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Published on May 13th, 2016 | by Guest Contributor


Debunking 4 Myths About The Clean Energy Transition, Part 1: The “Duck Curve”

May 13th, 2016 by  

This is part 1 of a 4-part series — in the coming days, we’ll also publish on: Myth #2: Excess renewables must be curtailed or stored, Myth #3: Clean energy increases consumer costs via higher rates, and Myth #4: Natural gas is the main reason for decreased emissions.

By Robbie Orvis, Michael O’Boyle, and Hallie Kennan of Energy Innovation

America’s electric system is at a stark inflection point: coal power plants are operating at all-time lows with growing retirements, natural gas prices are at historical lows while power generation is rising, electricity sales are flattening, extreme weather events are forcing more resilient infrastructure, and plunging renewable energy prices have made low- or zero-carbon sources cost-competitive with conventional fuel sources.

Rapidly reducing greenhouse gas emissions from the electricity sector is now possible without radically disrupting grid operations, costs, or reliability. But the grid will require a more substantial transformation as we rely on higher shares of variable renewable generation. Some critics argue technological, financial, and institutional barriers will prevent significant decarbonization in the electricity sector, or will drive up the costs at the very least. But four common clean energy myths are easily debunked by facts and experience that show a low-carbon energy future is possible without sacrificing affordable, reliable service.

Myth #1: The “Duck Curve” Puts a Ceiling On Renewables Integration

Reality: Electric loads can be managed dynamically to reduce ramping requirements

Unlike fuel-based generation, renewable sources like wind and solar cannot depend on stored fuel to generate electricity whenever they are called upon. Solar power is particularly concentrated during the day, whereas wind is more variable; however, both resources come and go with the weather. This necessitates a new way of thinking for grid managers who are used to exclusively dispatching electricity to meet demand.

Thankfully, myriad solutions can compensate for the variability created by increasing shares of renewables. Fears about a “duck curve,” when large shares of solar and wind during the day create ramping problems in the late afternoon (when demand goes up, but the sun goes down), are overblown. It is not necessary, for example, to retain a seldom-used, expensive backup fossil-fuel-based system sized for 100% backup to solar and wind. When the sun sets and the wind blows less, demand-side flexibility, smart rate design, storage integration, and increased regional coordination are promising low-cost, low-carbon alternatives to “make the duck fly.”

Solving the duck curve

One option, demand response (DR), can eliminate the need for peaking generation resources that are turned on only a handful of times a year, and can do so at a much lower cost than natural gas peakers or chemical storage. DR refers to a suite of demand-side options for balancing and reducing electricity load, including customer responses to time-varying prices and “emergency” demand response where customers are paid directly for reducing consumption in real time.

Utilizing DR for even a very small amount of time can yield enormous benefits. For example, the image below demonstrates how adding 5 gigawatts (GW) of DR capacity in California by 2050 could effectively displace fossil-fueled power plants used just a few hours each year (red line). Further, if we assume technology-enabled devices like smart thermostats or parked electric vehicles could allow aggregated DR to be called on 40 or 50 times a year by 2050, then another 5 GW of capacity need could be eliminated (grey line). That’s 10 GW of expensive, minimally-run peaking capacity avoided by DR.

California demand response potential

While 10 GW of DR may sound like a lot, some markets are already procuring DR on a similar scale. For example, PJM Interconnection, a wholesale market serving the US Mid-Atlantic region, already has 12.3 GW of committed DR for 2017/2018. That’s almost 8% of its peak load.

DR is also extremely cost-effective: since DR was introduced to PJM, capacity market prices have dropped dramatically, and PJM estimates DR participation saves $275 million per year. PJM relied heavily on DR to manage fuel shortages and demand spikes during the 2013–2014 polar vortex, which also greatly improved the system’s reliability. It’s no surprise that, by 2020, the DR industry is expected to be worth nearly $60 billion.

Of course DR is just one of the many options available to grid operators and planners to manage renewable energy variability. Battery technology holds major promise as well. Lithium-ion battery costs have already dropped 65 percent since 2010, and by 2050 these new load-modifying resources will provide an even greater potential to displace carbon-based generation, particularly dirty peaker plants.

Pulling It All Together

Accurately estimating the cost of electricity sector decarbonization is undoubtedly a difficult endeavor because of rapid cost declines, myriad technologies, market operations, and other nuances. Institutional inertia favoring an outdated system further clouds this picture.

Nevertheless, it is increasingly clear that today’s available technologies and options can successfully decarbonize the electric sector. In order to cost-effectively achieve the goals many states and countries have laid out, policymakers must have the best available information, and use it to guide policymaking.

Moreover, today’s economy is extraordinarily favorable for investment in renewable resources to make the leap policymakers know is necessary to avoid catastrophic climate effects. Low natural gas prices and the proliferation of energy efficiency technologies mean that utility bills will be kept low, providing a cushion for early investment in renewable resources. The cost of money is at an historic low, encouraging renewable developers to invest. And finally, federal tax incentives for solar and wind power are at peak levels.

