Making hydrogen electrolysers super efficient

The traditional electrolysis process is relatively inefficient.   If you use surplus green electricity to produce hydrogen and then burn the hydrogen to make electricity, its round-trip efficiency is low, much lower than alternative energy storage techniques:

 

Flora noted that converting power to hydrogen and then using the fuel to generate power has a relatively low round-trip efficiency. Round-trip efficiency is the percentage of electricity retrieved after being stored.

The technology to convert power to hydrogen and back to power has a round-trip efficiency of 18%-46%, according to data that Flora presented from the Massachusetts Institute of Technology and scientific journal Nature Energy. In comparison, two mature long-duration technologies, pumped-storage hydropower and compressed air energy storage, boast round-trip efficiencies of 70%-85% and 42%-67%, respectively. Flow batteries, a rechargeable fuel cell technology that is less mature, have a round-trip efficiency of 60%-80%. 

(Source: S&P Global --- Hydrogen technology faces efficiency disadvantage in power storage race
)

[Incidentally, Elon Musk claims that's Tesla's lithium-ion batteries have a round-trip efficiency of 93%]

But an Australian start-up, Hysata, is developing a process which enormously increases the efficiency of electrolysis.    I've already talked about this company and their super efficient hydrogen electrolyser, here.  

This update is from ARENA (Australian Renewable Energy Agency)

A pioneering, all-Australian hydrogen electrolyser technology is getting the chance to prove itself at a commercial scale.

If it works, the project has the potential to transform the economics of renewable hydrogen production.

ARENA’s support has helped develop this new technology since it was a concept in a University of Wollongong laboratory. That work saw a spin-off company, Hysata, established to commercialise the development.

Now, Hysata will receive $20.9 million ARENA funding as part of a $47.5 million project. Hysata will build and test a 5 MW system at its new Port Kembla manufacturing facility.

The plan then is to move the entire system to Rockhampton in Queensland, for installation and trials next to the Stanwell Power Station.

Queensland government-owned power company Stanwell Corporation is providing the site and facilities, and also backing the project with $3 million.

ARENA CEO Darren Miller says the project is a crucial step to enabling purchase orders for the technology.

“Hysata’s electrolyser technology could be a game-changer for renewable hydrogen,” Mr Miller said.

“The demonstration at Stanwell’s site will be key to unlocking commercial demand for Hysata’s product by proving the technology works at scale.

Currently, the production cost of renewable hydrogen (using renewable energy) is at least twice that of hydrogen produced from fossil fuels. Hysata says its technology will slash costs and produce hydrogen “well below” a competitive target price of $2 per kilogram (approx. US$1.50/kg).

FYI, if there’s one number you should remember, it is that price of $2 per kilogram. That’s the key to competing with fossil fuel-derived hydrogen and fully unlocking renewable hydrogen’s industrial and energy future.

It’s all in the bubbles.   All electrolysers work by passing an electric current from electrodes through H2O – water. The current splits the water into its two parts, hydrogen and oxygen. That process takes energy.

Now, if the entire process were 100 per cent efficient, all that energy would go into splitting the water. Nothing else.

But, until now, electrolysers have also produced a lot of heat. That’s because, just like an electric heater at home, they have electrical resistance.

The heat generated is not only wasted energy, but it must also be removed. Electrolysers need a lot of cooling and that uses even more energy.

So, if you can reduce resistance, a greater proportion of energy is available to split the water. Also, the system generates far less far less heat, which in turn requires less cooling.

Hysata has tackled the problem by completely redesigning their electrolyser to remove all the main sources of electrical resistance.

It turns out, that means eliminating hydrogen and oxygen bubbles. When bubbles form on the electrolyser’s electrodes, they reduce the surface area available for electrolysis and increase resistance.

In fact, Hysata says it has completely eliminated bubbles from its system and cut electrical resistance to virtually zero. As a result, Hysata says it expects a fully operational electrolyser will stay cool through good air ventilation alone.

The combined effect is what has raised the overall efficiency of a Hysata electrolyser to around 95 per cent. That’s a huge jump on current technologies, which operate with efficiencies closer to 75 per cent.

