Variability of Renewable Energy concerns not fact-based

by John Brian Shannon

Originally published on

Merit Order ranking control room
Most utility companies have Merit Order ranking control rooms similar to this one where decisions are made about which power producer will contribute to the grid in real time. Microprocessors make the instant decisions, while humans are present to oversee operations and plan ahead.


On the Variability of Renewable Energy; The ongoing argument about renewable energy additions to national electrical grids.

Solar Variability

Some people argue that solar photovoltaic (solar panels) produce ‘variable’ electricity flows — and they assume that makes solar unsuitable for use in our modern electric grid system.

And it’s true, the Sun doesn’t shine at night. Also, if you are discussing only one solar panel installation in one farmer’s field, then yes, there is the variability of intermittent cloud cover which may temporarily lower the output of that particular solar installation.

But when grid-connected solar arrays are installed over vast areas in a large state like Texas, or throughout the Northeastern U.S.A. for example, it all balances out and no one goes without power as solar panels produce prodigious amounts of electricity during the high-demand daytime hours. If it’s cloudy in one location thereby lowering solar panel outputs, then it is sunny in 100 other solar locations within that large state or region of the country.

So, solar ‘variability’ disappears with many widely scattered installations and interconnection with the grid. So much for that accusation.

NOTE: The marginal ranking for solar is (0) and that ranking never varies. (More on this later)

Wind Variability

The situation with wind power is essentially the same, One major difference though; In many parts of the world the wind tends to blow at its most constant rate at night, which helps to add power to the grid while the Sun is asleep.

In fact, complementary installations of solar and wind help to balance each other through the day/night cycle — and through the changing seasons. There is even an optimum solar panel capacity to wind turbine capacity installation ratio, but I won’t bore you with it.

NOTE: The marginal ranking for wind is (0) and that ranking never varies.

Natural Gas Variability

What? Natural gas is not variable!

Oh really? Over the course of the past 60 years, how has the natural gas price per gigajoule changed? Got you there! The natural gas price has increased by orders of magnitude and wild price fluctuations are quite common.

OK, that’s not ‘output variability’ but it is a variable factor with regard to energy pricing. And that’s a variable that actually matters to consumers.

Natural gas prices have swung wildly over the years forcing utilities to peg their rates to the highest expected natural gas rate. No wonder investors love natural gas!

So there is ‘supply variability’ and ‘rate variability’ with natural gas, which is why it is often the last choice for utility companies trying to meet daily demand. Gas is a good but expensive option and it comes with its own variability baggage.

We won’t even talk about the associated CO2 cost to the environment. (OK, it’s about $40 per tonne of CO2 emitted)

Coal variability

Not to the same degree as natural gas, but coal also faces price swings and potential supply disruptions — again forcing utility companies to set their rates against unforeseeable labour strikes at a mine, a railway, or shipping line — and against coal mine accidents that can shut down a mine for weeks, or against market-generated price spikes.

These things are impossible to foresee, so this ‘averaging up’ of the price results in higher energy bills for consumers and better returns for investors.

Yes, there is variability in coal supply, coal supply lines, coal power plant maintenance cycles which can have a plant offline for weeks, and market pricing. These things can affect total annual output, yet another kind of ‘variability’. (Again, that doesn’t factor-in the other costs to society such as increased healthcare costs from burning coal which releases tonnes of airborne heavy metals, soot, and nasty pollutants besides CO2 — which some estimates put at $40-60 per tonne emitted — in addition to the environmental cost of $40 per tonne of CO2 emitted)

NOTE: Should we talk here about how much water coal plants use every year? More than all the other energy producers put together, and then some!

Hydro power variability

What? Hydro power is not variable!

Oh yes it is. Nowadays, many hydro dams in the U.S. can barely keep water in the reservoir from August through November. They cannot produce their full rated power in a drought, they cannot produce their full rated power in late summer, they often cannot produce power during maintenance, or during earthquake swarms. Just sayin’ hi California!

