Since February 2014 I find that I’ve published 24 posts on renewable energy here on Energy Matters (linked to in order of appearance at the end of the post) . In them I’ve written about wind, solar and tidal power, hydro, biogas, hydrogen and methane, CO2 emissions, interconnectors, exports and imports, energy storage, load management, backup capacity and ramp rates, the UK, France, Germany, Norway, California, remote islands like Eigg and El Hierro, the world as a whole and even mythical places like Atlantis and the Island of Denmark. I’ve reviewed “energy future” plans formulated by others, such as DECC, the National Grid and France’s ADEME and even come up with some plans of my own. I can’t think of any stone I’ve left unturned, or for that matter anything more I can write about for the time being.
So, time to sum up.
The ongoing transition to renewables – is it leading us into a clean, green, sustainable energy future, or will it leave us freezing in the dark? Or will it do neither?
Before proceeding I should make my position clear. I’m not anti-renewables, as I think the 2.25kW PV array and solar water heater panels up there on my roof demonstrate. None of my posts was motivated by a burning desire to prove that renewables wouldn’t work. What I was trying to do was come up with plans that would work, and as proof of my bona fides I will begin by recapping two of my minor triumphs:
In Post 16 I looked into the question of where households might be able to go off-grid with a rooftop PV system. I found that by installing a PV system large enough to fill winter demand along with a modest amount of battery storage households at latitudes of less than 40 degrees probably could supply their year-long needs without grid input (system capacity and curtailment of surplus summer generation become prohibitively large at higher latitudes). Not a major breakthrough, but better than nothing. The graphic below summarizes the 20 degrees north case:
Figure 3: Demand, consumption and curtailment, rooftop solar system at latitude 20 degrees north. Installed capacity: 4.1 kW, load factor based on consumption 13.9%, annual generation 5,556 kWh, annual consumption 5,000 kWh, wind power curtailed 556 kWh (10%).
And in Post 23 I presented options for the UK that expand renewables generation and also meet UK emissions targets. As far as I know they are the only plans of their type in existence for the UK that have a realistic chance of working, although I’m willing to be corrected on that. Here’s Option 4, which cuts CO2 emissions to 16% of current levels and includes 39% renewables generation:
Figure 7: Top graph: Monthly demand & generation by source for February 20XX. Bottom graph: Gas generation needed to match demand (hourly data) – Option 4
But these minor triumphs were as far as I could get. A green, sustainable energy future requires a generation mix which is dominantly or entirely renewables, and I was never able to develop an acceptable plan that allowed for high levels of wind and/or solar generation. It can be done, but only by using load-following capacity (presumably gas) to fill the huge supply deficits that result from high levels of intermittent wind and solar output, such as those shown in the graph below (from Post 22):
Figure 3: National Grid “Gone Green” scenario for February 2035/36, total generation versus demand factored from February 2013 hourly National Grid data.
And these (from Post 6):
Figure 8: Supply & demand, January 20XX, 100% renewables
To match supply to demand in cases like these one has to abuse the gas plants, curtail huge amounts of surplus renewables generation and run both at very low capacity factors. Option 5 in Post 23 shown in the graphic below is an example. Both wind and gas operate at capacity factors down around 10% and 50% of the wind generation gets curtailed. And this is only a 50% renewables case. A 100% renewables case wouldn’t have any gas-fired or nuclear generation and matching demand would become impossible:
Figure 8: Top graph: Monthly demand & generation by source for February 20XX. Bottom graph: Gas generation needed to match demand (hourly data) – Option 5
The intermittency, or if you like non-dispatchability, of solar and wind generation – plus the added difficulty of managing the huge seasonal swings in solar output that occur at higher latitudes – is a problem presently without a solution. It can be solved only with enormous amounts of energy storage, which as discussed in Posts 15, 18, 19 and 20 don’t exist at present and won’t at any time in the foreseeable future. Yet many developed countries have committed themselves to CO2 emissions cuts that can only be achieved through a wholesale transition to wind and solar. How do they propose to handle the intermittency problem?
Well, if they’re like the European Commission they propose to ignore it. In its most recent public utterance Transforming Europe’s energy system – Commission’s energy summer package leads the way the EC dismisses the intermittency problem in three short sentences:
Brussels, 15 July 2015
What needs to be done to balance networks when there with (sic) variable solar and wind generation?
Firstly, by spreading renewable energy generation across Europe through interconnected networks, high generation can compensate areas with lower generation. At the same time the market has to give clear financial incentives for renewable energy generators to make their production as predictable as possible. Furthermore, in periods of low generation, and high prices, consumers can help fill the gap by reducing their demand, while the market has to ensure they are adequately compensated for this role.
These statements are typical of the thinking of the politicians and bureaucrats who presently formulate energy policy, and who if allowed to pursue their policies to conclusion will do more damage to society than climate change is ever likely to. One might hope that they will eventually realize that the wind isn’t always blowing somewhere, that the sun doesn’t shine at night, that wind turbines and PV panels don’t replace conventional generation, that interconnectors are useless when no one has any electricity to spare, that being able to predict shortfalls in advance doesn’t help if there is no way of avoiding them and that paying consumers to shut down to prevent blackouts is not an acceptable option in an energy-dependent society, but most of them won’t. Bearing this in mind, what might the future hold?
