Green, ethical, energy issues in the news

QrizB

Martyn1981 said:

They've now completed a larger unit which is 1MW/100MWh, with a ~90% round trip efficiency. [But remember this is a heat battery, it's not releasing electricty. Perhaps more akin to Economy7 and storage heaters.]

Comparing.it to domestic heat storage is interesting.

- A Tepeo ZEB holds 40kWh.

- A Sunamp Thermino holds 3-12kWh, depending on model.

- A Complex Quantum stores 7-23kWh, again depending on size.

So their sand battery is as capacious as 2500 ZEBs, 8000 large Therminos or 4000 large Quantums.

That's pretty chunky!

How many properties they can serve is going to be limited more by their ability to recharge the battery than by it's capacity. Let's imagine that a typical home needs 50kWh of heat a day (a ZEB plus a Thermino, or two large Quantum's). 100MWh is 2000 home-days. But if you can only recharge 24MWh/day max, that's 480 home-days; and if you are relying on "cheap surplus" electricity, you might only manage 8MWh/day, enough to support 160 homes. So it's the same resource-managememt game that all is domestic battery owners play every winter, on a bigger scale.

I would guess that, including the storage aspect, a battery this size might reasonably support 200 homes? Any more than that and you're going to have an increased risk of buying full-price electricity or falling back on other sources of heat, ag. during a dunkelflaute.

(I note from the article that they've got a backup wood chip boiler, so they've obviously thought of this already.)

200 homes is the same sort of number as is served by a suburban electricity substation, so conceptually you could have a sand battery supplying district heat to Aspidistra Gardens, Dracaena Avenue and Hydrangea Close.

Martyn1981

Hi QrizB, looks like Pornainen has around 2,000 residences and about 5,000 people. Been looking at other articles on this news, and general info about Pornainen and found that the majority of heating is from district heating ...... but one news article mentioned that this scheme is for the heating of municipal buildings including a swimming pool.

Piecing together bits and bobs from several articles, I got the feeling that this scheme may also serve some residences (but I may be wrong about that).

So maybe, if it all goes well, more (and/or bigger) of the same will be built in Pornainen?

It's a few years since I watched it, but saw a great interview of the company founders, explaining the idea. This may be obvious to everyone, but wasn't to me, till it was pointed out - but the thickness of the insulation actually remains the same, regardless of the scale. It's about 1m thick be it a small unit for a single business, or a ginormous structure. So it scales up really well.

Again from the interview, and just exploring how far this concept could be taken, it was suggested that a large hole (in this case an old quarry was suggested) could be used. Insulate it, build out the pipe network, fill with local sand, dirt, crushed stone etc. Top off with soil and you still have the land to use, perhaps a park, or solar farm.

Only my thoughts, but perhaps a good buffer for district heating that uses heatpumps powered by RE leccy. I'm thinking the sand battery adds LDES maybe to RE with SDES conventional batteries?



Edit - should have added, that this concept would appear to fit very well with what Donald Sadoway, the noted expert on batteries, suggested a decade ago - “If you want to make something dirt-cheap, make it out of dirt. Preferably dirt that's locally sourced.”

Martyn1981

Don't tell Donald - China is developing even bigger, even bigger offshore wind turbines IYSWIM. I suppose today 16MW would be classed as very big, so what's another 10MW between friends.

I make the swept area of the blades equal to about 11 football pitches, and assume the nacelle weighs in at a blue whale, but couldn't think of a reference to olympic sized swimming pools.

Dongfang installs 26MW offshore prototype

Dongfang has installed a prototype 26MW offshore turbine in China.

The Asian OEM, which claims to hardware is the most powerful installed globally to date, erected the unit (pictured) at the Dongying test centre.

The 26MW machine’s rotor covers a swept area of 77,000 square metres, according to the company.

It uses integrated semi-direct drive technology and features a typhoon-resistant design.

QrizB

Very bigly 🤣

Martyn1981

This week's Carbon Commentary newsletter from Chris Goodall.

[I thought item 10 was very interesting.]

1, Battery swapping. Exchanging batteries in electric vehicles has been largely limited to China, with CATL making recent moves to increase the use of this approach, particularly in rental cars. Now battery swapping may be spreading across Asia. Truck manufacturer SAIC and its partners including Dutch battery specialist UNEX EV have agreed to develop a heavy vehicles network across Thailand. Over 4,000 trucks will be supplied across the country with possible expansion into other countries and eventually into Europe and Latin America. But, on the other hand, we also saw details last week of China’s first 100 MW charging hub, able to deliver almost 1.5 MW to heavy trucks on some of its hundreds of chargers. The centre can run independently of the local electricity network and contains ‘grid-forming’ energy storage to help provide stability.

2, Google and renewables. BigTech’s urgent need for extra power has eroded its previous commitment to the use of wind, solar and other low carbon sources. Google has provided recent examples. In the last few weeks Ruth Porat, the second most senior person in the company, has publicly supported the anti-renewables stance of Trump’s cabinet. The latest Google position paper on electricity provision - partly written by her - focuses on nuclear, gas with CCS and geothermal. Solar and wind aren’t mentioned once. These moves are probably linked to the rapid growth in Google’s emissions, up over 50% since 2019, and the increasing difficulty of reaching the company’s target of net zero by 2030.