To put that in context, to make renewable hydrogen competitive with its fossil-fuel derived alternative, the International Renewable Energy Agency (IRENA) in 2020 set an electrolyser efficiency target of up to 85 per cent … by 2050.

I'm not sure that hydrogen by itself is in fact the future.   To transport it, you need to compress it and refrigerate it, which takes additional energy, further reducing its round-trip efficiency.  Also, it makes gas pipes brittle, and, because its molecules are so small, it easily escapes through the gaps in the molecular lattices of gas pipes or storage tanks.   But if you convert it to methane, using the Sabatier process, it's the equivalent of natural gas, and in fact is called synthetic natural gas (SNG, which is a bit of an oxymoron, no?)  And then you can use the existing gas distribution system and gas storage system, as well as existing gas turbine electricity generators.  On the other hand, to make SNG, you need a source of CO2, and unless you use the escape gases from a gas-turbine power plant flue, you have to produce CO2 using direct air capture, which is still very expensive.

We will need seasonal (or long-term storage)  to reach 100% renewables, and hydrogen, or more probably, SNG, will be how we fill that gap.  So, if this can be commercialised, it will be a huge step forwards towards a 100% green energy system. 

2/3rds of renewables cheaper than coal

 

From electrek

In 2021, 163 gigawatts (GW) – nearly two-thirds – of new renewable power added was cheaper than the cheapest coal-fired power plants in G20 countries, according to a new report released by the International Renewable Energy Agency (IRENA).

The G20, or Group of Twenty, is an intergovernmental forum comprising 19 countries and the European Union.

IRENA’s report, Renewable Power Generation Costs in 2021, states that the cost of electricity from onshore wind fell by 15%, offshore wind by 13%, and solar by 13% compared to 2020.

The Russian invasion of Ukraine drove up coal and natural gas prices, and high gas prices in Europe mean gas will become increasingly uneconomical.

As Electrek reported on Tuesday, plans in Europe to place a small number of coal plants on temporary standby would only add 1.3% to EU emissions annually, even in the worst-case scenario where they run at the highest levels.

Renewable costs plunged again in 2021

 From IRENA

The competitiveness of renewables continued to improve in 2021. Data from the IRENA Renewable Cost Database and analysis of recent power sector trends affirm their essential role in the journey towards an affordable and technically feasible net zero future. 

The global weighted average cost of newly commissioned solar photovoltaics (PV), onshore and offshore wind power projects in 2021 fell. This was despite rising commodity and renewable equipment prices in 2021 given there is a notable lag before these cost increases appear in project total installed costs; and significant improvements in performance in 2021 raised capacity factors, especially for onshore wind. 

The global weighted average levelised cost of electricity (LCOE) of new utility-scale solar PV projects commissioned in 2021 fell by 13% year-on-year, from USD 0.055/kWh to USD 0.048/kWh. With only one concentrating solar power (CSP) plant commissioned in 2021, after two in 2020, deployment remains limited and year-to-year cost changes volatile. Noting this caveat, the average cost of electricity from the new CSP plant was around 7% higher than the average in 2020.

The global weighted average LCOE of new onshore wind projects added in 2021 fell by 15%, year-on-year, from USD 0.039/kilowatt hour (kWh) in 2020 to USD 0.033/kWh. China again dominated new onshore wind capacity additions in 2021 and also experienced, against the trend elsewhere, falling wind turbine prices. The cost of electricity for new onshore wind projects excluding China, fell by a more modest 12% year-on-year to USD 0.037/kWh. The offshore wind market, saw unprecedented expansion in 2021 (21 GW added), as China increased its new capacity additions and the global weighted average cost of electricity fell by 13% year-on-year, from USD 0.086/kWh to USD 0.075/kWh.

Cost reductions were not universal however, the country weighted average total installed costs of utility-scale solar PV increased year-on-year in three of the top 25 markets, while for onshore wind this was true of seven of the top 25 markets in 2021. The period 2010 to 2021 has witnessed a seismic shift in the balance of competitiveness between renewables and incumbent fossil fuel and nuclear options. The global weighted average LCOE of newly commissioned projects utility-scale solar PV projects declined by 88% between 2010 and 2021, that of onshore wind and CSP by 68%, and offshore wind by 60% (Figure ES.2).