An impressive body of water behind the dam is meaningless when the water level isn’t high enough to ‘spill over the dam’. If the water level isn’t high enough to spin the turbines then all that water is just for show. Take a picture!

“In 1984, the Hoover Dam on the Colorado River generated enough power on its own to provide electricity for 700,000 homes because the water level of Lake Mead behind the dam was at its highest point on record. But since 1999, water levels have dropped significantly, and Hoover Dam produces electricity for only about 350,000 homes.” — CleanTechnica

 And then there is this problem; Global warming and its resultant drought conditions mean that some dams are essentially ‘finished’ as power producing dams for the foreseeable future.

Again, we have output variability; But this time it is; 1) lower power output due to reduced reservoir levels caused by anthropogenic drought and 2) the time of year that hydro dams cannot produce their full rated power.

Price variability: This is what Merit Order ranking is about

Merit Order ranking is a system used by most electric utilities to allow different types of electrical power plants to add power to the electric grid in real time. Thanks to a computerized grid, this occurs on a minute-by-minute basis every day of the year.

In the German example, electricity rates drop by up to 40% during the hours in which solar or wind are active, and this is what Merit Order ranking is all about; Using the cheapest available electricity source FIRST — and then filling the gaps with more expensive electrical power generation.

Solar and wind electricity are rated at (0) on the Merit Order scale making them the default choice for utility companies when the Sun is shining, or the wind is blowing, or both.

Why? No fuel cost. That’s the difference. And bonus, no environmental or healthcare costs with solar and wind either.

Once all of the available solar and wind Merit Order ranking (0) capacity is brought online by the utility company, then (1) nuclear, (2) coal, and (3) natural gas (in that order) are brought online, as required to match demand, according to the marginal cost of each type of energy. (German Merit Order rankings)

NOTE: In the U.S. the normal Merit Order rankings are; (0) solar and wind, (1) coal, (2) nuclear, and (3) natural gas, although this can change in some parts of the United States. Merit Order is based on cost per kWh and different regions of the country have different fuel costs.

(The one cost that is never factored-in to the kWh price is the cost of disposal for nuclear ‘spent fuel’ and for good reason, but that’s a discussion for a different day)

The Fraunhofer Institute found – as far back as 2007 – that as a result of the Merit Order ranking system – solar power had reduced the price of electricity on the EPEX exchange by 10 percent on the average, with reductions peaking at up to 40 percent in the early afternoon when the most solar power is generated.

Here’s how the Merit Order works.

All available sources of electrical generation are ranked by their marginal costs, from cheapest to most expensive, with the cheapest having the most merit.

The marginal cost is the cost of producing one additional unit of electricity. Electricity sources with a higher fuel cost have a higher marginal cost. If one unit of fuel costs $X, 2 units will cost $X times 2. This ranking is called the order of merit of each source, or the Merit Order.

Using Merit Order to decide means the source with the lowest marginal cost must be used first when there is a need to add more power to the grid – like during sunny afternoon peak hours.

Using the lowest marginal costs first was designed so that cheaper fuels were used first to save consumers money. In the German market, this was nuclear, then coal, then natural gas.

But 2 hours of sunshine cost no more than 1 of sunshine: therefore it has a lower marginal cost than coal – or any source with any fuel cost whatsoever.

So, under the Merit Order ranking of relative marginal costs, devised before there was this much fuel-free energy available on the grid, solar always has the lowest marginal cost during these peaks because two units of solar is no more expensive than one. – Susan Kraemer

It’s as simple as this; With no fuel cost, solar and wind cost less. Although solar and wind are expensive to construct initially (but not as expensive as large hydro-electric dams or large nuclear power plants!) there are no ongoing fuel costs, nor fuel transportation costs, nor fuel supply disruptions, nor lack of rainfalls, to factor into the final retail electricity price.