3, Hydrogen pipeline networks. The proposed 3,400 km network linking North Africa to Italy and then on to Germany via Czechia passed its initial feasibility assessment. The gas networks that own the project intend to start transmission in 2030. If completed, the pipeline will deliver about 0.5 TWh of energy a day, mostly into the industrial areas of Germany which are estimated to require at least 100 TWh per year of external hydrogen. A much smaller proposed Finnish network, that will eventually also extend as far as Germany, took a step forward as the feasibility was confirmed and detailed route planning began.

4. Linear generator for making electricity from hydrogen. The world would prefer to avoid any form of combustion when generating electricity. Burning usually produces a wide variety of pollutants such as nitric oxide. National Grid in the US said it had ordered a hydrogen-fuelled ‘linear generator’ from Mainspring Energy to operate at a power plant on Long Island. This would be a world first. The technology, which can also use biogas or other gases, uses low temperature compression to trigger an oxidation reaction and does not combust the gas. The generator is highly dispatchable, offering 100% output within 10 seconds of startup, meaning it is well-suited to providing back-up electric power at unpredicted times of shortage. The size of the generator was not given in the press releases but National Grid said it would be operating in a year and then would run on 100% hydrogen in a test phase.

5, Green steel in Oman. The use of hydrogen for making direct reduction iron will predominantly take place in countries with low electricity prices and good deep-water ports for ore imports and metal exports. Singapore’s Meranti announced a plan to develop a 2.5m tonne direct reduction plant in Oman, initially using natural gas but moving to a maximum of 85% hydrogen. Meranti indicates that the use of 100% hydrogen would currently add $300 to the cost of a tonne of steel, currently trading in Europe for around $650. It says that this is the reason why it will wait until the costs of hydrogen have fallen before increasing the percentage used in its furnaces.

6, Rise in African solar PV imports. Analysts at Ember showed that imports of PV into African countries other than South Africa and Egypt have risen sharply. Although still only 15 GW a year, African countries’ purchase of PV have nearly tripled in the last two years. In one case – Sierra Leone – imports in the last year alone might have added over 60% to total electricity generation. In another 15 countries the new solar panels will have supplemented total power supply by over 5% in the last year. This inflow, which appears to be mostly used in distributed generation and not at major installations, is partly fuelled by the continuing fall in prices. One analyst suggests that average panel prices from China have now reached around 10-11 US cents per watt, around half the level of 18 months ago. (Thanks to Raymond Betz).

7, Carbon capture and storage. Two new significant steps. Norway’s Northern Lights project, which will take CO2 from multiple sources around Europe, said it had successfully stored its first consignment in a deep offshore saline aquifer using a 100 km pipeline. In this case the CO2 came from the Heidelberg Materials cement works at Brevik. The Northern Lights company has recently committed to expand its CCS capacity to 5m tonnes a year. The expansion makes it one of the largest CCS projects in the world but even this figure is no more than about 1% of the annual emissions from burning oil and gas extracted from Norwegian fields. In Canada, Deep Sky announced its first storage of CO2 using one of several different capture technologies it is testing. This is said to be North America’s first ever storage of CO2 captured directly from the air. Although the company has been funded with $130m from investors, volumes are still small and the company just targets 3,000 tonnes of CO2 a year at its first Alberta site.

8, Ocean alkalinisation. The amounts of CO2 in oceans and in the atmosphere are in balance. More emissions into the air results in greater amounts of CO2 being absorbed into the oceans, increasing the acidity of the water. Planetary’s approach is to add alkaline rock particles (principally magnesium hydroxide, if I understand correctly) to seawater. The particles are strongly alkaline and react with the acidic CO2 in the water, generating a stable chemical that is highly stable. This lowers the amount of CO2 in the water thus causing more to be extracted from the atmosphere. This method of ‘carbon dioxide removal’ can claim to be amongst the safest and possibly cheapest CDR technologies with a target of $100 a tonne. Planetary announced it had raised another $31m from Frontier to extract 115,000 tonnes of CO2 before 2030.

9, Synthetic aviation fuel. Two announcements this month. Finnish start-up Liquid Sun will use CO2 from forest sources and merge it with hydrogen in a new form of advanced electrolyser to make kerosene to be used in aviation. This is a pilot project backed by the major participants in the Finnish aviation industry. A partnership between Japan’s Sekusui and US Velocys will use an innovative technology that turns biogenic CO2 into carbon monoxide and then reacts the product with hydrogen to make aviation fuel. The partners claim very high levels of efficiency for all the stages in the process. These two projects are examples of the many attempts to create aviation fuel (essentially kerosene, a hydrocarbon with a typical molecular formula of C13H24) at costs which can come close to matching conventional fuels. They are driven by the EU’s target of 6% sustainable aviation fuel by 2030.

10, Impact of renewables on electricity prices. I did some very simple econometrics on my web site, showing the short-term impact of renewables. I calculated the percentage of total electricity need that was provided by renewables each day in 2025 and plotted it against the average electricity price in the ‘day ahead’ market. Unsurprisingly, high renewable output correlates with much lower power prices. My numbers show that a day with 20% wind and solar averaged a wholesale price of £128 per MWh whereas a day with 50% of power from these sources had a typical market price of £73, a reduction of more than 43%. The UK plans to expand its renewables generation by about 2.5 times by 2030, meaning that we can hope for substantial cost reductions as the more expensive gas generators are forced out of the market.