The ‘Variability’ of Renewable and Non-renewable energy

The ‘Variability’ of Renewable and Non-renewable energy | 29/05/14
by John Brian Shannon John Brian Shannon

The ongoing debate about the effects of the Variability of Renewable Energy on national electrical grids

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.

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 electrical 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 to consider, 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 such as 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 likely to be sunny in 100 other solar locations within that large state or region.

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

NOTE: The marginal ranking (which reflects the wholesale kWh electricity price) 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 ratio between the number of solar panels and the number of wind turbines to better complement the other, but I won’t bore you with the details.

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 wholesale ‘price variability’ with natural gas, which is why it is the last choice for utility companies as they meet the peak demand hours of the day. Gas is a good but expensive option, however, 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 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, in coal supply lines, in coal power plant maintenance cycles which can have a plant offline for weeks, and coal market pricing. These things can affect total annual output, and is 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 for plain old CO2 emissions)

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 thanks to global warming, 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, in late summer, during maintenance, or during earthquake swarms. Just sayin’ hi California!

An impressive-looking 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 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 and variable output due to reduced reservoir levels caused by anthropogenic drought and 2) the months 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 producers 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 (default) on the Merit Order scale making them the default choice for utility companies when the Sun is shining, or when the wind is blowing, or both.

Why? No fuel cost. That’s the difference. And bonus, no environmental or healthcare hazards 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 ramped up 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; default (0) for solar and wind, (1) coal, (2) nuclear, and (3) natural gas, although this order can change in some parts of the United States and around the world. Merit Order is based on cost per kWh only 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 factor or more.

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 utility business.

Although utility companies were slower than consumers to embrace renewable energy, some are now seeing potential benefit for their business and henceforth things will begin to change. So we can say goodbye to the chatter about renewable energy variability and utility companies can eventually say goodbye fuel-related price spikes.

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

What Is New under the Sun?
Amonix 34.5% peak efficiency solar module record
Verified by National Renewable Energy Laboratory – May, 2012

by John Brian Shannon

Most installed solar panels (also known as solar modules) in North America and Europe have an 11% efficiency-rating. That is, of the sunlight falling on them approximately 11% of that sunlight is converted into direct current electricity.

These are the panels with which we are most familiar and for the countries mentioned, they provide a tiny percentage of total electrical production there.

For example, Germany has over one-million solar panels installed with more installed every day. Even so, all of Germany’s solar panels combined supply less than 3% of German electricity needs.

Thanks to our computer-controlled electrical grids, utility companies can switch to the lowest cost minute-by-minute electricity during the day due to something called ‘Merit Order’ ranking.

When the Sun is shining, every kilowatt of solar energy is spoken-for as it is by far the lowest-priced electricity available to utility companies during the daylight hours. In Germany, electrical rates drop by 15 – 40% during the daytime — due to the lower Merit Order price of solar power.

Solar provides lower cost electricity than the electricity produced by feeding a coal-fired burner with expensive coal ($70 – $155 per ton, plus transportation) with the required small army of personnel to unload coal from rail cars, oversee safety in the power plant, load the coal and otherwise maintain a billion dollar coal-fired power plant for example.

What is new under the Sun, is that many of those old 11% efficiency solar panels are soon to be replaced with 22%-24% efficiency solar panels. That’s right, technology marches along and not just in regards to video games! The latest production solar panels are a ‘drop in’ replacement for the older panels.

Yes, a 100 megawatt solar power plant can become a 200 megawatt power plant — just by replacing the panels with more efficient ones.

And, unlike doubling the capacity of a coal-fired, natural gas or nuclear power plant, this won’t cost another billion dollars, nor entail yet another lengthy political fight to obtain approval. No, the old, low-efficiency panels will simply be unbolted from their brackets and the new higher-efficiency ones will be bolted into place. All of which should take a few weeks while the rest of the solar power plant continues to operate normally.

It turns out that due to mass production and a competitive marketplace, the per panel price of the new efficient panels is lower than the originally-installed panels.

To oversimplify this equation, Germany will jump from 3% solar electrical power production to 6% — just by replacing their panels with more efficient ones.

Where will it end you ask? Earlier this year, a new solar panel was announced which surpasses the 24% panel by a significant margin.

In only ten years, we have come from panels with an 11% efficiency-rating typically costing around $100. per panel, to 24% efficiency-rating panels costing $20. per panel at utility-scale volumes. Within 24-months, Amonix 33% efficiency (CPV) solar panels will go into full production. At this rate, I can’t wait for 2030!

To watch a YouTube video about the Amonix 33% CPV solar program, click here.


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To Be… or not to Be… Green!