Note that the fossil fuel cost range includes cheap gas in the US.
Gas outside the USA is much more expensive.

 In 2021, the global weighted average LCOE of new utility-scale solar PV and hydropower was 11% lower than the cheapest new fossil fuel-fired power generation option and that of onshore wind 39% lower. Geothermal and bioenergy globally remain, on average, more expensive than the cheapest fossil fuel-fired option, but provide secure supply and can be very competitive in non-OECD regions. Rising commodity prices, especially materials prices such as steel, copper, polysilicon and aluminium; saw module and wind turbine prices rise from around Q4 2020. For instance, depending on materials prices and other supply chain pressures over the rest of this year, solar PV module prices might average a fifth more than they did in 2020. Yet, in 2021, the global weighted average cost of electricity from new solar PV and onshore wind fell. There are a number of potential reasons for this, including:

• Overall equipment cost increases were modest in late 2020 and into early 2021, when many projects commissioned in 2021 would have placed orders. 

• Larger projects have greater purchasing power and longer lead times, and are increasingly dominating capacity additions outside Europe. 

• Contingency allowances in many projects will have absorbed some or all of any increased costs. • Technology improvements (e.g. more efficient PV modules and larger wind turbines) and improvements in manufacturing efficiency and scale continue.

• China remains the dominant market for new solar and wind and has lower commodity prices, transport costs, while wind project developers squeezed turbine price reductions from manufacturers in 2021. 

However, the data suggests that not all of the materials cost increases witnessed to date have been passed through into equipment prices, while manufacturer’s margins have also been squeezed. If materials prices remain elevated in 2022, this suggests – when combined with the lag between materials costs increases and project costs – that price pressures in 2022 will be more pronounced than in 2021 and total installed costs are likely to rise this year in more markets. 

The impact on the levelised cost of electricity for solar PV and onshore wind is, however, likely to be modest – in the order of 2-4% for utility-scale solar PV and 4-9% for onshore wind. Increasing profit margins to the more sustainable levels seen in 2017, might increase this figure for onshore wind to an 8% to 12% increase, but it is not clear if all these cost increases could be passed through in 2022 alone. 

More importantly, with the extremely high fossil fuel prices already experienced in 2022 likely to continue, the additional cost is outweighed many times over by the economic benefit of new renewable capacity. 

Indeed, the extent of the benefits from renewables in 2022 will be unprecedented. Assuming average wholesale fossil gas prices in 2022 of USD 0.109/kWh in Europe, the average generated fuel-only cost (excludes carbon dioxide (CO2) prices) of existing fossil gas generators will be in the order of USD 0.23/kWh, or 540% higher than in 2020. The European Union (EU) Emissions Trading Scheme (ETS) emission prices also raises fuel costs to USD  0.27/kWh in 2022, or 645% higher than in 2020, (Figure ES.3). To put this figure of USD 0.27/kWh in context; this is 4 to 6 times more expensive than the new solar and onshore wind capacity added in Europe in 2021 and it exceeds the average retail tariff (excluding taxes and levies) paid by households in 13 EU of the 27 countries in 2020 that covered transmission, distribution, wholesale electricity purchases, marketing and overheads.

 Countries investments in renewables are paying huge dividends in 2022. Globally, new renewable capacity added in 2021 could save USD 55 billion this year alone, given the fossil fuel price crisis. Looking at the benefit of the cumulative stock of renewables draws an even starker picture. In Europe, between January and May 2022, solar PV and wind generation alone have likely avoided in the order USD 50 billion in fossil fuel imports, predominantly fossil gas. The unprecedented extent of the fossil fuel price crisis in 2022 has overshadowed the fact, that without renewables, the situation for consumers, economies and the environment would be much worse. 

Marginal fossil fuel electricity generating costs are so high in 2022, that a new onshore wind plant connected to the grid on 1 January 2022 and operating in the wholesale market might receive revenues in 2022 alone that are between around two (in Mexico) and thirteen times (in Brazil), the required annual return on capital required from the possible marginal avoided costs of fossil fuel generation for the full year. That countries have not prioritised accelerated renewable power generation capacity deployment in this year, but left the response largely to individuals and business, appears likely to have cost society billions of dollars this year and the next in direct energy costs. This is before accounting for the macroeconomic damage that accrues from the fossil fuel price crisis.

