German Renewable Energy Generation
- October 1, 2016
- 331 views
Almost all modern electrical systems have three categories of generating plants: base-loaded, intermediate, and peaking. The base-loaded plants produce at least 65% of all energy, are run 24/7/365, and have the lowest unit energy cost, about $40 – $45/MWh, included are the “must-run” plants. The intermediate plants produce about 30% of all energy, are run as needed to satisfy the daily variations of demand, and have higher unit energy costs, about $55/MWh. The peaking plants produce the remaining 5% of all energy, are run a few hours per day, and have the highest unit energy costs, about $100/MWh. Annual wholesale market prices average about $50/MWh.
German Renewable Energy: In 2015, German RE was about 187.4 TWh of a total generation of about 645.6 TWh, about 30.6% of generation; the variable wind and solar was 79.2 TWh, wind + 38.7 TWh, solar = 117.9 TWh). The difference between generation and billed consumption is due to net exports and T&D losses. See this URL for valuable information from German government websites.
German CO2 Emissions: Germany’s CO2 emissions are about the same as in 2009. The increase in RE over this period did not have the desired effect. The electricity sector contributes only about 45% of Germany’s total emissions. The 100% decarbonizing of the electricity sector, which is already about 45% decarbonized, if we add nuclear, would reduce total emissions by about another 25%. Yet Germany’s efforts to cut emissions continue to concentrate on the electricity sector. Germany likely will not meet its 2020 and 2030 emissions reduction targets.
German Economic Growth: Germany’s economy is in near-zero growth mode, because so much of its resources are diverted to expensive wind and solar energy systems that produce expensive energy. About 50% of German household bills appear as taxes, fees and surcharges, most of them due to the ENERGIEWENDE, which started around 2000. Germany’s subsidized RE production has led to high household energy bills and millions of “energy-poor” households.
German Household Electric Rates: German household electric rates are the SECOND highest in Europe, about 28.69 eurocent/kWh in 2015; Denmark is the leader with about 30 eurocent/kWh. Both are RE mavens. France, about 80% nuclear generation, has one of the lowest. See line items on German household electric bills in this URL.
Wind and Solar Adversely Affect Electric Grids: In Europe, variable, intermittent wind and solar are adversely affecting electric grids; the higher the wind and solar energy on a nation’s grid, the higher are that nation’s household electric bills. See URL.
The German Electrical System: The base-loaded category of the German system, mostly consisting of nuclear, coal, hydro and bio plants, operates at some constant percent of rated capacity. Most of that capacity has low ramp rates, MW/minute. The system’s intermediate category, primarily consisting of gas turbine plants, has higher ramp rates, i.e., is “flexible”. The system’s peaking category primarily consists of open cycle gas turbine plants with greater ramp rates.
Wind and Solar Energy Quantity and Cost: When German annual wind and solar energy quantities were minor, say less than 5%, the system’s inherent flexibility was able to accommodate that energy, which is variable and intermittent, due to the influences of variable solar, variable winds, variable weather/cloudiness and the seasons.
When those energy quantities became greater than 5% (the actual percentage depends on the system), more and more of various measures are required to accommodate that energy. Here is a partial list: grid build-outs; wind energy curtailments; connections to foreign grids to get rid of excess production; flexible reserve capacity (usually gas turbines); management of scheduling units; weather prediction; more elaborate grid connection requirements; energy storage systems; administrators; report writing; government, academia, and other folks involved in “energy”, etc.
The extra unit cost of all these measures, $/MWh, which increase as more and more wind and solar energy is added, typically are not charged to owners of wind and solar systems, thereby making their unit energy costs, $/MWh, appear more “competitive” compared with traditional unit costs. That “competitiveness” is significantly at variance with reality, as has become increasingly apparent, to more and more people, in recent years. Here is a report, which explains in detail much of the number fudging.
“Socializing” Wind and Solar Costs: As the growing presence of wind and solar energy requires much enlarged and elaborate additions to the energy system, as above described, it imposes a variety of additional costs on the electrical system and the German economy, which adversely affect Germany’s future living standards and its competitive position on world markets; the same is true for the US and other nations.