Planetary energy graphic - Perez & Perez 2009a
Planetary energy graphic compares finite and infinite (renewable) planetary energy reserves. Finite reserves are absolute totals– while the yearly available potential is shown for infinite (renewable) resources. Image courtesy of: Perez & Perez 2009a

by John Brian Shannon

What energy shall we use between now and 2050? That’s the real question, isn’t it? Our choices are laid out before us just like at the shoe store – all we have to do is choose!

So, lets see what’s available.

It turns out that there are two kinds of energy. Non-renewable and renewable.

Non-renewable energy:

Our worldwide 2009 energy consumption including all forms of transportation, was 16 Terawatt-years. We can see from the Perez & Perez graphic that the finite,  non-renewable energy sources are estimated to total 1445 – 1655 Terawatts. The total energy available from those sources is equal to 90.3 – 103.44 years of energy usage at 2009 consumption.

Once consumed, this kind of energy will be gone forever.

Renewable energy:

Keeping in mind the 2009 energy consumption total of 16 Terawatts per year, we see that renewable energy sources total 23,034.2 – 23095.7 Terawatts per year. That’s 1439 – 1443 times more energy than we required in 2009 – including all forms of transportation.

This kind of energy will be available every year until the sun burns out, the ocean’s freeze and the wind stops blowing.

What’s the difference some might ask, why worry? Even in the worst-case scenario we’re covered for 90 years of fossil fuel use if we keep our energy consumption at 2009 levels.

One, the difference in the actual cost per energy unit. Costs for renewable energy have been falling dramatically and it looks set to continue. Some kinds of renewable energy are already reaching price parity with coal and nuclear power.

Two, sustainable energy per-kilowatt-hour cost savings are becoming apparent when compared to conventional energy, because of something called “Merit Order” ranking, which is a program designed to help utility companies choose from the different kinds of energy available at different times of the day.

Three, the costs associated with certain kinds of energy use must be factored in as China’s leaders (for just one example) are now realizing that  410,000 people per year die from pollution of the air, water, soil and locally-grown food in that country.

Energy usage will continue to increase in developed nations with their 1-billion citizens. In developing nations, energy requirements will continue to increase exponentially along with their 6-billion citizens. Almost 3-billion more developing world citizens are expected by 2050.

To be… or not to be… Green? Isn’t the answer obvious?

Please see: “A FUNDAMENTAL LOOK AT ENERGY RESERVES FOR THE PLANET” — by Richard Perez and Marc Perez



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Utility-scale Solar Power — Now Cost-effective!

by John Brian Shannon

New, utility-scale photo-voltaic solar power is now competitive with new, utility-scale coal. (When neither is subsidized)

Timing is everything it is said. Which makes now a great time to be alive for green energy advocates.

Quite under the radar of the mainstream media, the costs to build utility-scale solar photovoltaic installations have fallen dramatically over the past 24 months with solar (PV) panel prices expected to bottom out in June or July of 2013.

Not only have PV solar panel prices plunged over the past two years — but due to U.S. EPA emission regulations which went into effect January 1, 2012, the costs to build (new and cleaner-burning) coal power plants, or to retrofit existing ones to burn natural gas, have risen dramatically.

These two developments have ushered in a profound shift to utility-scale power generation in the United States which are just now beginning to be recognized.

solar vs coal price 2011-2020

Quite separate from the cost of building new natural gas-fired power plants, or to retrofitting existing coal-fired power plants, are the actual day-to-day costs of producing power and transmitting it to numerous end-users.

To maximize efficiency, electrical utilities employ the Merit Order ranking system whereby the lowest-priced electrical generation is brought online first, then once that capacity is fully-enabled, even more power is added to the grid by using the second-lowest priced electrical generation – and so on. During times of peak usage several different kinds of electrical power may be brought online to meet demand.

You may be surprised to know that Germany, which also employs Merit Order ranking, has over one-million solar panels installed throughout the countryside with plans for another million to be installed within six years. Utility companies there are able to pass on significant savings to users between the hours of 10:00 am and 6:00 pm when solar panels are producing power most efficiently.

With only 4% of it’s electrical power coming from green energy sources, German utilities are able to pass along 10% to 40% savings on their customer’s electricity bills. Imagine the (daylight-hours only) cost savings there six years from now when fully 8% of Germany’s energy grid will be powered by sustainable energy.

The ‘golden age’ of U.S. low-subsidy sustainable energy infrastructure begins in earnest in 2013, only because it now makes economic sense to do so.

Here is a nice chart which shows (up to year 2009) the average yearly energy subsidy for different kinds of energy used in the United States.

Biofuels compare favorably to the other (primarily dedicated to) transportation fuels Oil and Gas. While Renewable electrical energy compares favorably to conventional Nuclear electrical energy.



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