My take on this:  

I don't think neither hoi polloi nor politicians are aware of just how cheap renewables are compared with fossil fuels.  Granted, current very high fossil fuels are likely to decline again as we go into recession, globally, but even in 2020, before the recent price surges, renewables were still cheaper.  Also, which everybody, from citizens, politicians, and electricity companies likes, the costs are fixed, once the wind or solar farm is built.  Fossil fuels aren't just more expensive.  They're also more volatile.

We have passed peak coal, that much is clear.  The Russian invasion of Ukraine has shown the dangers of relying on bloodthirsty petro-state dictators, and that means we will see peak gas soon too, as Europe weans itself off Russian gas.  And peak oil is close, as EV sales grow exponentially.  Good news for the climate, bad news for fossil fuel companies.

81% of net new generating capacity renewables

 From a report by IRENA

In 2 decades, the share of renewables in the net (=after plant retirements) increase in electrical generation capacity has gone from roughly 20% to roughly 80%.  In the last 4 years it's lifted from 60% to 80%.  If this improvement continues, net renewables will reach 100% of new generation capacity by 2025.  At that point, emissions from global electricity generation will start falling, because all new capacity will be renewable, while the retired capacity will be mostly fossil-fuelled.

How Solar Power is Reducing Maternal Mortality in Zimbabwe

 From IRENA

A renewable energy innovation has improved obstetric care to last-mile communities across Zimbabwe, successfully supporting over 180,000 deliveries per year since its introduction.

“Night-time deliveries and emergencies were no longer fraught with candle-lit uncertainty.”

Tendai Matimbe starts his day at 7:30 am every morning, but as Nurse-in-Charge at the Kamabarami Health Clinic, Zimbabwe, he is never sure when it will end. Tendai’s patients include pregnant mothers, children, and HIV positive people in need of anti-retroviral therapy (ART). While he and his colleagues conduct consultations in the morning and outpatient visits until 4 pm, they are on standby 24/7 in case there is an emergency, or someone goes into labour.

Providing health services at night can be tricky. The facility lacks electricity and clinicians struggle in near darkness to provide lifesaving care to patients. According to Tendai: “At night, we faced many challenges because we relied on candles to conduct medical services. It was scary, especially during complications.”

Without a source of light, health workers faced issues such as difficulty in administering Nevirapine (a medication to reduce the likelihood of maternal HIV transmission) to newborn babies. Healthcare workers across the sub-Saharan Africa region face similar challenges every day. Medical facilities in Zimbabwe feature among the 70 per cent of facilities across the region without reliable access to electricity, according to a joint report by IRENA and other SDG 7 custodian organisations.

As a result, health workers like Tendai and his colleagues found themselves forced to ask pregnant women from the poor communities to bring extra money to buy enough candles to last through the night – something many could ill afford.

To combat this, We Care Solar, a non-profit organisation, started introducing the Solar Suitcase to health centres in Zimbabwe in 2015. It is an easy-to-use solar electric system that provides last-mile health facilities with highly efficient medical lighting and power for mobile communication and small medical devices.

While the Suitcase was designed to support timely and efficient emergency obstetric care, it can be used in a range of humanitarian settings. The water-and-dust tight yellow case becomes a cabinet that mounts to the wall and is connected to the solar panels secured on the roof. The system includes rechargeable LED lights, USB ports, a fetal doppler, and an infrared thermometer.

The Kamabarami Clinic received the suitcase in 2019. Overnight, Tendai and his team found their work transformed. The practical and portable source of clean, steady electricity ensured that night-time deliveries and emergencies were no longer fraught with candle-lit uncertainty. Tendai says: “Attending to patients has become easier now, even at night. With the fetal doppler, we can listen to the fetal heart rate easily. With the lights, we can detect fetal abnormalities on the baby, especially when there is birth asphyxia.”

It is also helping to prevent maternal deaths. “One day a pregnant mother came while in labour,” Tendai recalls. “Out of fear about the costs of transport and the money for a caesarean section she lied, telling me that she’d had a normal birth from the previous pregnancy. But with the new, adequate lighting, l noticed that she had a big scar on her lower abdomen which l suspected to be from a prior caesarean section.”