Avoiding these four common myths about decarbonizing the power sector can help guide analysts and policymakers toward the solutions needed to reach an affordable, reliable, clean energy future.

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About the Author

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  • Bob_Wallace

    “The drilling and extraction of natural gas from wells and its transportation in pipelines results in the leakage of methane, a far more potent global warming gas than CO2. Preliminary studies and field measurements show that these so-called “fugitive” methane emissions range from 1 to 9 percent of total life cycle emissions [3].

    Whether natural gas has lower life cycle greenhouse gas emissions than coal and oil depends on the assumed leakage rate, the global warming potential of methane over different time frames, the energy conversion efficiency, and other factors [4]. One recent study found that methane losses must be kept below 3.2 percent for natural gas power plants to have lower life cycle emissions than new coal plants over short time frames of 20 years or fewer [5].”

    If field studies find methane leaks as low as 1% then setting a target of “no more than 2%” should be reasonable.

    Hopefully the new EPA regs will bring methane leaks from the NG stream down that low.

    And people should not forget. NG plants are highly dispatchable, unlike coal plants. We can turn them off and on as wind and solar produces.

    If we go from coal to natural gas (100% replacement) and control methane leaks from the gas stream down to 2% or less we get a large reduction in greenhouse gas emissions. About 50% in CO2 emissions.

    Then as we cut into gas use with wind and solar we lower both CO2 and methane leak emissions (we drill fewer wells).

    Moving to 40% wind, 30% solar and 30% NG takes us from 100% CO2 (coal) to 50% CO2 (NG) to 15% CO2 (30% NG).

    Then storage starts to eat into that last 15%.

  • John_ONeill

    These are three truisms and one myth. The ‘ Duck Curve ‘ is just a special case of the obvious fact that when you have uncontrolled variable supply, you have to adjust demand to meet it. In antiquity an example was the ‘ Procustean Bed ‘, which matched supply of bed length to the stature of the occupant by amputation or stretching of the latter. Hydro has a similar case to a much lesser degree – at times you have to push restraint, or spill water unused, but it’s a seasonal, not daily, thing.
    ‘ When the sun sets and the wind blows less, demand-side flexibility, smart rate design, storage integration, and increased regional coordination are promising low-cost, low-carbon alternatives ‘.
    ‘ Demand side flexibility ‘ = getting customers to switch off when they’d rather switch on. ‘ rate design..’ = charging them enough that they have to switch off. ‘. storage integration.’ = getting them to pay for storage. ‘ ..increased regional coordination..’ = getting them to pay for transmission. All doable to various degrees, but don’t say it’s not a cost either in cash or in convenience. Of course, if you can ramp up the gas turbines instead, it’s all good, right?
    The real myth is ‘ Natural gas is the main reason for decreased emissions ‘. CO2 output in the US did drop, though a big part of that was the 2008 financial mess. The switch from coal to NG helped too, but methane emissions have gone up more than enough to compensate, if you figure them over the short term – 100 x worse than carbon dioxide – rather than the long term, ‘ only ‘ 25 x.

    • Bob_Wallace

      Natural gas is the main reason CO2 emission have dropped. We have to control methane leaks. It can be done and EPA regs are coming that will work on the leak problem.

      “when you have uncontrolled variable supply, you have to adjust demand to meet it”

      When you have an uncontrollable fixed supply you have to make adjustments to fit supply to load.

      I suppose you don’t know that nuclear has time of delivery problems? That we built a lot of storage to time-shift nuclear output?

    • Joffan

      I’d be interested to clarify the methane emissions on the coal side of the equation as well, though. I haven’t really seen anyone try to do that, but it’s obvious that coal does outgas. (“firedamp”).

      • Bob_Wallace

        There’s a lot of information online. You could start here –

        “A study by the National Renewable Energy Laboratory estimated that surface mining releases 1.91 grams of methane per kilogram of surface mined coal. The same study estimated that mining releases 4.23 grams of methane per kilogram of underground-mined coal.[7]”

  • NRG4All

    So many things can be done to shave the head of the duck.

    First, regarding PV, daylight savings time tends to extend PV generation into the evening hours. Perhaps “summer hours” could add another hour to PV generation.

    Second, encourage some portion of PV panels to be facing west to increase production during the late afternoon to sunset.

    Third, rebuild the grid infrastructure so that PV (and wind) produced in one place can be sent to places where the local conditions temporarily prevent PV production.

    Fourth, overbuild PV such that #3 can be utilized to a greater extent. That is PV can provide enough extra power to be sent to another region.

    Fifth, Powerwalls and the like do not need to be installed to the extent that the house can move off the grid. They are best used to just cut down the peak times.

    Sixth, as mentioned, have a super peak period electrical rate that will encourage discretionary use of electricity to move out of the peak demand period. Water heater timers are an excellent example.