As solar panel and wind turbine prices continue to drop thereby encouraging more solar and wind installations, we will hear more about Merit Order ranking and less about variability. And that’s as it should be, as all types of grid energy face at least one variability or another.

Only solar, wind, hydro-electric, and nuclear have a predictable kWh price every day of the year. Coal, natural gas, and bunker fuel, do not. And that’s everything in the energy business.

Although utility companies were slower than consumers to embrace renewable energy, many are now seeing potential benefits for their business and henceforth things will begin to change. So we can say goodbye to the chatter about the Variability of Renewable Energy and utility companies can say goodbye fuel-related price spikes.

Buckle up, because big changes are coming to the existing utility model that will benefit consumers and the environment alike.

Follow John Brian Shannon on Twitter: @JBSNews_com

Distributed Energy – The Next Logical Step

by John Brian Shannon

Distributed Energy adds capacity to the electrical grid during the hours that electrical demand is highest, adding to grid stability and lowering costs for consumers

Over the centuries, different kinds of energy and energy delivery systems have been employed by human beings. In the Neolithic Period some 10,000 years ago, our ancestors sat around campfires for the light, warmth and security that a fire can provide. Neolithic people mostly ate their food raw, but are known to have cooked meat and occasionally grains over a fire.

For many centuries that general energy usage pattern continued and the only difference was the kind of fuel (coal later replaced wood and straw) and the size of the fire and the number of people it served.

New ways of using energy

The Industrial Revolution changed all that for people in those suddenly developing nations. New energy technology offered huge economies of scale — whereby the larger the power plant, the more efficiently it could produce affordable power for large numbers of people.

The first electrical grids were then formed to transport electricity from large-scale coal power plants or hydro-electric dams to population centres.

Since then, every decade shows larger and more efficient power plants and ever-larger populations being served by this wonderfully efficient grid system. Huge power plants and sprawling electrical grids delivered electricity to citizens over very long distances and at reasonable rates, while investors, utility companies, and power producers received reasonable rates of return on their investment.

It was (and still is) an excellent model to employ, one which brings electrical current from remote power plants to electricity users at an energy price that works for everyone. Except for the fact that some power plants produce unimaginable amounts of pollution and are necessarily and massively subsidized by taxpayers, this has been a winning energy model for a number of decades. And this very successful and reliable model will continue to provide our electricity for many years to come.

But there are serious drawbacks to grid power

Utility-scale power generation requires huge power plants, each costing tens of billions of dollars in the case of nuclear power plants, billions of dollars each in the case of hydro-electric power plants, and hundreds of millions of dollars in the case of coal power plants.

All coal and nuclear power plants were heavily subsidized by taxpayers, or they couldn’t have been built in the first place

It doesn’t end there, as coal fired power plants use hundreds or even thousands of tons of coal every day of the year at a cost of $50. to $160. per ton, not to mention the huge infrastructure costs required to build the ports and rail lines to transport the coal — paid for by taxpayers. And then add to that, the freight costs paid to the shipping companies and the railway companies to transport that coal to the power generation site. Most of the coal that Asia burns comes from North America and Australia. Even within coal rich North America, thousands of miles of railway tracks were laid down to transport North American coal to North American coal power plants.

Let’s not forget the environmental costs associated with all that toxic smoke either. China and the U.S. each produced 7.2 billion tons of coal fired CO2 in 2010 and that number is rising every year. Not to mention the many toxic oxides of nitrogen and sulfur, along with soot and airborne heavy metals that are produced wherever power plants burn coal.

Nuclear power plants likewise, use expensive to produce nuclear fuel rods or pellets and simply could not survive without massive government subsidies. Then there is the storage problem, as the so-called ‘spent fuel’ is highly radioactive and must be securely stored for up to 20,000 years in temperature-controlled conditions. Again, massive taxpayer funded infrastructure must be provided to store the world’s ever-growing pile of spent fuel.