Tendai was able to use the fetal doppler to listen to the baby’s heart rate, allowing him to detect the presence of any abnormalities. The baby’s heart rate was too slow. “I transferred the patient to the hospital at once, where the doctor informed me that her condition would only allow her to deliver by caesarean procedure. The doctor said that if l had not identified the abnormality and immediately transferred the patient, there were chances that we could have lost both the mother and the baby. Thanks to the new source of light, l was able to detect the physical abnormality and the fetal bradycardia.”

The clinic has seen an increase in productivity and lower maternal mortality rates since the introduction of solar power. The Solar Suitcases are now operational across 759 health centres in Zimbabwe, supporting more than 180,000 deliveries each year.

While this progress is encouraging, much more can be done. At present, Zimbabwe is tapping only a fraction of its full solar potential, estimated to be more than four gigawatts. In 2020, the country installed just 6 MW of new solar energy and now has a total installed capacity of 17 MW.

Despite this, renewable-based systems used to power rural health clinics are already having a transformative impact on the quality of life of rural communities, like the case of Tendai and the Kamabarami Health Clinic. Tendai feels that all clinics should enjoy the benefits of renewable energy solutions like solar power. “This is the best thing that has happened to our clinic. From the first day we used solar power to improve our working condition, we have not had any maternal death. It’s now easier to attend to our patients because we can see what we are doing and where we are going. We are no longer lost in the dark,” he said.

BNEF's renewables costs

The chart below shows the average global costs over time for different renewable generation technologies.   Offshore wind is more expensive than onshore, for obvious reasons, but has the advantage that winds are more reliable on water than they are on land.  Interestingly, tracking solar, where the solar panel rotates during the course of the day to face the direction of the sun, which you'd expect to be more expensive than fixed solar, is not.  The extra yield from a "squarer" insolation profile more than compensates for the extra expense of motors to rotate the panels.  Tracking solar is also better than fixed-tilt solar because output jumps to its maximum just after sunrise and lasts until just before sunset, which means output is better attuned to the daily demand profile, especially the morning peak.

So the cheapest global electricity comes from single-axis tracking solar, then onshore wind, then fixed solar, then offshore wind.  The green line shows a simple average of all four types, and you can see how it has fallen steadily over the last 12 years, falling from $256/MWh in H2 2009 to $52/MWh in H1 2021, or by 80%.  The recent uptick in LCOEs is driven by a three-fold jump in polysilicate prices (for solar) and a doubling of steel prices (for wind).   These are both cyclical, and will partly unwind as economic growth slows after the post-pandemic rebound.  The jump in polysilicate prices is particularly interesting, hinting at a massive build out of solar in China and globally.

Just like Lazard (whose data I have been using for a few years now) and IRENA, BNEF shows the same strong downward trends in the cost of renewables.   Lazard estimate the average cost of new coal at $112/MWh in the US, and the marginal/operating cost of coal at $41/MWh, though that will have risen this year because of the jump in the coal price.  This compares with the average for  onshore wind, and tracking solar of $40/MWh.   Lazard's calculation for the marginal cost of gas in the US is $28/MWh, but gas in the US is less than  half the price of gas outside the US.  For example, gas in Europe  has reached US$12.51/MBtu compared with $4.40 in the US.  And the US natural gas price is up 70% over the last year.   

The moral of this tale is obvious, but I'll tell you anyway:  coal is finished.  Because output from gas power stations can be ramped up more rapidly than from coal, to match supply shortfalls from renewables, gas is still "safe" for now.  Until battery prices halve again.

IRENA vs Lazard's solar costs

 The chart below is derived from two different sources:  IRENA  and Lazard.  The biggest difference between the two is that the Lazard report covers just the US, while IRENA's data covers the globe.  Another difference is that IRENA (in recent years) has used actual contracts instead of LCOE calculations as Lazard does, though in fact contract costings in the US have been broadly similar to Lazard's LCOE calcs.

The costs have been plotted on a log scale in the chart, which means that a similar percentage decline is the same distance on the chart.  This means that a sustained constant rate of decline produces a straight line.  

