to continue to fall. This does not create an environment in which it will be easy to increase the amount of money people get for exporting solar electricity to the grid.

          Now of course people exporting solar electricity should be compensated for the carbon emissions and health damage avoided. We did have a carbon price, but it got killed. We do have a Renewable Energy Target but with the Abbott government threatening to kill it and so investment in utility scale renewable energy has almost stopped.

          So we are faced with no good market for electricity during the day and no compensation for the fossil fuel externalities avoided by renewable power. And we have vested interests with a vested interest in making things worse.

  • jburt56

    Move to net-zero buildings. Integrate vertical PV. Introduce smart charging.

  • JamesWimberley

    Three prices for ev owners: that looks manageable. One danger with demand response is being too clever, and offering hosts of options, typically by yet another smartphone app. Too much choice, especially for small sums, overloads our cognitive circuits and makes consumers worse off. This has been documented in supermarkets, and helps explain the recent shift in shopping habits towards smaller stores.

  • Bob_Wallace

    This opens up a very large additional market – those drivers who have no place to plug in at home. About 46% of all drivers.

  • zn

    This seems like a con to me. If you have an EV there is a greater incentive to buy solar panels for your home to achieve the double cost saving of home and car transport cost reductions. Most businesses simply don’t have the space to install enough solar panels to cover their energy needs (plus an EV fleet). The utilities know this, and they’re terrified by the prospect of people going all in on home solar and leaving them out to dry.

    Perhaps this is cynical, but really, there really is no free lunch.

    • Bob_Wallace

      If you’ve got an employee parking space out in the open then you’ve got more space than you need to install panels to charge the EV. The extra panels power the business.

      • zn

        Perhaps it’s just my idea of a business is different to yours, but really, most workplaces in big cities wouldn’t have the space for this scale of installation above ground. Large office parks or shopping centres might be an exception.

        • Bob_Wallace

          In big cities, perhaps.

          Companies with large employe parking lots exist. They can take advantage.

      • Ronald Brakels

        “Hello. I am Queensland Australian business.”
        “Hello. I am Queensland Australian business employee.”
        “Hellos employee.”
        “Hellos boss. Can I haves electricities for car?”
        “Yes, you can has electricities for car. We has big solar panels and can’t exports electricities to grid.”
        “Why you no export electricities to grid?”
        “Because coals.”
        “How much is electricities?”
        “Spare electricities is free.”
        “Why you no charge?”
        “Because hates coals.”
        “Thanks boss!”
        “Gets to work. Them banannas not going to bend selves.”

        • vensonata

          Ronald, you really are funny! A pity you weren’t around to write for the National Lampoon. Those were the days, my son, those were the days.

    • JamesWimberley

      The utilities are facing increasing amounts of daytime solar on the grid, whether they own it or not, as well as nighttime wind. The “duck curve” isn’t fiction. Ev charging is a godsend for them, as it (a) naturally peaks in the daytime and overnight, (b) can readily be time-shifted during these long periods. So it flattens the load curve, and a flatter curve is more profitable. Their support for ev charging isn’t green smoke but based on solid business logic. Utilities and evs are a natural alliance – there isn’t the conflict of interest we see with rooftop solar.

      The alliance of electric utilities and ev carmakers is also politically influential, and should be strong enough to see off a late challenge from oil interests.

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