Other than costing billions of dollars and disrupting river flows and fish habitat, hydro-electric power is a benign and good electrical generation solution. If only there were enough rivers to provide all the electricity that 7.1 billion people require! With almost every possible river already dammed on the planet, hydro-electric power plants provide only 16.2% of the world’s electricity.

An even better energy model has arrived in the form of distributed energy

Simply stated, distributed energy is created when many homes or businesses place solar panels on their rooftops or wind turbines on their properties — and then connect it to the electrical grid. Either solar panels or wind turbines can be used in the distributed energy context.

With progressive policies designed to strengthen and balance existing electricity grids, distributed energy can play a large role in ameliorating our present energy challenges.

Distributed energy is the opposite of utility-scale electrical power generation in three very important ways

  • Distributed energy emits no measurable pollution.
  • Distributed energy assists the grid operator to locate the energy source close to electrical demand centres.
  • Unimaginably large and expensive national utility grids crisscrossing the countryside are not required in the case of distributed energy.

Connecting distributed energy to the grid results in many positives for micro-energy producers, homeowners, businesses, and the grid operator. During the daytime, solar panels may produce more electricity than the homeowner or business can actually use — although during that same time of day, the utility company power plants may be straining to produce all the electricity that the grid demands during those peak hours.

Net-Metering to the Rescue!

Therefore, energy-sharing takes place via the use of a net-metering system allowing the homeowner or business owner to sell their surplus electricity to the utility company. Net-Metering allows homeowners and businesses to sell their excess electricity to the grid at a profit, while retaining all the benefits of grid connection. Installation of a net-meter at each home is the essential part of a distributed energy grid.

New financing options are becoming available to homeowners and businesses to install rooftop arrays — and even renters are able to purchase renewable energy through innovative programmes designed to boost the market share of renewables.

Some auto assembly plants in Germany and in the U.S.A. have installed wind turbines on their properties, or on nearby land purchased specifically for that purpose. Both BMW and Volkswagen are famous for building great cars, and for being distributed wind producers that have installed wind turbines near their factories, to ensure more reliable power and to avoid energy price spikes. Many ‘world citizens’ admire their environmental commitment.

IKEA, WalMart and Walgreens are famous for installing solar power plants on their store rooftops and warehouses, and WalMart, Google and Apple Computer and others, have purchased wind farms in an effort to Go Green and to alleviate the energy price spikes which are so common in the U.S. and Europe. Well done.

Distributed Energy pays off!

In California, homeowners with solar panels on their rooftops are receiving cheques for up to $2000. — or even larger amounts in the case of larger rooftop solar installations — from their utility company every January, to pay for all the surplus electricity they’ve sold to the utility company during the course of the year. California law mandates that distributed energy producers be paid up-to-date by February 1 of each year and other energy policies in the Great Bear state prove their commitment to a

In Australia, many thousands of homes with solar panels on their rooftops have dramatically added to overall grid capacity and stability by curtailing the power outages common there during peak demand hours, and some coal power plants have shut down while other coal plants are now planning for decommissioning.

Understandably so, the heavily subsidized coal and nuclear industries fear the rapidly growing distributed energy model, although coal exports to China from coal giant Australia continue at a frenetic pace.

Turn down the burners — the Sun is up!

Natural gas and hydro-electric power producers cautiously embrace distributed energy as an augmentation of their efforts to provide reliable electricity to the grid — as they can all exist as energy producers at different hours of the 24 hour day — and for very different reasons none of them are able to eclipse the others.

Distributed energy typically produces its power during peak demand hours, and is known for reducing electricity costs across-the-board due to the Merit Order effect, which is a ranking system utility companies use to decide which energy generator to employ (in real-time) throughout the day and night.

In fact, distributed energy is all about adding peak demand power to the grid — resulting in a stronger, more reliable power grid while displacing dirty energy in the process — and monetarily rewarding citizens for their surplus electricity.