IRENA's costs for solar globally have until recently been higher than Lazard's in the US, but recently, this gap has closed, and assuming that the recent 5-year rates of decline are extrapolated forward, the average cost of solar internationally will fall below the cost in the USA.   This presumably reflects the expansion of solar into poorer countries in low latitudes, whose solar resources are way better than the Northern Hemisphere developed countries which are higher latitude.  It's ironic―and good news!―that developing countries which have hitherto been at an energy disadvantage will now start to benefit from really cheap energy.  If the extrapolations do reflect reality, by 2025, electricity from solar will cost just $17/MWh.  In 2010, it cost $378/MWh. 

One final point: the lowest fossil fuel cost is $50/MWh (presumably for gas in the US).  The highest is $177.  They are already uncompetitive, though gas at least is complementary to renewables, and will get more uncompetitive as costs continue to decline.  Anybody who invests long-term in fossil fuels―as opposed to holding trading positions―will lose their money.

5 milestones in green energy

 From the World Economic Forum

1. 2020 was a record year for renewables

Globally, 260 gigawatts (GW) of renewable energy capacity were added in 2020, exceeding expansion in 2019 by close to 50% – and breaking all previous records, IRENA says.

More than 80% of all new electricity capacity added last year was renewable, with solar and wind accounting for 91% of new renewables, according to the agency’s Renewable Capacity Statistics 2021. Total fossil fuel additions fell from 64GW to 60GW over the same period.

“These numbers tell a remarkable story of resilience and hope,” IRENA Director-General Francesco La Camera said.

Emissions won't peak until the increase in non-renewables is zero, which still seems to be a couple of years away if you extend the trend of the grey bars, and in any event depends heavily on China sorting out its coal muddle.

2. Britain had its greenest day on record

Easter Monday, 5 April, broke a renewable energy record for Great Britain.

The nation’s electricity grid reached the greenest it’s ever been, with zero-carbon power sources including wind, solar and nuclear making up 80% of the energy mix.

At the same time, the carbon intensity of electricity – the measure of CO2 emissions per unit of electricity consumed – dropped to 39gCO2, the lowest figure in history.

3. IEA crowns solar ‘the new king of electricity supply’

Solar power will be the new king of electricity supply and looks set for massive expansion, according to the International Energy Agency (IEA).

Its World Energy Outlook 2020 report predicts renewables will set new records each year after 2022, thanks to “widely available resources, declining costs and policy support in over 130 countries.”

“For projects with low cost financing that tap high quality resources, solar PV is now the cheapest source of electricity in history,” the IEA says.

This includes being more cost-effective than coal and gas in many countries today, including in the largest markets – the United States, European Union, China and India.

4. Adelaide’s operations run on 100% renewable electricity

Swimming pools, car parks, depots and community buildings in the Southern Australia capital of Adelaide are now powered entirely by renewable energy.

The city is the first council in South Australia to use 100% renewable electricity across its operations, including the historic Adelaide Town Hall, which was built in 1866.

The switch will reduce emissions by more than 11,000 tonnes a year – the equivalent of taking 3,500 cars off the road.

5. Viet Nam increases solar capacity by 25 times in just one year

Government-backed incentives to install rooftop solar systems helped Viet Nam soar to new solar energy highs in 2020.

By the end of December, 9.3GW of solar capacity had been added – equivalent to six coal power plants – and a 25-fold increase in installed capacity compared to a year earlier.

There are now more than 101,000 rooftop solar systems on homes, offices and factories across the country, according to Vietnam Electricity, the state utility.

Viet Nam has previously been heavily dependent on coal for electricity generation.

Renewables 72% of new gen capacity last year

From a report by IRENA.

As far as I can make out, these data are for net expansions in capacity.  The good news?  The percentage of renewables in new generation capacity is steadily rising, and is now nearly three-quarters of total new generation capacity.  At the rate at which this percentage is increasing, it wil reach 100% in 7 or 8 years.  The bad news?  The renewable share in total generation capacity rose from 33.3% in 2018 to 34.7% in 2019.  And at this measly rate of increase, it will take 46 years to reach 100%.  This is far, far too slow.  We need to get to a 100% renewable grid long before 2066. 