I think the following. The renewable energy transition as presently conceived will gradually grind to a halt simply because it can’t be done. In fact this is already happening in Europe. Germany’s massive investments in renewables have forced it to cut subsidies to try to bring its excessive solar generation back under control but have done little to wean it off its dependence on coal. Ireland already can’t handle all of its wind generation and has a growing curtailment problem. Despite its efforts to encourage renewables Italy is reportedly still going to have to import renewable energy to meet its EU targets. Spain, after running up a cumulative tariff deficit of 25.6 billion Euros, effectively abandoned further renewables development in 2012. The UK’s efforts to replace conventional generation with renewables have achieved little other than to reduce reserve margins to dangerously low levels. (Although things are now changing. The new UK government still pays lip service to renewables but is slashing green subsidies while making let’s-go-nuclear-instead noises. This statement in a Blowout Week 84 link (my emphasis) Ministers say the (Hinkley Point nuclear plant) subsidy represents value for money as it is the only realistic way of reducing UK carbon emissions while ensuring a consistency of supply is hard to interpret any other way. Cameron was apparently serious when he spoke of getting rid of all that “green crap”.)
The main reason renewables are grinding to a halt in Europe, however, is that funding is drying up. The graphic from the Is the European energy bubble about the burst? post reproduced below shows the decline in European “clean energy” investment since 2011. Even if investment now levels out at ~$50 billion a year it will still be totally inadequate to fund Europe’s grandiose plans for a renewable energy future. (The proposed North Sea supergrid alone will cost $250 billion and the offshore wind farms needed to feed it probably twice that. The only way of raising such sums is to dangle yet more lucrative subsidies under investors’ noses, and that isn’t going to happen. By this time renewables were supposed to be generating their own investment momentum in a free-market environment. But they aren’t, and Europe is already “subsidized-out”.)
What of the rest of the world? In the US the Obama Administration and the states that have jumped on the renewables bandwagon are still mostly in the first-flush-of- enthusiasm stage that Europe was in ten or twenty years ago. But wind and solar are just as intermittent in the US as they are in Europe, and the obstacles are already beginning to make themselves felt. Vermont, after committing to 55% renewables generation by 2017 now admits that it can’t do this without importing Canadian hydro. Massachusetts has the same problem, and California is beginning to butt up against the California Duck curve. Politics is another obstacle. Pro-renewables policies have come under fire in Colorado, Oregon and Texas and have been rolled back in Kansas, Ohio and Oklahoma. Obama’s Clean Energy Plan may not long survive his term in office. No significant progress in transitioning to renewables can in fact be expected in the US while the Republican Party continues to oppose it, and political unanimity on the need for this transition is not on the cards at any time in the foreseeable future.
And nothing much can be expected of Canada, Australia and Japan, none of whom has any lasting commitment to renewables, nor of the world’s developing countries, who are under no compulsion to stop burning fossil fuels and who have more important things than wind and solar to worry about anyway.
So if the world’s renewable energy transition as presently conceived is grinding to a halt, what replaces it? Well, the concept will have to change. Renewables growth will continue to be plugged in the developed countries, but with a more measured approach that balances intermittent renewables generation with conventional load-following generation, which as I noted above is the only way renewables can achieve any significant level of penetration. Such proposals are in fact already on the table, and from unlikely sources. The Energiewende blog, long a champion of Germany’s green transition, recently published one. Here is the relevant graphic. It looks like something I might have put together and leads to similar conclusions (although not to the same conclusions. In the 2020 example I think it would make more sense to add baseload generation and curtail some of the solar):
The intriguing feature of the 2020 energy mix is the continued heavy reliance on conventional generation (presumably coal and gas, since Germany is shutting down its nuclear), which fits in well with the Energie but not so well with the wende. If balancing intermittent renewable generation with fossil fuel generation is the approach to be adopted then Germany will never wend its way to a future based on renewable energy and energy efficiency, which was the Energiewende’s original goal. But with the obstacles that currently stand in the way of renewables there really is no other option.
However, the option will still come to naught if the fossil generation doesn’t exist, which is what will happen if countries continue to shut down fossil plants under legislative dictates such as the European Large Plant Directive and the US EPA’s CO2 emissions caps, or with pricing mechanisms that make it impossible for conventional generation to compete with renewables. Markets will have to be restructured so that fossil generation and renewables generation coexist rather than compete. So expect to see changes here too.
And we could of course always adopt the obvious solution to the CO2 emissions reduction problem, which is to forget about renewables and go nuclear. But this option has also been discussed at length in previous posts and this one is quite long enough already.
Finally an acknowledgement to Euan Mearns, who has also written a number of posts on the subject of renewables. I don’t link to any of them here because I’m providing my personal conclusions, which may not exactly coincide with Euan’s, although I think that for the most part they do.
1. How Much Windpower Can The UK Grid Handle
2. Renewable Energy Growth in Perspective
3. How to cut emissions, and how not to
4. Large scale grid integration of solar power – many problems, few solutions
5. Eigg – a model for a sustainable energy future
6. Electricity supply, electricity demand and 100% renewables
7. California public utilities vote no on energy storage
8. El Hierro – another model for a sustainable energy future
9. Google rejects renewables
10. UK Electricity Interconnectors – a Double-Edged Sword
11. Gridwatch France
12. Wind Blowing Nowhere
13. Wind Power, Denmark, and the Island of Denmark.
14. The German Grid and the Recent Solar Eclipse
15. How Much Battery Storage Does a Solar PV System Need?
16. A Potential Solution to the Problem of Storing Solar Energy – Don’t Store It.
17. A Trip Round Swansea Bay
18. Estimating Storage Requirements At High Levels of Wind Penetration
19. The Difficulties Of Powering The Modern World With Renewables
20. Renewable Energy Storage and Power-To-Methane
21. The DECC Pathways Calculator – A False Prophet
22. A Quick Look at the National Grid’s Future Energy Scenarios
23. Decarbonizing UK Electricity Generation – Five Options That Will Work
24. How Much Wind And Solar Can Norway’s Reservoirs Balance?