Politicians/bureaucrats, “working” with RE pressure groups, and using the mantra of saving the world from evil fossil fuels, etc., typically find ways to “socialize” these additional costs, by means of taxes, fees and surcharges, or allocating them to various budgets, i.e., not charge them to wind turbine and solar system owners, to make the cost of wind and solar energy, $/MWh, appear to be “competitive”.
Inadequate Flexible Capacity: The sum of German variable wind and solar energy has become a large percentage of all energy on the grid during windy and sunny periods, and the base-loaded and flexible capacity has become inadequate for balancing that variable energy supply with demand. An example of the rural wind turbine impact is shown in this URL.
Curtailments and Exports: Curtailing wind turbine output, by feathering the rotor blades, would reduce some of the excess energy, however, it likely would attract unfavorable media attention; curtailments were 0.1% in 2009, 1.2% in 2014. The leftover excess energy is exported to nearby foreign grids, usually at near-zero or negative wholesale prices, i.e., Germany is PAYING countries to import its excess energy. Curtailed energy is shown in this URL.
“Must Run” Plants: The German system is constrained by a somewhat fixed capacity of “must-run” plants for essential services, such as hospitals, trains, street and traffic lights, various 3-shift industries, etc. Those plants cannot be reduced in output below about 55% of rated capacity, to prevent them from being unstable, i.e., they cannot sufficiently and fast enough “get out of the way” of the larger surges of wind and solar energy.
Base-Loaded and Intermediate Plants: As a result of “getting out of the way”, base-loaded and intermediate plants produce less energy, MWh/y, over which to spread their annual costs, i.e., their levelized costs, $/MWh, increase to adversely affect their economic prospects, and yet, they are needed for “must run” and other demand, and they are required to operate in a market with wholesale energy prices often below their break-even points; clearly an untenable situation that must be dealt with by…. politicians, who, unthinkingly, were largely responsible for creating these outcomes.
German Grid Stability Issues: As asynchronous-wind turbine and PV solar system-generator energy becomes a greater percentage, and synchronous-generator energy a lesser percentage on the German grid, grid stability issues arise, i.e., excessive frequency variations, which often are exported to foreign grids.
Irish Grid Stability Issues: The below URL shows excessive grid frequency variations, when asynchronous-wind turbine energy becomes a greater percentage, and synchronous-generator energy a lesser percentage on the Irish grid during high wind conditions. See figure 2. Wind energy generation had to be curtailed by 40% to “make room” for additional energy from traditional synchronous generators, likely gas-fired CCGTs, to stabilize grid frequency variations within the required range. See figure 3.
German Export Energy Disturbing Foreign Grids: Germany’s energy exports have run into some roadblocks. France, Belgium, the Netherlands, the Czech Republic and Poland have installed phase shifting transformers, PSTs, to protect their grids from unwanted, grid-disturbing surges of German energy exports, and it’s only 2016. This implies, Germany will need to increase curtailments of wind and solar energy, as a near-term fix.
Wind Turbine Energy Quality Standards: Regulatory agencies are increasingly requiring utility-scale wind turbine and PV solar systems to comply with stricter rules regarding connecting to the grid to enhance grid stability. See grid connection in URL.
Older wind turbines consume reactive power from the grid, etc., instead of providing it to the grid, as do all synchronous generators. Germany, etc., are developing grid connection standards for wind and solar systems. Here is a relevant URL.
In the US, the FERC finally issued an order regarding reactive power requirements for non-synchronous generators (wind, PV solar) on 16 June 2016. Prior to that date, wind turbines were legally exempt from that requirement. It was up to the local grid operator, such as ISO-NE in New England, to determine safe grid connection requirements. For example, Green Mountain Power in Vermont, per ISO-NE order, had to install a $10.5 million, 62-ton, synchronous-condenser system to prevent the Lowell Mountain wind energy from excessively disturbing the NEK grid.