Renewables have to double by 2030 to achieve climate targets

From PV Magazine:

At the start of what has been billed as a ‘decade of action’, the International Renewable Energy Agency (IRENA) has issued another call for a sustainable future. Stressing fossil fuel investment must be redirected, IRENA said annual renewable energy investment needs to more than double, from around $330 billion today to near $750 billion, to deploy renewable energy at the rate required.   
The 10 Years: Progress to Action study published for IRENA’s 10th annual assembly charts recent advances and outlines the measures still needed to scale up renewables. The Abu Dhabi-based agency says the world needs to double the share of renewables in the global energy mix over the next decade to achieve energy transition objectives. Renewables must account for 57% of generation, said IRENA, renewable electricity must account for 29% of final energy consumption and fossil-fuel use must decline 20%.  [A doubling over 10 years implies an annual growth rate of 7.1%.]

“We have entered the decade of renewable energy action, a period in which the energy system will transform at unparalleled speed,” said IRENA director-general Francesco La Camera. “To ensure this happens we must urgently address the need for stronger enabling policies and a significant increase in investment over the next 10 years. Renewables hold the key to sustainable development and should be central to energy and economic planning all over the world.”

Much of the investment needed could be met by redirecting fossil fuel funds. IRENA calculates almost $10 trillion of non-renewables energy investment is planned to 2030, risking stranded assets and increasing the likelihood of exceeding the world’s sub-1.5 degrees Celsius carbon budget this decade. By comparison, the world invested $3 trillion in renewables in the last 10 years.

A rise from $329 bln to $737 bln implies an 8.4% per annum growth rate. 
Actual capacity growth would be greater because of falling costs.

“We know it is possible, but we must all move faster,” La Camera said. Given falling technology costs, additional investments bring significant external savings, including minimizing the significant financial losses caused by climate change as a result of inaction. The potential savings could amount to $1.6-3.7 trillion per year by 2030, three to seven times higher than the investment cost of the energy transition, according to IRENA.

Renewables have already become the world’s main source of new power generation, as illustrated by the graph below. However, IRENA underlined renewables can also become the most competitive source of power by 2030. With 2.84 TW of solar generation capacity expected to have been installed in 2030, IRENA forecasts solar electricity prices of $34-40/MWh. Onshore wind costs are expected to be in the $30-40/MWh range with 2,015 GW of capacity installed worldwide at the end of the decade. The two energy sources would then account for a third of global power needs.

An extraordinary shift in just 9 years.  Note this appears to be gross not net new capacity.  With coal plants shutting down, renewables would make up a higher proportion of net new capacity.
The increase from 39% to 62% means that the compound growth rate was just 5.2% per annum.
This is likely to accelerate rather than decline (see comments below)
To eliminate coal power stations, the percentage of  new capacity coming from renewables has to exceed 100%

Already delivering electricity access to 150 million people [in emerging economies], renewables can become a vital tool in closing the energy access gap, said IRENA. Data produced by the agency shows 60% of new electricity access can be met by renewables in the next decade with standalone generation systems and mini-grids providing the means for almost half that new access.

IRENA also repeated its claim the global energy transition could be an employment bonanza. By 2030, there could be 30 million renewable energy jobs, including 11.7 million solar opportunities, up from 4.4 million last year.

My comments:

• The growth rates implied by IRENA's targets seem doable
•  Many forecasters (the IEA, for example) assume that the take-up of renewables will be limited because as the percentage of renewables rises we will reach 'saturation'—too much wind or solar will push down wholesale electricity prices when wind peaks or at midday when solar peaks.  But this assumes storage costs won't fall.  Falling storage costs will allow us to soak up excess power for release later when demand is higher or supply lower.  It's likely that growth rates could actually accelerate.  At a battery pack cost of $100/kWh, 24 hours of storage will cost just $15/MWh (assuming 20 year life)  Cheap storage allied to cheap electricity production from renewables is likely to lead to deployment accelerating rather than slowing.
• We must build no more coal power stations.  Not only would they add to carbon emissions but because of the plunge in the cost of renewables they will also risk being stranded assets.  With no new coal and 100%  of gross new investment consisting of renewables, the entire generation fleet would within decades be 100% renewable.