    Seventh, encourage the use of insulation to allow A/C units to run less.

    Unfortunately, a lot of this “encouragement” would best come from the Federal Government especially for those items that cross state lines. But with a partisan “locked” congress of which 56% don’t support doing something about climate change, we may well reap the whirlwind.

  • John Moore

    Renewables opponents in general are a bunch of duckheads. I’m just sayin’….

  • JamesWimberley

    First time I’ve seen the neologism “Caliwende”. It’s not really needed, but I like the h/t to Fell and the other authors of the German EEG reform. It was brilliant PR to disguise a revolution in the unthreatening language of a “turn” or “change of course”.

    • eveee

      Yes, they tried Energiornia and it didn’t fly.

  • Marion Meads

    The duck curve is not a myth, it is the reality of the current average demand pattern that must be overcome. It can be overcome by 100% renewables not the strangleholding your balls and cough up all your money from those carbon using generators. Such common scenario would soon be overcome by cheap storage battery prices and peak rate pricing.

    • Frank

      Storage has some amazing properties. Some of it can ramp up and down in thousanths of a second, it can both put power on the grid, or take it off. But I think the most efficient solution will be a combination of that, demand management, and grid upgrades, and in the short term, gas, while we implement the other three. Grid, and demand management doesn’t need to wait, and storage is ramping.

      Anything that produces expensive power, and can’t ramp, has a bullseye on it’s chest, like coal and nuclear.

  • Freddy D

    Current antiquated pricing structures literally incentivize industrial consumption in the evening apparently. Good dialog currently underway to use simple pricing incentives to move demand into “the belly of the duck”.

    I hadn’t heard of the duck curve as “putting a lid on renewables”. California has the objective to get to 50%renewable generation by 2030. Clearly the only way to get there is to generate most of that 50% during 6 hours of the day with solar and either store it or shift demand into that period. This is what people are working towards. Today the state gets about 40% during peak hours but that’s leaves another 18 hours to work with where wind runs at about 10-20%.

    • eveee

      DR eliminates some of the ducks head without adding generation. Is the cheapest way. But some shifting using storage will be used, too.

      • Matt

        Demand shift with thermal storage, can flatten the curve more also. And move the demand to when the peak production is.

    • Bob_Wallace

      The duck curve is used by nuclear and coal advocates as a way to talk down renewables. Since neither can turn on rapidly they couldn’t be used to power the higher demand/low wind-solar input hours, thus renewables must be limited and nuclear/coal given a major role to play.

      As we chop down the head and tail of the duck that insistence on large thermal plants fades away

      • Freddy D

        Now I’m here hungry for one of those roasted ducks in the window!

      • Brunel

        How quickly can the most efficient LNG power station go from idle to full steam.

        If it is 4 hours, then that is not bad for now.

        But of course we should be developing cheaper batteries for overnight electrons.

        • Bob_Wallace

          The turbine part of a CCNG plant (and gas peakers) produce electricity very soon after turning on. The steam part of a CCNG plant can take 3 to 4 hours to get to full speed.

          Batteries/storage is what we need in the long term. NG is a temporary stand in for affordable storage. (It’s that “bridge” thing.)

          • Brunel

            Peaking gas power stations are not efficient.

            Anyway, there was a news article saying CA invited bids for a new peaking power station and the lowest bid was from a battery firm!

            Maybe someone can tell us the cost of electrons from a typical peaking power station – so we know how cheap batteries need to get.

          • Bob_Wallace

            “there was a news article saying CA invited bids for a new peaking power station and the lowest bid was from a battery firm”

            That’s the news we want to hear! (Got a link?)

            Peaking plant prices – we can use Lazard’s LCOE numbers. $165 to $218 per MWh. 16.5 to 21.8 cents per kWh.


          • Brunel
          • Bob_Wallace

            From the first link –

            “California’s goal is to produce at least 33% of its electricity from renewable sources, and while there’s plenty of sunshine and wind, their production fluctuates throughout the day, sometimes producing more than needed and other times falling short. Regardless of what’s creating the baseload electricity, peaker plants are needed to provide quick demand response. When Southern California Edison (SCE) sent out a request for bids on a 100 megawatt peaker plant, they received over 1800 responses. The winner turned out to be AES, an energy company that builds power plants of nearly every flavor: coal, diesel, gas, oil, wind, etc. What might be surprising is that the chosen technology isn’t any of those – it’s the world’s largest battery.”

  • Ivor O’Connor

    I looked for four myths but only the first had a heading. I suppose I’ll have to patiently wait for the other three. 🙁

    • Olivier Willemsen

      This is part 1 of a 4 part series. Every part discusses 1 myth. I think the title is correct and clear.

    • Part 2 is tomorrow, Part 3 Sunday, and Part 4 Monday. Stay tuned. Some great stuff to come. 😀

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