German Money-Losing Energy Trading: Foreign countries, such as the Netherlands, France, Denmark, Norway, Poland, the Czech Republic, etc., usually welcome Germany’s low-cost energy. They export energy to Germany, usually at higher wholesale prices, when Germany’s wind and solar energy is insufficient. As Germany is closing its nuclear plants, and continuing its ENERGIEWENDE-2050 wind and solar build-outs, Germany’s money-loosing energy trading, during high wind and solar periods, likely will increase in future years. The much-heralded energy trading profit, based on wholesale prices, is meaningless, because there is a significant energy trading loss on a cost basis.
The Fraunhofer Institute, an RE-boosting government website, periodically issues reports showing an energy trade surplus. The reports show, the revenue of a large quantity of export energy (85.2 TWh in 2015), generally sold at low export wholesale prices/kWh, exceeding the expense of a small quantity of import energy (33.5 TWh in 2015) bought at generally higher import wholesale prices/kWh, i.e., an energy trading surplus, which attracts much media attention. However, that surplus is a deception, because, the SUBSIDIZED COST/kWh of energy exports is much higher than the export wholesale prices/kWh, which often are near zero or negative, i.e., an energy trading deficit, which usually is not mentioned at all. See below Cost of Energiewende Energy.
Examples of Negative Wholesale Prices: On May 8, 2016, based on EPEX spot data,
The lowest export price was -178.01 euro/MWh, with a weighted average of -144.78 eur/MWh, between 12:30 and 12:45
Later in the day, prices went down even further to -374.00 eur/MWh, between 14:30 and 14:45
On May 15, 2016, Germany met all but 300 MW of its energy demand with renewable energy (mostly wind and solar) for a few hours. At that time, mostly fossil, nuclear, hydro and bio plants, with a total capacity of about 12,800 MW, operating at about 60% of capacity, had an output of about 7,700 MW. The resulting excess energy was sold at negative prices, per EPEX spot data.
Cost of Energiewende Energy: The Energiewende does not cover all German RE; some of it existed prior to the Energiewende. The 24 billion-euro EEG surcharge, shown on electric bills in 2015, is just one RE subsidy. There are other subsidies, taxes, fees and surcharges on electric bills, due to implementing the Energiewende, plus there are subsidies, such as for extra grid build-outs due to the Energiewende, that are not shown on electric bills.
If all such costs are added to base energy costs and then divided by the Energiewende energy quantity, the total cost is about 19 eurocent/kWh. In past years, that cost was much higher, but it has been declining, due to various reductions of feed-in tariffs, and other, recent measures, such as auctioning a fixed MW of wind, and a fixed MW of solar, etc., to be added for a year.
The legacy cost of Germany’s traditional energy is about 5 eurocent/kWh. For example, with, say 95% renewable energy on the grid, and total energy generation at about 105% of demand, the COST of that energy mix would be (5c x 10%, traditional + 19c x 95%, renewable)/1.05 = 17.67 eurocent/kWh, of which about 5% would be exported at significantly negative prices.
Future Energiewende CO2 Goals: German CO2 emission reduction has been near zero since 2009, due to various reasons, such as closing near-CO2-free nuclear plants and adding CO2-emitting coal plants. Based on official government data, Germany likely will NOT meet its CO2 reduction targets. See first and third graphs of this URL and END NOTES.
Going Forward to 2050: As part of adjustments to the Energiewende program, Germany has been reining in excessive wind and solar build-outs, due to increased curtailments, complaints from and blockages by nearby countries, and losing money on energy exports.
With energy exports partially blocked by the PSTs, Germany could respond by:
Curtailing wind and solar energy production during windy and sunny periods, but that would attract adverse media attention.
Adding quick-starting, flexible, gas-fired, plant capacity, MW, but that would “lock-in” CO2 emitting fossil fuels and gas imports.
Building more north-south HVDC transmission grid, but that has been constrained due to NIMBY for more than 15 years.
Adding battery-based energy storage, but that would be expensive and take many years, because economically viable, utility-scale storage, suitable for seasonal variations, has not yet been invented. See END NOTES.
Germany is very rich in money and technology, unlike many other countries, and likely will find a way to make it work. It will be interesting to see how it all will turn out.