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Renewables with reason

Ratification of Paris Agreement by major players means one thing: new investments on massive scale will soon begin. When we talk about reduction of CO2 emissions we usually imagine big chimneys with big, grey clouds being replaced by fields covered with wind farms on sunny day. But is it that easy?
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Modern world came to the point when human-caused climate change is no longer matter of belief or debate, but acceptance of facts. If we also accept that this change will not be positive, then by all means, we should do everything to prevent it. But at the same time we want to keep our electrical energy- dependent civilization same as it is, with technological development rising undisturbed. Every year, energy demand is rising. Are solar and wind farms enough to compensate for this demand, at the same time replacing old steam and gas power plant? And is it even possible to depend solely on sun and wind?

Controlling the grid
First thing required to understand the balance between  energy demand and energy production. One must always be equal to the other. On usual scales (not cosmic ones) electrical energy is reaching receivers instantaneously so there is always need for device or power plant able to give or take away the difference in demand or production.

"Too much energy" might sound ridiculous, but when power produced is larger than the demand, the results may be: increase of voltage or increase of frequency.   This may cause damage to electronic devices and acceleration of rotary speed of induction engines. Financial losses on production lines may be humongous. On the other hand, if the demand is larger, voltage or frequency will drop, slowing down turbines in a process, and further reducing capabilities of the grid to recover. Ultimately, blackout is imminent.

This is exactly the reason why grid needs large generation unit or large storage capabilities to maintain stability. So far, storage on industrial scales exceeds our technological capabilities, so hydro, coal, gas, oil or nuclear power plants are necessity, whether we want it or not. Supergrids, widespread net of wind farms may be also a solution, but we still don't know if they would be 100% effective.

Economical efficiency
With old solutions keeping electrical grid stable may soon be insufficient, with solar and wind farms being built, there is also a question of economical efficiency of photovoltaic panels and wind turbines. Skeptics say wind and solar farms are not cheap at all, time of their service is considered too short and materials used to produce are not environment-friendly. Is it really the case or is it just war waged by varying lobbies? Are solar and wind farms efficient? Can they change the world in reasonable way or is it utopia, beautiful one but still utopia? To answer those questions, let's see some basic numbers.

Power plant type

Cost [mln euro/MW]

Wind farm (onshore)

1,50

Wind farm (offshore)

3,09

Hydro

4,20

Solar

1,77

Hard coal

1,50

Natural gas

0,88

Nuclear

3,04

Table 1. Cost of max power installation.
Source: Ernst&Young, European Wind Energy Association.

As we can see in Table 1, the cheapest power plant appears to be natural gas-based, with hard coal and wind turbines following. The goal is, of course to choose energy source with the lowest CO2 emission, that's why coal and gas should be excluded.


At first glance, it appears that wind power is the most beneficial one, but there is one, big disadvantage- wind speed is not constant, so capacity factor must be taken under consideration (Capacity factor is a ratio of actual power output to its full potential, nameplate capacity). So, to calculate real cost of power plant, cost have to be divided by this factor.

Power plant type

Time

Capacity factor [%]

Wind farm (onshore)

2300

26,3

Wind farm (offshore)

3100

35,4

Hydro

4000

45,7

Solar

900

10,3

Hard coal

7000

79,9

Natural gas

7000

79,9

Nuclear

8000

91,3

Table 2. Capacity factor. Hours of full power work (8760h - 1 year).  
Source: Ernst&Young.

Using Table 2. we can see that the estimated cost of onshore wind farm is 5,77 mln euros, comparing to 3,3 mln of nuclear equivalent. Solar farms' situation looks even worse. We should also remember that during cloudy days, when air is motionless, conventional power plants must be kept at ready, to compensate for lack of power. That is why wind and solar energy isn't cheap at all, as we can see in the Table 3. To keep CO2 emissions low, along with costs, numbers show that we should invest rather in nuclear power plants then in sun or wind.

Energy source

Energy cost (Euro/

CO2 emission

Solar

598

0,2

Water

136

0,002

Wind

120

0,02

Natural gas

79

0,37

Hard coal

71

0,95

Nuclear

42

0,02

Table 3. Cost of energy production, including CO2 emissions. Source: CEZ, Oko-Institute, Darmstadt.

Something more
But are those numbers everything we should be focusing our attention on?  And if wind farms are so economically inefficient, then why so many countries build them? First of all, there is safety factor. Wind and solar farms may be outclassed by nuclear power plants (considering only low CO2 emission energy sources), but there are serious doubts about full containment of radiation, especially after Fukushima. No one want to make part of country inhospitable, with  population dying of radiation illness, cancer or to bear children with deformations. Whether this fear is reasonable with latest generations of nuclear fission power plants or not, in western democracies people have greatest impact on governments. And people usually want to stay as safe as possible.

Safety concerns are not the only arguments for wind power. Wind turbines producers and wind power associations often say that wind isn't as unpredictable as it seems.  In 80% cases amount of energy produced by wind farms can be predicted even 48 hours before planned production and 95% 10 hours, so  there is no need of keeping steam or gas turbines warm. That still leaves one in five cases misjudged 48 hours before planned production and one in twenty 10 hours before. And does not guarantee maximum power output. However this data shows some opportunities, with good space planning on government level. Of course, another solution is to store amount of energy that will suffice in time of demand, but we don't have the necessary technology yet. According to IHS, market research company, in 2017 we will witness ten times more energy storage installation than in previous years. This may seriously reduce cost of energy generated by wind turbines and photovoltaic panels, and outclass any other sources.

There are arguments that even without storage wind farms may effectively function as parts of a grid. Tools for that may be: redirecting energy consumption to high speed wind parts of day, by establishing lower prices according to those parts.

Solar power will face similar difficulties, with additional problem derived from necessity of inverter presence. Photovoltaic systems have DC output, so there is need for transforming it into AC. Inverters, like most of power electronics, causes disturbances in grids, especially higher harmonics. Nominal work of a grid can be presented as sinusoidal wave, but higher harmonics deforms it, creating currents and voltages of higher value, disrupting work of induction drives and electronics, even damaging them. That why filters must be installed, so cost of grid maintenance increases.

Protecting the Environment
Popularity of renewable energy and its development is also effect of climate research results.  Carbon dioxide must be reduced to prevent further warming of our planet. That may explain why, despite disadvantages listed in previous section, wind and solar power is growing so rapidly, at least in Europe.

Diagram. 1. Primary energy production by source in EU. Source: Eurostat.

Economical consequences of climate change may result in trillion dollar losses, so maybe expansion of wind and solar energy, despite being expensive is a good investment in a long run. Some regions are able to cover their whole demand only with renewables, at least for some time. Best example of that is Portugal, powering itself with only sun, wind and water for four consecutive days. On 15th of ma, Germany produced so much clean energy, that prices went negative, effectively paying consumers to use it. This is an impressive feat, if we don't look on real costs of installations that make it possible. Also, not every region has such good conditions for renewables as Iberian Peninsula to go for few days straight.

Price
Idea leading energy policies may be good thing form general perspective, but consumers may not be so forgiving seeing their electricity bill. As we can see in Diagram 2. and Table 3. prices aren't the lowest in countries with highest share of renewable energy.

Diagram 2. Energy prices in European Union. Source: Eurostat.

 

Belgium

Bulgaria

Czech Republic

Denmark

Germany

Estonia

Irleand

Greece

Spain

France

2 857.1

1 842.3

3 656.1

3 144.0

36 017.9

1 186.0

853.6

2 329.3

18 002.8

21 002.1

 

Croatia

Italy

Cyprus

Latvia

Lithuania

Luxemburg

Hungary

Malta

Netherlands

Austria

2 292.1

23 644.1

111.0

2 371.2

1 358.2

120.3

2 051.1

12.7

4 555.4

9 370.4

 

Poland

Portugal

Romania

Slovenia

Slovakia

Finland

Sweden

UK

Iceland

Norway

8 054.4

5 848.3

6 089.6

1 179.7

1 440.8

10 068.0

16 659.8

9 695.7

5 223.1

12 964.5

 

Montenegro

Macedonia

Albania

Serbia

Turkey

Bosnia&

Herzegovina

Kosovo

Moldova

Ukraine

328.7

277.6

620.6

2 068.4

12 010.2

2 277.7

262.6

302.7

3 263.0

Table 3. Primary energy production from renewables (1000 toe). Source: Eurostat.

            Price of electrical energy may be influenced by many factors, but Table 3 shows that large generation with renewables does not mean that prices will drop.

 

Support mechanisms
European Union seems to know this issue, that is why it's policy focus lots of funds on supporting renewable energy, making growth of the sector faster and encourages states on doing the same.
Basics of EU energy policy up to year 2020 are: 20% reduction of greenhouse gases comparing to 1990, 20% reduction of energy usage, 20% of energy generation purely from renewables. This goal is designed for whole EU, every member state has its individual share planned  (Diagram 4)

Diagram 3. Targets for greenhouse emissions in non Emission Trading Scheme (ETS) sectors in EU member States. Source: European Environment Agency.

Diagram 4. Greenhouse Share of renewables in EU member States. Source: European Commission.

Funding sources other than EU may be:

  • Environmental Protection Funds
  • State budget
  • Local autonomies’ budget
  • Partnership of private and public sector
  • Commercial banks, agencies, foundations
  • Foreign sources
    Specifics depend on state’s administration system.

Support for renewables  was recently reinforced by Paris Climate Agreement. EU was the first of world power to accept 40% reduction of greenhouse gasses before year 2030. This will result in committing even more funds mainly into wind and solar power.

Conclusion
Without help, solar and wind farms have no chance of rapid development, they are simply not efficient enough. Large costs of support equipment (like stabilizers, inverters, etc.), dependency on  certain weather conditions to be at full capacity, need for other power plants at the ready to compensate for insufficiencies, difficulties of grid maintenance, makes them not an easy partner. Does it mean that progress in that sector should be halted? No. It is essential to keep rising of global temperature below 2 degrees to prevent environmental changes and we have quite little time to do it. First of all, it is much more difficult to drop nuclear power plants on mass scale than cover fields and hills with wind and solar farms. Secondly, technology level is rising faster than we usually can predict and with effort focused on photovoltaic panels and wind turbines they are becoming more advanced. Almost every moth we can hear about some minor or larger breakthrough in efficiency, energy storage capabilities, reduction of power losses and much more. Last but not the least, to make something better we must acknowledge its weaknesses first. Pretending that issues do not exist is halting progress and progress in that particular sector is what our electrical energy dependent civilization needs the most.

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